Anyone got much experience of kerfing a board so it bends?

147 x 28 redwood. I'm looking at an inwards bend - concave?

I'm wondering what kind of radius you can get?

Any info/tips appreciated.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

The Medway Handyman wrote:
Anyone got much experience of kerfing a board so it bends?

147 x 28 redwood. I'm looking at an inwards bend - concave?

I'm wondering what kind of radius you can get?

Any info/tips appreciated.


soak it in ammonia for a few days. It will bend like blotting paper.

Nail up while still floppy.

The Natural Philosopher wrote:
The Medway Handyman wrote:
Anyone got much experience of kerfing a board so it bends?

147 x 28 redwood. I'm looking at an inwards bend - concave?

I'm wondering what kind of radius you can get?

Any info/tips appreciated.


soak it in ammonia for a few days. It will bend like blotting paper.


And be about as much use I expect.

On Fri, 27 Feb 2009 16:55:05 +0000, The Medway Handyman wrote:

Anyone got much experience of kerfing a board so it bends?

147 x 28 redwood. I'm looking at an inwards bend - concave?

I'm wondering what kind of radius you can get?

Any info/tips appreciated.

=========================================

Plenty of cuts (1" intervals if you've got the patience)on the outer face
to go into a bay or similar as a skirting. Use a fine tenon saw and cut to
a depth of approximately 3/4 of thickness of board. Support the board well
if it's a long board when you come to place it in position.

As a general indicator my bay is about 12' wide and the segment is about
30" deep at its centre. It helps if you can do the job (if it's a bay) in
two parts because you can get the correct outer angle where it meets the
other skirting and you can adjust the length of the second piece by
checking how much the first piece covers.

Cic.

--
==========================================
Using Ubuntu Linux
Windows shown the door
==========================================

On 27 Feb, 16:55, "The Medway Handyman"
wrote:
Anyone got much experience of kerfing a board so it bends?

147 x 28 redwood. *I'm looking at an inwards bend - concave?

I'm wondering what kind of radius you can get?

Any info/tips appreciated.

--
Dave - The Medway Handymanwww.medwayhandyman.co.uk

Ever tried steaming? No need to make all those cuts.

On Fri, 27 Feb 2009 11:44:20 -0800 (PST), gunsmith
wrote:

On 27 Feb, 16:55, "The Medway Handyman"
wrote:
Anyone got much experience of kerfing a board so it bends?

147 x 28 redwood. =A0I'm looking at an inwards bend - concave?

I'm wondering what kind of radius you can get?

Any info/tips appreciated.

--
Dave - The Medway Handymanwww.medwayhandyman.co.uk

Ever tried steaming? No need to make all those cuts.

Yes I was very successful when I steamed some 12" old oak floorboards
using a wallpaper stripper, then screwed them into position
immediately. Definitely worth trying before you start to make cuts in
the wood

Anna

Anna Kettle wrote:
On Fri, 27 Feb 2009 11:44:20 -0800 (PST), gunsmith
wrote:

On 27 Feb, 16:55, "The Medway Handyman"
wrote:
Anyone got much experience of kerfing a board so it bends?

147 x 28 redwood. =A0I'm looking at an inwards bend - concave?

I'm wondering what kind of radius you can get?

Any info/tips appreciated.

--
Dave - The Medway Handymanwww.medwayhandyman.co.uk

Ever tried steaming? No need to make all those cuts.

Yes I was very successful when I steamed some 12" old oak floorboards
using a wallpaper stripper, then screwed them into position
immediately. Definitely worth trying before you start to make cuts in
the wood


Did you enclose them in something to retain the steam?


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

On 27 Feb, 19:44, gunsmith wrote:
On 27 Feb, 16:55, "The Medway Handyman"

wrote:
Anyone got much experience of kerfing a board so it bends?

147 x 28 redwood. *I'm looking at an inwards bend - concave?

I'm wondering what kind of radius you can get?

Any info/tips appreciated.

--
Dave - The Medway Handymanwww.medwayhandyman.co.uk

Ever tried steaming? No need to make all those cuts.

Softwood doesn't generally steam-bend well.

For steam bending properly, you'd need to (a) build a box and (b)
substitute something like oak (which steam bends well). If you get
into extreme radiuses you need to strap the outside to stop the outer
cells exploding. In terms of what is possible, the tightest I've done
is about a 12" radius in ex 1" oak. That was without strapping, and
it wasn't the limit.

If you have the ability to buy, or tools to saw, thin slices,
lamination is simpler.

Kerfing will work,but only if only the face is visible (and it's
interior).

On Fri, 27 Feb 2009 22:52:13 GMT, "The Medway Handyman"
wrote:

Anna Kettle wrote:
On Fri, 27 Feb 2009 11:44:20 -0800 (PST), gunsmith
wrote:

Yes I was very successful when I steamed some 12" old oak floorboards
using a wallpaper stripper, then screwed them into position
immediately. Definitely worth trying before you start to make cuts in
the wood


Did you enclose them in something to retain the steam?

No just held the flat steamer end against the timber for a few minutes

Anna

The Medway Handyman wrote:

Anyone got much experience of kerfing a board so it bends?

147 x 28 redwood. I'm looking at an inwards bend - concave?

or convex if looking from the other side ;-)

I'm wondering what kind of radius you can get?

Probably about a 8" radius or perhaps a bit tighter. You can do a test
with a thin lath of the same stuff - see how much a bit a couple of mm
wide will bend.

Any info/tips appreciated.

Depends on exactly what you want to achieve. Steam can work if you make
up a steaming tube of some description - a length of soil pipe can work
well for smaller sizes. Laminating is another option.

An index peg mounted on a table saw can make it relatively easy. Cut the
first kerf against the peg, then the next by running the peg in the
first kerf and so on.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Feb 28, 5:52*am, "The Medway Handyman"
wrote:
Did you enclose them in something to retain the steam?

I've steamed softwood torus skirtings to fit curved walls by putting
them inside a poly tube made from a couple of builders bags (folded
and stapled together).

--
Nige Danton

John Rumm wrote:
The Medway Handyman wrote:

Anyone got much experience of kerfing a board so it bends?

147 x 28 redwood. I'm looking at an inwards bend - concave?

or convex if looking from the other side ;-)

I'm wondering what kind of radius you can get?

Probably about a 8" radius or perhaps a bit tighter. You can do a test
with a thin lath of the same stuff - see how much a bit a couple of mm
wide will bend.

Any info/tips appreciated.

Depends on exactly what you want to achieve. Steam can work if you make
up a steaming tube of some description - a length of soil pipe can work
well for smaller sizes. Laminating is another option.

An index peg mounted on a table saw can make it relatively easy. Cut the
first kerf against the peg, then the next by running the peg in the
first kerf and so on.


Assuming you have a fine blade. TCT blades are a bit wide I would have
thought.

Stuart Noble wrote:
The Natural Philosopher wrote:
The Medway Handyman wrote:
Anyone got much experience of kerfing a board so it bends?

147 x 28 redwood. I'm looking at an inwards bend - concave?

I'm wondering what kind of radius you can get?

Any info/tips appreciated.


soak it in ammonia for a few days. It will bend like blotting paper.


And be about as much use I expect.
Nope. After it dries it will be perfectly woodlike, and retain its shape
forever.

That's how they make curved chair backs..

The Natural Philosopher wrote:
Stuart Noble wrote:
The Natural Philosopher wrote:
The Medway Handyman wrote:
Anyone got much experience of kerfing a board so it bends?

147 x 28 redwood. I'm looking at an inwards bend - concave?

I'm wondering what kind of radius you can get?

Any info/tips appreciated.


soak it in ammonia for a few days. It will bend like blotting paper.


And be about as much use I expect.
Nope. After it dries it will be perfectly woodlike, and retain its shape
forever.

That's how they make curved chair backs..

Yes, you're right. Not the easiest stuff to work with on a d-i-y basis
though

"The Medway Handyman" wrote in message
.. .
Anyone got much experience of kerfing a board so it bends?

147 x 28 redwood. I'm looking at an inwards bend - concave?

I'm wondering what kind of radius you can get?

Any info/tips appreciated.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

The joinery firm who made the double bull nose step for my stairs used the
thickness of the table saw blade, and 2/3 rd depth of the wood..

The distance apart will depend on bend radius ... sides of the kerf
obviously must not meet.

Looks to be about 150mm radius.


The other way is to steam it ...

"The Medway Handyman" wrote in message
.. .
Anna Kettle wrote:
On Fri, 27 Feb 2009 11:44:20 -0800 (PST), gunsmith
wrote:

On 27 Feb, 16:55, "The Medway Handyman"
wrote:
Anyone got much experience of kerfing a board so it bends?

147 x 28 redwood. =A0I'm looking at an inwards bend - concave?

I'm wondering what kind of radius you can get?

Any info/tips appreciated.

--
Dave - The Medway Handymanwww.medwayhandyman.co.uk

Ever tried steaming? No need to make all those cuts.

Yes I was very successful when I steamed some 12" old oak floorboards
using a wallpaper stripper, then screwed them into position
immediately. Definitely worth trying before you start to make cuts in
the wood


Did you enclose them in something to retain the steam?


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk



I steamed some supports for a boat hull repair .... improvised a steam box
using a length of drain pipe blocked end to get a bit of steam build up.
Plenty of articles on line about steaming.


BTW ... other way to do a curve is simply laminate up ... using multiple
thin strips, glue and clamp around a former ..... often used for stairs.

On Fri, 27 Feb 2009 16:55:05 GMT, "The Medway Handyman"
wrote:

Anyone got much experience of kerfing a board so it bends?

147 x 28 redwood. I'm looking at an inwards bend - concave?

I'm wondering what kind of radius you can get?

Any info/tips appreciated.

http://www.shopsmith.com/academy/tblsaw_specialops/

gives formulae and advice...

--
Frank Erskine

On 27 Feb, 17:52, The Natural Philosopher wrote:

soak it in ammonia for a few days. It will bend like blotting paper.

********. If you're into doing this industrially, you're working with
anhydrous ammonia and that's evil stuff. You can't just "soak" it in a
bit of .880. It will also turn any hardwood timber with tannins in it
to black.

On 27 Feb, 22:52, "The Medway Handyman"
wrote:

Did you enclose them in something to retain the steam?

Yellow plastic gaspipe is the best stuff. Flimsier plastic pipe does
at a pinch.

Don't use any sort of iron (esp. wwith oak!) or you'll get staining.


What are you making, and what sort of bend do you need? If this is
"wide", then kerfing is the way to go (I've mostly done it in MDF or
ply). If it's chair backs, then steam. Steaming also needs hardwoods
to work easily, and green ones at that - resinous softwoods are a
sod.

For kerfing, go with "50:50" cuts from your favourite circular saw,
leaving the min thickness at least 2 kerf widths thick, otherwise it
tends to crimp.

Andy Dingley wrote:
On 27 Feb, 22:52, "The Medway Handyman"
wrote:

Did you enclose them in something to retain the steam?

Yellow plastic gaspipe is the best stuff. Flimsier plastic pipe does
at a pinch.

Don't use any sort of iron (esp. wwith oak!) or you'll get staining.


What are you making, and what sort of bend do you need? If this is
"wide", then kerfing is the way to go (I've mostly done it in MDF or
ply). If it's chair backs, then steam. Steaming also needs hardwoods
to work easily, and green ones at that - resinous softwoods are a
sod.

For kerfing, go with "50:50" cuts from your favourite circular saw,
leaving the min thickness at least 2 kerf widths thick, otherwise it
tends to crimp.

I'm thinking of kerfing a 147 x 28 deck board to follow the edge of a curved
deck, so I suppose wide would describe it. It would be concave looking at
the face (back won't be seen).


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk