Not much luck brushing on KTM-SV switched to spray.

[johnnparchem]

Well I tried. For the last 4 weeks I have been attempting to get a brushed on finish with KTM-SV. I came close, I was happy with the neck and even the sides with the brushed on finished. And I did get to the point where I could apply finish with very little brush marks. The problems I had on the back was getting a coat on the back without lap lines, and then getting an even coat across the entire back. Then finally when I thought I was close, Getting the back level without witness lines when I went through one layer of finish. I waited a week after the last coat and polished the back. It looked great under a bright light, but under normal light the back clearly showed the areas that were not the same layer of finish.

I finally gave in and bought an Earlex HV5000 this weekend. I sanded the back and sides to level with 400 grit sandpaper, leaving a good coat of finish on the wood and have sprayed on 3 coats of KTM-SV. The last coat looks level. I will wait a week to see how it polishes out.

It was quite a learning experience with the brush but...

[johnnparchem]

Not knowing when to stop, I level sanded again and sprayed on 3 more coats. I was happy with the back but the sides still needed work. When level sanding the sides I burned through the top layer of finish in a couple of areas.

Currently I have an even coat on the back and sides, although the back shows a bit of orange peel. Never having sprayed a guitar with KTM-SV I am not sure what to expect. I believe that I can level this finish and polish it.

We shall see.

I think on my next guitar I will try EM6000 as it supposedly burns in coat to coat like nitro.

The picture shows the back about an hour after spraying. It is dry to the touch but you can see the orange peel.

[Ken C]

Hi John,

I haven't used the KTM, so I don't know how well it burns in. EM6000 burns in okay as long as the previous coat was shot within the past 12 hours. Beyond that all bets are off. I sand the surface with 600G paper until it is completely dull if I am shooting coats after 12 hours. I have found that 8 to 10 coats are good for the top and 12 to 15 for everything else. I level well with 600G prior to applying my final coats, and then I'll shoot 4 coats over a three hour period. These 4 coats will burn in giving me a good base for final sanding and buffing. Prior to buffing I'll level sand, starting with 800G. Going any coarser risks could leave scratches that might be tough to get out without sanding through those last 4 coats.

Looks like you are getting a decent finish building up though, no?

Ken

[johnnparchem]

I did get a good build up. I was able to level sand the top and sides with no burn through. The KTM does not really ever burn in past an hour or so. I have been able to level sand the back and sides without burning through.

I have not polished the guitar, but did take the back through a progression of polishing sanding cloths and am happy with the way the finish is looking. I hope to finish the guitar this weekend.

John

[johnnparchem]

With much panic, after I burned through 1 layer of the finish, I proceeded to buff the finish, and it turned out OK. To finish the guitar I need to spend a bit of time on the top padding on qualasol, but maybe I can glue on the neck by sunday.