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Hi Guys,

I've been reading with great interest about KTM-9. It seems like it is not the most forgiving finish in the world. I've almost used up all my KTM-4A, which I like. It's not nitro, but it is easy to apply and I think it looks pretty good. KTM-9 on the other hand doesn't sound like fun. Soft finishes, long drying time, lack of burn-in, etc. have come across this forum (and others) quite a bit. I really don't like the idea of an epoxy filler or using DA in the finishing process - I went to KTM to stay healthy, now it seems like KTM-9 needs other chemical compounds/solvents to make it work. Is this really the best waterbased finish out there? Has anyone tried the Colortone Finishes from Stew Mac or any others? The irritation of KTM-9 looks like it may convert me back to McFaddens.

Just Wondering,

Ray

I peeked at your profile Raymond.... cooking and guitars. Everyone's gotta eat. I shared three recipes recently, Sweet Italian Bread, Cajun Red Beans and Rice, and my holiday favorite, Peanut Brittle....

Recipes and Miscellaneous, you know, stuff you can't seem to fit into a luthier website....



My wife took four loaves I finished up after midnight last night. Teacher's and food, they potluck once a month.... mmm mmmm....
Dickey38376.9930092593

ColorTone is Target Coatings USL, which I've used. It's a mite soft for my feeling, but seems to go on OK. Mario's reported some very positive results with Target's 9000 series varnish, and as soon as I get set up with a power buffing system I'll be trying some (Mario very much stated it's a bit of a bear to buff out, and don't bother if you ain't got power).

I have had no issues with soft finishes using KTM-9. In fact in my opinion it is much harder than Colortone. I have problems with MEK or I would try Nito. but I can't find a real reason to to put myself at risk. I am very pleased with KTM-9. I have read that some have issues, but I think the vast majority of use that use it like it.

KTM9 is my current favorite. I've done several guitars with it recently and all have turned out very good. If you don't like epoxy there are several other waterbases fillers. Some have use the pumice method typically used with french polishing. Give it a try, at least your shop won't smell like lacquer. No matter what you spray wear your mask.

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

I just sprayed a neck with the Target 9000. I found that it sprayed better than the KTM-9 -- better flow out, less solvent pop. Mike Doolin tested the stuff and found that the 9000 was a little harder than the KTM-9, but it still was a little rubbery.

I've been researching other waterbornes and found out some interesting information. Traditional guitar finishes as well as the synthetics -- catalyzed polyurethane or catalyzed polyester (be it UV catalyzed or chemical catalyst) -- are evaluated for their hardness using the lead pencil test, i.e., how hard is it to dent the film with a pencil.

Waterbornes, because of their use on flooring tend to be evaluated using the Taber abrasion test. This test consists of a weighted wheel that spins on a surface covered with the finish. The weight of the panel before and after the test is compared. Typically, single component waterbornes -- KTM-4A, KTM-9, all of Target's products, lose somewhere on the order of 150ug in a Taber abrasion test. Two-part waterbornes lose 20mg -- a factor of seven.

I'm about to test three, two-component systems and will report on the results as soon as I receive the samples and prepare panels. The game plan is to spray them with a base of epoxy. I'm betting they are going to be very difficult to buff out, requiring higher buffing speeds. I haven't gotten the product spec on all of the samples, but one has 1/3 more solids than either the Target or KTM products -- around 45%. One of the products I was turned on to by a fellow in my building who does fine art finishing. He described the finish as being almost brittle. If we're getting to that kind of hardness, we might have found a waterborne worth using.

Several of the finish chemists with whom I spoke, all agreed that any waterborne finish that contains acrylic will be easy to buff, but won't get anywhere near the hardness we're talking about. They described acrylics as being a "cheap" resin, but not terribly durable. All of them, thankfully, admitted to a full 15 day cure time. One of the chemists I spoke with acknowledged that the waterborne finish chemistry still isn't there yet at least when compared to solvent based catalyzed systems. I don't know what kind of burn-in, if any will happen with these finishes. All of the catalyzed finishes I'm aware of don't burn in, and I suspect that the waterbornes won't be any different.

It will take an adjustment.

I'll keep you posted.

David,

Thank you for the information. I look forward to hearing the results of your tests.

Jeff

Hi Bruce,

What kinda food are you into? I worked in restaurant kitchens for years doing everything that you can think of in addition to washing dishes. When I was much younger, I wanted to be a chef, working as many as 12 hours a day peeling shrimp, chopping cabbage or preparing vegetables for cooking and then having to break down a kitchen after all of that cured me! Took years, but I was cured! After all of that, I still love to cook - in short spurts!

Mexican, Fried Catfish, Italian Lasagna, Breads, Steaks, just about anything good to eat. I cooked Sweet Italian Bread this afternoon. Kind of a nice way to entertain or just enjoy with the family.

I think the issue with KTM-9 is that you have to have the right process down, mixing it with some DA (read 5 to 1) seemed to solve the burn-in problems I had and made it flow and level better.

As for hardness I won't know for a couple weeks more when I level and buff, I trust Mike Doolin and he says it holds up well.

-Paul-

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-Paul-

Patriot Guitars

Well, when we're talking hardness, we've got John Greven using Target's stuff and liking it, so there are supporters for each waterborne system out there.

Me, I'm using it because a) no spray booth and b) no good Nitro can be found over here.

[QUOTE=dberkowitz] Typically, single component waterbornes -- KTM-4A, KTM-9, all of Target's products, lose somewhere on the order of 150ug in a Taber abrasion test. Two-part waterbornes lose 20mg -- a factor of seven.[/QUOTE]

Just to clarify: you mean micrograms (mu) in both cases, ie 2-part finishes are better. Correct?

I'm looking forward to hearing your findings. Definitely something to keep an eye on!

Mattia: The last I spoke recently with John he was still using KTM-9 and not Target. He said he would be doing some testing on the Oxford 9000 in the near future though.

I have some 9000 that I will be shooting in a week or two. I have been shooting nitro for several years and I think I am starting to see some related health problems.

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

Mattia, yes I'm talking micrograms, but this forum doesn't have the proper "u" with the tails to put the proper symbol, hence "ug."

As for John, I know he's pleased with the the KTM-9 (he's not using the Target, as I spoke with him last week about it). My feeling, and I believe I can speak for Mike Doolin in this regard (he's switching to a solvent based system) that it isn't hard enough. Mike would tell you that the KTM-9 isn't as hard as the Macedon Hardcourt waterbased finish he'd used for a while. He only got away from it because it was hard to spray, had terrible shrinkage and took a minimum of four weeks to properly cure.

One additional note, waterborne chemists will tell you that current waterbornes can only get an 80% gloss (versus 90% gloss or better for solvent based systems). What you need to understand is that this is based upon spraying on a black glass panel and measuring the gloss at 60 degrees. The problem is that they are measuring the gloss "off the gun," i.e., no leveling or polishing. Waterbornes typically don't flow out as well as the solvent finishes and in many cases actually are a little pebbly which would diffuse the gloss. Clearly we're getting good gloss from the waterbornes we're using, so I think the test isn't particularly telling.

I'd be curious as to what Jeff Weiss's feeling about that comment would be.dberkowitz38378.5124652778

Tim,

Just wondering what you are experiencing? I used Nitro for the 1st time just recently.

Jeff

Breathing problems, shortness of breath (yes I wear a good repirator) and lately I have been having some lower back and kidney pains. Only flares up when I shoot nitro and a week or so after while it is off gassing then the symptoms subside.

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

Thanks. That would be scary, and seems pretty much tied to the nitro use. Something for me to think about.

Jeff

Tim, hey bud, time to start new finish. At least get a toxic substance suit. Guitar building wouldn't be at all fun sick or worse. I have to wear a full face respitrator and with sleeves rolled all way down and rubber band to close the cuffs, and surgical gloves. It might be over kill, but when I don't, I get bad headache and a rash. I go over the top and look weird, and can be clumbersome,but no problems since. At home shop I use waterbourne and french polish( becoming my favorite)

Tim, remember the addition of the butyl acetate to your mix as a thinner. Did you have this problem before you added that? Also, it's hard to keep hands out of the lacquer thinner during cleanup, but it can be done with some effort. I've seen your knock-down booth. One question that comes to mind: Is the room fogged when you finish? If so the fan may not be powerful enough. Before I set up my temporary booth, the double garage would just be a fog. Now it gets sucked right outside, and the room is clear as a bell.

Tim Nitro can get in through your skin too, I haven't had any issues with the KTM stuff, in fact I added a couple coats to the necks tonight (don't ask) and it's nice to not have to worry about poisoning myself

If I go back to regular nitro it will be in a new shop with a proper boot and a pressure mask and spray suit, I will never shoot nitro in the shop again. Even with the KTM I use a HVLP to keep the overspray down to a minimum...

Cheers

-Paul-

_________________
-Paul-

Patriot Guitars

I leveled and buffed out a pegehead this afternoon that had been sprayed with the Target 9000. My impressions are mixed. It's a lot harder to buff out, but there were other problems.

First, there were micropits in the finish. I called Jeff Weiss who explained that it is a result of the component cross-linker. You don't see it with the satin but do occasionally with the gloss. It had the look of very tiny pin-tip pits in the finish. I sanded them out and thankfully didn't go through.

Witness lines. Didn't disappear the same way they do with the KTM-9. I couldn't get the same depth of gloss. The finish had cured 14 days before I buffed out.

So I'm not convinced to switch at this point.

OK, so we're back to KTM-9 as the 'best bet' for now, right? I'm still trying to work out what works 'best', and frankly I'm almost tempted to learn how to french polish properly, and stick with that, although I do kinda like spraying, and I've spent out on a SATA MiniJet, so..

I've got a boatload of Target USL sitting here right now that I'll keep trying to work with, maybe get a small amount of 9000 series to experiment with as well, as a topcoat over the USL.

I've also heard of 2-part component finishes by Sikkens (which would be local) and the like, which I suppose would be local, but I'm not really sure what to ask for/look for if I call up the manufacturers. What, high gloss, hard, low abrasion?

Bruce, Stan & Paul:
I have used Butyl Acetate for years and it hasn't affected me like this before. I wear long sleeves, nitrile rubber gloves and a good repirator. The booth does an excellent job of evacuating the overspray and there is little fogging outside of the booth. I think the problem is the month long of off gassing. I keep the finished guitars hanging in my wood room and that's where I do all of my glue ups to (and I must admit that I don't wear a respirator in there) and I should. The wood room is only a couple of years old and .... I guess I answered my own question, eh?

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