Could Acrylic Be Used as a Substrate in Back Mounting Large Prints (not face mount)

[GLE]

After doing much research about which RIGID substrates would work best with a vacuum press and with large size prints such as 40x50", there seems to be very few choices on the market. Acrylic sheets could indeed be a viable possibility however no one seems to be using this material as a back substrate, although many use it for face mounting prints, but that is not my preference. The question remains, what technical reasons do exist for acrylic not be used, particularly when less inert substances, such as PVC substrates, continue to be popular?

Please be aware that substrates such as Dibond, Sintra, Foamex and others, can't tolerate the heat of the vacuum press adhesives (175-190F). MDF and all smooth wood substrates produce 'outgassing.' FoamBoard/FoamCore are simply not rigid enough and have a tendency to warp. GatorBoard is not to be found in the country I currently reside. Thick acid-free mounting boards absorb too much humidity which also leads to warping. And even Aluminum planks do not work because they tend to emit too much heat which ultimately cooks the prints under the vacuum press (so I've been told). In essence, I can't think of another material to do the job, maybe someone has back mounted inkjet prints onto acrylic, or may have other alternatives I'm not aware about.

 

[Steve Werner]

Acrylic obviously would work and is one of the cheaper options for you. Depending on the dwell time on your vacumn press styrene or ABS might work for you also and be more cost effective. I believe the melt point of styrene's is around 220 F while acrylic is around 250 F, you should check on that though. Styrene would shave up to 20% off of acrylic costs and be just as durable.

 

[GLE]

The dwell time Steve could vary between 5 - 7 minutes depending on several variables, like the type of adhesive, paper, print size, etc. As far as the information I have been able to procure, it appears that most acrylic brands tend to start softening at around 200 F. There are some a little stronger like Plexiglass 'G' which begins softening at 205 F. As far as ABS (styrene), this is the first I hear of this option, but if it does soften at a lower temperature than acrylic, it would not work. Not sure what size styrene sheets comes in, nor if it produces any 'outgassing,' but if you are sure of about the 220 F, I will look into it.

 

[Steve Werner]

ABS is usually a stock item for most people in 48" x 96" sheets in white or black. It would be worth looking at for you.

 

[GLE]

From the search done last night, it does appear ABS has less tolerance to 'SUSTAINED' heat than acrylic. As it now stands, I will be at the 'heat maximum limit' tolerated by acrylic. In addition Steve, some of the reports perused last night led me to the understanding that ABS begins outgassing at above 100 F.

 

[cainnech]

Related subject - we use a cold laminate to mount onto Foamex 5mm. Works fine and no one has come back about it peeling off.
However we are VERY new to this area of large format, and on a similiar theme we need to mount onto 10mm Foamex. Sounds easy but this is black board and the image has a black border - number one problem substrate is white! It is visible as a white line around edge when trimmed to A2 block.
Problem number 2 - registration onto a precut block. We cannot cut that depth of Foamex and buy in the cut sheet. How do others register as precut sheet with bevel is obviously a standard item.