Stabilizing long piece of wood

H

hawkwind

Joined
Oct 26, 2004
Messages
298
Hi folks!

I m bowmaker by trade, I only make knives as a hobby. Here is my problem - I come across piece of yew here and there. This wood became scarce and the price went up 250% in last 5 years.
Local yew is very inconsistent quality and not very good for bowmaking.

Only idea which occured to me was to stabilize whole piece. My thinking is to hack basic bow shape and before tiler (that is actually wood removal to make it bend evenly) stabilize.

It is say 1 1/2´´ X 1´´ of wood which is porous like pine. But I need to stabilize whole lenght at once! Which means 78´´ long piece of wood!

Now - those knowledgeable if you could help me.

How good vacuum one need to stabilize wood.
Which epoxy or resin use to get best mechanical properties?
How thick the resin?
Any info on proces as such?

I have been thinking about using long plastic pipe as container, but that depends on how good vacuum is needed.

Its bit cheating to improve wood this way, but I dont care in case of yew!


Thanks all for help.

Jaroslav in Czech republic
 
Hello Hawkwind,

I think this sounds like and interesting project. I have made a few selfbows, however, none out of yew. From what I remember reading about yew it needs to be from higher elevations to make a good bow. I think the higher elevations make the wood denser and for yew this helps with compression on the belly of the bow. If you stabilize the wood with vacuum you are essentially pulling the stabilizing material into voids in the wood through out the piece. In other words this is not a surface treatment to the wood. Since the stabilizing fluid penetrates the wood completely I would be concerned about changing the other properties of the wood such as how it performs in tension and loss of cast due to the wood being heavier from the stabilizing. Having said that, give it a try and post your results, I’d be interested in hearing how it turns out.

Good Luck,

Mark
 
Mark I actually use exotic very heavy and dense woods mostly such as IPE, or Buletwood. These have SG over 1.0 - 1.2 and dont float.

But yew....is yew... this is not yew country, not anymore.. Yew which I get is mostly park grown stuff and it has "gingerbread structure".

I dont mind adjusting tips and tiler if the wood gets more heavy, thats not a big deal.

Jaroslav
 
I use a Foodsaver Vacuum bagger top vacuum bag pieces of homemade micarta. I got the idea from people that use them to make model planes. They vacumm bag whole wings and often times the wings they do are really, really big. Maybe try to find a used Foodsaver or one of the cheap knockoff brands or there are plans for building vaccum pumps out of old refrigerator compressors out on the internet. No idea what would be best to try and stabalize with. Hope that helps.
 
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