"Pressure Backing"

[Dave]

Has anyone found a good acceptable way to have a slight inward pressure on a backing board so as to apply a bit of pressure to the center of a framed work?

I have cross hatched polyflute board to have a two dimenssionally stable backer and DiBond, though somewhat expensive, is also usable in that manner, but sometimes I'd like to have a bit more center pressure to hold a mat firmer against a watercolor, for example. Using either one with a 4 ply board smaller than the overall backing board could possibly do it... Mm-mm.

Mounting on one side of foam core can cause a bow which would cause inward pressure, but I would think, over time, that would be reduced or eliminated.

Other thoughts?

 

[Artistic Framer]

Back in my cold mounting days, I would countermount with a watered down gesso "X" (corner to corner...maybe 2" brush) on the back of the foamboard.

 

[Dave]

Interesting... so that worked pretty well?

 

[Artistic Framer]

Interesting... so that worked pretty well?

It did. Just do some experimenting first. I would water to a cream consistency using Utrecht standard gesso.

 

[Rick Granick]

What about gluing a piece of 4-ply or 1/8" FC (somewhat smaller than the overall size) in the center of your FC backing before fitting?
:kaffeetrinker_2: Rick

 

[GUMBY GCF]

dave
this may sound like it will relax later but it does not.
Take your spray bottle. Spray back of foamcore. Then take an iron to it until dry and bowed. It will not relax later...promise..
I have done this for years. Just took one apart I did 15 years ago it still had the bow in it.

 

[Dave]

Thanks!

Lots of great input. I'll do some experimenting.

 

[CB Art & Framing]

If the back of the frame has enough depth, how about a strainer or even just one strip of wood down center.

 

[Prospero]

Once upon a time I would take the dropout from the mat window and tape it to the back of the undermount. Carefully aligned so that it is in register with the hole it came out of.
Clipping an inch or so off the corners makes it sit better so the backboard is slightly bowed out and therefore applies a gentle pressure to the edges of the mat.
I say "Once upon a time" as I haven't done this for ages. But it does work.