Behlen stringed instrument lacquer7/16/2023 ![]() So anyway, if you are setting up a new system and need to buy all new equipment anyway, consider HVLP. For a large industry it makes a lot of sense because of the saving in material and the reduction in overspray, but for one guy, like me, working in my own shop, the only advantage would be less overspray, and since I don't have a problem with overspray, well. With the amount of material (lacquer, etc.)that I spray, I would never in my lifetime save the price of converting from my conventional spray equipment to HVLP in material savings. The quality of the surface is up to the operator, thought it is dependent on having a good tip/nozzle combination, but that can be had with either system. The big advantage to HVLP is material saving and less overspray. Why? It's what I have, it's what I'm used too, and it works just fine. I've used both, HVLP and conventional, and I spray with conventional guns. A week is OK, two weeks is better, longer may or may not be better still.īuy an HVLP rig and learn how to use it! I have used both conventional and true-turbine-based HVLP extensively, and my DeVilbiss conventional guns just sit there as pretty decorations. Spray once more and let the lacquer cure for buffing. As you build film thickness, eventually you will be able to completely level sand the whole surface. The sanding of the first spray or two needs to be very light just a brush over withe sandpaper to knock off the roughness of the surface. Simply, put, spray two or three coats, wait overnight, sand, repeat. Now, your surface is prepared and the process of applying the lacquer begins. I use blonde shellac, many manufacturers of lacquer recommend vinyl sealer (and usually their own brand), but whatever, apply the sealer and follow the directions for timing if it is a vinyl sealer (the amount of time between vinyl sealer and first coat of lacquer can be critical to good adhesion). ![]() You'll want a sealer of some sort to improve adhesion of the lacquer. If you are going to apply stain (dye) decide how you will do that (rubbed on bare wood, sprayed on bare wood, sprayed over sealer, etc.) I'm sure a spray gun makes the job easier, but its possible to achieve a high quality finish using spray cans.Sand some scrap wood exactly like your mandolin and go through the finish process to see what problems you have (hopefully none, possibly quite a few). I was more careful when I wet sanded this time and the finish came looking beautiful. ![]() ![]() The second time around, I sprayed 6 coats of black followed by about 12 coats of clear. I though about just reapplying more clear coats, but there were a few areas where my scraping of the binding was less than perfect so I ended up stripping it and starting over. In the areas where I went through the clearcoat the black finish was dull and did not buff to a high gloss like the surrounding clear did. The finish looked thick when it was wet, but apparently once the solvents dry out the solids that are left are quite thin. After allowing the finish to cure for several weeks I wet sanded then buffed and I ended up going through the clear coat in a few areas. I didn't want a super thick finish and so I though this was enough. The first time around, I applied 5-6 coats of black, followed by 7-8 coats of clear. My first refin project was a rattle can top-only refin to convert a goldtop to a blacktop which I ended up doing twice because I didn't apply a thick enough finish. Then do GENTLE flat sanding and polishing, being super careful around all edges and corners, and I get the look of a guitar dipped in glass. I then spray two full coats, leave it alone to cure for a day or two, sand back to flatten it all out, then spray two more full coats and forget it even exists for a month. The rule of thumb that I follow with urethanes is to first adjust the gun for a good wet look on the item to be sprayed. When working with urethanes, it's important not to overdo the coat thickness or you get solvent popping problems, which is where solvent in the paint tries to escape but it's trapped because the layer is too thick, and the evaporated solvents create tiny bubbles in the coat which are permanent unless you sand them out. I do a PRS-like finish but I keep my finish thinner than PRS does so my finishes don't have that "trapped in plastic: feel of most PRS guitars. I nearly always shoot automotive acrylic urethane these days. The answer is truly totally dependent on the kind of paint you're using.
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