Warping

[w.2014.h]

I am having a large problem with my finished Intarsia projects warping. I use kiln dried wood, seal the project with Deft poly and use 1/8 in plywood for a backboard. When I look at my older projects, they are not warped and I used 1/4 in plywood. So is 1/8 plywood to thin to support an Intarsia project?

[DWSudekum]

The problem with kiln dried wood is it generally is between 6 - 9% moisture which in this area is pretty dry so it will attempt to regain moisture and warp when it does. The thicker plywood would resist warpage as there are more plys that are cross ways to each other and that fights the warpage. You may want to seal the backboard before you put the intarsia on it that might stop the warpage issue.

DW

[Janette]

Do you edge glue your pieces together before gluing to the backing? I live in Oregon where it's really damp and have never had an issue.

[w.2014.h]

I do edge glue the pieces.

[workin for wood]

I think if it's gonna warp it's gonna warp regardless how thick the backer is because wood movement is based on water coming and going and you can equate that to the power of ice in the winter..if water is in a steel pipe and water freezes it breaks that super strong pipe. No doubt the environment is the largest factor, and how you store your wood is another. If your wood is in a shop or garage then the air moisture content will be different than in a house and if the wood is on the floor or close to the floor that will add even more moisture to your wood. It be kiln dried to say 7% but then goes on a truck and sits in a building and then in your truck and your shop and is likely not 7% anymore, more likely over 10. It's not feasible, but the only way to guarantee true stability of your wood is to store it in your living area, as it will acclimate to that environment and as long as it's always there will stay the same. I too have had intarsias warp on me over time. I have found that as I make pieces smaller and smaller, the odds decrease for warping and it's likely due to smaller pieces of wood will have less movement. Pictures I create during the winter time also tend to be more stable. I do edge glue my pieces together and I don't think edge gluing has any effect on stability as the wood glue is flexible so it can expand and contract with wood movement to a point of course. I'd say that warping is the nature of the beast when you work with wood you can never be sure what will happen and certainly can't guarantee it's future. I'm pretty happy that I've only lost one major piece due to warping and the few others that have done so where not so special and I just give those away to family.

[w.2014.h]

Thank you. I think I understand the problem at hand and I'll just have to live with it I guess

[tgiro]

I have been using 1/8th masonite board (sometime called melamine) for a backer board. I try to get the kind with both sides finished. If I can't, I spray the back of the board with some poly to seal it.

I also coat each piece, on all sides, at least once, before gluing them together or to the backer board. Before gluing to the backer board, I rub the back of each piece across some 220 grit paper to set a glue surface. Don't rub real hard, just enough to cut through any finish that me be on the back of the piece.

When I did my first Grizzly Walk project, from JGR, the aspen plywood warped, even after coating both sides. For the second one - I laminated some 1/8th masonite to the back of the plywood and that one hasn't warped at all.

Tony