one last veneer question

jim capozzi

Member
Messages
280
Location
oswego county , upstate n.y.
hi all

ok one more question :huh:

i was reading the book that came with my vac. press . it said to make your cauls the same size as your project if you were working with 1/8" or 1/4" sheet goods. the book didn't say anything about 1/2 or 3/4 plywood , do i also have to size these cauls the same way . to my little brain this seems incredibly wasteful and could get insanely expensive after a very short time . if i use 3/4 baltic birch ply is this still the rule? i cut it to a managable size for my platten board and a top caul , both are 30x30. if i use these for smaller projects will it work or will they bubble or not seal the veneer in the middle of the piece ?
thanks for the help AGAIN! :dunno:
 
When I do an expensive project, say a table top, I make a caul the size of the glue-up. But you're right that it can get expensive if you make a custom caul for every project. If you work with the same thickness substrate all the time (say 3/4 inch), you can make some supports that can be used to hold up the outside of the top caul so that the caul doesn't dome over when you pull vacuum. You can make these supports out of failed veneer projects, or from test projects you ran. Stick your project into the bag, put your caul on top, and then put your caul supports around the outside and under the caul. If the supports are one veneer thickness different than your project, it won't make any difference. That will allow you to have a few cauls that you can use for odd sized panels.

Interesting question. I'll be interested to find out what Tod does. Maybe he has a better solution.

Mike
 
This is probably blasphemy, but I've been using 1/2" foam insulation for cauls lately. It has worked well for me, and I don't have to worry about sharp edges damaging the bag. Like Mike, I'll be interested in what Tod has to say.
 
mornin`, foam works but i`ve had occasions of bubbling.......for flat work i use waxed melimine over screen wire then place the veneer directly on the melmine with the glued substraight on top, cover in visqueen and suck-`er down for an hour or two depending on glue and temp.....prepare the other sides veneer, remove the veneered on one side piece trim veneer, apply glue to the other side of the substraight place right back on the waxed caul and suck-`er down again.....for curves i use aluminum roof flashing waxed then veneer then substraight.....tod
 
I was thinking some more about your question. One thing I do with small odd sized panels is press them between a couple of torsion boxes instead of using the vacuum bag. My torsion boxes are 18" by 24" so I can press anything that big or smaller with them.

Two reasons for this: One is that I have a very small shop and when I set up the vacuum bag and pump, it takes up most of the shop so all other work stops. Second, when I use the torsion boxes, I don't have to worry about a caul and how well it fits. In essence, the torsion boxes become the platen and caul. The only disadvantage is storing the torsion boxes - you can't roll them up like you can a vacuum bag.:)

Mike
 
Top