The patent on Alucobond an Dibond that Alusuisse had is no longer valid after more than 20 years. Most of the less expensive alu -polyethylene composite material is now produced in China and sold under different names. Alusuisse became part of Alcoa and later Alcan or the other way around. The China plants even got some support on knowhow as I was told. Differences still exist, the alu surface plates can either be 0.2mm or 0.3mm. The aluminium itself can vary in hardness grades, the step from the 3mm or thicker Alucobond to the thinner but still rigid DiBond became possible when the harder (magnesium addition) aluminium was used, less stretch in the alu layers possible so more rigid. The white or colored surfaces are usually polyester based lacquers.
I use the China produced 2mm 0.2 or 0.3 variety with less hard alu as I can score one side with a heavy knife and break and swing the sheet to be used free from the large sheet. The sheet has to be clamped thoroughly over the full length near the cut to keep all parts flat. There is no warp then in either part. Sencys 25mm snap off blade cutter is excellent. After laminating the print I cut the edges on a board cutter, waste about 1/4 inch on each side. That way I do not loose much image either when the image runs up to the edges. Above say 50x70 cm I add a 10mm thick expanded PVC sheet at the back (kind of Forex, which was also an Alusuisse invention) with one component polyurethane glue, the hardening is done in a vacuum table on thick glass so flat. The PVC is 12 cm smaller in both dimensions so not visible when on the wall.
Smaller prints up to 50x50 cm are more often laminated on 2mm polystyreen which gives white edges. Similar process. And then framed. I think that gluing a sheet like that on a smaller 8mm MDF board could deliver a good product too.
Zenith 2 sided laminating products are used. For the matte art papers with looser fibers the thicker glue quality. I mount the larger matte art paper prints first in the vacuum table and then pull them through the laminator with enough paper protection for an intenser bond. The gloss papers that keep their dimensions better go directly through the laminator, you can not pull air out anyway between an RC sheet and Dibond so that has to happen in the laminator in the marriage of the two.
Whether it is "archival" is another question. Conventional framing with acid free tape hinges, boards and matte is the most archival method and also reversible. I tell my customers to check the framers that do that on the materials they use and it is quite often not done correctly. Lamination to foam core and then framed free floating for example. I do not trust foam core at all. I have no urge to go in the framing business though.
Paul, any liquid glue is a risk with canvas but you might check your transparent aliphatic polyurethane varnish or a glue version of it again. And a vacuum table for the curing period. Half an hour for the less sophisticated wood construction glue I use, bonds the composite and pvc (both slightly sanded) without problems. I have done a year long 3x weight/bond area outdoor test and it holds forever.
However any non reversible method should be a conservator's nightmare. Hypocrazy is prominent there though, art is bought on the name not on the media specifications, restorers need a future too and I make facsimile that replace the originals that never leave the archives anymore.
Met vriendelijke groet, Ernst
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