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A couple of weeks ago I sprayed KTM-9 for the first time on 2 classical guitars. After letting Them cure for 2 weeks I buffed the first one today with my new buffing set-up. I stupidly burned through the finish in a spot where the neck and side meet. Can I repair it? Will Ktm-9 melt together like nitro or will it leave a witness mark?
Please give me some good news and tell me it's easy to repair KTM-9.
Talk me down. I just drank some poison, tied a rope around my neck, have a gun to my head and I'm standing on a bridge railing.

OK calm down first...

KTM does not burn in very well at all, I can give you some ideas to try but no guarantees...

1. I would clean the area with some good Denatured Alcohol and see if they softens it a bit.

2. mix your KTM with some alcohol to thin it out and then brush it over that area, don't spray brush.

3. Leave it for a couple of hours and repeat until you get a good fill over the area.

Now the hard part...

let it sit for a week (3 would be better but you sound stressed) and then sand that area flat with the rest of the finish, I use 800, 1000 and then 1500. Take it to the buffer and buff the area out and let it get warm, that should work..

Now a couple of points here about buffers

A trick Kathy Wingert taught me was to loosen the belt so if you leaned in to burn the wheel would stop. Also do not skimp on the compound LOAD THAT SUCKER UP, it will keep it from burning as well.

One last thing is that I have my wheel slowed way down to about 900 rpms, I know other people use a faster wheel but at faster speeds it easier to burn through, even with my setup I've done it on headstocks...

Let me know if that helps...

-Paul-

P.S. I should add that I've done drop fills using this method and have had no witness lines on the back...Sprockett38589.7393287037

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-Paul-

Patriot Guitars

I'm not that stressed really, just wante dto make it sound dramatic! Thanks for the info, I'll give it a try it sounds like it should work.

I did some drop fills last week on KTM9. I cleaned with naptha and sanded the area and then lightly rubbed it with acytone. That softened it just enough to let the drop grab. I don't know how big your area is but it sounds like it might be more than just a drop fill. you may be able to brush some on after softening the area or maybe you can use an airbrush.let it cure and repeat your leveling and buffing very carefully.

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Tickle your guitar daily, and it'll tickle you back.

I have burned through on the top with KTM. I used the denatured alcohol method that Paul mentioned. It worked fairly well. Not perfect, but acceptable. Take your time and you should be able to fix it.

Josh

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Josh House

Canadian Luthier Supply
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I have used John's tip amd airbrushed with good results I use ed DA to soften. I did not notive any wittnes lines but KTM or anyother Waterborn for that matter does not burn as does solvent based finish

This is timely for me. I also got a couple of places where I burned through on KTM-9. I'll try to touch it up tonight.

On a related note, after reading MichaleP's advice I stopped by the local Woodcraft store and picked up a micromesh sample kit. Its got 3X4" pieces ranging from the 1500 grit to the 12000 grit plus a 3X3" foam block. Other than going through a couple of thin spots in my fininsh, I'm real pleased with the results. By the time I got through the 12000 grit, the sanding scratches were small enough that you couldn't see them without holding the guitar at an angle under a bright light.

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[QUOTE=WayneC] I'm real pleased with the results. By the time I got through the 12000 grit, the sanding scratches were small enough that you couldn't see them without holding the guitar at an angle under a bright light. [/QUOTE]

By the time you get throught 8000 you should not see much of any scrateches. To finish off the basic polish use so Meguair's #7 glaze or #89 swirl free polish to remove the 12000 scratches and polish up. 3M perfectit worke well also. For the first couple years, before I got a buffer set up this is where I ended my finish

Also next time you buy Micromesh I would go to the source. Micro-Surfaces. at micro-surface.com you can get the sample packs 1500-12000 for $13 each, 3 sample packs = $39 most resalers sell the kits for $42+. That is like getting one sheet of each grit for free as compaired to the kit price by resalers. I also get all of my Micromesh pads for my RO sanders there.MichaelP38590.4504166667