Woodworking Talk banner

1 - 19 of 19 Posts

·
Registered
Joined
·
47 Posts
Discussion Starter #1
Can you seal ... say a 2x10x8' when you first buy it with some product - so that it does not expand and contract? i've seen some weird stuff with filling the grains with various chemicals..

but I was wondering what this process might be... and it it's possible. too many table tops moving around.. just interested. all info appreciated.

J
 

·
Registered
Joined
·
26,869 Posts
The only way you could seal it is in a vacuum chamber and remove all the air. If you want to use the board then no there is nothing. Wood movement is something we all must suffer with.
 

·
Registered
Joined
·
620 Posts
Theoretically maybe: practically, no.

I've read a few articles on heating wood until the internal temp goes over 400F, which "carmelizes" the lignin resulting in a dimensionally stable wood that is extremely rot resistant. There were some commercial attempts to market the wood as decking. But since it costs out at more than Ipe, and is actually harder to work, it never got any traction.
 

·
bzguy
Joined
·
581 Posts
I've never tried it but supposedly PEG treated green wood remains stable.
The plastic "polyethylene glycol" replaces the water in the cells so it cannot shrink.
 

·
Old School
Joined
·
24,017 Posts
Can you seal ... say a 2x10x8' when you first buy it with some product - so that it does not expand and contract? i've seen some weird stuff with filling the grains with various chemicals..

but I was wondering what this process might be... and it it's possible. too many table tops moving around.. just interested. all info appreciated.

J
Not as a deterrent to movement issues in preparation for using in a project. You could totally encase the lumber in a pour on epoxy, and hope that it's proclivity to E&C is restrained.




.

 

·
Banned
Joined
·
382 Posts
As others have said, from a practical standpoint, no you can't eliminate wood movement. There's nothing I can think of that is 100% impermeable to water. By the time you do make the wood completely waterproof, you've spent so much money and effort that it's not just not worth it anymore. Solid wood table tops move, plain and simple.

The only thing I can think of that gets you close is plywood. It is mostly dimensionally stable (not 100%, but darn close) and put a nice veneer on it to give it the illusion of a solid wood item and have it be effectively dimensionally stable. Nature only made trees that moved, so all of our wood moves.
 

·
Registered
Joined
·
1,151 Posts
There are resins that can be impregnated into wood under vacuum and heat. Knife makers send their handles out to pro's for this treatment. Not really practical for large pieces.
 

·
where's my table saw?
Joined
·
28,579 Posts
stabilizing wood part 1 and 2

Can also be done with larger pieces in a vacuum bag.... 0:32 sec in part 2

 

·
bzguy
Joined
·
581 Posts
I first read about PEG treatment 30 years ago.
It is time consuming and tedious, but leaves me very curious, I am wondering if anyone on this forum has any experience?
It sounds iseal to me if it does work because it treats and stabilizes "green" wood before it warps and checks.
Sounds like and ideal material to work with, stable, no voids, like Corian but more unique and beautiful.
 

·
Registered
Joined
·
25 Posts
Not possible; I tried to fit together pieces of different wood types to make a gigant puzzle with many natural colors... And it was a disaster, every type of wood had a different reaction to the temperature and in the end you could see the lines between the pieces =(
 

·
Registered
Joined
·
91 Posts
Can you seal ... say a 2x10x8' when you first buy it with some product - so that it does not expand and contract? i've seen some weird stuff with filling the grains with various chemicals..

but I was wondering what this process might be... and it it's possible. too many table tops moving around.. just interested. all info appreciated.

J
I bet penetrating epoxy would work, but I don't know how well it would penetrate a 2x10.
 

·
Registered
Joined
·
1,160 Posts
I believe "penetrating epoxy" is used on rotted wood. It penetrates that but I don't believe it will penetrate "healthy" wood. Might want to call West Systems and ask them.
 

·
Registered
Joined
·
110 Posts
In wood boat repair and restoration, the most popular sealer epoxy is called "CPES" (Clear penetrating Epoxy Sealer) made by Smiths. It's specifically made to penetrate deeply into the wood. Its mostly to prevent rot by encasing any mold spores present. Here is a link:

http://www.smithandcompany.org/CPES/

HOWEVER, if you read the page, the CPES protects the wood "while allowing normal expansion and contraction". In other words, the wood will still expand and contract with temperature and humidity.

In boat restoration, its generally considered bad to encase wood in "hard" epoxy because this will constrain the outside from moving but generate a lot of internal stress. Eventually a small defect will appear in the epoxy coating and moisture will permeate into the wood and its all downhill from there. Maybe on a table top which is in a stable temp and humidity and doesn't have the twisting and bending forces on it like a boat hull or structure it might work better, but I would be cautious.

Steve
 

·
Registered
Joined
·
236 Posts
I'm currently replacing wood/carpet in my fishing boat and it is a tedious project. I'm sealing the marine ply with "Seal-Once". Good stuff and a pleasure to work with. Topping off with DAP Weldwood Marine carpet glue. It is waterproof, not just water resistant.
 

·
Master firewood maker
Joined
·
1,973 Posts
It is probably also related to the way that there is air "trapped" (if you will) in the wood, and when the environment is warmer the air expands, just like it does everywhere else. This expansion makes the wood swell. When it cools, the air contracts, and the wood goes back to its other state.

So unless you can do something to get all the trapped air out of the wood, just sealing the outside won't affect the expanding and contracting nature of the wood.
 

·
Registered
Joined
·
2,763 Posts
There are very effective processes that wood anatomy researcher use. I have done dozens in my grad school days. Not a single process is useful for furniture service because to work properly, the wood blocks have to be 1/2" cubes or less.

If I got all hot and steamy to build a table. Relief cuts for the drying stresses and movement like in totem, mortuary and story pole. Sliding joints. If movement is inevitable, let 'er rip!
 

·
Registered
Joined
·
47 Posts
Discussion Starter #17
well I have been working on these benches. the stand of the bench is awesome - the top comprises of two 2x6x6's. I screw them down with 4 long screws from the top - plug the holes - stain and apply 6 coats of Spar urethane. They stay in my garage during this process. After one week - there is a 1/4" gap between the two boards - where before they were touching.

Any ideas on how to avoid - adjust for this?
J
 

·
Registered
Joined
·
2,763 Posts
I was really desperate for a really bash-worthy "work bench." Anything at all. It was winter. I bought a bunch of frozen 2x6. Kiln dried SPF construction lumber here is 22%MC.
Got it done, 8' long, and the top boards shrank, of course. No. Big. Deal.
I filled all the cracks with 2 loads of white bathtub silicone. Got 'er done and nobody cares.
At least, there's no constant rain of sawdust on the stored goods on the shelf below.
 
1 - 19 of 19 Posts
Top