Best material for resisting warp?

[Sean Rainaldi]

Of all the engineered – composite woods available, which one has the best dimensional stability as far as warp is concerned?


I'm building a jig for printmaking, out of a 20” x 28” piece, and need to keep warp down to a minimum; was wondering which composite material is best at resisting humidity changes and warpage?

[Jamie Buxton]

Resisting warp is best done with structure. For instance, if you make your jig a 6"-thick torsion box, it will not change shape after you build it. All the internal bracing ensures that it will not move.

Do you have some limit in the thickness direction?

[Sean Rainaldi]

I would like to keep it under two or three inches if possible, but if it goes thicker I can deal with it because I have an adjustable stool.

I will be using this as a jig on a tabletop to do drawing, stenciling, tracing on, and to properly register multiple printing plates (woodblocks) to drawings, stencils, photos and paper...

[John Coloccia]

I've personally had good luck with MDF but building a structure is better. I don't think I have one piece of plywood in my shop that has even started off straight, and it usually doesn't get better with time. The phenolic coated doesn't seem any better. I guess it depends on you're definition of straight :)

For some of my jigs where I need to machine the face (like some of my tapering jigs) and I don't really want make a mess chopping into MDF, I'll laminate a piece of MDF and plywood together, and then work the plywood. When I do this, I typically seal the back of the MDF as well so that it doesn't absorb moisture asymetrically. So if I laminate with epoxy on the front, I'll seal with a thin layer of epoxy on the back.

I don't know what you're jig looks like, but If you REALLY want it straight, I've had good luck going down to my local countertop manufacturer (the guy who actually cuts the stone, not the showroom dealer) and buying pieces of granite. They'll usually have a supply of offcuts that are completely worthless to them. Often times they'll be happy to cut it for you and will let you have it very cheap...basically you're paying for a couple of minutes of their time on the saw.

This is just my personal experience.

[Sean Rainaldi]

Hey I just had a thought how about building a wood frame and just pour some self leveling compound in it? The stuff they use for tile flooring?

Think it would get flat enough?

[Josiah Bartlett]

I would suggest using a thick piece of plate glass on top of a torsion box for a bench, or a granite machinist's bench for registering plates.