Mat Creep

Art Creations

Apr 24, 2006
Hello all...
Last weekend I listened to Jim Miller speak about Shadowboxes. Which was very interesting. Jim had mentioned Mat Creep, and a special glue that he used to help keep them where they belong. I am sure this is a topic that has been discussed before, I tried searching past Grumbles and was unsuccessful in finding an answer to what this magical glue is and where if comes from.
Does anyone know what this magical glue is?
Nah, the Mat Creep is the person that insists on taking the fallout with them because "they payed" for it.
Paul, you are thinking of the "mat gremlins".....I think the "Mat Creep" is the one who delivers them to you with bent least I have been known to chase after my delivery guys "Hey you creep, come back here, look what you did to my mats".
Elmer's = PVA glue is fine for use with matting
materials that have buffering = calcium carbonate
in it. The vast majority of board made, today, is
laminated with PVA, anyway.

Hugh does your comment about the compsition of vast majority of boards include that they are "ACID FREE"also?LOL

But seriously maybe for some of the new commers you should explan why and how useing PVA on mats is OK.It sounds to me like there may be some who aren't familar with our previous discussions and the "MYTHS" of framing, since they may be looking for those magic compositions and methods.
If you hand cut your double mats (like in the old days) line up the bottoms flush before you tape them together and they can't creep because both mats will sit on the bottom frame rail. Gravity sucks straight down.

On the CMC mat cutters I think you can cut double mats in place with the bottoms aligned - also no slip.
I do cut mats the old fashioned way... I don't have the fancy Wizard... and I have always aligned the mat at the bottom as to allow gravity to keep it there... I also always use ATG tape to hold them together, after hearing Jim speak about Mat creep, I thought maybe there was something I wasn't doing correctly... trying to keep up with the correct ways to do everything!

However, I am feeling that the mat creep must be...
"I think the "Mat Creep" is the one who delivers them to you with bent corners"
"the Mat Creep is the person that insists on taking the fallout with them because "they payed" for it" "Isn't The Mat Creep the guy who visits frame shops at night and damages our mats....?"

Thanks again for amusing the "newby"
Kelli you may think you were being ridiculed but I assure you you weren't. The problem is that some times new comers get the impression that there are "secrets" of the trade that they haven't been allowed to see as yet .When in truth a lot of those things are just common sense .My suggestion to Hugh was to bring out a thread where we on TFG discussed a list of Framing Myths that where commonly held by even some very experienced framers( it actually was resurrected some time afterwards by another newer Grumbler ).What is worse is that this special info type stuff often continues because no one challenges it's an "emperors new cloths " sort of thing.

Do a search useing Myths both in the normal section and again in "before 2004 section" you may find even more tips you can use.
And more importantly welcome to a host of knowldgeable framing info TFG.And some light hearted industry jokeing as well. This forum is a lot more relaxed ,but another good source of purely Business type stuff is PPFA's ONLINE Hitch Hikers.
The origional post specified a shadowbox. Is this glue in reference to shadowboxes also. Are we talking about sticking mats to the inside of a shadowbox moulding or just mats together?
The origional post specified a shadowbox. Is this glue in reference to shadowboxes also. Are we talking about sticking mats to the inside of a shadowbox moulding or just mats together?
Jay, the original post was about lining the sides of shadowboxes.

I believe the general consensus is that ATG is not reliable over time. So use a little ATG in conjunction with glue, preferably PVA. The ATG holds everything in place so you can keep working while the glue holds things permanently.
Kelli, when preservation is an issue I use Lineco's acid free PVA, often in addition to #908 ATG Gold (acid free). In matting posters & other decorative-only items, a few spots of our CornerWeld frame glue work OK with ATG. The ATG holds temporarily, the glue holds permanently.

Jay, the conversation took place in the context of object framing, but "mat creep" could happen in any frame design using multiple mat layers.

The issue is that the top mat layer, in direct contact with glazing, is the one most reactive to temperature changes, so it expands & contracts more and faster than mat layers below it. The difference of expansion & contraction imposes a sliding force on the surfaces.

ATG alone may flow under that kind of force. So, if ATG is used on four sides of a mat, only the strongest of those bonds may hold. A mat may expand in an unpredictable direction (up, down, or sideways) and then, in contraction, re-stick in a different position. Thus, the margins on top, bottom, and sides may shift over time.

Hard-setting glue will not flow and holds securely, preventing that movement.

Many of us notice unequal accent mat margins in framing and assume the assembly was just sloppy. But I KNOW the mats on the photos in my bedroom had equal margins originally. Now, instead of 1/4" all around, the margins are more like 5/16" on one side and 3/16" on the other. I've never actually witnessed mat creep as it happens, but this is my theory.
Ok. I do ATG AND glue. I have tried several types of glue and I will try PVA too.
Since conservation quality board has calcium carbonate in the paper, there is no problem with
having PVA as an adhesive. The PVA from University
does, as Jim mentioned, have chalk in it, too.

I use Mathesive 101 from Glue Fast, in their Solo Glue Riter applicator. It is great! You can move the mats a little, if needed, but in about 30 seconds the glue sets, and there will be no creep.
I also use it for attaching the black paper on the back. Apply glue, set it face up on the paper, wait one minute, trim, and there's just enough moisture in the glue to tighten the paper in a few minutes. So a nice, neat, tight paper back.
Thanks Jim, for clearing up exactly what I was meaning!
Buddy-- Thank you also, Don't worry I do not feel as though I was "being ridiculed" I have read other posts.. and I appreciate the fun that everyone has on each post! We all need a little humor in our line of work! Too much seriousness makes for way to long of a day!
How about a refresher primer on attaching mats to the backing board? I was taught ATG to the backboard for inexpensive stuff or "booking" with linen tape for all else. Some say no attaching is necessary at all.

Jim and Hugh?
Am I missing something here?

We have 1 or 2 mats, even 3-4 if you want. The mats are on top of the art, glass is on top of everything, FC or acid free FC is on the back. The frame is around the whole thing.

How are those mats creeping?? Is there a space left somewhere where they would move around??

Isn't everything cut to fir perfectly and snuggly against the frame (in)sides?? So, where is the mat(s) creep?

Jim Miller - What hast thou started??
The issue develops when the bottom mat is slightly smaller overall than the top mat, which results from the preferred method of cutting a double mat on a manual cutter. As Jim points out, ATG never hardens as does PVA glue, so eventually gravity will allow the back mat to creep down to rest on the bottom frame rail along with the face mat, resulting in an uneven reveal.
:cool: Rick
Just a side note or question. Hasn't ATG always had the problem of not being secure( despite the fact that it can come in "TOTALY ACID FREE" LOL)? I have had very large problems with anything that was secured with it when my clients would carry their work hoome in their trunks, to meat temperature changes have a horrible affect on it especially HEAT. But then the heat could come from the client turnning off their AC to conseve energy. Down here that could make the temperature in the home/office swing unbeliveably.

When ever I now do carveings onmats and their are small pieces that need to be replaced frombeing cutt away i always use a samll dot of PVA in place of the ATg i used to use for the afore mentioned proble,s and it is a whole lot easier to apply. Besides I saw Brian Wolf teach Mosaic matting and that is what he used also a long time ago.but it wasn't a matter of C/P but how to amke it stay put, And as Hugh points out there isn't any additional problems with it's C/P proprties anyway.( MYTH???)
"Isn't everything cut to fir perfectly and snuggly against the frame (in)sides?? "


I hope that's not true. Most of the time a frame is cut 1/8" larger to allow for expansion and contraction. yes? Now, suppose we accept Jim's theory. (created from emperical evidence!) then how would you like your bottom mat to move 1/8" off from your top mat. If you accept the theory, it's possible.

Of course, if you don't, maybe you get them back in for a remat job! ;)
Originally posted by Paul N:
...Isn't everything cut to fit perfectly and snuggly against the frame (in)sides??
Nope. Materials in a frame may expand & contract differently, so it is necessary to have some dimensional allowance. And for practical purposes of cutting, joining & fitting a frame package, dimensional tolerance is needed.

For typical framing 1/16" to 1/8" is normal, but more or less may be necessary, depending on frame size. Most suppliers who offer chop service add 1/8" to whatever nominal dimensions are given on the order. 1/8" allowance is the specification for the MCPF exam, as well.
Mat creep is not only downward. If you look at several-year-old frames, accent mat margins will sometimes indicate that an under-mat has shifted sideways, or even upward.

The stick-unstick-restick process of mat creep can overcome gravity. When attending PPFA meetings, we often can find one of those in a hotel lobby or hallway.