Question Hot Press Use

[Ian Goodman]

How many of us use Hot Press for Haet sealing Images and then Dry mounting onto 5mm Foam Core?

I have had to replace the diaphragm in my HGP-360 recently and when nearly everything placed into the press moved I started to wonder what is going on and the image were not sticking to the foam core.

I was told by a support person that to dry mount you use 90degc for 4-5 minutes, so i did this only to find that the heat seal film migrated off the image.

So back to experimenting again.

if I heat seal images(Digital Images) I have found that 86deg c for 5 minutes + dwell time is sufficient.
Then if this image is to be dry mounted I drop the temperature of the press to 80deg for 2 minutes + dwell time with the foam blanket on top of the image.

If I put release paper on top of the heat sealed image the foam texture that was put onto the image during the heat seal process is removed but if I use the foam blanket the texture is retained.

Has anyone else experienced this problem?

if so how did you fix it?

Please share your experiences.

 

[Jeff Rodier]

Are you using the laminating film first and the mounting second? I always mount the art to the foam core before applying the laminate.

 

[Ian Goodman]

Hi Jeff

Thanks for your reply.

I have always Heat Sealed RC Images first ( Or laminate depends on where you are located)
Then Dry Mount using Unimount Dry Mount Tissue, the reason for doing this is that the temperature for laminating is higher than Dry mounting in a Hot Press. So if you dry mount at 80deg c for 2-3 minutes and then Laminate at 86deg c for 6 minutes you would run the risk of softening the dry mount tissue and end up with it lifting in an irregular pattern.
So I use Drytac Laminating Film and Drytac Unimount tissue so since i have ignored the expert advise of using 90degc I have not had any problems.

Can you tell me the temperatures you use and the type of dry mount tissue and laminating films you use?

Thank you

 

[Lemon_Drop1]

If I'm reading the question right, it seems like the laminated photo will not stick to the foamcore after drymounting.

I think the dwell time of 2 minutes on the drymounting cycle seems on the low side.
I use a Hotpress 360 also, and to get it to pull full vacuum it takes 30 seconds, so your press with a new diaphragm would take about the same time.

Plus using the foam blanket be it the 5mm gray or the 10mm cream foam instead of release paper of film would increase the time needed to drymount on account of the extra air trapped in the foam.

ie. it would take longer to pull vacuum using foam instead of release paper / film.

I understand the reason for using the foam blanket so as not to loose the foam pattern on the photo during drymounting.

I use Hotpress/ Drytac filims and tissues, but dont do alot of photos just mainly mass produced prints.

So for example for a 30 x 20 print I would drymount first at 90 deg. for 4 minutes covered with release film and let it cool under weights.

Then Heatseal at 6 minutes at 90 deg. also, covered with a foam blanket.
If I use foamcore to mount onto I add about 3 inches larger than the print all around, and trim back to the print.

Full vacuum will crush the edge from 5mm to nearly 3mm, so the other option is to cut back on the pressure.

I think thought I'm not an expert, is that the dwell time is very low during drymounting, and thats the reason the process fails.

The support person your talked to seems to be right.

I dont understand the problem with the heatseal migrating off the image if you, drymount first.

If the heatseal film is cut larger than the image it would stick to the foamcore by itself.

If your happy with the heatseal finish, and the print falls of the board after drymounting. then somethings wrong with the drymount process.

My shot in the dark. is that the dwell time of 2 minutes during drymounting is way to low in a vacuum press, you might get away with it using a hardbed press.

 

[Jeff Rodier]

First of all I use the International Brand Fome-Cor heat activated board. The board has a very heavy adhesive similar to fusion. I have used many different laminates all with good luck.

As far as temperatures the fome-cor works in a range from about 155 F to over 200 F. At temps between 160 and 200 I only need 1 or 2 mins in a 500T-X. The RC photos may need to be weighted after the laminate process. I use United's Clear Bond 2000 tissue which has a stated temp of 190F for items which may pose a problem in addition to fabric or canvas.

This tissue would help by bringing your 2 temps in line with one another. One reason I like to mount first is that there is less chance of edges lifting since I mount to an oversized board then laminate beyond the edges of the image. Let it cool completely before trimming and you don't have the film pulling the edges of the art up away from the board.