No Vacuum pressure in heat press

framer12056

Grumbler in Training
Joined
Apr 29, 2010
Posts
7
Hello, I have a Bienfang 3648 vacuum press which is not getting any pressure. I purchased the table a few years back, and had it up and running for several years and it ran perfectly. We recently moved the table to our new home, and after setup it heats to temp, but no vacuum. I have tried the following:

Covered both vacuum intakes with plastic, and I get 28 hg
unscrewed the hinges and repositioned the top several times, but no vacuum
verified the table is completely level.
Removed and replaced the thin foam strips all around the underneath of the diaphragm.
Placed weight on all sides of the top to see if I could get a better seal, but nothing.
I tried to place a candle all around the openings while running to see if any smoke was drawn in, but I cannot see anything.

Are there any other tricks out there that I could try ?
Can anyone direct me on where I could hire a technician to come out and look at it ?
Thank You in advance.
 
I assume you've inspected the diaphragm carefully for holes, but that would do it for sure! I would try letting the pump run for a couple of minutes, then you and a friend go around the table putting weight on the sides/corners/etc to see if you can get suction. If you can get the vacuum up, at that point you can readjust the hinges (while the press is still under pressure) to "reseat" them in the correct position.

Good luck with it!
 
I will go ahead and look at it a little more carefully. Another question I have is on the underneath of the diaphragm, should the foam strips go completely around the perimeter of the diaphram, and would it make sense to try and "double up" on the strips in order to push the diaphragm up higher for a better seal ?
 
Sometimes I have a problem with obtaining pressure on my press as well. Try this

  • Sometimes the bladder has moved and needs to be readjusted - usually that happens if I lift the lid before allowing all of the vacuum to have escaped
  • If the problem persists I lightly use one of these on each front corner
    quick-release-clamp-15cm.jpg
 
Agree with the Birthday Boy that Wendy is a wealth of information. She gave me a tip that saved me thousands of dollars and prolonged the life of my 51 x 100 press - even though she could have said that the only solution was to buy the expensive parts for repair.

A vacuum press is relatively simple in it's mechanics.

You have already determined that the airflow from the vacuum intakes to your pump are solid and that your gauge and the lines to it are intact.

You have already determined that the hinges at their lowest setting do not provide enough pressure to "seal" the diaphragm to obtain vacuum.

While you have not determined that there is not a hole in the diaphragm, my experience is that even with a hole, there will be the ability to draw a vacuum although it week.

Even with applying clamps externally, if the foam that pushes the bladder to the top of the press is old or has lost it's elasticity, all the clamping in the world will not allow a proper seal around the entire perimeter.

On the bottom of the diaphragm (bladder) should be a piece of masonite that has the foam pieces that are attached to the bladder. That masonite rests on the frame holding the press together. There may be a few screws also holding the masonite to the frame and/or some silicone, hot glue or VHB tape (depending on when the press was made). If there are screws, you will see the tips coming through the frame. You may have to move the foam aside to access the heads for removal.

To extend the "life" of the foam strips, you can "break" the masonite away from the frame and apply "shims" under the masonite to lift the entire bladder/foam strips upwards towards the platen. You may have to use a putty knife to get to whatever is holding the masonite down.

We used 1/4" strips of Innerspace because they fit and are "clean" - but any 1/4" thick material that can run completely around the perimeter of the frame between the underside of the masonite and the frame will work.

Once lifted, do the "hinge adjustment" procedure and I bet unless you do have a hole, you will be back in business.
 
Longshot, but is the felt cloth in the machine?
 
Thanks for all of the tips. I have tried everything and I still get no pressure. I thought about hooking up my fog machine to the vacuum line and blowing the fog into the closed unit to see if I can spot any leaks that way. Any comments on whether that would be a good idea or not would be great. Any other ideas or tips that I have not yet tried ?

Thanks
 
If you know somebody who uses an electronic cigarette it is the same vapor as the fog machine. Hold the lid shut and have them blow the vapor around the lid while it is running. There is no residue that will result from this.
 
The fog machine is a great idea..that is how the pharmaceutical and electronic industry check there positive pressure clean rooms...
 
All good info, I'll be bookmarking this one.

Do you leave the lid closed or partially open when not in use? If closed, try cutting a couple 1X 2 prop sticks, and put under the front of the lid edgewise (1.5") and allow to sit over night. The foam may need a chance to rebound a little in order to pull vacuum.

If I read what you asked correctly, the answer would be that the foam strips need to be continuous and consistent in thickness.

I had a pinhole leak in an old vacuum press and finding it was a b****. Once located a simple bicycle inner tube repair patch (on the outside of the diaphram) solved the problem.
 
Wally- were you able to pull any vacuum with your pin hole leak? I had a tear on the side of one of the two valves where the air is sucked out of the press and even with the tear, I was able to achieve a vacuum - but it would never get to full pressure.
 
Rob, the vac press in question was pre-Seal. I think some local guy was making them in his garage. It was 32X40 and only had one manifold for the vacuum and a glass platten (beneficial in finding leak since we were able to paint the bladder with soapy water and look for bubbles).
It would pull a vacuum, but maybe only 10% of what it did with no leak.
 
After speaking with Wendy, and upon further review of the diaphragm, it seems as though the foam inside the diaphragm has been compressed to the point where it needs to be replaced. It is fine on both sides, but on the front and back of the diaphragm, there is hardly any left. I completely removed the diaphragm and opened the rubber to access the foam strip. I am wondering if anyone has ever replaced this foam, and if so, where and what product have you used ? Thanks again for your help in advance.
 
Google "Gasket Supply" with your zip code and you will find a neoprene supplier. Take a piece with you and you will get what you need most likely in a local spot.
 
After speaking with Wendy, and upon further review of the diaphragm, it seems as though the foam inside the diaphragm has been compressed to the point where it needs to be replaced. It is fine on both sides, but on the front and back of the diaphragm, there is hardly any left. I completely removed the diaphragm and opened the rubber to access the foam strip. I am wondering if anyone has ever replaced this foam, and if so, where and what product have you used ? Thanks again for your help in advance.
 
Jeff-

While my Print Mount press uses a rubber seal, The SEAL (Bienfang/D&K) brand press uses grey high density foam rubber under the rubber bladder that is best sourced cut into strips from DK.

It would be pretty bold to call Wendy for advice if you used other than OEM parts and she is a great resource.

I would order the foam from Wendy and allow her to assist you in replacing it. It isn't that hard.
 
Sorry Rob I thought it was some emergency they couldn't take care of in a timely fashion since after the advice the part was not on the way. :shrug:
 
I have spoken with Wendy and I ordered the foam through her. Thanks for all of the info everyone, hopefully this will resolve the issue.
 
Back
Top