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O.K., I give, I cannot get a decent finish with my spray equipment, now I'm going to a brush. When applying KTM-9 with a brush, do I put coat after coat one hour apart like I would if spraying? Then wait until the next day like usual, wipe with DA, and brush on another four or so coats.

By the way, the spraying was a nightmare, my coats looked like alligator skin....if I tried to fill in a bit it ran like a scalded dog.

Thanks for your help it is greatly appreciated.

Greg

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Gwaltney Guitars

Greg, the process is exactly the same. Just no need to thin out the KTM-9 with DA. I know KTM-9 can be tricky to spray but you'll be happy with the results if applying with a brush! But make sure to apply LIGHTLY!!

Good luck....

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com

Greg,
I don't know why you've had so much trouble spraying KTM9. For me, it's
been very forgiving. A little alcohol or even water will thin it a bit to give
you better flow-out, but don't expect a glass-like finish right from the
gun. You have to level it before you can rub it out. I use an $89 gravity
fed gun and get excellent results with no runs. What are you using for
spray equipment and what kind of pressure are you using?
Craig S.

I'm using a cheap touch-up gun, siphon fed. Maybe I'm expecting too much from the sprayed finish, it is just so darn rough I can't imagine getting it smooth enough to polish unless I sand forever which seems like it would remove most/all of the finish. If what I'm ending up with by spraying is normal(any pictures available of what KTM-9 should look like after spraying and before final sanding/buffing would be great to see)then what do you guys use to sand the bumps down...hand or ROS for this job? I brushed some on yesterday and it was pretty darn smooth, looks like what I expected from the gun actually. I've been spraying under a light until the rough texture is "filled" if you will, then it runs like crazy. Any pictures or other help would be greatly appreciated.

Greg

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Gwaltney Guitars

Hi Greg,


I hope these pics assure you that a rough looking finish will rub out well with KTM

From that to:



While I am still needing to improve surface prep and leveling, I am having no trouble getting a good deep shine


Best Wishes,

Tomas

Maybe you could post a pic of the part that you{re concerned about, so we can get a sense if what you are dealing with is normal?

Congratulations Tomas, you sure made a nice recovery!, it shines well now!

Greg,

What psi are you spraying at? You should be around 40PSI. Also, spray multiple thin coats instead of a few heavy ones.

Greg,

I sprayed with KTM-9 for the first time about the same time you sprayed. Mine also has a rough texture but from all that I've read that is the norm until you level it.

Before brushing try leveling it and see what happens. You may be closer to being finished (pun intended ) then you think.

Yep you almost always get a little orange peal effect unless you have some high end hvlp equipment and lots of practice. the first couple coats should be a bit dry application then the remaining a bit wetter but never heavy. I spray 3 coats allow to cure for two days very lightly level then spray 3 more coats repeat the cure and level the spray 2 more and allow to cure 12-15 days final level and buff. I have rushed the process by not leveling till all the finish was on curing for 10 days then level and buff and had no issues but the longer you can allow the film to cure out the better. My personal advise if you do go to a brush on is to use a high end China bristle brush or a foam brush. If you use a foam keep your pressure light to avoid bubbles. If you use a bristle brush get a good one the cheap China bristle brushes will drop hairs. Never go back over the same path after an aplication, over lap by 1/8th the brush width before the previous pass starts to jell. Never back brush.MichaelP38904.4791782407

I have tried both ways , brushing only one direction, as well as briskly back and forth as I did on the above guitar. I was going more for level than smooth. I think ethier way it all comes out in the buffing process.

I also brush out my runs when spraying. rather than wiping with my finger. Again I go for level rather than smooth. Sanding and buffing take care of that. Do you have an arbor and buffing wheels?

Peace

TETomas38904.5005555556

Greg,
I had trouble spraying KTM-9 too. It was very rough. For me, it turned out that the spray nozzle was too small - (0.7mm I think). I bought a new, very cheap spray gun on eBay with a larger nozzle (1mm) and it worked great.
I tried brushing, but did not get very good results.


1.0 spray gun.SteveS38904.55125

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

Robbie,
I was spraying at approx. 40psi, at least that is what the gauge on the compressor indicated. Do you guys use a pressure gauge at the gun for more accurate pressure, or just rely on the output gauge reading on the compressor.

I sanded the guitar AGAIN, decided to brush on the KTM-9 with a good quality brush....hold my breath, it seems to be working very nicely. I'm putting on the last coats tonight, I'll wait 2 weeks, sand and buff, then see what I've created.

All of the leveling and bump/dust/crud removal is done with the sanding stage...correct. The final buffing/polishing is only for glossing the already perfectly smooth surface...Yes?

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Gwaltney Guitars

Yes Greg, You can progressively sand down to level from 600 to 2000 (or 4000) grit. Once level buff it out and stand back and watch it shine (sunglasses recommended) Tomas38907.9667592593