Is the core of foam-core acid free?


Aug 18, 2003
Is the core of foam-core acid free? How about the gasses inside the foam? How can I test this? I have a tester for mat board, will it work on foam? I am sure if I were to ask Crescent or Bainbridge they would insisted their products are acid free.

My experience with "foam" products (foam rubber, styrofoam, etc..)is they deteriorate over time.


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Love It! - Thanks Jay H
The issue that is raised in relation to foam
centered boards is not acid emission, but rather
it is emission of styrene monomer, from the break
down of the polystyrene foam. If one opens a box
of these boards, the pungent smell that may issue
forth is the monomer coming out. That material is
a solvent for plastics, but whether it represents
any threat to art papers and materials is not
known. Since the board is used in back of the frame and it can off gas into the surrounding air
and since there has never been any evidence of
such boards causing any harm to paper or other
art materials, there is no reason to avoid using
those boards in framing.

"Since the board is used in back of the frame and it can off gas into the surrounding air
and since there has never been any evidence of
such boards causing any harm to paper or other
art materials, there is no reason to avoid using
those boards in framing."
Your post is very interesting!! From what I understand, most everything offgasses, the question is, does it cause harm to the art if the art has a full four ply preservation grade board behind it and the art is at least an inch from the edge of the matting and while we are at it, if the board has zeolites in them? This seems like a small question, but it seems that framers can get so hung up on the chemical properties of what we use in framing instead of asking whether the material causes harm or not. The simple act of framing causes harm by putting the object in light and in a vertical position, If harm has not been noted over time by foam board, can one assume the damage is light or none existant?

Nona Powers, CPF

Of all the things to worry about in this world, foamboard outgassing is pretty low on my agenda.

Now get me started on tapes.... :D

The FACTS Foamboard Committee would like input on this subject. We are developing a questionaire, albiet somewhat slowly, to determine what damage, if any, a framer has seen that can be directly related to foamboard. Perfereably in a frame package, but any evidence will do. Email me directly if you'd like, but be as specific as possible concerning the details. We are still working on getting scientific data and would like to have it reviewed before issuing a FACTS Standard.

Yeah, ReBeCcA, what about tapes?

Oh, and I need to send the picture that I emailed pictures to you of.
Things to worry about using tapes.

Linen tapes:

1) Type with heavy layer of gum (or whatever it is) intended to be used for hinging windowmat to mount board. When used on art, the adhesive bonds strongly and in most cases irreversibly to the paper. Variations in moisture can cause puckers/swelling and texture changes in paper.

2) Pressure sensitive linen tape. Adhesive is much too strong and the tape/adhesive is very difficult (sometimes impossible) to remove.

P-90, "archival" mending tapes etc. Are often impossible to remove. The adhesive bonds change over time, becoming stronger. Can be very difficult if not imposible to remove.

Pressure sensitive tapes in general, including framer's tapes. These have plasticisers in them which are oily and goopy and will sooner or later migrate into the paper. These can make oily stains in the paper.

This is just a quick, off the cuff reply. Search Conservation on Line for more info such as:

It's too early - I need a coffee!

As long as we're talking about tapes (are we done talking about fome-core?) I have a basic question.

For hinging the mat to the mount board, which is better - pressure-sensitive linen tape or the water-activated?

I'd gotten into the habit of using the Lineco pressure-sensitive (again, just for hinging the mat to the mount board) 'cause it's less messy to work with. My only objection is it's sometimes hard to get the release paper off.

Recently I ran low and used some water-activated linen tape instead. It's a mess, but I wonder if it might be stronger and more permanent. It would seem like those would be GOOD things for this particular application.

It's almost certainly cheaper.
I’m studying hard
….from what I can gather the “Preservation” water activated type tape would appear to be the best choice….this I gather is to reduce the risk of adhesive damage should the hinges fail on the art and the art comes in contact with the hinge adhesive (tape) on the Mat/Mount (we say Mount not Mat in this part of the world :rolleyes: ) and Backing Mount Board……… where I will get “Preservation” type tape in this part of the world is anyone’s guess
…..perhaps I will end up making my own…with starch paste
Ron, if it were me I'd use the pressure sensitive linen tape. It is plenty strong and it is WAY easier to use than the gummed tape.

I'm not sure that the gummed tape would stick better to mount/mat boards. I've found the gummed tape to be most difficult (read impossible)to remove from soft sized papers and most matboards are pretty hard surfaced.

But on hard sized papers and paperboards, I've found that the gummed stuff can have uneven sticking properties depending on how it's applied. In some areas it can be easy to remove, and in others it's a permanent weld.

I bet people who use the gummed tape a lot for the window/back mat hinges have it down to a successful fine art, but for once-in-awhile users, I'd go pressure sensitive.

Dermot and Rebecca, you are both treasures. Different kinds of treasures, but treasures none-the-less.

Dermot, I would be very happy to send you a nearly unused rolled of gummed water-activated linen tape as soon as I get some more pressure-sensitive in.
Gummed linen tape is a bit like an enevelope, a little dna makes it hold better, non-conservation. Maybe ok for coservation for all I know. Has anyone done a test?

Are you saying licked gummed linen holds better than watered? If this is true, you're brilliant!

Remember that great Seinfeld episode when George killed his fiance with cheap gummed envelopes?

Interesting comments regarding gummed linen tape- especially that it is so difficult to remove. I've had the opposite experience. I have used the water activated gummed linen and when dried (several hours), I gave it a little "test" to make sure it was adhered. It flaked right off! It didn't stick at all. Someone told me it needed quite a bit of water to make it stick but that didn't work any better. The roll is sitting in a drawer waiting for me to figure out what I'm doing wrong.

I'm off to whack weeds and pick up rocks so I can plant some grass seed. At least I'll get a tan - or a wasp sting.

Enjoy the rest of the weekend.

Amy McCray
Hickory Hollow Framery
The most important property of the tape that creates the hinge spine on a window mat is its
functional needs to hold, tight,
for as long as it is in place. The pressure-sensitive tape may work for twenty or more years,
but a cursory examination of pressure-sensitive
adhesives of that age does not inspite confidence.
Very old water-activated tapes are still holding.
Some modern ones have poorer adhesive and all of
them should be activated with hot water, to ensure
that one does not have the problem that Amy did.

Ah, it's the temp and not the DNA. In all the years I've used this tape I've never come across instructions. Thanks Hugh. Old dogs can learn something new.
There now,

Isn't it nice to have a variety of opinions and experiences? I love this give and take of ideas, experiences and techniques.