drymount press trouble-shooter


SGF, Supreme Grumble Framer
Dec 31, 2001
New York's Hudson River Valley
Newburgh Mercantile
Trying to set up the 40 x 60 Seal press.

Can't get it to hold a vacuum. Never gets past 9 to 10 pounds.

Can't find Seals phone number - do I still call them or are they owned by someone else now?

I could use some advise - by phone or email

Your problem is almost cetrainly in the seal between the glass and the sides of the base. You could have a vacuum leak in one of the vacuum lines but I've never seen that. On the presses I've worked on, there is a way to loosen the hinges so that the top is resting completely on the base with no support from the hinges. Do that and see if you get a seal. If you do, tighten the hinges while the pump is running. In not, examone the seal material closely. Try putting downward pressure on the top to force a seal. Vacuum presses are real simple. Usually we can hear the leak but our pump is in another room. Warren
Does the rubber bladder or vacumn lines and fittings have any holes? Is the vacumn pump working properly?

Is the unit flat on a table?

If it is, and has been transported the hinges could need adjusting from the back. With the top down on the body of the unit the rear hinges can be loosened and then reset.
Is the Vacuum adjustment turned out too far? It's the little valve knob on the left side of the control panel facing into the tool tray - not all seal presses have this.

It's a handy control - most drymounting works well at 12-14 and laminating at 18-20 but you can crank it up to 26 - 28 if needed.

Vacuum pressure adjustment can be added if you don't have it - seal sells a retrofit kit.

PS - it's not pounds - it's inches of mercury like a barometer.


Please note that you have been told to undo the hinges on the back, but they forgot to tell you that you MUST REMOVE the air pistons from each side BEFORE you loosen the hinges on the back. If you do not REMOVE the air pistons you will have a horrible time trying to remove the air pistons from a loose top.

However first do this

1. Are the outlets in the back right and left corner of the lower bladder properly covered with the felt blanket? If not make sure they are. If the felt blanket is slipping off the metal outlet reglue it down for now with ATG.

2. Cut 1" wide strips of paper 11" long out of photocopy or similar paper.

3. Place them in the press about every 12 inches on all four sides and gently lower the lid and turn on the machine. When you get whatever vacuum you can then try and pull each strip out. If the piece is tight to pull out the seal is fine. If the seal is poor at that strip the piece of paper will pull out much easier. This test may give you some idea where the problem may be

4. Sometimes the black lower rubber blanket on Seal press deteriorates over time. I have seen small shall concave "grooves" about 1/2" wide running from left to right on the sides of the machine show up over time. These can be seen by eye and if you run your finger back and forth over the side of the outer edge of the blanket you can feel them. To repair this buy high temperature gasket material from an auto supplier store. Sand the grooves and then spread the gasket material over the the grooves and lay a piece and 3 or 4 mil clean poly plastic over it, turn the vacuum on with no heat and after it gets up to vacuum turn the press off and leave it to set up overnight.

5. Removing air pistons. The end of each piston simple pops on and off the ball stud at each end. However each end of the piston has a small round locking clevis pin to hold it on the ball stud. It is hard to see and you may need to shine a flashlight in to see it as it may be covered with dust or grease. Use a narrow screw driver to pop the clevis pin off and then pull it out of the holes with needle nosed pliers. Then have a second person hold the lid up to the exact ended length of the pistons and with a closed fist hit the top and botton of the piston to dislodge it off the ball stud. When reinstalling the pistons I have never bothered to reinsert the clevis pins. I have simply banged the end of the piston on to the ball stud.

Then you can lower the lid, loosen the screws that fasten the lid hinges to the lower base and let it settle on the lower foam/rubber blanket. Visually note how the lid closes on the foam BEFORE you start the process and then note what it looks like after you have removed the pistons and loosened the hinges.

You might even need to remove the upper locking clasp in the centre front of the Model 4468 presses. This permits the lower ball stud on the lid hasp to easily fit up into the hole. Sometimes this locking mechanism is the problem.

6. Now you can turn on the vacuum with the lid floating on the top of the rubber and foam. If all goes well your press should hit vaccum in about 60 seconds. If this happens then with the press at maximum vacuum tighten the screws back up on the lower part of the lid hinges. Then turn the press off and and reverse the process of taking out the air pistons.

A small hint. On a SEAL vacuum press do not leave it overnight or when you are closed with the lid in the down position without slipping in a small piece of 1” high wood at the front to keep the press pushing down on the foam. This piece means the full weight of the press in not pushing down on the foam and experience has shown that the foam lasts longer without compressing.

If you still have problems phone or e-mail me. 604-247-1771

little puffs of talc around the press edge while its running then slowly open and look for the white on the black bladder. this will tell where the leak is then the right correction can be made.

is it a new press that you have just set up? if not leaving something sticking between the seals over the weekend is enough to cause a leak too.
I forgot one of the other very useful technique to find leaks at the edge of the press. Light a cigarette and with the press on and vacuum working slowly slide it around the edge of the press and watch for the smoke to be sucked into the press.

The toll free number to the Elmers/Hunt/Bienfang (formerly SEAL) technical service dept is 1-888-240-6021

Thank all for the input!!

It is a press that I bought about 4 years ago and then had in storage while I was setting up my new location.

I may have an issue with the rubber seal - I'll inspect and try the various techniques you have suggested. Some are quite ingenious!

John - thanks for the link and info about the retro fit on an adjustment vavle. Oh, and the whole 'pounds of pressure' vs. 'inches of mercury' thing . . . it just slipped my mind ;)

If you do not REMOVE the air pistons you will have a horrible time trying to remove the air pistons from a loose top.
Thanks for the tip, but too late. And yes it was horrible.

I have pretty much done the process you have decribed with the loose hinges and all. You have added a few fine points that I will try next