Help Warped Mats

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JRAM1

JRAM1

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Feb 13, 2007
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We have rematted a picture (34 x 26) to overall size (40 x 30) using a double mat, reverse bevel that has come back to us twice because the mats are warping. It's very similar to water damage, but there is no evidence of that and the customer insists that's not the problem. The piece was getting direct sunlight from a very large window, so I thought that might have some reason the mats are warped. However, the customer just replace those windows with double-pane heat resistant glass. The piece we just rematted was done less than a week ago and it hasn't been hung. I am at a loss to why this is happening! Any suggestions would be greatly appreciated.
 
Maybe fitting to tight, leaving no expansion room ?
 
When you incresed the size did you also add strips so the piece is level across the entire span. If it is on a thick board you can cut a couple or 3 additional mats to level it araound the outside of the board. Foam core strips can be used also.

If it is not level it will warp into infinity.
 
I thought that might be the case, but there is enough room for expansion. Still at a loss!
 
CAn you take a picture? Where is it warping at??? :popc:
 
There's gotta be some moisture somewhere. Are you gluing the mats together or using ATG?
 
Can you describe the warp? Or a photo?

Also some description of specifically how it is matted might help ...

Art hinged or drymounted?
If hinged, to mountboard or to window mat?
What is mountboard? 4ply? Foamcore? Other? Is it flat or warped?
Window mat booked on long edge to mountboard? Or glued? Or not?
Any spacers? Below window mat? Above window mat?
Mats glued together? PVA? Or ATG? Or not?
How much frame allowance? 1/8"?
 
Perhaps this is a stupid question, but does the picture use glazing?

I have seen plenty of things framed in other parts of the country where mats are used in a framing job, but no glass is used. We can't do that here. Our environment is too hot and humid and nearly all mated pieces without glazing suffer buckling like an asphault road in summer in very short order. So we just don't do it.
 
We had two jobs returned to us for warped mats: 1. Customer had one on the south side of a wood frame house, with little or no insulation. Frequent temperature change. The humidity came through the backing and warped the package. We re-did them with coroplast backing and now they're fine. 2. Mats were too tight. Our fitter did not leave 1/8th, but squeezed the package together. In your case it must be the sunlight with frequent temperature change and a closed package.
 
Mats are ATG. Art is dry mounted to foam core. Standard 1/8 allowance. Customer brought in their own frame with premium clear acrylic. Mats are not attached to artwork, but I'm thinking I'll ATG them to the foam core backing. The art was printed at our shop and has no value and we can easily replace if needed. I recommended that the customer upgrade to conservation acrylic due to the placement across from large window. They thought since they just spent a lot of money on new windows that it was unwarranted. I'll post pictures later. Thanks everybody for your thoughts!
 
When you extended the size of the piece did you add foam core to the full size of the frame. Foam core strips around the outer perimiter taped front and back side and everything also attached to a backing board the full size of the frame.
 
The answers to Jeff's two questions here are important. Maybe you do have
it built out to depth all around, but if any of the back mats are very much smaller than the outer one, it can cause warping.
 
The top and bottom mats are cut the same width on a CMC. The art was drymounted with the same borders left on to match the same width of mats/frame. I did not build up anything around the outter sides as I didn't see the need to do so. I have done the exact same to numerous pieces with no problems. This is really baffeling to me because I have never experienced this kind of issue in the past. Thanks once again for everyone's input. It's a great feeling to know that you all are out there to give assistance.
 
Easily replaceable decorative art, glue/ATG the mats down. With all of the heat, humidity and sun here I see a lot of warped and bowing mats that are not adhered to the backing boards. Provides a ton of reframing business.
 
You might even want to use the 969 extra sticky ATG.
Don't put it on the art, just around it, close to the artwork. If the borders are still around the artwork and are the same width as the mat, then I guess you will have to stick the mat right to the art.
Whenever I drymount cheap replaceable art, I trim off most of the border before mounting so the mat can be stuck to the foam core and not the artwork.
Then if anyone has to remove the mat later on, it won't tear the h*ll out of the artwork.
 
2 layers of 924 is the same as one layer of 969. It's just a double thick adhesive on the 969.
 
Jeff Rodier said:
2 layers of 924 is the same as one layer of 969. It's just a double thick adhesive on the 969.
Click to expand...

I don't believe that they are the same except for thickness.
I believe the adhesive on the 969 is stronger.
I have experimented with a strip of 969 and a double thick strip of 924 on a piece of matboard.
I could pick up the matboard with one finger applied to the 969 and even shaking it would not release.
The double thick strip of 924 released easily.
According to 3M's tech sheet, they use a different adhesive.
969 uses a 300 and 924 uses a 400.
969 is .13 mm thick. 924 is .05 mm thick.
 
jim_p said:
My regular supplier (Don Mar) doesn't seem to carry 969 ATG... know anyone who does?
Click to expand...

Larson, CMI, United all carry it. CMI has the best price in my area. They have a warehouse in Phoenix. Larson has it but they're a little high on the price unless they have it on sale.
 
If it was really hot weather, I'd wonder if the customer had
left the art in their car to bake before taking it inside, but
this time of year that doesn't seem likely. I'll be interested
to hear how it works out this time around, and I hope that
all goes well for you this next week. :smiley:
 
That you have never or rarely had this problem with other pieces you have framed leads me to believe it has to be something to do with something the customer has done to it (like leaving it in a car on a hot day) or something to do with its environment. It sounds to me like a temperature fluctuation issue. You might ask if they have the work on either an exterior wall or a wall with a A/C unit or vent in it (or a vent that blows directly at it). Have you seen any signs of even the slightest bit of condensation inside the glass? You might ask them to put a different matted poster in the same place where they were hanging the problematic picture to see if the same problems occur. Or once you redo the problematic one, ask the customer to hang it in a different spot to see if the mat gets wavy again.
 
My bet is that the acrylic isn't perfectly flat...its probably bowed slightly.

Lie the piece on a flat surface. Push down at various points on the face. You should be able to tell if the acrylic gives.

I think the mats are bowing because its not flush.
 
Normal expansion/contraction can be restricted by too-tight fitting, even if the sizing is done correctly. The most obvious symptom would be ruffling at the edges of the board, but it could also manifest as gentle waves across the sheet.

Fit loosely enough that the glass can rattle a little bit.
 
I just did a re-fit of a piece that was very similar... it was in a metal frame, tho', and the mat was very buckled.
I believe that the previous framer that actually framed the piece had some trouble with the mat as well, and put spring clips about every 2" around the piece, which was 32X36, to try to get it to lay flat.

I did some measuring, and I believe that when they ATG'd the two mats together, tho top mat was not totally flat. The 2nd mat was of course cut a bit smaller than the 1st, and the cut was made and it LOOKED ok, but didn't lay correctly...hence the buckling.

I wonder if that is what happened here....
 
Julie's post brings to mind the question of what your frame is
made of. For the sake of anyone else who might bring this up
in archives at a later date, I'll second her comment. If anyone
ever uses acrylic with a metal frame, it's important to build out
to depth rather than using spring clips.
 
I hate spring clips. I have long since switched to laminating strips of FC and/or matboard to achieve the needed thickness to fill a metal frame's channel after the backing board. I find that this gives a much more even pressure all around, looks more professional, and avoids creating dust wells in the back of the frame. Besides, we are always looking for ways to productively use scrap materials that would otherwise end up in a landfill.
:cool: Rick

A bonus of this is that it is much easier and safer to unfit if needed.
 
Framing Goddess said:
Spring clips=warped mats
Click to expand...

Yes! They restrict normal expansion & contraction of the frame's contents.

We're now using the grey foam roping available from the insulation department of the home improvment stores. It installs as easily as springs, compresses perfectly, stays in place, and does not impose too much pressure.
 
Jim, I have been using built up mat strips or foam cor for years. And it works. But that is just brilliant! I am going to be giving that a try.
 
This is really digressing, but I fail to see how spring clips in metal frames exert anymore real pressure than framers points every 3" in wooden frames. A little more pressure, yes, I will agree, but not a lot. I guess it may simply be that I've never seen any kind of issues with mats warping from spring clip pressure; not in the ones we've framed, and not in any of the ones that have come to us to be reframed from some other shop.

However the foam insulation stripping does sound interesting, as there are times we can't or don't want to use spring clips and have to fill the space with something else (typically matboard or foamcore). The foam would hold in the space better I think. I'm going to take a look at it this week as I actually have it in stock in my supply room already for a different reason (insulation, duh!).
 
JWB9999999, I think it is because wood and board absorb heat and humidity at similar rates. Aluminum and board are dissimilar enough that bowing is far more likely.

In any case, we have a lot of business "flattening" mats. Often we can fix them by just removing the spring clips, let them set overnight, then replace the clips with board.
 
I have always relaxed spring clips by taking some of the bend out of them. I also use wire cutter to staighten the ends a bit so they don't push down so hard since they push against the back rail of many metal frames. Once they are relaxed a bit they pose no real problems.

I hate unfitting metal frames where the clips have been forced into place. They dig into the foam core so they won't slide out when needed.
 
JWB9999999 said:
... I fail to see how spring clips in metal frames exert anymore real pressure than framers points every 3" in wooden frames.
Click to expand...

Well, you can press down on the the fitting tool and install the points too tightly, too.

The general rule is that when the fitting is done, the glass should be able to rattle a little bit, regardless of the frame type*. If the glass can not rattle, then the fitting is too tight.


* Exception: Acrylic DCO framing, where pressure of the assembly compresses the polyester batting and holds the mounted item in place.
 
Jeff Rodier said:
I have always relaxed spring clips by taking some of the bend out of them. I also use wire cutter to staighten the ends a bit so they don't push down so hard since they push against the back rail of many metal frames. Once they are relaxed a bit they pose no real problems.

I hate unfitting metal frames where the clips have been forced into place. They dig into the foam core so they won't slide out when needed.
Click to expand...

I do this too when I use clips. However, I turn the clips "upside down" when inserting them into the frame. The center of the clip slides very nicely over the foam core. When I do it the other way, the ends of the clips dig into the matboard. I have also used a small piece of release paper to help make the clips slide into place easily.
 
Not sure if everyone missed this . . . "The piece was getting direct sunlight from a very large window".

Doesn't matter if the window is double glazed, perhaps heavy tinted glass would help, but if they are getting direct filtering sun on the piece, it is heating up with infra red light.

This will cause all sorts of issues with expansion / contraction (higher than normal), and internal issues with moisture (which will also affect the paper art long term).

Get them to move it.
The first advice a framer should give re hanging framed art is do not hang in strong light, especially heat building light like sunlight through a window pane.

Cheers,
Les
 
Dang, I just read the part that says "The piece we just rematted was done less than a week ago and it hasn't been hung."

So, it has warped again BEFORE going back up on the same wall ?

If so, use the bombproof ATG and ensure any gaps between mats are packed up.
 
Jim Miller said:
Yes!
We're now using the grey foam roping available from the insulation department of the home improvment stores. It installs as easily as springs, compresses perfectly, stays in place, and does not impose too much pressure.
Click to expand...

Best tip of the day/week/month/year/decade/century!

Thanks Jim!!!!!
Like Jeff; I bend my clips too before using them to get some tension out (off?); I also liked the upside down fitting clip tip.
 
realhotglass said:
...use the bombproof ATG and ensure any gaps between mats are packed up.
Click to expand...

Almost any pressure sensitive adhesive can fail over time, if there is any stress on the bond. ATG is OK for temporary holding, but spots of wet paste or hard-setting glue (such as acid free PVA) hold much better for the long term.
 
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