Spraying Shellac - Anything I should know?

Rennie Heuer

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This morning I brushed 2 coats of the dewaxed garnet shellac on the underside of the mantel shelf just to see how well I could do. I used a 1.5 lb cut in behkol (expensive solvent but used by luthiers because it flows better than DNA - or so I've heard). The results were less than stellar. In spite of the upgraded solvent and a rather expensive natural bristle brush I still had problems with brush strokes and overlap marks. Granted, some of this is definitely technique, but I think it is mostly just that it is the nature of shellac - the solvent flashes off too quickly and so is very unforgiving. (Sorry Dan)

I have a Fuji 3 stage turbine HVLP I purchased about 10 years ago to lacquer two dining tables I built. Have not used it since. I think it's time.

So, I place this before the collective - any tips, tricks, warnings I should be aware of? Those of you for whom spraying is your go to and oft used method of finishing, have you any guidance to offer?
 

fred hargis

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I can apply shellac 2 ways: I can spray, or I can pad it on. Give me a jar of shellac and a brush and I'll trash a project very quickly. Anyway, I usually spary a thinner mix, something a little less than a 1# cut. I do use a Fuji HVLP, with their XPC gun. No specific advice about spraying, other than try your settings before you hit the workpiece. But for cleaning the gun, use household ammonia instead of DNA (no sense wasting that). the ammonia absolutely destroys the shellac and gives you a much better cleaning. then rinse everything off really, really well. The ammonia can stain aluminum, ay last that's what happened to me.
 

glenn bradley

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I have only sprayed shellac out of a can so I am going to offer alternatives. That doesn't mean I think spraying shellac is a bad choice. I just have no valuie to add there. Is shellac going to be the final topcoat? I pad shellac with good success but, I get that others may not. I do a lot of dovetails and I still stink at them. Like golf, there are some things I may ever be good at no matter how much I practice.

Back to the finish. Test padding shellac and spraying your top coat. Plenty of articles out there on making a pad. I use cheese cloth wrapped in old t-shirt material. Keep it well charged, keep the face tight and wrinkle free and use thin-thin coats with about 30 minutes between coats (at least out here on the left coast). Worst case, if the shellac is for color and depth . . . pad it on, sand out any wrinkles with 600 and spray your top coat (I'm being presumptuous that shellac is not the final top coat). If you test this you will find that the foggy-looking 600 grit sanded shellac will go crystal clear when the top coat hits it.

P.s. +1 on ammonia for cleanup of fresh shellac. I keep a bottle at the sink to wash hands in the shop for times I fail to put a glove on for "just this little thing".
 

Rennie Heuer

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Constantine, MI
I can apply shellac 2 ways: I can spray, or I can pad it on. Give me a jar of shellac and a brush and I'll trash a project very quickly. Anyway, I usually spary a thinner mix, something a little less than a 1# cut. I do use a Fuji HVLP, with their XPC gun. No specific advice about spraying, other than try your settings before you hit the workpiece. But for cleaning the gun, use household ammonia instead of DNA (no sense wasting that). the ammonia absolutely destroys the shellac and gives you a much better cleaning. then rinse everything off really, really well. The ammonia can stain aluminum, ay last that's what happened to me.
Excellent advise about the ammonia - did not know that. I'm all out of behkol so thinning down any more might be out of the question though I suppose nothing would blow up if I mixed in a little DNA.
I have only sprayed shellac out of a can so I am going to offer alternatives. That doesn't mean I think spraying shellac is a bad choice. I just have no valuie to add there. Is shellac going to be the final topcoat? I pad shellac with good success but, I get that others may not. I do a lot of dovetails and I still stink at them. Like golf, there are some things I may ever be good at no matter how much I practice.

Back to the finish. Test padding shellac and spraying your top coat. Plenty of articles out there on making a pad. I use cheese cloth wrapped in old t-shirt material. Keep it well charged, keep the face tight and wrinkle free and use thin-thin coats with about 30 minutes between coats (at least out here on the left coast). Worst case, if the shellac is for color and depth . . . pad it on, sand out any wrinkles with 600 and spray your top coat (I'm being presumptuous that shellac is not the final top coat). If you test this you will find that the foggy-looking 600 grit sanded shellac will go crystal clear when the top coat hits it.

P.s. +1 on ammonia for cleanup of fresh shellac. I keep a bottle at the sink to wash hands in the shop for times I fail to put a glove on for "just this little thing".
I've padded shellac....a lot. Its a good method for me on smaller projects with primarily flat surfaces. I gave it a lot of thought for the mantel but decided the details, corners and aircraft carrier size were all against me.

The shellac is the top coat for this project as it was the topcoat for the original woodwork that I am trying to match.
 

Dan Noren

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apology accepted. i've sprayed shellac straight from the can, with no thinning without any problems. as for cleaning, i use denatured alcohol, and spray outside until it runs out. i've never used a bristle brush of any kind for shellac, just good quality foam brushes (working on a plaque with one right now), with no problems. as you are working on a very long item, i would spray. once other thing, very important, make sure spraying part of the gun is pointed away from you.
 
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