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I can spot a waterborne finish right away, also. Maybe not in photographs, but in person. There's also a feel to it. A different feel...

Terry

I'm working on a spray booth, but in the meantime I just step outside the door of my shop and spray. Eventually I want to have a booth that will allow me to spray inside, but this is working okay for now. The draw backs are that you need a nice day and you can't do anything else in you shop because that could disturb dust.

Like many have said KTM is great for the hobby builder, but for those who are building guitars to sell it is probably not the right finish.

Josh

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Josh House

Canadian Luthier Supply
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House Guitars - Custom Built Acoustic Instruments.
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[QUOTE=Mario] Tim, what did you use as a medium for the colors for your sunbursts? The 'bursts you had at IBMA were really, really nicely done.[/QUOTE]

Hey, thanks for the compliment. I have two sets of dyes. One is powdered aniline alcohol based dyes and the other is a MEK based liquid metal acid based "nasty" stuff dyes.

Both are available from LMI. Either of them will work with organic solvent based finishes but only the aniline will work for waterbournes.

Alcohol based aniline dye

Solvent based dye

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tim...
http://www.mcknightguitars.com

Yes yes, I have the same dyes <bg> What I want to know is what medium did you put the dyes into to spray? The binder, so to speak. Did you use it in a shellac? A nitro? Or did you add the dye to the urethane? Or?

See, with only 3 coats needed with the polyester finish, I can't add the dye to the topcoats, because the levelling would be into the colors. I guess I could, then add 3 coats of cear on top, but that would build a thick finish, which I am dead set against doing. I could thin the polyester and use that thinned mix to do the colors, but it stays tacky so long that there's a chance of getting a dust spec in it.
I've always used shellac or nitro as my binder for dyes, and it works well, but your bursts were nicer than mine, so I ask <g> Mario38747.5490046296

Oops, sorry I missed your point. The yellow was applied with alcohol to bare wood. The burst finish was Urethane and the binder was a very thinned urethane mixture as well. Yes it did build up a nasty ledge next to the purfling which I sanded as best I could and then clear coated the purfling edge with a round pattern keeping most of the clearcoat towards the edge. Let it set for two days and level sanded to fill the ledge then clear coated the entire top.

Having learned that I don't want to do that again, I just sprayed a couple of bursts in my current batch. Yellow on bare wood then burst colors were sprayed with a 1/4 nitro/thinner & dye mixture. Hardly any build up at the ledge. Clear coated with Urethane after one week of off gassing. It came out much better with a LOT less build up.







I'm bursting a couple of Mandos right now the same way. Sheesh are these boogers hard to hold. How do you do it? I used a 1" dowell and 3/16" wood screw into the end pin hole. It still feels really awkward though.

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tim...
http://www.mcknightguitars.com

For mandolins, a 4" #8 wood srew in what will be the end pin hole, and I have an "L" shaped thingie that screws into one of the tuner holes at the other end.

That is for the clear coats. For the colors, I mask off the neck, but not the headstock area, and use it as a handle to do the body. Once the colors are on the body, I take the masking and paper off the neck, holding the mandolin by the headstock, and then rest the mandolin on the fretboard. Since we won't burst the headplate, we can reach all of the neck from here, and blend the colors into the back and sides from here. Works like a charm..., and is not as cumbersome as it sounds, once you've done it.