Vacuum Veneering

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Forum topic by kolwdwrkr posted 10-14-2009 07:53 AM 1456 views 1 time favorited 6 replies Add to Favorites Watch
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2821 posts in 3012 days

10-14-2009 07:53 AM

Topic tags/keywords: question

I haven’t had much experience with vacuum veneering large panels simply because you can pretty much buy whatever you want, which is what I have always done. On smaller projects, such as my marquetry projects, I have always glued my veneer to my substrate (one on front, and one of back for stabilization) and then put a caul on the front and back as well. Then placed it into the bag. The question is do you use a caul on larger panels. The caul would be the same size as the panel being veneered.
The reason I ask is because I am working for a company that uses bamboo. We have to veneer one side of the bamboo to match the interiors if they aren’t glass. The interiors are prefinished maple. So I had to veneer a few panels with maple veneer. I put glue on the material, spread it out equally, and then taped the veneer to it. I then placed some plastic on it, then a caul the same size. The plastic was to protect the caul from sticking to the piece. I put the piece into the bag and let it run. I took it out after a few hours and there was wrinkles. So I tried again, and the same thing. Is it the caul? How do you all veneer in a vacuum press? Is there a tutorial here somewhere? Thanks

-- ~ Inspiring those who inspire me ~

6 replies so far

View Les Hastings's profile

Les Hastings

1300 posts in 3195 days

#1 posted 10-14-2009 12:40 PM

Don’t use the plastic, if it wrinkles the veneer will wrinkle with it. Use 1/4 or 1/2 melamine, wax it good and it will not stick to the veneer if the glue rises. If you still think you need to cover it with something use brown craft paper it will not wrinkle like plastic will.

-- Les, Wichita, Ks. (I'd rather be covered in saw dust!)

View Moron's profile


5032 posts in 3315 days

#2 posted 10-14-2009 02:06 PM

I use a melamine substrate with kerfs cut into lt to make a “chessboard”........the kerfs allow the air to escape and the melamine wont stick to glue being squeezed out. That goes into the bottom of the bag…...then place the piece being veneered into the bag. I dont use a caul, just the bag and by using a PL roller I can flatten the veneer to remove wrinkles by squeezing out any trapped air and I can see through the clear vacumn bag

-- "Good artists borrow, great artists steal”…..Picasso

View Karson's profile


35032 posts in 3822 days

#3 posted 10-15-2009 12:33 AM

Keith: I didn’t like the idea of cutting a caul to the size of my panels every time I wanted to do some veneering. So I did something very unique I do my veneering upside down.

I have a 4 X 8’ piece of melamine in the bottom of the bag. It has saw slices every 6” to allow the air to move around. The hose from the vacuum pump goes through the bag into a hole in the side of the melamine panel and then has a hole from the edge to the vertical hole. That allows the vacuum to get to the slots.

As to the upside down veneering, I make a caul that is a lot bigger than my panel and I put Butcher paper over the caul. It is taped on the opposite side. The butcher paper has a plastic coating and the glue that comes through the veneer doesn’t stick to the paper.

So what I do is put my glue on the plywood or whatever I’m veneering. I put the veneer on the butcher paper upside down. The face is against the butcher paper surface. I then put my glued pane on top of the veneer. So what I’m getting is the panel acts as the caul and the larger butcher papered sheet does not flex when the veneer is active.

This keeps a caul from bending under a vacuum pressure if its too large for the panel being covered.

I only veneer on one side this way after It is glued I do the same for the backer veneer.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Southern Delaware soon moving to Virginia †

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Dan'um Style

14167 posts in 3404 days

#4 posted 10-15-2009 01:02 AM

Hey Keith

Have you ever used this sight ?


-- keeping myself entertained ... Humor and fun lubricate the brain

View John Ormsby's profile

John Ormsby

1283 posts in 3158 days

#5 posted 10-15-2009 01:10 AM

I use EvacuNet for veneering. It is very simple and works great. Below is a link to the site.

-- Oldworld, Fair Oaks, Ca

View kolwdwrkr's profile


2821 posts in 3012 days

#6 posted 10-15-2009 04:35 AM

Okay, so the mistake was #1- I used plastic, which could have caused air pockets and allowed the veneer to wrinkle #2- I’m positive I used to much glue, #3- my platen (I called a call, but am learning otherwise) was to thin and should have been kerfed like the bottom platen. I noticed on (thanks for the link Dan) that they do use 2 platens, one on top and one on bottom. It shoes both platens at 3/4” thick, both with kerfs to allow air flow. However, It shows that the kerfs on both pieces are facing the bag. I believe in the set up instructions to the press that the bottom platen has the kerfs facing the piece. So that is something new.
I think I will leave the platen off for the next try, as well as look into that EvacuNet. With everyones help I’m sure this will all smooth over and work out peachy. Thanks guys.

-- ~ Inspiring those who inspire me ~

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