Using workshop press to laminate timber?

[Mark Bolton]

Our skid steer bleeds off pretty quickly but hydraulic presses are common in the woodworking industry. We have a Italpress frame clamp that holds pressure. Doors and windows are cycled quickly through this but sometimes we face glue scantlings in this where they are pressed for 4 hours or sometimes overnight with no loss of pressure. I also used a Barth hand hydraulic press in a shop we were setting up and it held fine.
a couple local shops here had shop built stile presses made with steel beams and hydraulic cylinders that the owners said worked well.
Attachment 391511

Right but dont those presses clamp on the rod of the cylinder? I was always under the assumption that the hyd. clamps applied pressure and then the cylinder rod was clamped so the hyd. is now out of the loop.

I dont disagree that a high quality hyd. setup may hold plenty well but was more referring to a shop style press even something like a Dake or Baleigh. Something in that class has nothing in its design for holding a fixed pressure for long periods.

[Albert Lee]

Right but dont those presses clamp on the rod of the cylinder? I was always under the assumption that the hyd. clamps applied pressure and then the cylinder rod was clamped so the hyd. is now out of the loop.

I dont disagree that a high quality hyd. setup may hold plenty well but was more referring to a shop style press even something like a Dake or Baleigh. Something in that class has nothing in its design for holding a fixed pressure for long periods.

I have a similar press like that but its pneumatic. I have considered utilising this clamp for what I want to achieve but I need 20 pneumatic cylinder each with 5" bore to reach the desired pressure (10 up 10 bottom), the cost is the same as 2 quality hydraulic press (Compac or AC Hydraulic). the pneumatic will maintain the pressure

here is a picture of my existing press

13307444_10153906317938813_4623044939678889481_n.jpg

The issue I have with this press is that it doesnt give enough pressure. each cylinder can only do about 400kg at 8 Bar.

[Joe Calhoon]

Mark, I don’t know much about hydraulics. The cylinders on my press are double action. Maybe that is why they hold. I believe the Barth presses are double acting also even though they pump up manual.

Albert,
pneumatic is OK for cabinet size components but weak for face laminating and entry door - window pressing.

[Joe Chritz]

Seems like for as many as you are looking at doing a vacuum press would be the best and fastest option.

That said good hydraulic presses would work but I know you can get into a good electric vacuum system with an 8 foot capacity bag for around $500ish. Less for a venturi setup.

Joe

[Mark Bolton]

the pneumatic will maintain the pressure

Right, That was kind of my point with the hydraulic all along. With air cylinders you apply pressure and just leave the air on so if a cylinder or valve has a tiny, imperceptible leak, its of no issue, the air pressure remains at all times. Thats not how standard/non-dynamic, hydraulics work.

You see it on large presses that need to hold pressure. Commonly, a cylinder applies pressure, and then a set of wedges, blocks, or something, are actuated between the platten and a set of physical stops. Those physical stops hold the clamping force over whatever period of time because the pressure cylinder WILL leak off, and the only way to apply constant pressure is to either cycle the valve pulsing pressure back in or to simply force the pump to dump to relief constantly (ruining your pump, relief, and oil) or some other extremely costly proportionate flow control valve.

Im not positive because Ive never been around one but I thought presses like the one Joe shows have a clamp that engages the extended rod when the clamping happens. This locks the rod at whatever extended length its at not allowing it to retract when the pump is shut off. But may well be wrong.

[Larry Edgerton]

I made a couple of column presses as I make columns out of Versatex and I have to be fast. I used two 14" LVL's, threaded rod every foot on both sides ever foot. Slip in the glued column, grab the air ratchet and snug up, go back and set tension by hand. This was kind of an experiment so I could build some permanent ones, but they worked so well that they have been in use for ten years now. I built two ten footers and when I need to make something longer I can set then end to end. Only bad point is they are kind of heavy. They get heavier every year ?