Vacuum Bag Veneering Tips

      Some detailed advice about vacuum bag veneer methods. April 2, 2013

Question
I bought some beautiful birds eye maple flitches to use on 5 door faces (approximately 24 x 26"). I'm very excited about building my wall mounted (tilt-down) press frame, and building my vac (veneersupplies.com), but would like to postpone the expense till after this particular job. Can these reasonably small panels be done easily without vacuum? I'm concerned the bird's eye figure won't be perfectly flat without pulling a vacuum, and the job has to be right the first time. I don't want to invest too much time or cash to buy some other product and learn another system (i.e. hide glue or other) unless there would be times in the future where I'd choose these over the vac system. In other words, once you use the vacuum system, do you ever go back, in certain applications, to the other ways?

Regarding the use of the other methods (veneer hammer, etc.), would the eyes pop back up after you pass over them with the pressure of the tool?

Also, if you use the mesh on the top in a frame press and not a caul, how do you keep the overhanging edges from breaking from the pressure? Do you just have other panels close by the edges?

I do want first rate results, so tell me what I need to hear. I plan on including veneering as a beautiful upgrade in my work from here on out.

Forum Responses
(Veneer Forum)
From contributor R:
As far as the pressing, it's pretty simple, and was done for generations before the vacuum presses were used. You can buy used mechanical presses, build your own, use lots of clamps and cauls, park your truck on it, brace it to the ceiling with bowed 2x4's, etc. You can oversize your blank and trim to final size if you are worried about overhanging veneer breakage. I've never clamped without a melamine cover sheet. If your veneer is not flat and you are worried about pop back, press it flat before glueup. Do a little research here and buy a DVD.



From contributor J:
You can do it without the vac, but you'll have to build something to do that with anyway. You may as well just get busy and build the press. You'll be glad you did. If you're in a big hurry, find somebody close with press.

Always press with caul. You will have trouble without one. Yes, the breather mesh can leave indentations all along the edges. One of my shopmates uses foam core. Not sure what you're talking about with the eyes. There's nowhere down for them to go. The veneer hammer isn't really a hammer, but a wide flat burnisher.

Have fun. Learn on cheap veneer that you can screw up.



From contributor F:
I have used every type of press known. They all have some specific work they are just right for. A vacuum press is the most versatile. Hand veneering with hot glue and a veneer hammer is the only process for some applications. It can be quicker than building the forms for the vacuum bag. I use this method often.

The idea behind pressing is to achieve the thinnest consistently even glue line. This prevents air pockets and lumps that can be sanded through.

I cover the bottom caul first with coated butcher paper to avoid any mishap between the veneer and the caul. Any wrinkles in the paper will transfer to the veneer. A couple of pieces of tape around the edges of the paper will keep it flat. Place the veneer face down on the prepared bottom caul.

Apply adhesive to the substrate and place on top of the veneer. Any oversizing of the veneer will not be broken off by the bag - it is fully supported by the bottom caul - and glue squeeze-out does not dribble down the edges of the substrate. It pools on the proud edges of the veneer and the butcher paper.

Because the bottom caul provides the flat for the veneer, I have evolved my process to using cardboard as buffers on top of the substrate to protect the bag.

Use 3M blue tape, applied to the face of the veneer, and then fold over the back of the substrate to position the veneer to the substrate and assure accurate alignment. This tape comes off the easiest after vacuum pressing. If the veneer is fragile, I use veneer tape on the face of the veneer and locate the blue tape on these bits of veneer tape. When the blue tape is removed it removes some of the veneer tape, not the fibers of the veneer from sharp edges.

I agree with contributor J - build the press now. The one from Joe at veneersupplies.com is very good and inexpensive with excellent customer service. Veneering opened up a whole new pallet for me as a designer. It will for you, too.



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