I'm about to start a project which basically involves building lots of MDF boxes then stacking them in a brick-like fashion to make a wall-to-wall bookshelf.

The boxes will be constructed out of 18mm MDF, and be either 280x350x400mm or 180x250x400mm in size. (I'll use 2mm MDF for backs.)

I haven't decided yet whether to use veneered MDF. If I don't then I need to treat the whole lot (probably a satin varnish, although I may paint them as MDF is quite boring), but if I use veneered then I only need to treat the cut edges, none of which will be visible once complete (assuming I use a veneer edging strip on the visible edges). I can't get 2mm veneer for the backs so I'll paint those to roughly match whichever veneer I choose.

What's the best way to treat the "invisible" edges? I'm thinking both in terms of the product and the method - I obviously don't want the product coming over the edges onto the veneer, and my DIY skills are "basic". I considered stacking all the parts together and treating all the edges in one go but I wasn't sure if I'd end up sticking them together or leaving a rough edge when they were separated.

A couple of people have suggested diluted PVA to seal the edges, which would certainly be cheap but would it work? (The shelves will be going into a bedroom so I don't expect them to be damp.)

In total I'll have around 60 boxes to build so anything complicated is out, I don't have the patience!

wrote

I'm about to start a project which basically involves building lots of MDF
boxes
then stacking them in a brick-like fashion to make a wall-to-wall
bookshelf.

Urk, I prefer to do wall to wall bookshelves by welding Dexion slotted 25mm
square
steel tubing into floor to ceiling rectangles, dynabolting them to the walls
and floor
and using aluminium flats cut to length in the slots, with MDF shelves on
those.

Works very well indeed. Do that for the kitchen pantry too and all the other
shelves in the house.

Mostly wall to wall or close to that.

The boxes will be constructed out of 18mm MDF, and be either
280x350x400mm or 180x250x400mm in size. (I'll use 2mm MDF for backs.)

I haven't decided yet whether to use veneered MDF.

I use the white melamine coated MDF myself.

If I don't then I need to treat the whole lot (probably a satin
varnish, although I may paint them as MDF is quite boring),

I did white paint the first ones I did.

but if I use veneered then I only need to treat the cut edges,
none of which will be visible once complete (assuming I use
a veneer edging strip on the visible edges).

I didn't bother with the white melamine coated MDF I used,
just need the front edge coated and it comes like that.

I can't get 2mm veneer for the backs so I'll paint
those to roughly match whichever veneer I choose.

What's the best way to treat the "invisible" edges?

I just leave them raw with shelves.

I did paint the edges with epoxy paint with the
kitchen bench which is full laminex on MDF.

I'm thinking both in terms of the product and the method
- I obviously don't want the product coming over the
edges onto the veneer, and my DIY skills are "basic".
I considered stacking all the parts together and treating all
the edges in one go but I wasn't sure if I'd end up sticking them
together or leaving a rough edge when they were separated.

Likely but easy to try with some scrap.

A couple of people have suggested diluted PVA to seal the edges,
which would certainly be cheap but would it work? (The shelves
will be going into a bedroom so I don't expect them to be damp.)

I don't see any point in bothering with those.

I did fill and paint the edges of the ones I did with white paint,
but didn't bother with the melamine coated ones and they have
survived fine.

In total I'll have around 60 boxes to build so anything
complicated is out, I don't have the patience!

I'd go the slotted metal tube route myself, MUCH less work.

On Tuesday 12 February 2013 08:51 wrote in uk.d-i-
y:

I'm about to start a project which basically involves building lots of MDF
boxes then stacking them in a brick-like fashion to make a wall-to-wall
bookshelf.

The boxes will be constructed out of 18mm MDF, and be either 280x350x400mm
or 180x250x400mm in size. (I'll use 2mm MDF for backs.)

I haven't decided yet whether to use veneered MDF. If I don't then I need
to treat the whole lot (probably a satin varnish, although I may paint
them as MDF is quite boring), but if I use veneered then I only need to
treat the cut edges, none of which will be visible once complete (assuming
I use a veneer edging strip on the visible edges). I can't get 2mm veneer
for the backs so I'll paint those to roughly match whichever veneer I
choose.

What's the best way to treat the "invisible" edges? I'm thinking both in
terms of the product and the method - I obviously don't want the product
coming over the edges onto the veneer, and my DIY skills are "basic". I
considered stacking all the parts together and treating all the edges in
one go but I wasn't sure if I'd end up sticking them together or leaving a
rough edge when they were separated.

A couple of people have suggested diluted PVA to seal the edges, which
would certainly be cheap but would it work? (The shelves will be going
into a bedroom so I don't expect them to be damp.)


I would not - the water content will swell the MDF.

Perhaps a diluted polyurethane varnish, spirit based?


In total I'll have around 60 boxes to build so anything complicated is
out, I don't have the patience!
--
Tim Watts Personal Blog: http://squiddy.blog.dionic.net/

If you are reading this from a web interface eg DIY Banter,
DIY Forum or Google Groups, please be aware this is NOT a forum, and
you are merely using a web portal to a USENET group. Many people block
posters coming from web portals due to perceived SPAM or inaneness.
For a better method of access, please see:

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On 12/02/2013 08:51, wrote:
I'm about to start a project which basically involves building lots
of MDF boxes then stacking them in a brick-like fashion to make a
wall-to-wall bookshelf.

The boxes will be constructed out of 18mm MDF, and be either
280x350x400mm or 180x250x400mm in size. (I'll use 2mm MDF for
backs.)

I haven't decided yet whether to use veneered MDF. If I don't then I
need to treat the whole lot (probably a satin varnish, although I may
paint them as MDF is quite boring), but if I use veneered then I only
need to treat the cut edges, none of which will be visible once
complete (assuming I use a veneer edging strip on the visible edges).
I can't get 2mm veneer for the backs so I'll paint those to roughly
match whichever veneer I choose.

What's the best way to treat the "invisible" edges? I'm thinking both
in terms of the product and the method - I obviously don't want the
product coming over the edges onto the veneer, and my DIY skills are
"basic". I considered stacking all the parts together and treating
all the edges in one go but I wasn't sure if I'd end up sticking them
together or leaving a rough edge when they were separated.

A couple of people have suggested diluted PVA to seal the edges,
which would certainly be cheap but would it work? (The shelves will
be going into a bedroom so I don't expect them to be damp.)

In total I'll have around 60 boxes to build so anything complicated
is out, I don't have the patience!


I've done a bit of this for my siblings over the years, mainly 15mm, and
the various finishes they were threatening to use never materialised.
That neutral, scruffy mdf look grows on you. Any clear finish tends to
give them a dark tan "wet" look, which is not very appealing on mdf. Try
it on a scrap first.
Sixty boxes? Blimey, you're going to waste a lot of space with the
thickness of the mdf. I prefer to make half a dozen modules with shelf
supports so that you can change the spacing. There always seems to be
one thing that's slightly too tall for any of the boxes.
I'm sure you have a plan for the assembly but FWIW I'd have the whole
lot cut to size by a timber merchant, and treat yourself to an electric
stapler. Great for putting the backs on and holding the four sides in
position if you're working alone

On Tuesday, February 12, 2013 9:21:34 AM UTC, Rod Speed wrote:

Urk, I prefer to do wall to wall bookshelves by welding Dexion slotted 25mm
square steel tubing into floor to ceiling rectangles, dynabolting them to
the walls and floor and using aluminium flats cut to length in the slots,
with MDF shelves on those.

It may not be the most "functional" design but we quite like the look of the design (whether we'll like it once finished I have no idea though!)

I considered stacking all the parts together and treating all
the edges in one go but I wasn't sure if I'd end up sticking them
together or leaving a rough edge when they were separated.

Likely but easy to try with some scrap.

Good point, I will do that.

Thanks

Mark Rogers

On Tuesday, February 12, 2013 9:52:07 AM UTC, stuart noble wrote:
I've done a bit of this for my siblings over the years, mainly 15mm, and
the various finishes they were threatening to use never materialised.
That neutral, scruffy mdf look grows on you. Any clear finish tends to
give them a dark tan "wet" look, which is not very appealing on mdf. Try
it on a scrap first.

I have some MDF shelves that were varnished (to protect the MDF not for effect) and as you say, the effect grows on you. But that was stuck in an office, this is going to be a "feature" in a spare bedroom that is supposed to become more of a library/snug, so I want to at least try to make something "nice".

Using veneered MDF is obviously a lot more expensive, but is somewhat offset by the saving in varnish and would be a considerable time saving, for a much better end result, which is why I'm leaning that way at the moment.

Sixty boxes? Blimey, you're going to waste a lot of space with the
thickness of the mdf. I prefer to make half a dozen modules with shelf
supports so that you can change the spacing. There always seems to be
one thing that's slightly too tall for any of the boxes.

The bottom boxes (35cm internal height) are tall enough for box file (I haven't 100% decided on dimensions yet). They will likely be filled with magazine archives - ie will be heavy. I need to be sure they will take the weight without bowing. (They'll also have the weight of the upper boxes to support.)

If I could be convinced that a thinner MDF would suffice I'd drop down a size - with 18mm I'm playing it safe.

By constructing it from boxes laid out like bricks (ie each row is 50% offset from the ones either side of it) I end up with quite short gaps between verticals without making the shelves too short, which should lend strength. However this is all speculation from a software engineer with no experience of constructing projects like this so if anyone thinks I'm taking a big risk let me know!

I'm sure you have a plan for the assembly but FWIW I'd have the whole
lot cut to size by a timber merchant,

Absolutely! In fact it was partly my lack of skill when it comes to cutting timber that lead to the design - this is very easy to get supplied almost in kit form just from a set of measurements. Aside from treating the MDF, all I should need to do is to put in 2 or 3 screws on each edge and either pin or staple the backs on. Given that I have a lot of nearly identical boxes to make, I may even make up a jig to hold the sides in place while I screw them together.

[...] and treat yourself to an electric
stapler. Great for putting the backs on and holding the four sides in
position if you're working alone

I wondered about this too. It wouldn't be worth me spending a lot on one though as this could well be the only time it gets used. I can get a cheap one for about £20 with 1000 staples and 1000 nails, or a Stanley one for twice that - is it worth it?

--
Mark Rogers

The bottom boxes (35cm internal height) are tall enough for box file
(I haven't 100% decided on dimensions yet). They will likely be
filled with magazine archives - ie will be heavy. I need to be sure
they will take the weight without bowing. (They'll also have the
weight of the upper boxes to support.)

If I could be convinced that a thinner MDF would suffice I'd drop
down a size - with 18mm I'm playing it safe.

By constructing it from boxes laid out like bricks (ie each row is
50% offset from the ones either side of it) I end up with quite short
gaps between verticals without making the shelves too short, which
should lend strength. However this is all speculation from a software
engineer with no experience of constructing projects like this so if
anyone thinks I'm taking a big risk let me know!

Most kitchen unit shelves are 15mm chip, and an unsupported span of a
metre is pretty normal. Mine are stacked with crockery, which is a hell
of a lot heavier than books.

I'm sure you have a plan for the assembly but FWIW I'd have the
whole lot cut to size by a timber merchant,

Absolutely! In fact it was partly my lack of skill when it comes to
cutting timber that lead to the design - this is very easy to get
supplied almost in kit form just from a set of measurements. Aside
from treating the MDF, all I should need to do is to put in 2 or 3
screws on each edge and either pin or staple the backs on. Given that
I have a lot of nearly identical boxes to make, I may even make up a
jig to hold the sides in place while I screw them together.

Clamping a piece of the shelving to the sides gives you a "ledge" to sit
the cross piece on. If screwing thorough the sides into the edges, these
might be useful
http://www.screwfix.com/p/mdf-tite-s...equestid=54415

but I've found drywall screws just as good. Standard woodscrews tend to
be a bit too fat, and will swell the mdf if not 100% accurately positioned.
Oh, and get one of those combination bits that do the hole and the
countersink in one. Then, with a jig, you can pre-drill all the sides
accurately in one operation. You don't want to be doing that by eye!


[...] and treat yourself to an electric stapler. Great for putting
the backs on and holding the four sides in position if you're
working alone

I wondered about this too. It wouldn't be worth me spending a lot on
one though as this could well be the only time it gets used. I can
get a cheap one for about £20 with 1000 staples and 1000 nails, or a
Stanley one for twice that - is it worth it?


I've had a Bosch for years and wouldn't be without it. Takes generic
staples too, so you're not tied in to expensive Bosch stuff. IME forget
the nail option on cheap tools, they misfire so often it'll drive you crazy.

"stuart noble" wrote in message
...

The bottom boxes (35cm internal height) are tall enough for box file
(I haven't 100% decided on dimensions yet). They will likely be
filled with magazine archives - ie will be heavy. I need to be sure
they will take the weight without bowing. (They'll also have the
weight of the upper boxes to support.)

If I could be convinced that a thinner MDF would suffice I'd drop
down a size - with 18mm I'm playing it safe.

By constructing it from boxes laid out like bricks (ie each row is
50% offset from the ones either side of it) I end up with quite short
gaps between verticals without making the shelves too short, which
should lend strength. However this is all speculation from a software
engineer with no experience of constructing projects like this so if
anyone thinks I'm taking a big risk let me know!

Most kitchen unit shelves are 15mm chip, and an unsupported span of a
metre is pretty normal. Mine are stacked with crockery, which is a hell of
a lot heavier than books.

I'm sure you have a plan for the assembly but FWIW I'd have the
whole lot cut to size by a timber merchant,

Absolutely! In fact it was partly my lack of skill when it comes to
cutting timber that lead to the design - this is very easy to get
supplied almost in kit form just from a set of measurements. Aside
from treating the MDF, all I should need to do is to put in 2 or 3
screws on each edge and either pin or staple the backs on. Given that
I have a lot of nearly identical boxes to make, I may even make up a
jig to hold the sides in place while I screw them together.

Clamping a piece of the shelving to the sides gives you a "ledge" to sit
the cross piece on. If screwing thorough the sides into the edges, these
might be useful
http://www.screwfix.com/p/mdf-tite-s...equestid=54415

but I've found drywall screws just as good. Standard woodscrews tend to be
a bit too fat, and will swell the mdf if not 100% accurately positioned.
Oh, and get one of those combination bits that do the hole and the
countersink in one. Then, with a jig, you can pre-drill all the sides
accurately in one operation. You don't want to be doing that by eye!


[...] and treat yourself to an electric stapler. Great for putting
the backs on and holding the four sides in position if you're
working alone

I wondered about this too. It wouldn't be worth me spending a lot on
one though as this could well be the only time it gets used. I can
get a cheap one for about £20 with 1000 staples and 1000 nails, or a
Stanley one for twice that - is it worth it?


I've had a Bosch for years and wouldn't be without it. Takes generic
staples too, so you're not tied in to expensive Bosch stuff. IME forget
the nail option on cheap tools, they misfire so often it'll drive you
crazy.


I have bookshelves in 18mm mdf - they have bowed under the weight at 750mm
length. MDF is not as rigid as it looks. Pine is stiffer - shelves that
long stay straight.

On Feb 12, 8:51*am, wrote:
I'm about to start a project which basically involves building lots of MDF boxes then stacking them in a brick-like fashion to make a wall-to-wall bookshelf.

The boxes will be constructed out of 18mm MDF, and be either 280x350x400mm or 180x250x400mm in size. (I'll use 2mm MDF for backs.)

I haven't decided yet whether to use veneered MDF. If I don't then I need to treat the whole lot (probably a satin varnish, although I may paint them as MDF is quite boring), but if I use veneered then I only need to treat the cut edges, none of which will be visible once complete (assuming I use a veneer edging strip on the visible edges). I can't get 2mm veneer for the backs so I'll paint those to roughly match whichever veneer I choose.

What's the best way to treat the "invisible" edges? I'm thinking both in terms of the product and the method - I obviously don't want the product coming over the edges onto the veneer, and my DIY skills are "basic". I considered stacking all the parts together and treating all the edges in one go but I wasn't sure if I'd end up sticking them together or leaving a rough edge when they were separated.

A couple of people have suggested diluted PVA to seal the edges, which would certainly be cheap but would it work? (The shelves will be going into a bedroom so I don't expect them to be damp.)

In total I'll have around 60 boxes to build so anything complicated is out, I don't have the patience!

There is special primer paint for MDF.
Other paints allow pinholes to form as they dry.

A 1 metre span of 15mm chipboard will carry very little unless pinned along the back to the back panel and even then I would't risk a lot on it. We use 25mm for shelves in an office environment and don't go beyond 900mm with it. Even at that it will still deform slighty under a load of books.

I would not be a big fan of screwing into mdf. If necessary we use drywall screws but even with pro drilling etc. it can still split.

F.Y.I. and further enlightenment read here

http://www.geoffswoodwork.co.uk/book%20weights.htm

On Tuesday, February 12, 2013 1:17:40 PM UTC, stuart noble wrote:
The bottom boxes (35cm internal height) are tall enough for box file

(I haven't 100% decided on dimensions yet). They will likely be

filled with magazine archives - ie will be heavy. I need to be sure

they will take the weight without bowing. (They'll also have the

weight of the upper boxes to support.)



If I could be convinced that a thinner MDF would suffice I'd drop

down a size - with 18mm I'm playing it safe.



By constructing it from boxes laid out like bricks (ie each row is

50% offset from the ones either side of it) I end up with quite short

gaps between verticals without making the shelves too short, which

should lend strength. However this is all speculation from a software

engineer with no experience of constructing projects like this so if

anyone thinks I'm taking a big risk let me know!



Most kitchen unit shelves are 15mm chip, and an unsupported span of a

metre is pretty normal. Mine are stacked with crockery, which is a hell

of a lot heavier than books.



I'm sure you have a plan for the assembly but FWIW I'd have the

whole lot cut to size by a timber merchant,



Absolutely! In fact it was partly my lack of skill when it comes to

cutting timber that lead to the design - this is very easy to get

supplied almost in kit form just from a set of measurements. Aside

from treating the MDF, all I should need to do is to put in 2 or 3

screws on each edge and either pin or staple the backs on. Given that

I have a lot of nearly identical boxes to make, I may even make up a

jig to hold the sides in place while I screw them together.



Clamping a piece of the shelving to the sides gives you a "ledge" to sit

the cross piece on. If screwing thorough the sides into the edges, these

might be useful

http://www.screwfix.com/p/mdf-tite-s...equestid=54415



but I've found drywall screws just as good. Standard woodscrews tend to

be a bit too fat, and will swell the mdf if not 100% accurately positioned.

Oh, and get one of those combination bits that do the hole and the

countersink in one. Then, with a jig, you can pre-drill all the sides

accurately in one operation. You don't want to be doing that by eye!





[...] and treat yourself to an electric stapler. Great for putting

the backs on and holding the four sides in position if you're

working alone



I wondered about this too. It wouldn't be worth me spending a lot on

one though as this could well be the only time it gets used. I can

get a cheap one for about £20 with 1000 staples and 1000 nails, or a

Stanley one for twice that - is it worth it?





I've had a Bosch for years and wouldn't be without it. Takes generic

staples too, so you're not tied in to expensive Bosch stuff. IME forget

the nail option on cheap tools, they misfire so often it'll drive you crazy.

On Tuesday, February 12, 2013 4:09:45 PM UTC, fred wrote:
A 1 metre span of 15mm chipboard will carry very little unless pinned
along the back to the back panel and even then I would't risk a lot
on it. We use 25mm for shelves in an office environment and don't go
beyond 900mm with it. Even at that it will still deform slighty under
a load of books.

That ties in with what I figured, hence using 18mm MDF doubled up. But I think I may still be overdoing it - the box width is 40cm but by staggering them it is supported underneath at the midpoint, but then it is also taking weight from above at its own midpoint which works against it....

Even so, 18mm doubled is 36mm (1.5"). 12mm doubled to give me 24mm (1") would surely be enough, wouldn't it? (it's a big project to get wrong!)

I would not be a big fan of screwing into mdf. If necessary we use
drywall screws but even with pro drilling etc. it can still split.

That is another advantage of the thicker MDF - I'm going to be quite a long way from the edges. This could be where I'd regret having 12mm.

Just so we're clear, the design is something like this:

----------------------------------------------
| | | | | | | | |
----------------------------------------------
| | | | | | | | |
----------------------------------------------
| | | | | | | | |
----------------------------------------------
| | | | | | | | |
----------------------------------------------

... with the span between uprights 40cm, and because each box is independently constructed from 18mm MDF each horizontal and vertical is actually two adjacent 18mm pieces, ie 36mm total)

--
Mark

"Tim Watts" wrote in message
...
On Tuesday 12 February 2013 08:51 wrote in
uk.d-i-
y:

I'm about to start a project which basically involves building lots of
MDF
boxes then stacking them in a brick-like fashion to make a wall-to-wall
bookshelf.

The boxes will be constructed out of 18mm MDF, and be either
280x350x400mm
or 180x250x400mm in size. (I'll use 2mm MDF for backs.)

I haven't decided yet whether to use veneered MDF. If I don't then I need
to treat the whole lot (probably a satin varnish, although I may paint
them as MDF is quite boring), but if I use veneered then I only need to
treat the cut edges, none of which will be visible once complete
(assuming
I use a veneer edging strip on the visible edges). I can't get 2mm veneer
for the backs so I'll paint those to roughly match whichever veneer I
choose.

What's the best way to treat the "invisible" edges? I'm thinking both in
terms of the product and the method - I obviously don't want the product
coming over the edges onto the veneer, and my DIY skills are "basic". I
considered stacking all the parts together and treating all the edges in
one go but I wasn't sure if I'd end up sticking them together or leaving
a
rough edge when they were separated.

A couple of people have suggested diluted PVA to seal the edges, which
would certainly be cheap but would it work? (The shelves will be going
into a bedroom so I don't expect them to be damp.)


I would not - the water content will swell the MDF.

Perhaps a diluted polyurethane varnish, spirit based?

The MDF shelves that I painted white were fine with water based paint.

In total I'll have around 60 boxes to build so anything complicated is
out, I don't have the patience!

wrote
Rod Speed wrote

Urk, I prefer to do wall to wall bookshelves by welding Dexion
slotted 25mm square steel tubing into floor to ceiling rectangles,
dynabolting them to the walls and floor and using aluminium
flats cut to length in the slots, with MDF shelves on those.

It may not be the most "functional" design but we quite like the look of
the design

My superficial reaction is that you're going to have a problem
with the fact that the boxes will have a lot of wasted space
vertically, because there is so much variation in the height
of the books so if you have 60 uniform sized boxes, most of them
are going to have a lot of free space above the books in them.

If they aren't all going to be the same size, you'll have a problem
stacking them so they look good, particularly at the top.

(whether we'll like it once finished I have no idea though!)

And a bit hard to mock up and try too.

I considered stacking all the parts together and treating all
the edges in one go but I wasn't sure if I'd end up sticking them
together or leaving a rough edge when they were separated.

Likely but easy to try with some scrap.

Good point, I will do that.

Thanks

Mark Rogers

"Geoff Pearson" wrote in message
...

"stuart noble" wrote in message
...

The bottom boxes (35cm internal height) are tall enough for box file
(I haven't 100% decided on dimensions yet). They will likely be
filled with magazine archives - ie will be heavy. I need to be sure
they will take the weight without bowing. (They'll also have the
weight of the upper boxes to support.)

If I could be convinced that a thinner MDF would suffice I'd drop
down a size - with 18mm I'm playing it safe.

By constructing it from boxes laid out like bricks (ie each row is
50% offset from the ones either side of it) I end up with quite short
gaps between verticals without making the shelves too short, which
should lend strength. However this is all speculation from a software
engineer with no experience of constructing projects like this so if
anyone thinks I'm taking a big risk let me know!

Most kitchen unit shelves are 15mm chip, and an unsupported span of a
metre is pretty normal. Mine are stacked with crockery, which is a hell
of a lot heavier than books.

I'm sure you have a plan for the assembly but FWIW I'd have the
whole lot cut to size by a timber merchant,

Absolutely! In fact it was partly my lack of skill when it comes to
cutting timber that lead to the design - this is very easy to get
supplied almost in kit form just from a set of measurements. Aside
from treating the MDF, all I should need to do is to put in 2 or 3
screws on each edge and either pin or staple the backs on. Given that
I have a lot of nearly identical boxes to make, I may even make up a
jig to hold the sides in place while I screw them together.

Clamping a piece of the shelving to the sides gives you a "ledge" to sit
the cross piece on. If screwing thorough the sides into the edges, these
might be useful
http://www.screwfix.com/p/mdf-tite-s...equestid=54415

but I've found drywall screws just as good. Standard woodscrews tend to
be a bit too fat, and will swell the mdf if not 100% accurately
positioned.
Oh, and get one of those combination bits that do the hole and the
countersink in one. Then, with a jig, you can pre-drill all the sides
accurately in one operation. You don't want to be doing that by eye!


[...] and treat yourself to an electric stapler. Great for putting
the backs on and holding the four sides in position if you're
working alone

I wondered about this too. It wouldn't be worth me spending a lot on
one though as this could well be the only time it gets used. I can
get a cheap one for about £20 with 1000 staples and 1000 nails, or a
Stanley one for twice that - is it worth it?


I've had a Bosch for years and wouldn't be without it. Takes generic
staples too, so you're not tied in to expensive Bosch stuff. IME forget
the nail option on cheap tools, they misfire so often it'll drive you
crazy.

I have bookshelves in 18mm mdf - they have bowed under the weight at 750mm
length. MDF is not as rigid as it looks.

That's the other reason I prefer to use the 25mm square
slotted steel tube verticals, you can space those closer so
you can use the much cheaper MDF and not get any bowing.

I did that with the pantry, with 12mm melamine coated MDF 580mm
between verticals, 330mm deep shelves. Those handle the 4 deep
600ml glass jars that I do the marmalade and relish in 200 of them
in the case of the marmalade, without any bowing in years now.

Pine is stiffer - shelves that long stay straight.

Yes, but its much more expensive, its cheaper to have more
verticals the way I do bookshelves and other shelves.

Not as easy to do in his case with his boxes either.

fred wrote

A 1 metre span of 15mm chipboard will carry very
little unless pinned along the back to the back panel

That's just plain wrong. I did my kitchen pantry shelves
with 15mm melamine coated MDF 580mm between
verticals, 330mm deep shelves with no support at all along
the back edge. Those handle the 4 deep 600ml glass jars
that I do the marmalade and relish in 200 of them in the
case of the marmalade, without any bowing in years now.

and even then I would't risk a lot on it.

I did and it worked fine.

We use 25mm for shelves in an office environment
and don't go beyond 900mm with it. Even at that
it will still deform slighty under a load of books.

Mine doesn't with a load much heavier than books.

I would not be a big fan of screwing into mdf.

Yeah, I don't screw into mine at all, they just lie on
the flat aluminium that goes from the front to the
back of the Dexion slotted square steel verticals.

If necessary we use drywall screws but
even with pro drilling etc. it can still split.

F.Y.I. and further enlightenment read here

http://www.geoffswoodwork.co.uk/book%20weights.htm

That's not that useful for bookshelves, it would be better to
give the shelf thickness needed for various spans and woods.


On Tuesday, February 12, 2013 1:17:40 PM UTC, stuart noble wrote:
The bottom boxes (35cm internal height) are tall enough for box file

(I haven't 100% decided on dimensions yet). They will likely be

filled with magazine archives - ie will be heavy. I need to be sure

they will take the weight without bowing. (They'll also have the

weight of the upper boxes to support.)



If I could be convinced that a thinner MDF would suffice I'd drop

down a size - with 18mm I'm playing it safe.



By constructing it from boxes laid out like bricks (ie each row is

50% offset from the ones either side of it) I end up with quite short

gaps between verticals without making the shelves too short, which

should lend strength. However this is all speculation from a software

engineer with no experience of constructing projects like this so if

anyone thinks I'm taking a big risk let me know!



Most kitchen unit shelves are 15mm chip, and an unsupported span of a

metre is pretty normal. Mine are stacked with crockery, which is a hell

of a lot heavier than books.



I'm sure you have a plan for the assembly but FWIW I'd have the

whole lot cut to size by a timber merchant,



Absolutely! In fact it was partly my lack of skill when it comes to

cutting timber that lead to the design - this is very easy to get

supplied almost in kit form just from a set of measurements. Aside

from treating the MDF, all I should need to do is to put in 2 or 3

screws on each edge and either pin or staple the backs on. Given that

I have a lot of nearly identical boxes to make, I may even make up a

jig to hold the sides in place while I screw them together.



Clamping a piece of the shelving to the sides gives you a "ledge" to sit

the cross piece on. If screwing thorough the sides into the edges, these

might be useful

http://www.screwfix.com/p/mdf-tite-s...equestid=54415



but I've found drywall screws just as good. Standard woodscrews tend to

be a bit too fat, and will swell the mdf if not 100% accurately
positioned.

Oh, and get one of those combination bits that do the hole and the

countersink in one. Then, with a jig, you can pre-drill all the sides

accurately in one operation. You don't want to be doing that by eye!





[...] and treat yourself to an electric stapler. Great for putting

the backs on and holding the four sides in position if you're

working alone



I wondered about this too. It wouldn't be worth me spending a lot on

one though as this could well be the only time it gets used. I can

get a cheap one for about £20 with 1000 staples and 1000 nails, or a

Stanley one for twice that - is it worth it?





I've had a Bosch for years and wouldn't be without it. Takes generic

staples too, so you're not tied in to expensive Bosch stuff. IME forget

the nail option on cheap tools, they misfire so often it'll drive you
crazy.

"Rod Speed" wrote in message
...


"Geoff Pearson" wrote in message
...

"stuart noble" wrote in message
...

The bottom boxes (35cm internal height) are tall enough for box file
(I haven't 100% decided on dimensions yet). They will likely be
filled with magazine archives - ie will be heavy. I need to be sure
they will take the weight without bowing. (They'll also have the
weight of the upper boxes to support.)

If I could be convinced that a thinner MDF would suffice I'd drop
down a size - with 18mm I'm playing it safe.

By constructing it from boxes laid out like bricks (ie each row is
50% offset from the ones either side of it) I end up with quite short
gaps between verticals without making the shelves too short, which
should lend strength. However this is all speculation from a software
engineer with no experience of constructing projects like this so if
anyone thinks I'm taking a big risk let me know!

Most kitchen unit shelves are 15mm chip, and an unsupported span of a
metre is pretty normal. Mine are stacked with crockery, which is a hell
of a lot heavier than books.

I'm sure you have a plan for the assembly but FWIW I'd have the
whole lot cut to size by a timber merchant,

Absolutely! In fact it was partly my lack of skill when it comes to
cutting timber that lead to the design - this is very easy to get
supplied almost in kit form just from a set of measurements. Aside
from treating the MDF, all I should need to do is to put in 2 or 3
screws on each edge and either pin or staple the backs on. Given that
I have a lot of nearly identical boxes to make, I may even make up a
jig to hold the sides in place while I screw them together.

Clamping a piece of the shelving to the sides gives you a "ledge" to sit
the cross piece on. If screwing thorough the sides into the edges, these
might be useful
http://www.screwfix.com/p/mdf-tite-s...equestid=54415

but I've found drywall screws just as good. Standard woodscrews tend to
be a bit too fat, and will swell the mdf if not 100% accurately
positioned.
Oh, and get one of those combination bits that do the hole and the
countersink in one. Then, with a jig, you can pre-drill all the sides
accurately in one operation. You don't want to be doing that by eye!


[...] and treat yourself to an electric stapler. Great for putting
the backs on and holding the four sides in position if you're
working alone

I wondered about this too. It wouldn't be worth me spending a lot on
one though as this could well be the only time it gets used. I can
get a cheap one for about £20 with 1000 staples and 1000 nails, or a
Stanley one for twice that - is it worth it?


I've had a Bosch for years and wouldn't be without it. Takes generic
staples too, so you're not tied in to expensive Bosch stuff. IME forget
the nail option on cheap tools, they misfire so often it'll drive you
crazy.

I have bookshelves in 18mm mdf - they have bowed under the weight at
750mm length. MDF is not as rigid as it looks.

That's the other reason I prefer to use the 25mm square
slotted steel tube verticals, you can space those closer so
you can use the much cheaper MDF and not get any bowing.

I did that with the pantry, with 12mm melamine coated MDF 580mm

Sorry, just measured it, the MDF must be 15mm, the
overall with the melamine coating is about 18mm

between verticals, 330mm deep shelves. Those handle the 4 deep
600ml glass jars that I do the marmalade and relish in 200 of them
in the case of the marmalade, without any bowing in years now.

Pine is stiffer - shelves that long stay straight.

Yes, but its much more expensive, its cheaper to have more
verticals the way I do bookshelves and other shelves.

Not as easy to do in his case with his boxes either.

wrote
stuart noble wrote

I've done a bit of this for my siblings over the years, mainly
15mm, and the various finishes they were threatening to use
never materialised. That neutral, scruffy mdf look grows on
you. Any clear finish tends to give them a dark tan "wet" look,
which is not very appealing on mdf. Try it on a scrap first.

I have some MDF shelves that were varnished (to protect the
MDF not for effect) and as you say, the effect grows on you.

Yeah, I don't mine the effect at all myself, but
presumably it doesn't grow on everyone.

But that was stuck in an office, this is going to be a "feature"
in a spare bedroom that is supposed to become more of a
library/snug, so I want to at least try to make something "nice".

Using veneered MDF is obviously a lot more expensive,
but is somewhat offset by the saving in varnish and would
be a considerable time saving, for a much better end result,
which is why I'm leaning that way at the moment.

So why not use 18mm ply instead of MDF ?

Sixty boxes? Blimey, you're going to waste a lot of space with the
thickness of the mdf. I prefer to make half a dozen modules with
shelf supports so that you can change the spacing. There always
seems to be one thing that's slightly too tall for any of the boxes.

The bottom boxes (35cm internal height) are tall enough for box file
(I haven't 100% decided on dimensions yet). They will likely be filled
with magazine archives - ie will be heavy. I need to be sure they will
take the weight without bowing. (They'll also have the weight of the
upper boxes to support.)

My gut feeling is that the upper box weight should
not be a major problem with your brick approach.

Never tried it tho.

If I could be convinced that a thinner MDF would suffice
I'd drop down a size - with 18mm I'm playing it safe.

By constructing it from boxes laid out like bricks
(ie each row is 50% offset from the ones either side of it)

Trouble with that approach is the end of each row. You'll either
have every second row with a gap half a box wide at each end,
or have every row with half a box gap at alternating ends.

I end up with quite short gaps between verticals without
making the shelves too short, which should lend strength.
However this is all speculation from a software engineer
with no experience of constructing projects like this so if
anyone thinks I'm taking a big risk let me know!

I'm sure you have a plan for the assembly but FWIW I'd
have the whole lot cut to size by a timber merchant,

Absolutely! In fact it was partly my lack of skill when it
comes to cutting timber that lead to the design - this is
very easy to get supplied almost in kit form just from a
set of measurements. Aside from treating the MDF, all
I should need to do is to put in 2 or 3 screws on each
edge and either pin or staple the backs on. Given that
I have a lot of nearly identical boxes to make, I may
even make up a jig to hold the sides in place while
I screw them together.

[...] and treat yourself to an electric stapler. Great for
putting the backs on and holding the four sides in
position if you're working alone

I wondered about this too. It wouldn't be worth me
spending a lot on one though as this could well be
the only time it gets used. I can get a cheap one for
about £20 with 1000 staples and 1000 nails, or a
Stanley one for twice that - is it worth it?

You could go for the more expensive one and flog it
on ebay when you're done.

That ties in with what I figured, hence using 18mm MDF doubled up.
But I think I may still be overdoing it - the box width is 40cm but
by staggering them it is supported underneath at the midpoint, but
then it is also taking weight from above at its own midpoint which
works against it....

As long as the bottoms rest on the floor, you'll be ok


Even so, 18mm doubled is 36mm (1.5"). 12mm doubled to give me 24mm
(1") would surely be enough, wouldn't it? (it's a big project to get
wrong!)

I would not be a big fan of screwing into mdf. If necessary we use
drywall screws but even with pro drilling etc. it can still split.

That is another advantage of the thicker MDF - I'm going to be quite
a long way from the edges. This could be where I'd regret having
12mm.

It's 15mm you need. You can screw into the edge, but it doesn't look
ungainly.

Just so we're clear, the design is something like this:

---------------------------------------------- | | | |
| | | | |
---------------------------------------------- | | | | |
| | | | ---------------------------------------------- |
| | | | | | | |
---------------------------------------------- | | | | |
| | | | ----------------------------------------------

.. with the span between uprights 40cm, and because each box is
independently constructed from 18mm MDF each horizontal and vertical
is actually two adjacent 18mm pieces, ie 36mm total)

I think you could store car engines on that :-)

On 12/02/2013 14:57, harry wrote:


There is special primer paint for MDF.
Other paints allow pinholes to form as they dry.

Certainly seen that claimed several times.

But when I painted lots of MDF shelves, I used ordinary emulsion -
rollered on - two or three coats. And a topcoat of quite a good
water-based acrylic floor "varnish" (got from Screwfix - made somewhere
in Essex, IIRC).

Excellent, remarkably tough finish - though had to dispose of some
recently and they looked immaculate as they were turfed into skip at dump.

--
Rod

In article , Tim Watts
writes
On Tuesday 12 February 2013 08:51 wrote in uk.d-i-
y:

I'm about to start a project which basically involves building lots of MDF
boxes then stacking them in a brick-like fashion to make a wall-to-wall
bookshelf.
snip
What's the best way to treat the "invisible" edges? I'm thinking both in
terms of the product and the method -
snip
A couple of people have suggested diluted PVA to seal the edges, which
would certainly be cheap but would it work? (The shelves will be going
into a bedroom so I don't expect them to be damp.)


I would not - the water content will swell the MDF.

Perhaps a diluted polyurethane varnish, spirit based?

What about clear cellulose dope?
--
Chris Holford

On 12/02/2013 18:47, stuart noble wrote:

That ties in with what I figured, hence using 18mm MDF doubled up.
But I think I may still be overdoing it - the box width is 40cm but
by staggering them it is supported underneath at the midpoint, but
then it is also taking weight from above at its own midpoint which
works against it....

As long as the bottoms rest on the floor, you'll be ok


Even so, 18mm doubled is 36mm (1.5"). 12mm doubled to give me 24mm
(1") would surely be enough, wouldn't it? (it's a big project to get
wrong!)

I would not be a big fan of screwing into mdf. If necessary we use
drywall screws but even with pro drilling etc. it can still split.

That is another advantage of the thicker MDF - I'm going to be quite
a long way from the edges. This could be where I'd regret having
12mm.

It's 15mm you need. You can screw into the edge, but it doesn't look
ungainly.

Just so we're clear, the design is something like this:


----------------------------------------------
| | | | | | | | |
----------------------------------------------
| | | | | | | | |
----------------------------------------------
| | | | | | | | |
----------------------------------------------
| | | | | | | | |
----------------------------------------------

.. with the span between uprights 40cm, and because each box is
independently constructed from 18mm MDF each horizontal and vertical
is actually two adjacent 18mm pieces, ie 36mm total)

I think you could store car engines on that :-)


My bookshelves are 50 and 60cm supports with 15mm chip with a laminate
coating. They don't bend enough to notice.

That design seems to have the uprights staggered. I think it would be
better if they went all the way to the floor, else the load from the
upper shelf is carried by the shelf below and not transferred through an
upright.

Andy

On Tuesday, February 12, 2013 6:25:26 PM UTC, Rod Speed wrote:
So why not use 18mm ply instead of MDF ?

Is "never crossed my mind" a good reason? I'll add that to my list of possibilities.

[...]
Trouble with that approach is the end of each row. You'll either
have every second row with a gap half a box wide at each end,
or have every row with half a box gap at alternating ends.

That's correct, and from my attempts at drawing something up is part of it's charm (the room is 7.5 boxes wide, so the end box at alternating ends will be 50% width).

You could go for the more expensive one and flog it
on ebay when you're done.

Looking on eBay I can get the Stanley for £20 anyway. I know that's not going to be the best stapler in the world but should do the job?

--
Mark

On Tuesday, February 12, 2013 6:47:00 PM UTC, stuart noble wrote:
It's 15mm you need. You can screw into the edge, but it doesn't look
ungainly.

Thanks, I'll get the timber merchant to price that.

It also crossed my mind that the smaller boxes at the top may not need to be the same thickness but I'd need to mock something up on my PC to see what it would look like. (Any recommendations for a sort of CAD "Lite" for this sort of job much appreciated.)

[...]
I think you could store car engines on that :-)

I did say it might be overkill!

--
Mark

On Wednesday, February 13, 2013 9:12:56 AM UTC, Andy Champ wrote:
That design seems to have the uprights staggered. I think it would be
better if they went all the way to the floor, else the load from the
upper shelf is carried by the shelf below and not transferred through an
upright.

Structurally I can't decide whether you're right or not - I'm 50% on the side of staggered being better, and 50% on the side of it being worse. But I prefer the stacked brick look so I guess my goal would be to find a way to make it strong enough, rather than change it to use thinner materials. Within reason, of-course - if the design is simply not workable I need to go back to the drawing board.

--
Mark

"Andy Champ" wrote in message
. uk...
On 12/02/2013 18:47, stuart noble wrote:

That ties in with what I figured, hence using 18mm MDF doubled up.
But I think I may still be overdoing it - the box width is 40cm but
by staggering them it is supported underneath at the midpoint, but
then it is also taking weight from above at its own midpoint which
works against it....

As long as the bottoms rest on the floor, you'll be ok


Even so, 18mm doubled is 36mm (1.5"). 12mm doubled to give me 24mm
(1") would surely be enough, wouldn't it? (it's a big project to get
wrong!)

I would not be a big fan of screwing into mdf. If necessary we use
drywall screws but even with pro drilling etc. it can still split.

That is another advantage of the thicker MDF - I'm going to be quite
a long way from the edges. This could be where I'd regret having
12mm.

It's 15mm you need. You can screw into the edge, but it doesn't look
ungainly.

Just so we're clear, the design is something like this:


----------------------------------------------
| | | | | | | | |
----------------------------------------------
| | | | | | | | |
----------------------------------------------
| | | | | | | | |
----------------------------------------------
| | | | | | | | |
----------------------------------------------

.. with the span between uprights 40cm, and because each box is
independently constructed from 18mm MDF each horizontal and vertical
is actually two adjacent 18mm pieces, ie 36mm total)

I think you could store car engines on that :-)


My bookshelves are 50 and 60cm supports with 15mm chip with a laminate
coating. They don't bend enough to notice.

That design seems to have the uprights staggered. I think it would be
better if they went all the way to the floor, else the load from the upper
shelf is carried by the shelf below and not transferred through an
upright.

He's doing it with boxes tho, so it should work fine
apart from having double thickness horizontals etc.

Mark Rogers wrote
Rod Speed wrote

So why not use 18mm ply instead of MDF ?

Is "never crossed my mind" a good reason?

Yep.

I'll add that to my list of possibilities.

Not as cheap as MDF but likely cheaper than veneered MDF.

Trouble with that approach is the end of each row. You'll either
have every second row with a gap half a box wide at each end,
or have every row with half a box gap at alternating ends.

That's correct, and from my attempts at drawing something
up is part of it's charm (the room is 7.5 boxes wide, so the
end box at alternating ends will be 50% width).

On further thought I guess it doesn't really matter because
the end gaps are like a box without the wall side to the 'box'

You could go for the more expensive one
and flog it on ebay when you're done.

Looking on eBay I can get the Stanley for £20 anyway.

Yeah, didn't think of that.

I know that's not going to be the best
stapler in the world but should do the job?

Dunno, don't have any personal experience with those.

I am more into welded steel with drop in melamine
faced MDF instead of doing stuff with MDF myself
so I don't need to nail anything at all.

Even the house oregon facia board uses plated gutter
bolts into angle iron verticals welded to the galvanised
steel beams that are part of the Stramit ceiling/roof
system and the timber rafters for the flat metal decking
roof are bolted to the top of those galvanised steel beams.

On Tue, 12 Feb 2013 02:30:20 -0800 (PST),
wrote:

If I could be convinced that a thinner MDF would suffice I'd drop down a size - with 18mm I'm playing it safe.

You might find the Sagulator
http://www.woodbin.com/calcs/sagulator.htm
useful.

On Wednesday, February 13, 2013 11:30:51 AM UTC, Peter Parry wrote:
http://www.woodbin.com/calcs/sagulator.htm

Thanks, I'd used that before ages ago but forgotten where to find it.

I've now pretty much convinced myself, based on advice here, to go with ply instead of MDF. Birch ply looks pretty good (better than MDF anyway!) and should be stronger. Using the Sagulator, 500kg/ft on my 40cm spans, even at 12mm (not 12mm doubled up), produces only 0.01mm sag/ft, so I think that even for the biggest boxes 12mm ply should do what I need? (Again, remember that's 12mm for the box construction so the actual shelf thickness would be twice that.)

Also, I assume that ply would not need to be treated for preservation purposes, so treatment becomes just a matter of aesthetics? And that it should be easier to (eg) varnish than MDF?

The only big question, if the above assumptions are correct, is how to secure the corner joints - I assume that screwing into the ends of the ply isn't a great idea? Would long(ish) nails be better?

As far as I can see, 12mm birch ply will cost me about the same as 12mm veneered MDF, and give me a "real" wood finish, extra strength, and easier treatment into the bargain, so it feels like a no brainer.... (Someone is about to tell me I'm wrong!)

--
Mark

On Tuesday, February 12, 2013 6:15:31 PM UTC, Rod Speed wrote:
"Rod Speed" wrote in message

...





"Geoff Pearson" wrote in message

...



"stuart noble" wrote in message

...



The bottom boxes (35cm internal height) are tall enough for box file

(I haven't 100% decided on dimensions yet). They will likely be

filled with magazine archives - ie will be heavy. I need to be sure

they will take the weight without bowing. (They'll also have the

weight of the upper boxes to support.)



If I could be convinced that a thinner MDF would suffice I'd drop

down a size - with 18mm I'm playing it safe.



By constructing it from boxes laid out like bricks (ie each row is

50% offset from the ones either side of it) I end up with quite short

gaps between verticals without making the shelves too short, which

should lend strength. However this is all speculation from a software

engineer with no experience of constructing projects like this so if

anyone thinks I'm taking a big risk let me know!



Most kitchen unit shelves are 15mm chip, and an unsupported span of a

metre is pretty normal. Mine are stacked with crockery, which is a hell

of a lot heavier than books.



I'm sure you have a plan for the assembly but FWIW I'd have the

whole lot cut to size by a timber merchant,



Absolutely! In fact it was partly my lack of skill when it comes to

cutting timber that lead to the design - this is very easy to get

supplied almost in kit form just from a set of measurements. Aside

from treating the MDF, all I should need to do is to put in 2 or 3

screws on each edge and either pin or staple the backs on. Given that

I have a lot of nearly identical boxes to make, I may even make up a

jig to hold the sides in place while I screw them together.



Clamping a piece of the shelving to the sides gives you a "ledge" to sit

the cross piece on. If screwing thorough the sides into the edges, these

might be useful

http://www.screwfix.com/p/mdf-tite-s...equestid=54415



but I've found drywall screws just as good. Standard woodscrews tend to

be a bit too fat, and will swell the mdf if not 100% accurately

positioned.

Oh, and get one of those combination bits that do the hole and the

countersink in one. Then, with a jig, you can pre-drill all the sides

accurately in one operation. You don't want to be doing that by eye!





[...] and treat yourself to an electric stapler. Great for putting

the backs on and holding the four sides in position if you're

working alone



I wondered about this too. It wouldn't be worth me spending a lot on

one though as this could well be the only time it gets used. I can

get a cheap one for about £20 with 1000 staples and 1000 nails, or a

Stanley one for twice that - is it worth it?





I've had a Bosch for years and wouldn't be without it. Takes generic

staples too, so you're not tied in to expensive Bosch stuff. IME forget

the nail option on cheap tools, they misfire so often it'll drive you

crazy.



I have bookshelves in 18mm mdf - they have bowed under the weight at

750mm length. MDF is not as rigid as it looks.



That's the other reason I prefer to use the 25mm square

slotted steel tube verticals, you can space those closer so

you can use the much cheaper MDF and not get any bowing.



I did that with the pantry, with 12mm melamine coated MDF 580mm



Sorry, just measured it, the MDF must be 15mm, the

overall with the melamine coating is about 18mm



between verticals, 330mm deep shelves. Those handle the 4 deep

600ml glass jars that I do the marmalade and relish in 200 of them

in the case of the marmalade, without any bowing in years now.



Pine is stiffer - shelves that long stay straight.



Yes, but its much more expensive, its cheaper to have more

verticals the way I do bookshelves and other shelves.



Not as easy to do in his case with his boxes either.





Melamine film is paper thin. In fact melamine faced board as supplied in untrimmed format will rapidly give paper cuts if not handled with gloves. No way would it equal 1.5mm per face. Even if it was a natural wood veneer it would not be 1.5mm thick, and the thickest, and far from being very common, Formica is only 1.1mm thick. What you have is 18mm board plain and simple..

The o.p. mentioned spanning 1m with 15mm board and claimed this would carry a load of dishes. This now seems to have changed to 18mm board spanning 580mm. Quite do-able.

On Wednesday, February 13, 2013 12:38:13 PM UTC, Mark Rogers wrote:
snip


Ply sounds good and will look a lot better.

I know it may not be the effect you want but I would be inclined to run horizontals the full width, or as wide as possible, and insert verticals in the appropriate places. Board will carry a heavier load when the ends are cantilevered as opposed to being held by the ends only. As you are staggering the uprights it would be a simple matter to screw through them into the verticals.

Mark Rogers wrote
Peter Parry wrote

http://www.woodbin.com/calcs/sagulator.htm

Thanks, I'd used that before ages ago but forgotten where to find it.

Yeah, when I tried to add it to my favourites, it said its already there |-)

I've now pretty much convinced myself, based on advice here,
to go with ply instead of MDF. Birch ply looks pretty good
(better than MDF anyway!) and should be stronger.

And easier to screw into too.

Using the Sagulator, 500kg/ft on my 40cm spans, even at 12mm
(not 12mm doubled up), produces only 0.01mm sag/ft, so I think
that even for the biggest boxes 12mm ply should do what I need?

Yep.

(Again, remember that's 12mm for the box construction
so the actual shelf thickness would be twice that.)

Yeah, they'll be fine, it's a lot stiffer than MDF.

Also, I assume that ply would not need to be treated for preservation
purposes, so treatment becomes just a matter of aesthetics?

Yep.

And that it should be easier to (eg) varnish than MDF?

I doubt there would much in that.

The only big question, if the above assumptions
are correct, is how to secure the corner joints -
I assume that screwing into the ends of the ply
isn't a great idea? Would long(ish) nails be better?

Pass, like I said, I'm not really into wood joints.

As far as I can see, 12mm birch ply will cost me about
the same as 12mm veneered MDF, and give me a "real"
wood finish, extra strength, and easier treatment into
the bargain, so it feels like a no brainer....

Yep.

(Someone is about to tell me I'm wrong!)

I doubt it.

On Wednesday, February 13, 2013 1:44:56 PM UTC, fred wrote:
Ply sounds good and will look a lot better.

Thanks

I know it may not be the effect you want but I would be
inclined to run horizontals the full width, or as wide as possible,
and insert verticals in the appropriate places. Board will carry
a heavier load when the ends are cantilevered as opposed to being
held by the ends only. As you are staggering the uprights it would
be a simple matter to screw through them into the verticals.

I haven't ruled this out. The effect can be gained anyway by still using two 12mm lengths on top of each other, with small cuts on the outer edge where the verticals are (just 1mm into the wood would give the effect of it being a separate piece).

Alternatively I could switch to 25mm ply, without doubling anything up, and look at the ply as being the "mortar" between the brick-shaped "holes" - I need to try and mock this up.

The only major question I have left is how to do the joins. I've just invested in a basic 18ga nail gun (15-35mm nails or 15-30mm staples), which I think would probably be better than screws? Almost all the stresses should be pushing downwards such that everything would probably be fairly stable without any screws or nails anyway (albeit very hard to construct in the first place), and any sheer there is should be countered by having backs on the units?

--
Mark

"fred" wrote in message
...
On Tuesday, February 12, 2013 6:15:31 PM UTC, Rod Speed wrote:
"Rod Speed" wrote in message

...





"Geoff Pearson" wrote in message

...



"stuart noble" wrote in message

...



The bottom boxes (35cm internal height) are tall enough for box file

(I haven't 100% decided on dimensions yet). They will likely be

filled with magazine archives - ie will be heavy. I need to be sure

they will take the weight without bowing. (They'll also have the

weight of the upper boxes to support.)



If I could be convinced that a thinner MDF would suffice I'd drop

down a size - with 18mm I'm playing it safe.



By constructing it from boxes laid out like bricks (ie each row is

50% offset from the ones either side of it) I end up with quite
short

gaps between verticals without making the shelves too short, which

should lend strength. However this is all speculation from a
software

engineer with no experience of constructing projects like this so if

anyone thinks I'm taking a big risk let me know!



Most kitchen unit shelves are 15mm chip, and an unsupported span of a

metre is pretty normal. Mine are stacked with crockery, which is a
hell

of a lot heavier than books.



I'm sure you have a plan for the assembly but FWIW I'd have the

whole lot cut to size by a timber merchant,



Absolutely! In fact it was partly my lack of skill when it comes to

cutting timber that lead to the design - this is very easy to get

supplied almost in kit form just from a set of measurements. Aside

from treating the MDF, all I should need to do is to put in 2 or 3

screws on each edge and either pin or staple the backs on. Given
that

I have a lot of nearly identical boxes to make, I may even make up a

jig to hold the sides in place while I screw them together.



Clamping a piece of the shelving to the sides gives you a "ledge" to
sit

the cross piece on. If screwing thorough the sides into the edges,
these

might be useful

http://www.screwfix.com/p/mdf-tite-s...equestid=54415



but I've found drywall screws just as good. Standard woodscrews tend
to

be a bit too fat, and will swell the mdf if not 100% accurately

positioned.

Oh, and get one of those combination bits that do the hole and the

countersink in one. Then, with a jig, you can pre-drill all the sides

accurately in one operation. You don't want to be doing that by eye!





[...] and treat yourself to an electric stapler. Great for putting

the backs on and holding the four sides in position if you're

working alone



I wondered about this too. It wouldn't be worth me spending a lot on

one though as this could well be the only time it gets used. I can

get a cheap one for about £20 with 1000 staples and 1000 nails, or a

Stanley one for twice that - is it worth it?





I've had a Bosch for years and wouldn't be without it. Takes generic

staples too, so you're not tied in to expensive Bosch stuff. IME
forget

the nail option on cheap tools, they misfire so often it'll drive you

crazy.



I have bookshelves in 18mm mdf - they have bowed under the weight at

750mm length. MDF is not as rigid as it looks.



That's the other reason I prefer to use the 25mm square

slotted steel tube verticals, you can space those closer so

you can use the much cheaper MDF and not get any bowing.



I did that with the pantry, with 12mm melamine coated MDF 580mm



Sorry, just measured it, the MDF must be 15mm, the

overall with the melamine coating is about 18mm



between verticals, 330mm deep shelves. Those handle the 4 deep

600ml glass jars that I do the marmalade and relish in 200 of them

in the case of the marmalade, without any bowing in years now.



Pine is stiffer - shelves that long stay straight.



Yes, but its much more expensive, its cheaper to have more

verticals the way I do bookshelves and other shelves.



Not as easy to do in his case with his boxes either.

Melamine film is paper thin.

This stuff isnt. Its not as thick as the much thicker laminex, but
is thicker than paper, about as thick as the thinnest card stock.

In fact melamine faced board as supplied in untrimmed format
will rapidly give paper cuts if not handled with gloves.

I don't get that problem with the edges that I have cut it to length.

No way would it equal 1.5mm per face. Even if it was a natural
wood veneer it would not be 1.5mm thick, and the thickest, and
far from being very common, Formica is only 1.1mm thick. What
you have is 18mm board plain and simple.

I've just measured it again, and its actually 16mm.

The o.p. mentioned spanning 1m with 15mm board
and claimed this would carry a load of dishes.

The OP never said anything about dishes,

This now seems to have changed to 18mm
board spanning 580mm. Quite do-able.

Nope, its actually 16mm spanning 580mm.

On 13/02/2013 12:38, Mark Rogers wrote:
On Wednesday, February 13, 2013 11:30:51 AM UTC, Peter Parry wrote:
http://www.woodbin.com/calcs/sagulator.htm

Thanks, I'd used that before ages ago but forgotten where to find
it.

I've now pretty much convinced myself, based on advice here, to go
with ply instead of MDF. Birch ply looks pretty good

The birch ply *faces* look great, the edges....er....not great at all.

On Wednesday, February 13, 2013 3:07:43 PM UTC, stuart noble wrote:
The birch ply *faces* look great, the edges....er....not great at all.

I actually don't mind them (it has more "character" than MDF anyway). But adding an edging isn't too big a deal if I decide it bothers me.

On Wednesday, February 13, 2013 2:14:00 PM UTC, Rod Speed wrote:
snip.



Melamine film is paper thin.



This stuff isnt. Its not as thick as the much thicker laminex, but

is thicker than paper, about as thick as the thinnest card stock.

Well given that you had problems measuring the overall thickness of the board (first 15mm?? Then 18mm ?? and now 16mm?? I'm astonished you can measure the thickness of the laminate.




In fact melamine faced board as supplied in untrimmed format

will rapidly give paper cuts if not handled with gloves.



I don't get that problem with the edges that I have cut it to length.


Read what I said. I somehow doubt you are dealing with untrimmed sheets. In fact I doubt if you ever saw one.





No way would it equal 1.5mm per face. Even if it was a natural

wood veneer it would not be 1.5mm thick, and the thickest, and

far from being very common, Formica is only 1.1mm thick. What

you have is 18mm board plain and simple.



I've just measured it again, and its actually 16mm.


See above


The o.p. mentioned spanning 1m with 15mm board

and claimed this would carry a load of dishes.



The OP never said anything about dishes,



Quote '
Most kitchen unit shelves are 15mm chip, and an unsupported span of a
metre is pretty normal. Mine are stacked with crockery, which is a hell '

I've no intention of arguing semantics ( http://www.thefreedictionary.com/semantics) with you.




This now seems to have changed to 18mm

board spanning 580mm. Quite do-able.



Nope, its actually 16mm spanning 580mm.


When you're in a hole stop digging.

On 13/02/2013 14:00, Mark Rogers wrote:
Alternatively I could switch to 25mm ply, without doubling anything up, and look at the ply as being the "mortar" between the brick-shaped "holes" - I need to try and mock this up

25mm ply _would_ carry car engines. The bottom of my boat is 12mm, and
feels solid as rock (though it does have interesting curves), but that's
mostly to get the weight up to the class limit. Most are 6mm, and people
run about on them.

Unlike chipboard it doesn't creep with age. (Don't know whether or not
MDF does)

Andy

Mark Rogers wrote
stuart noble wrote

The birch ply *faces* look great, the edges....er....not great at all.

I actually don't mind them

Yeah, I have one that someone else made, just a single piece
which was intended to drop into a steel frame where the edge
isnt visible and the edges look fine. It is estapoled tho.

(it has more "character" than MDF anyway).

Yeah, the MDF shelves that I painted, 19mm, I filled
with filler before painting them with white water
based paint. Quite a bit more work than just painting.

But adding an edging isn't too big a deal if I decide it bothers me.

fred wrote
Rod Speed wrote

Melamine film is paper thin.

This stuff isnt. Its not as thick as the much thicker laminex, but
is thicker than paper, about as thick as the thinnest card stock.

Well given that you had problems measuring the overall thickness of the
board (first 15mm?? Then 18mm ?? and now 16mm??

The original 15mm was a guess, not a measurement.

The second one was a guess too, just noticed it was more than 15.

I'm astonished you can measure the thickness of the laminate.

Even you should be able to measure the actual thickness of the whole thing.

No way would it equal 1.5mm per face. Even if it was a natural
wood veneer it would not be 1.5mm thick, and the thickest, and
far from being very common, Formica is only 1.1mm thick. What
you have is 18mm board plain and simple.

I've just measured it again, and its actually 16mm.

See above

See above.

The o.p. mentioned spanning 1m with 15mm board
and claimed this would carry a load of dishes.

The OP never said anything about dishes,

Quote '
Most kitchen unit shelves are 15mm chip, and an unsupported span of
a metre is pretty normal. Mine are stacked with crockery, which is a hell
'

That's not the OP, that's someone else.

I've no intention of arguing semantics
( http://www.thefreedictionary.com/semantics) with you.

You just did.

This now seems to have changed to 18mm
board spanning 580mm. Quite do-able.

Nope, its actually 16mm spanning 580mm.

When you're in a hole stop digging.

You're one in the hole with your claim about mine
being 18mm and that the OP said anything about dishes.

On Wednesday, February 13, 2013 6:34:49 PM UTC, Rod Speed wrote:
fred wrote

Rod Speed wrote



Melamine film is paper thin.



This stuff isnt. Its not as thick as the much thicker laminex, but

is thicker than paper, about as thick as the thinnest card stock.



Well given that you had problems measuring the overall thickness of the

board (first 15mm?? Then 18mm ?? and now 16mm??



The original 15mm was a guess, not a measurement.



The second one was a guess too, just noticed it was more than 15.



I'm astonished you can measure the thickness of the laminate.



Even you should be able to measure the actual thickness of the whole thing.



No way would it equal 1.5mm per face. Even if it was a natural

wood veneer it would not be 1.5mm thick, and the thickest, and

far from being very common, Formica is only 1.1mm thick. What

you have is 18mm board plain and simple.



I've just measured it again, and its actually 16mm.



See above



See above.



The o.p. mentioned spanning 1m with 15mm board

and claimed this would carry a load of dishes.



The OP never said anything about dishes,



Quote '

Most kitchen unit shelves are 15mm chip, and an unsupported span of

a metre is pretty normal. Mine are stacked with crockery, which is a hell

'



That's not the OP, that's someone else.



I've no intention of arguing semantics

( http://www.thefreedictionary.com/semantics) with you.



You just did.



This now seems to have changed to 18mm

board spanning 580mm. Quite do-able.



Nope, its actually 16mm spanning 580mm.



When you're in a hole stop digging.



You're one in the hole with your claim about mine

being 18mm and that the OP said anything about dishes.

You're nit picking my dear boy.

Regrettably indication of an E.S.N.

I'll leave you alone now. Its not fair to pick on the afflicted. More to be pitied than laughed at.