This might be more appropriate in the joinery disucssion, dunno –
I’m thinking of building our bathroom vanity using some really nice salvaged mahogany from …. a pallet that a Kubota tractor was shipped on. I experimented this evening re-sawing one of the roughly 3 1/2″ pieces into 1/8″ slabs. My little Delta bandsaw didn’t seem to mind all that much.
So – I realize whatever finish you put on one side of a door you should put on the other as well to balance the stresses. I was thinking for the vanity doors what I’d do is slice off 1/8″ veneers and glue them to the face and back of 1/2″ plywood to reach a 3/4″ thickness then edgeband the doors. Without a veneer press of vacuum bag, I figure a few concrete blocks over a good flat sheet of plywood could suffice for pressuring these veneers to stay put.
Does this sound feasible? Understand, while I probably *could* simply go buy some nice 3/4″ cherry, walnut or whatever plywood, it’s the idea that I made a fairly handsome piece out of a packing crate that inspires me to such fantasies! (grin)
Replies
>> ... a few concrete blocks over a good flat sheet of plywood could suffice ...
First, calculate 10 PSI (and most vacuum presses can actually do better than that) times the surface area of your doors, and see what you think.
Edited 12/1/2003 2:33:13 AM ET by Uncle Dunc
Unc -
Guess I better go buy some more blocks! Good thing I've got a big truck. (hehehe)
Come to think of it, all I really need is a vacuum pump - I've got most of the makings of a vacuum press lying around in my .... raw material storage supply room.
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Dennis in Bellevue WA
[email protected]
Try this place - http://www.joewoodworker.com/veneering/whybuild.htm complete instructions for a DIY vaccum bag and vaccum reservoir. i made the reservoir for a veneering job and have also found the reservoir works with my vacuum system on the lathe, it saves the pump and electricity.
One of the things that I have found to work great for a resevoir tank(surge tank) is an old booster tank from a well system.. All you need to do is tee off the line that goes to the vacuum bag and run it to the surge tank. Make sure you have a check valve between the pump and the tee to prevent "backfeeding" the vacuum pump when the pump shuts off. Allmost any size pump will work, just make sure you draw down the surge tank prior to starting you glue up. I recommend a control that is by Qualityvak http://www.qualityvak.com The controller part #EC. Runs around $250. Seems really cheap compared to the tractor you just uncrated. I have even used a clear plastic trash bag with 2 sticks and 3) 2" spring clamps to hold the bag closed until the bag draws down, then the clamps are not needed. A little putty like they use on RV's to seal the hose. Works great
Another great thing about the controller is that it has a setting for using it as a vacuum holddown/clamp
Still time to order one to have shipped in time to be under the tree
On the veneering forum at http://www.vacupress.com it is recommended that resawn veneer not be thicker than 1/16" or it starts to expand and contract strongly enough to act like solid wood (i.e. split, warp, ...).
Ahhhhhh - 1/16" thick veneers is, at least, part of the secret!! I figured it wouldn't be as simple as it looked! (grin)
Gotta get with the links folks have posted and think seriously about my vacuum press! (grin)
Thanks, all.
So few hours and so many fun things to experiment with.
By the way, I didn't get the tractor that was on the shipping pallet. I just scrounged the lumber from the dealer. If I had the tractor I'd be out playing in the mud and wouldn't have time to fritter away on such benevolent pastimes as woodworking!
hehehehe
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Dennis in Bellevue WA
[email protected]
Dennis—
I heartily share your enthusiasm for using old pallet wood for veneer. It’s ranks high for bragging rights, plus it’s a great way to make new from old and to recycle. Above all, the part-Scot in me cherishes a good value. (Read: Free or cheap.)
While I realize the board over at Vacuum Pressing Systems advises veneer no thicker than 1/16 in., I think you can go a little thicker. Good evidence of this can be seen by over 200 students’ and instructors’ work that has come out of the woodshop at The College of the Redwoods in Ft. Bragg, California— “Old Jim” Krenov’s teaching school for many years. This stuff is some of the finest hand-made furniture in the world, and the resawn veneered pieces, for which the school is renown for, have withstood the test of time. In my own work, I’ve never had a problem using thicker resawn veneer.
Sawn veneer that’s roughly 1/8 in. thick should be fine for your application. Having said this, the final result will most likely be a tad thinner. I saw my stock at 1/8 in. on the bandsaw. However, by the time I’ve smoothed it and readied it for a finish, the veneer probably nets out at 3/32 in. In either case, I find this extra thickness provides just enough workability for shaping edges so I can provide rounded or chamfered corners in my work. You can even carve into the surface as a decorative element. And there hasn’t been a problem with wood movement.
Sticking the veneer to the substrate correctly is, of course, the key to success. When working with thick veneer, I like to rough up the back of the veneer and sometimes the core material slightly to give them some “tooth” to which the glue can bite. (I normally never perform this step when dealing with thin, commercial veneers.)
You can rough up your stock by cross-sanding with 100-grit sandpaper wrapped around a flat block, or by using a toothing plane—a plane with an iron that has small serrations on its cutting edge, made expressly for this purpose. Sometimes, if my resawing technique is spot-on and the veneer is nice and flat, I glue the sawn surface directly to the core, as the saw marks provide the right amount of tooth. But my standard practice is to thickness-plane the sawn surface to unify it, and then give the planed surface some tooth as mentioned above.
I use a vacuum bag for gluing up, but the setup is expensive for the general hobbyist. Making your own vacuum system is one way to go, and your concrete blocks will work for applying clamping pressure but—man! As you found out, you’re going to need a truckload. A simpler and less back-breaking approach is to use “platens” and “cauls” to help distribute clamping pressure.
Cut a platen from 3/4 in. (or thicker) plywood, MDF or particleboard to the exact size of your core material, and place this on top of the veneer. It’s a good idea to place a platen underneath, too, especially if you’re going to veneer both sides at once.
Next, use several stout cauls at least as long as your assembly is wide—they can be 2x4s or any scrap about 4 in. wide—and place them every 6 in. or so across the platen, both above and below the work. Make sure to align each bottom caul with its respective top caul. I typically place the entire assembly, including the bottom cauls, on 4-in. riser blocks made from scrap plywood to provide clamping purchase. And—very important—the entire setup takes place on a dead-flat bench, so my panel comes out flat after glue-up.
With this setup, you can use your meager collection of C-clamps or quick-clamps on the perimeter only, clamping pairs of cauls to bear pressure over the entire panel. If you find that you’re not getting enough pressure in the middle of the panel, try placing some thin shims under the center of the cauls before applying pressure, or use cauls with a slight belly in the middle.
By the way, like Darryl Keil and his crew over at Vacuum Pressing Systems, I prefer Unibond 800 for veneer work. It’s a plastic-resin glue that does not introduce moisture in the joint, unlike the conventional hardware-store powder variety that you mix with water. With Unibond, you mix a powder with a resin. It has a long open time, allowing you to get your clamps just right, and the wet glue cleans up conveniently with water. It dries super hard, which helps prevent creep, making it great for bent work. This very brittleness makes subsequent sanding and smoothing a real breeze. Plus, it sets in only about an hour—even in a vacuum-sealed (no air) bag. If you haven’t tried it, you can get it from Darryl at Vacuum Pressing Systems, 553 River Road, Brunswick, ME 04011 (207) 725-0935 << http://www.vacupress.com >>.
One last tip, since you’re using thicker, sawn veneers: Why not edgeband the core first with your wood banding, and then apply the veneer? Typically, you need to edgeband commercial veneers to protect their thin and delicate edges, but not so with the sawn stuff. After veneering, you can ease, round over or chamfer the edges of the veneer itself. The most compelling reason for this appproach is you won’t see the joint lines on the face of your finished doors.
—Andy
Wow - great tips & tricks, Andy.
I have seen (read about) using the platen & clampint cauls method for gule-up of veneered panels. I don't think I understand how one would go about doing both sides at the same time, though. Wouldn't one risk having the strips of veneer shift when the panel's turned over?
Given that I would only do one side at a time, is there any time constraint(s) for how long one should wait before applying the opposite side to avoid differential expansion of the panel due to unequal materials on the faces?
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Dennis in Bellevue WA
[email protected]
To keep the veneer from shifting, I use a trick suggested by Darryl Keil, Paul Schurch and others - masking or packing tape. Most use blue masking tape, either sandwiching the upper veneer, core, and lower veneer; or assembling the upper and lower cauls with the veneers and substrate and applying a few strips of tape across the edges of that. Paul Schurch tapes the first assembly, and uses clear packing tape. I had used blue masking tape on just this inner sandwich and found that the pressure of the cauls had made the tape very hard to remove, and indented the veneer slightly under the masking tape. For the last couple veneering jobs I used the clear packing tape with no problem.
Dennis—
Don’s advice is right on, and his mentors are top-notch veneering guys. My pal Frank Pollaro advises the same in regards to tape. The tape can be a problem, so look for “cheap” clear packing tape, or a cheap (non-3M!) masking tape. Press it down good on the veneer, then wrap it over the side of the assembly. In fact, if you’ve got two or more sheets that need butting together to make a seam, you can use the clear tape. But veneering tape—the kind that’s made from paper, has little holes punched through it, and has fish-glue or otherwise weak adhesive backing—is the best tape to use for joining seams.
I’ve used the clear tape with great success, but don’t let it sit too long after veneering; peel it off as soon as possible. And peel slowly or you’ll rip off tiny little wood fibers. You’ll have to wet the paper veneer tape to remove it, then scrape the excess with a card scraper.
The same time-sensitive approach applies when veneering only one side: Try to get the opposite side veneered as soon as possible—the same day if you can. If you can’t, it’s OK. If you have to let it sit, stack the panel on a flat surface with stickers (3/4 x 3/4 strips of wood) below so air can circulate, and make sure to weight it on top to keep it from warping. Big hand planes work great for weights. Your concrete block collection might also come in handy here!
If it were me, I would favor gluing both sides at once. Easier, more time effective, and safer in the long run. Same thing applies, though: After veneering, stack and weight, then wait a few days for the glue (and any possible moisture) to cure and the panel to equalize before putting it into service.
—Andy
Wow!
All this started, to tell the truth, as a result of testing for drift on a new brand of bandsaw blade I recently bought. The first piece of 'scrap' timber I reached for was this packing crate stuff. One thing leading to another, I thought I'd explore the veneering possibilities.
Now I'm really inspired to try to make something of it.
Please, everyone, don't hold your breath waiting for further reports on this [side] project. I've got a full set of kitchen cabinets underway and I need to focus on that part of our house-overhaul to keep thee Ms. from going bannanas on me. But I'm sure gonna sneak a few minutes here and there to apply to this 'experiment'.
Thanks again for all the great advice and encouragement.
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Dennis in Bellevue WA
[email protected]
Ok, Ten replies and you almost have the right answer, thanks to Andy. As a professional, I have to use the fastest method available, and vacuum bags, though well worth it, are not useful for my few times of veneering. I find it just as fast to use the clamping caul method, but Andy forgot the most important part - tapering the ends of the cauls. This way you apply pressure to the middle of the panel, pressing the glue OUT from the center. Otherwise you risk "pooling" the glue in the middle. BTW - Mahogony is one of the lowest dimensional changing woods - very stable, although you're crate aint likely real mahogony -probably lauan - not even botanically related, but close enough - should look real good.
Veneering 101 for a typical 2' x 3' door: Lay down 4-5 cauls across 3' of blocks (clearance for clamp heads) then lay down a layer of MDF or two, then lay down a layar of 1/4" blue styrofoam 'cuz your bandsaw veneer thickness may vary - this will even it out. Then, if it were regular veneer, you'd lay down a layer of plastic to keep from gluing to your backer caul, but here you can lay down your thick veneer directly, then glue both surfaces (I use polyurethane), add the ply substrate, add the rest of the veneer (top layer) and repeat the steps in reverse.
If the tapered ends of the cauls were 1/8" in 2' on 2" x 1-1/2" cauls, you'd get good even pressure. Clamp til the cauls straighten out of course.
SInce I have deep throat Wetzler clamps, I was able to veneer the deck of my boat without tapered cauls, and got great results:
Dennis,
I was reading last night the Aug 02 FWW (#157) which deals with this issue...the veneering of plywood....not putting a tractor in your bathroom.
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