WWA Info Exchange

Well, in light of my upcoming veneering I thought I'd better do some practice as I've never veneered anything before.

After first buying contact cement from Woodworker's source-- research showed me for the size (15x48) and type of (shop made 1/16 thick) veneer I will be working with I really should a vacuum press and use a hard-curing glue (like PPR / urea resin glue)



Although I hadn't used it yet, about a year ago, I purchased a roarockit veneer kit from rockler on clearance for a song (I think it was either 19.99 or 29.99... either way it was pretty darned inexpensive. This included
1. A 14x47 inch - 20 mm vacuum bag
2. 3 tar-tape-like reusable seal tapes
3. A large piece of "breather netting" (a net-type nylon material)
4. A manual pump similar to those used to pump air out of wine bottles
5. Instructions


Last night I did my first glue-up and gave it a go---
I mixed my PPR glue as specified on the label (5/2 powder/water mix), spread it on my MDF substrate, added my veneer, wrapped it in the netting to allow the bag to breathe and create an even vacuum, and then carefully removed the wax paper covering the sealing tape and fixed it shut. As specified in the instructions, I carefully checked the seal for any light spots indicating air bubbles and massaged them out-- the whole sealing ordeal took about 30 seconds.


I then put a half-bottlecap of water into the valve to help create a seal (as specified in the instructions), put the manual pump onto the valve (It just sits in place and does not "click" or anything), held my breath, and pumped...

after about 3 pumps (zero resistance felt) I could visually see the bag compressing... after about 10 I could feel and see actual vacuum pressure on the pieces. The instructions say you can feel when the required pressure (around 12-15 psi) is reached because it gets much harder to pump-- this happened after about 30-40 pumps or so (about 30 seconds of effortless pumping) and was indeed noticable because the bag had sucked very hard against the netting to such an extent that it looked like a plump girl's fishnet stockings (sorry, no other way to describe it well) There was also an even squeezeout (even though I had only put on a quite thin coat of glue) The instructions indicated that I should pump for 1 minute after reaching this point and I did so but did not notice much appreciable change in the bag as it was hard as drum-- at this point the pump provided resistance but was not overly hard to pump for 1 minute (about as hard to pump as the first one or two pumps of a bb gun)


I left the bag inside and checked it every couple of minutes for the first half-hour or so - there was no sign of the vacuum letting up at all-- I then left it overnight and in the morning it still looked the same. I put it back out in the shop and didn't open it until this afternoon-- The tape is quite sticky (almost 3-hour chewed bubble gum consistancy with a tar-like appearance) but it came apart with little resistance. I then replaced the wax paper to keep the tape from becoming contaminated. As I pulled the bag itself apart, there was a very noticable "whoosh" when I finally broke the seal to the netting and I could feel air rush by my hand-- the glue squeezout came off the netting and bag with no problem, I remove the piece from the net, and ran a piece off to check for delamination and even press--


A very good bond was created all over the piece and it is consistantly thick throughout ( put chalk on top and ran it through a tuned drum sander to check) I am quite happy with the results of the glue (no bleeding through the wood- though it really shouldn't anyway with white oak) and the vacuum pressure worked better than I could have hoped.

The company makes various sized kits and custom-sized bags are offered as well. I figure the 36x52 inch one I have on the way will cover me for just about anything I will throw at it-- coincidentally this is just about the same size as my kitchen table which is where I will leave the pieces to dry....

I'll let you know how the sealing tape holds up as that seems to be the possible weak point (though reviewers state that if cared for it has lasted for 20+ projects for them and replacement tape costs about $3)

I was slightly skeptical of the seal and will remain so for a few projects-- the company states that they have found glue ups after 1 year (skateboards) that were still under full vacuum and I have to say that after seeing this I believe them.

Thanks for taking the time to read this, and if you have any questions or comments (like telling me if I'm wrong about the glue for instance...) or have any hints about vacuum presses in general I'd love to hear them as this is a very new experience for me and I have quite a bit (275 linear feet or so of 5 inch wide veneer) of MDF to laminate for this project. I will be veneering top and bottom white oak for some pieces and top oak and bottom secondary wood veneer for others-- this piece was veneered top only and will be used as a finish test piece and to test how much bowing is created in the MDF by only laminating one side.
Thanks again,
Lawrence

it looked like a plump girl's fishnet stockings

The tape is quite sticky (almost 3-hour chewed bubble gum consistency with a tar-like appearance)

It's descriptions such as these that really bring it into being "the minds eye".



Great work, Lawrence!

I've had opportunities to buy that same kit at greatly reduced prices ... and haven't done so. May add it to my list.

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~Dan.

Really an interesting post Lawrence. It looks like the cost of equipment to get into a vacuum press is very reasonable. Veneering has always interested me but I've never attempted it. Thanks for the details and I'm really interested to see your progress.

Couple of questions:
Since the veneer is relatively thin in comparison to the substrate, is warping an issue when the veneer is applied to only one side? I suppose applying veneer to both substrate surfaces is fairly common practice since both surfaces are most likely visible in most situations which would negate the warping issue.

I've just purchased some DAP Plastic Resing glue but have never used it. I got it to assist with a time consuming glue up that I'm faced with - lots of joints coming together at the same time. I'm thinking that the longer open time with the PPR will reduce the glue up angst! Any advice on using the PPR?

Thanks again for the informative post.
Tom

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T-n-T

Hey Lawrence....it looks great and seems as though you figured in the learning curve. Good luck with your future veneering..I admire and respect the patience required for the final results. Looks great from here!

All the Best,
Bruce

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"In Wilderness is the preservation of the world"...Thoreau

Nice review. I may even look into that.

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Frank
WWACOAUX#1
"I love the smell of Sawdust in the morning, it smells like, victory."
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Stumbled on this post - my $.02... last Xmas, I bought my 10 yr old son a skateboard-building kit directly from Roarockit, came w/ all press parts that Lawrence described, 14 pre-cut maple sheets (enough for 2 skateboard decks), two bottles of TB III and a foam mold to give the decks all the necessary bends. Instructions and customer service were excellent and the press worked as advertised, though we were a little agressive w/ the sealing tape and will probably have to replace before building the next deck. The finished product came out really well, a great dad-son project. I will find photos to prove it happened

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Mike