How to avoud bubbles on mounted prints

[Boris]

I've been mounting color prints using Seal press and colormount tissue. I mount on foam board. Initially mounted prints look good. But after about 6 months some of them developed bubbles. What is the way to avoid this?

 

[Donald Miller]

Boris,
The things that I would check are the temperature of the press and the pressure of the platen when it closes (clamps down) on the work. I don't know of a published criteria on pressure. The platen must clamp down on the work securely. The pressure on my press is such that I could not move a piece of 4 ply mat board when it is inserted and clamped down.

I use colormount tissue on my fiber prints (not recommended I know) but I have been doing it for over 20 years. This tissue is supposed to work best at 190-200 degrees. I have mounted on foamcore at one time and I did not have the problem you mention, so I doubt that foamcore is the problem.

I don't know which Seal press that you have. On my 210 M the platen does have an adjustment for clamping pressure (the two round protrusions that pass through the cross bar).

I hope that this helps. Good luck.

 

[Les McLean]

How long are you leaving the print in the press? I had similar problems many years ago and cured it by leaving the print in the press for about 3 minutes. Any dampness in the board before you start mounting the print can also cause problems.

 

[glbeas]

Dampness in the board can be cured by cooking it in the press for 5 minutes before mounting the print on it. Fiber prints may need the same treatment too.

 

[ann]

are you placing the print under something heavy after removing from the press?. The weight helps to bind the tissue to the print and board.

 

[Sean]

In college we used to heatpress, then put it directly into another heatpress which was turned off and left it in the 'cold' press to cool.

 

[Boris]

Thanks for all your replys. I've been doing everything you've syggested. I think I know the problem - it could be uneven pressure. I adjusted the press for 3/16 board, but when I ran out of this board I purchased 5/16 and did not re-adjust the pressure. Looking at the areas where the bubbles are - they are all at the adge of the prints, so this could be dues to uneven pressure.

 

[glbeas]

Another thing that could happen is uneven heating pattern. If you were to be able to get a thermocouple and clamp it down in various spots in the press and take a reading this would be easy to determine. Unfortunately thermocouples are not real easy for the average bum like me to get hold of. Anyone know of another good way to check the heating pattern?

 

[Donald Miller]

I believe that at one time Seal offered a type of material that melted at a given temperature. However that is a "go--no go" type assessment and really not indicative of anything other then a threshold temperature.

I have a digital thermometer with thermocouple readings but these are fairly expensive instruments. If you are really interested in obtaining a thermocouple activated digital instrument then I might suggest Ebay (if that is a politically correct mention of names) and search for a thermometer under the business and commercial heading.

 

[Loose Gravel]

Long ago, my prints would lift just a bit at the edges. I increased the time in the press to a couple or three minutes and have had no such problems since. I use a Seal press and the pressure is fairly high compared to other presses I've used.