Looking at building a hutch for a friend that wishes it to be around 6' high
by 5' long & probably 2' deep. She wants to paint the piece, so question 1)
is cabinet grade plywood what I want to use regardless of finish?

The shelves on the top of the hutch are to span the entire 5' width without
breaks. They will be approximately 5' x 20". Assuming I use a lipped edge
of solid wood to cover the edge of 3/4" ply for shelves in the front,
(question 2) will the shelves need reinforcement at that length & width?
They will probably be holding china, bowls, dishes, etc. and lots of them.
I've never used plywood for shelves in that length and am concerned they
will sag. What are my options?

Cheers!
Duke

check this out duke - http://www.woodbin.com/calcs/sagulator.htm

Dave

Dukester wrote:

Looking at building a hutch for a friend that wishes it to be around 6' high
by 5' long & probably 2' deep. She wants to paint the piece, so question 1)
is cabinet grade plywood what I want to use regardless of finish?

The shelves on the top of the hutch are to span the entire 5' width without
breaks. They will be approximately 5' x 20". Assuming I use a lipped edge
of solid wood to cover the edge of 3/4" ply for shelves in the front,
(question 2) will the shelves need reinforcement at that length & width?
They will probably be holding china, bowls, dishes, etc. and lots of them.
I've never used plywood for shelves in that length and am concerned they
will sag. What are my options?

Cheers!
Duke

"Dukester" wrote in message
. ..
Looking at building a hutch for a friend that wishes it to be around 6'
high
by 5' long & probably 2' deep. She wants to paint the piece, so question
1)
is cabinet grade plywood what I want to use regardless of finish?

The shelves on the top of the hutch are to span the entire 5' width
without
breaks. They will be approximately 5' x 20". Assuming I use a lipped
edge
of solid wood to cover the edge of 3/4" ply for shelves in the front,
(question 2) will the shelves need reinforcement at that length & width?
They will probably be holding china, bowls, dishes, etc. and lots of them.
I've never used plywood for shelves in that length and am concerned they
will sag. What are my options?


Answer to number one is MDO if painting.

Answer to 2 is to have a couple inches of wood on all edges, and at least
one, though I'd go two, up the middle underneath.

Duke,

Fine Woodworking Magzine recently published an article about painted
cabinets. The main point of the article was that if you are painting
the finished product, there is no need to use anything but MDF. It
won't warp and is much cheaper then cabinet quality plywood. Not sure
why you would use MDO, unless you were building an outdoor cabinet.
Here in Hershey, PA, MDO goes for $75/sheet, compared to $20 for MDF.
Also, if you paint it according to another article FWW did, you can
acheive excellent results.

I have made floor to ceiling cabinets that are 4' wide on which I store
books and have not had a problem with sagging. Some of those are 3-4
years old. When I made those cabinets, I routed dados in both sides,
as well as reinforcing the front with a Face Frame through the midpoint
of the shelf. On the back I used a backer board and some L brackets at
the midpoints, to provide additional support, but also to secure the
cabinet to the walls. MDF will sag over a 5' length if not supported
properly, but most hardwoods also will, just not to the same extent
that MDF will.

You could always make the carcase out of MDF and choose another
material for the shelf. The end result is using MDF will save you
$$$$$.


Good Luck,

Chuck

"Woodchuck34" wrote in message
ups.com...
Duke,

Fine Woodworking Magzine recently published an article about painted
cabinets. The main point of the article was that if you are painting
the finished product, there is no need to use anything but MDF. It
won't warp and is much cheaper then cabinet quality plywood. Not sure
why you would use MDO, unless you were building an outdoor cabinet.
Here in Hershey, PA, MDO goes for $75/sheet, compared to $20 for MDF.
Also, if you paint it according to another article FWW did, you can
acheive excellent results.

I'll check this out; do you remember the issue number by chance?

Not having worked with MDF, what is the appropriate joinery method for
constructing a carcase made from one? Are you saying to use a standard
shelf edge of solid wood on the MDF edges?

Cheers!
Duke

"Woodchuck34" wrote in message
ups.com...
Duke,

Fine Woodworking Magzine recently published an article about painted
cabinets. The main point of the article was that if you are painting
the finished product, there is no need to use anything but MDF. It
won't warp and is much cheaper then cabinet quality plywood. Not sure
why you would use MDO, unless you were building an outdoor cabinet.
Here in Hershey, PA, MDO goes for $75/sheet, compared to $20 for MDF.
Also, if you paint it according to another article FWW did, you can
acheive excellent results.

Well, he's building for someone, which means they're paying the bills.

Second, check the sagulator referenced above.

Third, good plywood joints like combination joints are _much_ stronger than
the same in MDO.

Lot of benefit for small cost?

Current issue

Duke,

It was only 3 or 4 issues ago. The cabinets I made are completely
manufactured with MDF. It sounded like you wanted to use a hardwood
shelf. I suggested you could make the carcase out of MDF and just
construct the actual shelf piece out of hardwood.

On any edges of MDF that have been cut or routed, I apply a thin coat
of spackle, lightly sand, and use an oil base primer before applying
the final coat. Once again, this is outlined in the FWW article.

The only joinery method I use is dados with regular woodworkers glue.
Sometime I uses "a couple of brads", but I just started trying dowels
based on another article I read. Prevents any splitting.

Chuck

Duke,

I just checked FWW's index and can't find the issue. When I get home
tonight, I'll pull it out and post the #.

Chuck

Yeah, but he's building for a friend vs. a "For Profit". Maybe they'd
like to save some money.

Chuck

"Dukester" wrote in message . ..
| Looking at building a hutch for a friend that wishes it to be around 6' high
| by 5' long & probably 2' deep. She wants to paint the piece, so question 1)
| is cabinet grade plywood what I want to use regardless of finish?
|
| The shelves on the top of the hutch are to span the entire 5' width without
| breaks. They will be approximately 5' x 20". Assuming I use a lipped edge
| of solid wood to cover the edge of 3/4" ply for shelves in the front,
| (question 2) will the shelves need reinforcement at that length & width?
| They will probably be holding china, bowls, dishes, etc. and lots of them.
| I've never used plywood for shelves in that length and am concerned they
| will sag. What are my options?
|
| Cheers!
| Duke
|
|

If it is to be painted MDF is the way to go. A waste of money buying ply unless you are really after strength. I doubt you will be able to do the 5' without some kind of centre support. You might want to make the centre support a "selling" point.

A few facts on sag:

1. Typical shelves vary from 8" to 12" deep
2a. 3/4" Solid Wood has a maximum span of 36" before it starts to sag
2b. 1 1/16" solid wood has a maximum span of 48"
3. Veneer Core ply is the same span as solid wood cited in (2)
4. MDF of the same thicknesses is 32" and 42" span respectively.

The following chart illustrates the weight required to make a 12"-wide shelf bend 1/4" across a 36" 3/4" thick span and a 48" 1 1/16" thick span.

Shelf Material -------- 36" Span -- 48" Span
a.. Yellow Poplar -------- 284 lbs ---- 117 lbs
b.. Hard Maple ----------- 313 --------- 232
c.. Red Oak --------------- 313 --------- 232
d.. Birch -------------------- 348 --------- 146
e.. MDF -------------------- 87 ----------- 38
f.. Birch Ven Core ply -- 129 --------- 54
g.. Birch Veneer MDF ---109 --------- 46
h.. MDF .05" Laminate -- 205 -------- 87
i.. MDF 1/8" wood lam ---- 79 ----------- 33
j.. MDF 3/4" wood lam --- 90 ------------ 38
The following illustrates the weight required to make a 12"-wide shelf bend 1/4" across a 36" span and a 48" span for a manufactured shelf wherein there is a solid wood edge which is wider than the MDF material is thick (dropped edge) added to the shelf.

Shelf Material -- 36" Span -- 48" Span
a.. 3/4" x 1 1/2" ---- 241 lbs ---- 107 lbs
I hope all this bumph helps.

--
PDQ

"Woodchuck34" wrote in message
oups.com...
Duke,

It was only 3 or 4 issues ago. The cabinets I made are completely
manufactured with MDF. It sounded like you wanted to use a hardwood
shelf. I suggested you could make the carcase out of MDF and just
construct the actual shelf piece out of hardwood.

Thanks for this info and the rest of the posts on the sagulator. Another
(!) question on MDF fastening: attaching solid wood face frames - do you do
this the same way? Is glue & brads the best way on this?

Cheers!
Duke

Duke,

You can use normal methods. I know people use biscuits. I just glue
mine on and admit that I use "a couple of brads". When working with
MDF, you just have to be careful about the placement of the fastners.
Too close to the end of a board might split the MDF. Keep brads 2 - 3"
from the ends of any boards. Biscuit don't really cause this problem
since you are essentially routing out the exact size of the biscuit.

I also actually have heard of people the make MDF cabinets with
construction adhesive, but I haven't tried that myself.

Chuck

"Dukester" wrote in message =
. ..
| Looking at building a hutch for a friend that wishes it to be around =
6' high=20
| by 5' long & probably 2' deep. She wants to paint the piece, so =
question 1)=20
| is cabinet grade plywood what I want to use regardless of finish?
|=20
| The shelves on the top of the hutch are to span the entire 5' width =
without=20
| breaks. They will be approximately 5' x 20". Assuming I use a lipped =
edge=20
| of solid wood to cover the edge of 3/4" ply for shelves in the front,=20
| (question 2) will the shelves need reinforcement at that length & =
width?=20
| They will probably be holding china, bowls, dishes, etc. and lots of =
them.=20
| I've never used plywood for shelves in that length and am concerned =
they=20
| will sag. What are my options?
|=20
| Cheers!
| Duke=20
|=20
|=20

I forgot myself earlier and sent this in HTML, so, here it is again. As =
long as you put a dropped edge on your shelves, MDF seems the material =
of choice for your hutch. Given the 5' span envisioned, it seems a =
mid-span support is the best bet as this approach will afford the most =
capacity. You might have to use this idea as a selling point. It can =
be quite an accent to the shelf. Be sure to include a "plate groove" on =
the shelf in case your friend wants to stand some of the plates up.=20

Extracted by "Popular Woodworking" from the "Architectural Woodwork =
Institute" for their "Winter of 2000" edition.

In general here are the guidelines for how long a shelf can be before it =
starts to sag:

Material ------------- Maximum Span 3/4" Thick ------ Maximum Span 1 =
1/6" Thick
Solid Wood -------- 36" ------------------------------------- 48"=20
Veneer Core Ply - 36" ------------------------------------- 48"
MDF ----------------- 32" ------------------------------------- 42"

The following illustrates how much weight it takes to make a 12" wide =
shelf bend 1/4" across a span.

3/4" Thick Material ------------- 36" Span ------ 48" Span
Yellow Poplar -------------------- 284 lbs. -------- 117 lbs.
Hard Maple & Red Oak ------ 313 -------------- 232
Birch ------------------------------- 348 -------------- 146
MDF ------------------------------- 87 ---------------- 38
Birch Veneer-Core Ply ------- 129 -------------- 54
Birch Veneer MDF ------------ 109 -------------- 46
MDF .05" thick Laminate ---- 205 -------------- 87=20
MDF 1/8" wood edge --------- 79 --------------- 33
MDF 3/4" wood edge --------- 90 --------------- 38
MDF 3/4"x1 1/2" wood=20
edge, dropped ----------------- 241 -------------- 107

Hope all this bumph helps.

--=20
PDQ

On 15 Jun 2005 12:45:28 -0700, "Woodchuck34"
wrote:

Duke,

You can use normal methods. I know people use biscuits. I just glue
mine on and admit that I use "a couple of brads". When working with
MDF, you just have to be careful about the placement of the fastners.
Too close to the end of a board might split the MDF. Keep brads 2 - 3"
from the ends of any boards. Biscuit don't really cause this problem
since you are essentially routing out the exact size of the biscuit.

If for some reason you're using screws (and it's certainly possible,
it's MDF, not expensive cherry ply) it's not a bad idea to drill out
a hole a little way from the edge you're screwing into and plug it
with a hardwood dowel, and then drill some pilot holes for the screws
from the edge into the dowel. That way your screws have something
tangible to bite into (MDF will just strip out). Used that method for
lag screws going into 2x4 end grain on my router table, and it worked
great.

I also actually have heard of people the make MDF cabinets with
construction adhesive, but I haven't tried that myself.

Chuck

If for some reason you're using screws (and it's certainly possible,
it's MDF, not expensive cherry ply) it's not a bad idea to drill out
a hole a little way from the edge you're screwing into and plug it
with a hardwood dowel, and then drill some pilot holes for the screws
from the edge into the dowel. That way your screws have something
tangible to bite into (MDF will just strip out). Used that method for
lag screws going into 2x4 end grain on my router table, and it worked
great.

MDF? Nasty stuff; I work with it all too often, particularly for shelving,
etc. in cabinetry with a nice timber faceplate. Occasionally I've made
entire cabinets solely from 18mm for cheap housing projects. I wouldn't use
it on anything I plan to keep for myself...

There're dedicated screws for use with MDF which use a coarser thread than
the norm, this helps improve the grip and prevent tearout. I recommend
these, although I haven't tried the dowelling method. IMHO biscuits aren't
suitable for edge joiunting as MDF has little lateral strength and tends to
split with very little help. Not good for kiddies toy-boxes, for example.

Two tips: ANY time screws are used with MDF a pilot hole should be used,
especially for edge-screwing.
and: Always use a dust mask! It really is 'orrible, 'orrible
stuff...

- Andy