Building a Glue Press

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Creating a glue press system in-shop. April 2, 2004

I need to sandwich some 12 ft boards together. Does anyone have a nifty design for a glue press?

Forum Responses
(Veneer Forum)
From contributor L:
I've borrowed some long 6" by 12" I beams from my metal supply friends before. Works great and you have a lot of clamping surface to work with. They are also very heavy.

From contributor W:
A vacuum bag will give the most uniform pressure. I buy 2' wide nylon bags by the foot (as long as you need). Surface both faces to be glued, apply a coating of urea resin to one face (5 mil), assemble and slide into the bag. Clamp time for PPR is 5 hours. Less with heat.

From contributor B:
We use polytubing for our long bag pressing. It's available in widths from about 1" to 36" and is very cheap. Use once, cut it off the moulding and toss it. Use 6 mil thick material... 8 mil if it's available. We mostly use the 8" wide material for curved door jambs.

From contributor M:
Here's a simple, effective clamp we've used for laminating boards face to face when building oversize stiles for house doors. We'd typically place these about 8" apart.

From contributor D:
What a great idea to use disposable bags. I have been using a regular 20mil bag. The disposable ones would speed it up. I found 6mil bags at Uline. Do you glue a nipple in the bag each time and cut out and reuse it or do you have another method?

From contributor B:
We package our mouldings when complete in 4 mil polytubing. We keep 4", 5", 6", 8", 12" and 16" rolls on a pull-off rack. We use these for laminating when we need other than the 6 mil sizes we keep only in 6" and 8".

I mention this because I want to emphasize that you will have to be very careful handling your setup... the polytubing will tear or puncture easily. When we use the 4 mil stuff, we have to be even more careful. We keep clear packing tape close to the work table for quick repairs. The first 2 or 3 times we tried this system were total failures. Now we have nearly a 100% success rate. I guess I'm suggesting you do a few dry runs before using glue.

We do our bending setups on a 4x8 piece of melamine with rounded over edges. We used to screw our bending forms down to this work surface... now we put vacuum pods on the bottom of blocks and screw the forms to the blocks. This way we don't put holes in the melamine sheet that could catch the polytubing and tear it.

We seal one end of the polytubing with our 8" heat sealer. Then we insert the lamination sandwich along with a 3/8" polyethylene tubing that goes full length and sticks out the open end about a foot. We are careful that we have a foam sheet on the edge of the bench for the polytubing to be sliding over when inserting the sandwich. We trim the open end of the tube to a point and wrap it tightly around the 3/8" tube. Then we wrap about 6" of wrapped bag/tube with electrical tape. This seals the second end of the bag.

The 3/8" tube goes to a quick connect fitting on our vacuum manifold.

At first you might feel this is a lot to go through instead of just using a vinyl or polyurethane bag. The first time you have to unwrap a very tight radius lamination though you will appreciate being able to just cut away the polytubing instead of fighting to remove the lamination sandwich. Once you've done the process a few times you'll never even consider going back. I have about a half dozen vinyl cigar tube bags that haven't seen the light of day in years.

From contributor D:
Thanks for the quick and detailed response. As soon as I read “disposable bags” I knew it would be faster then the old way. Although we don’t do the quantity of glueups you do, we do occasional radius glueups, plus we use a vacuum for gluing up stave core door stiles and face glued trim. The only question I have is getting a tight seal at the open end with electrical tape, but we will try it and work it out.

From contributor B:
Yes, it would seem unlikely to get a good seal with the electrical tape. We go up and down the 6" bag/tube overlap section 2 or 3 times plus run the tape out an inch or two onto the tube itself. Occasionally we'll get a small leak, but not enough to effect the process.

Give it a try... it's worth sticking it out for a few failed no glue attempts until you get it to work.

From contributor W:
The nylon bags I referred to are fairly durable. I can get at least a half dozen uses before I start to notice leaks. I've yet to find an adhesive that will bond the nylon to the work piece, so they remove easily. The end seal consists of a 1/4" nylon rod and a "C" shaped cap piece. The rod is placed under the bag and the "C" cap snaps onto the rod pinching the bag in between. A steel 1/4" barbed fitting attaches the hose to the bag. It is a two piece fitting with an o-ring for a seal. Cut a 3/8" diameter hole and hand tighten.

From contributor M:
New use for your latex stain gloves. I use them as a glue press for small complex parts.

From contributor A:
I helped my best friend lay up a custom 40 foot racing sailboat a couple of seasons ago. We got a plastic bag material from a company in Rhode Island that supplies all of the local boat builders (it's not Jamestown Dist.). They are a glass/resin supplies company. Anyway, it comes in 36" rolls and you seam a bag with this silly putty like stuff that the boat builders like to call "monkey gunk." We were able to use the same bag about 3 times on a forty foot glass/foam boat. Almost no tears at all. For our purposes the plastic may be more expensive than the Homie Dopie 6 mil poly. I was told that the boat builders like this stuff because it is not micro porous like the 6 mil poly and once pulled the vacuum with last much longer and not wear out the pump. The monkey gunk is well worth it. You can wrap a little around the vacuum tube to seal it tight. It is also a perfect material to bond the bag to the board. We likewise used a lot of melamine for vacuum boards.