Hi Heidi,
I feel you're caught in between the behaviors of the given materials and the rules about how you need to mount them. I believe that the curling you're experiencing is primarily caused by having the poster adhered to the one side of the foam core, but not a similar membrane adhered to the back side. Laminating a similar material on both front and back can equalize the stresses caused by dissimilar materials reacting to the variations in humidity, and thus help reduce curling.
Since the posters you are looking to mount are not collections objects requiring maximum archival treatment, I think I would actually recommend a different substrate.
Gatorfoam board is a foam core board with a phenolic reinforced paper covering that is one of the stiffest lightweight materials I know. The 3mm board would probably be very suitable as a substrate for the posters, and it comes in black which has a pleasing edge. I would recommend this over Sintra which is much more flexible and would probably need a back lamination to help keep it from curling. The Sintra is also probably heavier than the Gatorfoam and thus will cause more mounting issues. Gatorfoam can be cut with a razor knife, but the surface is quite tough and you will need to take care in doing so. A mat cutter can be a good tool for the purpose if one is available, but will probably require multiple passes. A table saw is the most common tool for this sort of fabrication so you may want to seek outside assistance for this. Double laminated regular foamcore board can also work and will be easier to fabricate yourself.
The other issue is the prohibition on using mounting hardware, and thus having to be dependent on tapes such as Command strips. I would gently inquire whether tiny holes such as those made by
Floreat type picture hanger nails might be acceptable. Pinning the assembly to the wall at the top corners may be a very successful way to proceed while doing very little damage to the wall.
My other recommendation, if using adhesive strips is required, is to use the strips to adhere a pair of
French Cleats of Gatorfoam to the wall, and attach mating cleats to the back of the poster substrate. By using cleats instead of direct adhesive, the movements of the board substrate are not placing stresses on the adhesives attaching the cleats to the wall. By maintaining as light a panel as possible, and decoupling the forces generated by the humidity induced movement, it should help keep the adhesives from detaching from wall or panel. It also gives a slight shadow line behind the poster which is aesthetically pleasing.
Please get in touch if I can be of further help.
Jamie
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[Jamie] [Hascall]
[Mountmaker]
[Hascall Consulting LLC]
[Seattle] [Washington]
[206-954-4141]
[Mountmakingfocus.com]
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Original Message:
Sent: 08-27-2021 11:20
From: Heidi Mead
Subject: Mounting signage and posters
Hello! I have enjoyed reading the posts on this resource for several years now. I now have a few questions of my own, but am unsure if this is the correct space within which to pose them. Please forgive me if so!
My field is fossil specimen preparation and research. About 5-6 years ago, I was asked to step in as a temporary replacement for our retired exhibits designer. It seems a reasonable request, as I was to directed to maintain the exhibits, not necessarily design new ones. I did assist with the original designing and installment under the direction of the then designer, but I am definitely lacking in knowledge.
I am now in need of remounting the museum's exhibit posters. Strathmore papers, color graphics via inkjet printer, were originally mounted 17 years ago on 6mm foam core sized 13" x 19" or smaller. Papers were mounted using a spray adhesive following the manufacturer's directions. The Foam core boards were then mounted to the walls using 3M command strips (no hardware attachments to the walls allowed). Some boards have warped to varying degrees, but not all, and size does not appear to play a role, nor does their location within the exhibit space. I was hoping to find a mounting surface that wouldn't be so susceptible to the humidity fluctuations found in our indoor exhibit space. Granted, 17 years is a long time. However, attempts to keep the boards on the wall have been ongoing, using larger quantities of larger command strips to maintain the signage. Our humidity fluctuations are due to our regional location as well as HVAC maintenance, proximity to exterior doors and constant foot traffic. I would GREATLY appreciate any direction towards board/adhesive products and why.
Currently, I am considering replacing the warped mount board with the more foam core, as it did last a good while, and our building's HVAC system was replaced last summer (although we did have a failure in the backup generator twice this summer). I have been doing a lot of reading on how to mount quality Strathmore papers on foam core, but there appears to be mixed procedural approaches i.e. counter mount or not. Insight on this matter would be greatly appreciated as well!
I am open to using 6 mm Sintra, but after researching how to cut the stuff, I would have to invest in a saw, unless I ordered pre-cut packages. Ultra-board seems viable as well.
I seem to be caught in a too much information and not enough experience to decide position! I can purchase supplies with our coordinator's approval, but would like to have a more authoritative perspective on what I should be looking at before I start proposing supplies. It may be useful to know that the posters and signage were created digitally in-house and serve to inform or direct the public (My hope is to not have to reprint them, as our in-house printer no longer functions, and my lengthy attempts to clean everything internally using tutorials on YouTube have failed. Perhaps there are those out there with experience in this area as well?).
I look forward to your experience and insight.
Again,
Please accept my apologies if I should have posted this elsewhere.
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Heidi Mead
Vertebrate Fossil Preparator
William P. Wall Museum of Natural History
Georgia College
Milledgeville GA
She, Her, Hers
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