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Veneered columns with PVC substrates Question
Forum Responses
When using PVC as a substrate, Flam Base Contact seems to bond the best. Prepare the surface by sanding with 120 grit paper before applying the adhesive. Make sure to let your adhesive flash off the proper time before applying your veneer. Make sure to apply 100% coverage to both your veneer and the PVC pipe. Locke Wilde, forum technical advisor
We recently did a job with 1/2 columns, using PVC pipe. On the advice of the glue supplier we used polyurethane glue and put it in the vacuum press. We had the best bond and cleanest, flattest, and smoothest results ever. It took slightly longer. From the original questioner: I veneered the columns before getting the response about using polyurethane. I sanded the sheen off the PVC and applied a generous amount of flam-based contact cement to the veneer and PVC. I waited the recommended time before applying the veneer. I used the edge of a 1x2 to scrape the veneer to assure good contact (I tried using a scraper and caught an edge). The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment). Comment from contributor A:
Comment from contributor B: I did an award winning production run of Art Deco hall mirrors a few years back that utilized raw, unbacked, bookmatched veneered 4" PVC columns as the main vertical design/structural members. These columns utilized two adhesive methods that I kept as trade secrets for a while, but now I develop color-changing laminates, so I'll share them freely. The veneering method is more production efficient and permanent than all the aforementioned methods due to the adhesive I used - clear PVC cement loaded in my HVLP spray gun. The results were incredible in the flatness - no telegraphing of lumpy contact cement, and clear glue squeeze-out through the pores of the wood took the high-solids topcoats without any discoloration. The key to success is speed in the following: Make a clamping sleeve out of .010 - .020" decorative, perforated aluminum, the kind used for radiator grills that simulate chair caning. It should wrap around the pipe exactly, and you must attach 3/8" x 3/4" oak strips with a 70° bevel (3/4 face down) to the long edges of this metal sleeve using epoxy for super strong bond into the perfed metal. You will clamp the sleeve around the pipe with three or four wood hand-screw clamps (long edges of jaws), one clamp every foot of length. Now load the spray gun (large nozzle for thicker paint) with clear PVC cement, thinned a little with solvent cement or MEK, or straight. Do outdoors or in good booth for fume evac, though there will be no suspended overspray. Spray the raw veneer heavily - say 30 mils, place the veneer in the sleeve and immediately lay the pipe into the wet cement and clamp immediately. Bond time is about four minutes. Remove clamps after seven minutes for a full solvent weld of the veneer to the pipe - totally permanent. I veneered about ten columns an hour, and have done close to sixty columns, 3" and 4" DIA in these three grand mirrors using hand selected, bookmatched (left vertical column mirrored the right column) veneers from fiddleback redwood, pommelle sapele, quilted maple, quartered Avodire, to easy bending fiddleback makoreŽ. The other adhesive method that was quite revolutionary to me for strong structural bonding of wood to PVC or other solvent-softening plastics is a wet-on-wet adhesive method by bedding plywood coated with PL Premium polyurethane into PVC that was primed with wet PVC cement. The two adhesives bond molecularly, then solvent weld into the plastic. I had to do structural break tests on this type of joint because my mirrors - at over a hundred pounds - were hung on walls where the hanging wire was mounted to 3/4" x 1" x 40" plywood rips that held the weight, and were bonded to the inside radii of the PVC pipe using this method. Tests were done with a variety of serious adhesives on roughed-up PVC, but break tests on the W-O-W method showed primary substrate failure, not glue joint failure - on smooth PVC. I absolutely guarantee that there is no stronger adhesive tactic for wood to plastic due to the incredible adhesion of the polyurethane on the wood, as we all know with PL Premium, coupled with the solvent weld to the PVC. Would you like to add information to this article? Interested in writing or submitting an article? Have a question about this article? Have you reviewed the related Knowledge Base areas below? 
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