Thank you Bill,
That was very helpful. They are do damn heavy, that is my only hesitation about buying one and having it shipped. So hard to return.
On my old Seal I have always put one sheet of 2 ply smooth rag board on the top and one on the bottom, preheat it, and I've never had a problem mounting anything.
To be honest I don't trust the cold mount process, because of de-lamination issues, and I've never gotten to the bottom of the longevity of these various adhesives. I do know that the traditional seal thermo plastic dry mount tissues were tested thoroughly by RIT labs and they found that silver prints actually tested better dry mounted than not, because of their protection against acidic compounds coming through the back of the print. There was a lot of confusion about how Ansel Adams, Paul Caponigro, Ralph Gibson dry mounted their portfolios in the 70s . But after the RIT tests of the 90s it actually seems very save for museum standards, and certainly nice t hold in your hands.
Anyway I'm starting to do some of my own framing and would like to be able to do some of the mounting at least. The really big stuff I still don't know what to do. I called the big lab Laumont in NY several times, that does mounting for all the big shots in NY and they would never give me any info on the longevity of their mounting, and they do it for all the major museums there. They always said they would call me back with figures, but they never did. I gave up completely trying to find out data on cold mount stability. If you look online they best you will find is some statement saying "acid free" and some use the worthless adjective "archival". There is just no reliable info on anything but the traditional thermo plastic dry mount process, unless you want to wet mount with polyvinyl acetate book binders glue, with a heavy weight on top. I'm going to try that on metal, but unless you work very fast you are in for rippling. However once it is down it is down.
john
quote author=bill t. link=topic=114928.msg947667#msg947667 date=1481243977]
I have a Seal 500 T-X which is an excellent drymount press. Bought it for about $800 used but mint a few years ago. It's something like 26 x 34 (sorry, it's in the garage) with a opening gap big enough to handle prints about 32" tall by any length in a single row of sections, or much larger with multiple rows. Listen to what framah says about an oversize top sheet. Moving that heavy monster around is difficult in the extreme.
Be careful: that's one of the earliest models with a really good thermostat that doesn't swing wildly between too-hot and too-cold. A lot of older presses I have used over the years could swing the temperature around enough to blister RC paper or even glossy rag paper at the extreme high end of the swing...had to always do a printless heat-soak press to guard against too much temperature build up. You can buy compact digital temperature readers small enough to fit into the opening of a typical drymount press. Recommend you "scan" the interior with one of those before you buy a used press. Also, a lot of old presses are severely scratched on the platten, which is not usually a problem if you use a cover sheet. And most older presses will need to have the foam compression pad replaced. And most used presses on ebay look to me like worn out trash. Best used sources for used presses are framers going out of business. Worst source is t-shirt companies, where drymount press abuse is out of control.
FWIW, if you always preheat the print and mounting board to drive out the moisture and let them cool down a minute before doing the actual mounting press, your print will stay mounted just about forever. I have some pieces I mounted that way in the 50s that are still nicely attached, but a "steamy" mounting attempt will be short lived.
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