KTM-9 - compatible waterbased substitute?

[Matthew Szostak]

Hi all - it's been many years since I've posted here. I've got an instrument in progress which I'm hoping to finish after years of inaction. The wood body has KTM-9 finish on it. I have to finish a few bits to match, and I'd also like to have something on hand in case I need to fix any finish issues that come up. Can anyone recommend a water-based finish that I can apply by hand (wipe- or brush-on) that would not be incompatible with the KTM? The KTM is definitely fully cured!

Shipping in Maine in winter can be a challenge, but I can get to a retailer which may carry CrystaLac's "Brite Tone" product...

[Matthew Szostak]

Hmm... looks like my "local" shop won't be able to help me after all...

[Bob Gramann]

Target EM6000 will match it pretty well but it is not as hard and scratch resistant. I believe that it was recommended by KTM at one time for repairs. You’ll need to fine sand the KTM to get a mechanical bond.

[Matthew Szostak]

Thanks Bob - I'll check it out.

I've actually still got some KTM that seems workable - I'll do some scrap tests to see if it's still viable. I don't need to do a complete instrument, just a few small "accessory" bits. The frustrating part is the idea of having to buy "large" quantities of finish and tints to match what I used before, when I'll probably only actually end up needing about a tablespoon... oh well...

[Matthew Szostak]

Nope. It's not hardening off correctly. A few coats following my usual routine results in a finish that still feels slightly soft 24 hours later. A good dig with my fingernail, and I can peel bits off, right back down to the wood.

Does this sound typical of "expired" finishes of this nature?

[Christ Kacoyannakis]

What's the shelf life of something like KTM9 or Emtech 6000? I have cans of each that are several years old. If they are no good for instruments now, I will just use them for sealing molds or something. Don't want to get involved with having to strip uncured finish of a guitar I put a lot of time into.

[Matthew Szostak]

Good question. As for KTM, for a general answer, I'm going to go with "less than 10 years..."

[Bob Gramann]

I generally use up my EM6000 within 2 to 3 years of purchase and have had no problems with it. The KTM seems to have a much more complicated formulation and I think had a stated shelf life of a year or less. I’ve only used one quart of it in my life, no longer have the can, and don’t miss it. The finish was beautiful, hard, and very hard polish out. But, when it cracked as I tightened the tuners, I decided I wanted something just a bit softer that would bond with itself.

[Matthew Szostak]

Good to know Bob. My problem now, other than probably having to buy a pint or even quart of finish when I only actually need about a tablespoon, is finding some. I worry about mail ordering anything, shipping to Maine this time of year presents a real risk of freezing - which I'm pretty sure is not recommended for these finishes...

[Bob Gramann]

The FAQ here https://www.targetcoatings.com/faq/ at Target Coatings says you ought to be okay with shipping in winter.

[Matthew Szostak]

The FAQ here https://www.targetcoatings.com/faq/ at Target Coatings says you ought to be okay with shipping in winter.

So it does! That may be a game-changer.

Can EM6000 be brushed or padded? "Official" instructions only indicate spraying. I'll only be applying finish to small ancillary items, and not any large flat areas...

[Bob Gramann]

Brushing works. Use a very supple synthetic brush. Brush very thin coats. Build it up like you are spraying. Level sand when appropriate. Patience is rewarded.