wood warpping after thinning

[twodoctors]

Hi all,

I made a pistol grip for my pistol (obviously) from a 20mm thick piece of Cherry. I was using it with the grain running parallel to the grip itself. Most part of the grip has been filed down to about 8mm to make a ergonomic grip (with some bits that remains 20mm for contouring). There are a few sections where I needed to file the wood down to 2mm, at one "corner section" of the grip, and it's this part that is now warping/curling outwards away from the frame. The piece I used was flat to start wtih.

I suspect the warping is because I've filed it down to quite thin and the wood may well have been stressed before. The grip is otherwise very good but I am looking into making a "harlequin" version using a glued boards of different wood. Am I likely to encounter similar problem or would the glue help with keeping the wood straight?

Haven't got pic of the defect but this is the grip. Area of defect circled.

Thanks.

Adrian

 

[ED65]

Nice grip Adrian. From the grain it doesn't look like there was stress there but I don't think you can tell for sure, and this sort of thing can happen anyway when you thin wood that much. Don't know if it's a factor here but many makers say that problems like this are more likely when the wood isn't as dry as it could have been.

 

[twodoctors]

I wouldn't know how dry it was to start with... Just bought it from a mill that sells "exotic" wood.

I had a lot of problem with previous attempts using oak bought from B&Q (before learning about local wood mills) but was told by my wood guy that they are over-kilned and are too dry. They do chip an break quite easily when I get to the thinner sections, but that could be the nature of oak (I don't know as I've only got back to woodworking for a few weeks after a 25+ years absence).

I'm guessing making my "harlequin" grip using thinner sections may be the answer... as least the thinner and narrower sections will declare itself as straight/warp, and the glue might help. Or am I wrong?

Adrian

 

[sunnybob]

Adrian, whats the gun?
i used to have many pistols untill the 97 fiasco. I'm well out of touch now.

 

[twodoctors]

It's a Browning Buckmark. I've only started about 2 years ago... pistols are all long-barrel-ed now. The law says 12" minimum barrel and overall length of 24", so most guns would have a "coat hanger" at the grip end extending backwards to make it 24" overall. This obviously makes it unbalanced so I suspect not as much fun to shoot.

Mine is quite modified so you may not recognise it immediately...

Adrian

 

[sunnybob]

I would have got it with a full picture. I knew several people who shot the original pistol.
I tried to get on with the new "rifle" sized guns but lost all the enthusiasm.
i just have a shotgun now, thats all that you are allowed in Cyprus (apart from 177 air rifles)

 

[CHJ]

I would suggest a couple of things to try with another attempt.

Take note of growth ring pattern in the end grain.
Whilst conditioning (drying) it in house or workshop note if it is cupping at all.

Take note of this direction and make your side cheeks/grips with this hollow side towards the inner face.

Partially rough sculpt the side cheeks and let acclimatise for a few days/weeks to see if it starts to cup further.

 

[AJB Temple]

A few thoughts:

Luthiers frequently bake wood (before final work is done) to achieve more predictable behaviour. I may be able to find an article on this. Thin stuff does not necessarily need to warp but you do need to get it stabilised before final shaping. It took me ages to learn how to deal with this effectively.
Wood used for gun stocks has a hard life and I know some stock makers also bake the wood and use deep impregnation finishes. Certainly shotguns get used in the rain, are handled with wet hands and go from hot cars to freezing moors.
I know nothing about pistols but sweaty hands may well add a periodic moisture hit.

 

[iNewbie]

A few thoughts:

Luthiers frequently bake wood (before final work is done) to achieve more predictable behaviour. I may be able to find an article on this. Thin stuff does not necessarily need to warp but you do need to get it stabilised before final shaping. It took me ages to learn how to deal with this effectively.
Wood used for gun stocks has a hard life and I know some stock makers also bake the wood and use deep impregnation finishes. Certainly shotguns get used in the rain, are handled with wet hands and go from hot cars to freezing moors.
I know nothing about pistols but sweaty hands may well add a periodic moisture hit.

Yeah, they call it under different names. Caramelised/baked etc,.....its Thermo-treated..... originally from Scandinavia iirc.

There was one musical instrument manufacturer (forget his name) who used a Microwave for small sized pieces!

 

[twodoctors]

Here are more photos.

The sculpting process took bloody ages until I bought the powerfile, but it was very dusty.

I wonder whether it's going to be better if I glue 2cm strips together to for a block? Likely to bow/cup? if I do that?

Adrian

PS How would I bake the wood before working on it? Would I then need to buy a moisture meter? :-O

 

[sunnybob]

Thats good carving. I've seen professional ones that didnt look that good. Once you get over the problems I suspect you'll start getting orders.

 

[iNewbie]

PS How would I bake the wood before working on it? Would I then need to buy a moisture meter? :-O

You'd buy it from a supplier - more wood types have become available because luthiers require it. There are some guys who have thrown Maple body blanks into their own ovens and baked it - I'm not recommending it! The process itself is a bit more complicated than that. Just google Thermo treated wood/lumber/timber, etc.

 

[AJB Temple]

I do actually bake mine in the domestic oven at home. I use the process for guitar parts and knife scales.

 

[novocaine]

I think you've fallen foul of not reading the grain twodocs. we've all done it. as said above, look at the end grain, it will give you an indication of cupping i.e. lots of complete rings will want it to cup away (up in the picture above), fewer complete rings should be stable and multiples either side is a real issue as you've got a magic tree.

in truth you could have been lucky and flipped it over at which point you'd have never known about it. **** happens.

laminated grips will fair far better as you change the grain direction between plys.

oh and cracking job. I'm partial to a larger heel myself for resting my little pinky on. but each to their own when it comes to holds. get on with the laminate, they always look wonderful (even Anschutz with their silly 20 colour stocks )

 

[Racers]

You could try steaming/heating it and clamping it straight, or possibly a bit to far encase it springs back.
I have seen a video of gunstock bending where they pored hot linseed oil over it to heat it, not recommended!


Pete

 

[twodoctors]

Thanks for all the replies.

I did "read the grain" novocaine... it looked lovely that's why I chose that part of the board. Hahaha!

Seriously though I think you are probably right. I was trying to get as much grain as I can on the grip, but forgot about the risk of bowing. Lesson learned.

I don't think it will steam anymore though. I've shellac-ed it already.

Next grip will be a harlequin one.... planning on making a cross with tenon joint using thinner wood (6mm) and put a block of something in each sections. I'll be testing this concept with on a bandsaw box first. :-D

Adrian