Question Backing for frames 47.5"x63.5"

[thedarkroom]

We have 6 frames that are 47.5"x63.5" and are not sure what to use as backing to add rigidity. The customer is very concerned that all of the materials used be archival.
The moulding is Studio Moulding 24601, which is not very deep and therefore can not accept anything too think once the double mat and acrylic are in the frame. The art is backed by 4ply white mat and therefore is pretty flimsy.
Can anyone offer any advice on how to tackle this large frame?

Thanks

 

[Larry Peterson]

That frame has a 5/8" rabbit. Your acrylic and mat/backing should be about 1/4" to 5/16" thick leaving you about 5/16" to 3/8" for the backing.

I don't have a recommendation for the backing but am putting out the thickness for any one that recommends a backing.

One other comment. That moulding is 2" wide. I use it a lot for smaller frames, but am not sure about using it in a frame that wide. You may need to use FrameStrap or other similar product for support.

One more comment. Since the 4 ply backing is already archival, I see no reason why the backing needs to be archival, especially if you seal the backing in place with Frame Sealing tape. Other might flame me for saying this but if the art/backing is sealed and isolated from the support backing then you could use something like gatorfoam for the back support.

 

[Jim Miller]

I suggest fulted polypropylene for the backing; 6 mm, 8 mm, or 10 mm; the thickest you can stuff into the rabbet. Whether you select white or "archival" Coroplast, you can buy it in 48"x96" sheets. It cuts easily on a mat cutter or wall cutter and it's cost effective, too. Sealing the back with Lineco's foil tape is a good idea if everything under it is inert and chemically stable.

Since the 4 ply backing is already archival, I see no reason why the backing needs to be archival, especially if you seal the backing in place with Frame Sealing tape.

4-ply alphacellulose is not an effective barrier. When preservation is an issue, the final backer should also be inert and chemically stable. If you use a chemically reactive or unstable board backer, such as Gatorfoam, sealing the frame's back would only seal the backer's nasty chemistry into the frame package.

 

[Jeff Rodier]

If you are looking to add rigidity to the frame as well as the backing you can use the Alupanel located on page 52 of this catalog.

http://www.proveer.com/

Aluminum on 2 sides with polyflute center. They also make it with aluminum on only one side for less money. They will cut to size for a very small fee and offer free delivery to most areas of the US.