Dry Mounting Problems

[Peter Lewin]

Finally have enough FB prints toned and ready to mount, after a "darkroom gap" of close to five years. Pre-heating board & print, tacking & trimming all went fine, but print failed to bond properly. So a bunch of questions: (1) My ArchivalMountPlus tissue is about 5 years old - does mounting tissue have a shelf life? (2) After the first try (temp 175F, "sandwich" in the press of spare 2-ply mount board, actual mount board, print, cover sheet of mount board, 2 minutes, then under weights) I tried a 2nd time, this time with only a sheet of Kraft paper over the print (i.e. thought maybe not enough heat got through the top mount board in the first effort) but it still didn't adhere. If "at 1st you don't succeed" can you try again, or does the tissue only give you one shot? (3) 2 minutes at 175F seems "by the book" with either 2-ply or Kraft paper over the print; if this is wrong - obviously not working for me - any suggestions? (I stopped after the 1st failure, didn't want to sacrifice any more prints if possible!)

[Doug Dolde]

I always use only release paper over the print. 2 ply would certainly decrease the heat and possibly the adhesion as well. I don't know if the tissue age is a factor. Temp seems about right.

[Turner Reich]

Use release paper to sandwich the board in and the problem will be over. The tissue is fine and the temp is OK, just get some Seal release so the entire thing won't end up like a toasted cheese sandwich.

[bob carnie]

I would check the spec sheets for the particular tissue you are using, I have seen the same problem and it is very perplexing. Here is what I think may be the problem, some of the archival tissues merits were that they were to be unmountable. This unmounting proceedure required heat. Not surprising to me that I get corners lifting no matter how much heat and pressure applied.
I think this was a common problem with this *archival* tissue , You may want to try less heat on a scrap sheet and see if it works, same pressure.
We use a compression blanket on the bottom , two sheets of clean rag 4ply*print is face up between the two sheets, and a foam blanket above the rag boards.
Make sure you steam out the boards before a long day, and as will humidity if not around 60 will give you problems, One solution is to mist the back of the print , seconds before going into the sandwich. much like the steam principle for ironing white shirts.
good luck and post if you get success at lower heat.
Compression blankets and foam can be purchased at Drytac

[Bruce Barlow]

1. I dry the print and the board separately in the press for about a minute each prior to tacking adhesive and trimming.

2. Try a higher temperature for starters - that's what I had to do, especially with the replacement for Seal MT-5. I think I use 225, but I also don't trusrt my old thermostat to give me accurate information. Nevertheless, you need hotter than the instructions say.

3. Try a longert time - I use 2 minutes with the print between 2 pieces of 4 ply and no release paper. From what you describe you shouldn't need this, but it won't hurt.

4. Wrap two bricks in paper and tape the paper so they aren't messy. Take your print out of the press, put it on a flat surface, cover the picture area with a clean scrap board and put the bricks on the board to weight it down. The MT-5 replacement's instructions say the bond actually occurs while it cools, and holding it down with the bricks will help. Years ago we made jokes about selling paper-wrapped bricks: "Zone VI bricks - $29.95!" We had to restrain Fred Picker from actually doing it.

5. If it still doesn't stick, put it back in the press again.

These are the lessons from having to mount 1,200 pieces for a limited edition book. I miss MT-5, which was far easier to work with than the new stuff, which claims to work at a lower temperature, but doesn't. Even doing all of the above, about one out of twenty didn't adhere the first time and went into the press again. A mystery. It sure cured me of ever needing to do that many pieces again!

Good luck,

Bruce

[Merg Ross]

As Bruce suggests, the bonding takes place during the cool down, so pressure is a critical step. My method, in brief, is press at 225 degrees, two ply board over the print, 1 1/2 minutes press time. The last, and critical step, remove print from press, cover with piece of 2 ply and roll the print with a rubber roller exerting pressure for about 30 seconds. There is that odd time that it doesn't work, but more press time cures the problem. Good luck.

[Doremus Scudder]

Peter,

ArchivalMount (now renamed BufferMount is a tissue that bonds as it cools. That means 1) you need to get it hot enough (time and temperature are important here) and 2) you need to press the print to the mount board during the cooling time. If a print does not adhere properly you can return it to the press (for a longer time if your temp is OK) and try again. I have done this often (especially when using a new press or different materials) with excellent results. I have even returned prints to the press after some years to fix a corner that had come loose, etc. with no problems.

Many use a weighted platten to keep the print in contact with the mount board while it dries. I have had good luck with pulling the print quickly from the press and pressing with cotton-gloved hands, making sure the edges and corners adhere properly. I use either one sheet of 1-ply interleaving or a 4-ply mat board over the top of the print when heating, but remove this for the "smoothing" by hand (do make sure everything is clean!). I find that I can get the edges of the print flatter this way than by weighting alone.

If you have bad adhesion, try to identify if the problem is not enough heat (time/temp) or if the problem is not enough contact during the cooling. If the former, simply increase time/temp in the press (keep notes for various presses and materials that you can refer to in the future). If the latter, make sure that the print is removed quickly from the press, goes onto a flat surface and is somehow weighted, "smoothed" or otherwise pressed to the mount board during the cooling. Do not flex the mount board at all with BufferMount as some recommend for other tissures, or you will destroy the bond.

Also, don't worry about longer times in the press or turning up the temp a bit. Thermostats on presses are notoriously inaccurate and presses fluctuate a lot during the heating/cooling cycles. Also, mat board in the sandwich requires a bit of time to heat through. When using 4-ply board as top layer when I mount, I routinely use 5 minutes or more. Experiment with the time until you know the minimum time it takes for the tissue to adhere properly and then add a fudge factor. Erring on the side of longer/hotter is always better as long as you don't get the print way to hot.

Finally, if you make a mistake that damages the mount board but the print is still alright, or if the print simply won't stick, you can remove the print (BufferMount is one of the few tissues that allow this) by heating it well above the melting temperature of the tissue, pulling it quickly from the press, flexing the board to lift up a corner of the print and then peeling the print from the board by pulling from the corner. Go slowly; if the print sticks, it has cooled to much and you need to work hotter/quicker to remove the print. After the print has been removed, you can tack a new piece of tissue to it, trim and remount.

Hope this helps,

Doremus Scudder

[Peter Lewin]

First, thanks to all who responded! Since the most frequent suggestion was raising the temperature and time in the press, that's where I went. Despite the ArchivalMount recommendation for 160-170F, I set the press to about 210F, and ended (after some not-quite mounted prints) on a time of 4 minutes. I changed the "sandwich" slightly to a sheet of 4-ply, then the 2-ply mount board and print, then a 2-ply "top cover" - I switched to the 4-ply to make a more rigid sandwich which was less likely to bend as I moved it to my "drying press" (more on that later). In retrospect, perhaps the heat making it through the top 2-ply is closer to Seal's number than the platten thermoset setting. I went to 4 minutes so that the sandwich would stay hot as I transferred it to my version of the "drying platten" - a large coffee table with a heavy thick glass plate over a wooden top! (My basement, besides having my darkroom and mounting equipment, is also the repository for our unused furniture.) I would take the sandwich, slide it quickly under the glass plate, and then - to make you all laugh - I sat on the plate, so the sandwich had 140lbs of me, instead of the ZoneVI bricks which Bruce mentioned (and I have fond memories of attending a ZoneVI workshop in the early 80s, pretty sure a young Bruce was one of the assistants!) This process, which smells of superstition and alchemy, worked consistently. And you can definitely keep re-heating the print/archivalmount if the first attempt doesn't work, one of the prints went through three iterations of changed time and temp before it finally took!

[Kirk Gittings]

I have found the tempuarture settings in Seal presses to be way off. Mine runs 40 degrees off! So I set it by measuring the actual teperature with a candy cooking thermometer clamped in the platen.