warped foamcore

A.Wise

CGF, Certified Grumble Framer
Joined
Jul 16, 2002
Posts
130
Loc
Wadsworth, Oh
Have a customer that wanted a bow flex poster mounted to foamcore to make it last longer. I cold pressed it and looked great. Now that he has been using it the foamcore is starting to warp. I put it back in the press but it is still warped. Any ideas on how to straighten it out. I thought about cold pressing another foam to the back of it. Do you think that will keep it from warping?
shrug.gif
 
No, but it will result in a much more determined warp.

The way to keep it from warping is to frame it.

Fomeboard is fairly stabile until you attach something to it. Then it tends to warp.

If the customer wanted to preserve it without framing, a double-side lamination would have been a good idea, but I think a bow flex poster is going to bow and flex no matter what you do to it.
 
Ron beat me to the bowing and flexing.

Nothing will keep it from bowing and warping better than actually putting a frame on it. Failing that, counter-mount it. Get some paper (anything) similar in weight to the poster and mount that to the back of the board. The expansion and contraction of both pieces of paper will mostly cancel each other out.

I've also mounted posters on foam board and attached stretcher bars to the back. Down and dirty, and serves to keep it on the wall a few months.


I was told that most photographers used to mount their photos to boards themselves just as a matter of course. Very often they would use prints that they were not happy with as the counter-mounted paper. So one can find a lot of old Ansel Adams or Avedon prints used just as "throwaways" on the back of their prints. Huh.
 
I have pine boards milled to size 1/2" x 1" x 10 feet knots are ok. I cut the "support" frame 2" smaller all around than the actual mounted piece then glue it to the foam in the back.
Example: if your poster is 18" x 24" cut the support frame to 14" x 20" (outside corners). If the poster is over 24 x 36 I add corner brace pieces for more support.
It's very cheap and easy and works like a charm. We have items in the shop that have been flat for over 20 years using this method. It also makes it easy to put a hanger with wire. We do this on a daily basis, customers love it.
Bill
 
we would have suggested - plak-it (we do this to a lot of workout posters for in-house gyms) or mount to gatorboard if they didn't want it to bow, otherwise framed to prevent bowing.

elaine
 
If a piece of paper, of the same weight as the
poster, is mounted to the other side of the board,
it should help to restore the stability of the
whole.

Hugh
 
I'll assume the bow is concave - as the art hangs, the middle touches the wall and the top and bottom or sides bend away from the wall. To prevent this in the first place, put the materials (art and foam - NOT the mount tissue) in a hot (180 degree F) vacuum press for a few minutes - usually 5. Don't use the vacuum, you just want the heat. This drives out the humidity and "balances" the moisture levels. Then mount as usual being sure to put the mounted work under a cooling weight right out of the press.

How to solve this problem as it exists? The counter mount will work as described in some other posts, but here's another solution IF the bow is as described above. Get some acrylic gesso (available from art stores), and slowly add water to a few tablespoons and stir until you get to a thick creamy consistency. Using a large brush, paint an "X" on the back of the art. As the gesso dries, the board will be pulled back into shape. Let the piece dry thoroughly, and if the problem isn't solved, you can paint the whole back with the gesso mix. But BE CAREFUL...If you use too much gesso, the warp can be pulled the other way - making the piece convex. Experiment first on some "trash."

Good luck!
 
It would be helpful to know the size, and what kind of "cold pressing" adhesive you used, but here are a couple of other observations:

1. For mounting large things that will hang unframed, I use a high-density foam center, clay-coated board, such as Gatorfoam or Mighty Core, and often black. It looks pretty good, holds tooth-type hangers and will not warp, even when vacuum mounted with a generous coat of water-based paste.

2. To fix the problem you now have, I suggest counter-mounting with a piece of 3/16" Gatorfoam/Mighty Core. That backer should be stiff enough to correct the warp.
 
I agree with Ron, the best way to flatten it is to frame it.
I also like Plak-it.
I have used the strainer bars glued to the back as well. Just wait until that customer brings the poster back in to be framed and you have to get those bars off to get it in the frame without damaging it. Good lu-u-u-u-uck.

edie the justframethedangthing goddess
 
We do a very brisk business in what Bill mentions.

We call it a Backframe.

Usually 2 inches smaller (on each side), or 4 overall. The wood strainer or wedge stock (with the wedge facing inward, to make a good hanging edge) is white glued to the back.

So a frame is glued to the back, hence: Backframe!

Stays very flat.

Raises the artwork from the wall 1/2 to 3/4 of and inch and makes it look very fine.

Hangs easier than a sticky tab stuck to the back of the f/c that usually comes off.

Not intended for long term exposure or use, and the corners will get dented over time, cleaning, moving, etc . . .

Very nice for commercial accounts with temp display needs.

Kids room, or game room posters, or even home gyms.
 
What about the time it takes for the glue to dry? Do you have the posters laying around under weights taking up space while waiting for the glue to dry, or do you use hot glue?
 
Time: The gule is set in about 1/2 hr, but it usually sits for 2 hrs or more (like overnight. We try to do them at the end of the day.

Space: I count 17, 4 x 8 foot tables at the moment.
Take away one each for joining, matting, mounting, joining, packing, shipping, and 4 for fitting, that leaves 8. OK, take away 3 more for misc crap, and we still have 5 clear open spaces that see service as needed: More fitters, stacked materials for large jobs, oversize orders (we have 1, 8 x 16 work area, and 2, 8 x 8 areas if needed).

I like to have the shop organized in space that can be cross utilized as needed. So space is not a problem.

But if you don't have open space in your shop, them something that takes up space for any given amount time might not be a good product or service to offer.

Hot glue: Not stong, a more temp bond. Also, since it is usually a laarger (as in poster) size being mounted in the fashion, the hot glue will be too cool for over half the are to even make a bond by the time you get back to where you started.

White glue, wood glue, pva glue all have much onger open time, or working time.
 
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