Using water based products for instrument finishing, Target Coatings 9000 6000 and Varathane WB

[Bruce Johnson]

Just thought I'd share this experience -- bought two quarts of VU off of amazon and started getting bad cratering/fisheyes no matter what I did. Switched to the second quart, same issue. I went and grabbed a quart from home depot and sure enough the issue disappeared. So basically, there definitely are bad batches of VU floating around. I don't know if amazon sellers are selling really old stock or something, but I haven't had any problems with the ones I've bought from HD, so I'm going to pay the little extra going forward.

Okay, thanks, that's interesting information. I've always wondered about the shelf life of Varathane Ultimate. I don't think I've ever had any problems with the cratering, but I have had a few problems with patches not fully curing. Right now, I have a gallon of VU here which I bought through Amazon about a year or so ago. Back in May, I used some of it on a bass and had some of the soft patches. I sanded it off and re-did the finish with EM9300.

However Jeremy has continued to use the VU in that can with no problems. He just did that beautiful metalflake blue hollow body guitar that's over on his thread. It all seemed to cure properly and buff out great. I don't know what happened when I had the problems.

It sounds like we should be cautious about buying VU if it appears to be old stock.

 

[Bruce Johnson]

A follow-up to my previous post about foam rubber and vinyl making discolored marks on the EM9300 finish:

I did some experimenting. I often ship my Scroll Basses in Pelican cases, which are lined with heavy black foam rubber, no plush fabric over it. Obviously, I was concerned whether my basses would end up being marked up all over after a cross-country trip in a Pelican case.

I placed the Scroll Bass, painted with EM9300, on top of a slab of the foam right from a Pelican case. The flat back surface of the body right on the flat surface of the foam, the weight of the bass pushing it in contact. I left it there for three days.

When I picked up the bass three days later, the foam came up with it. The foam was sticking to the body. But it wasn't bonded on there with any strength. I easily pulled the foam off. It didn't pull off any foam or any of the finish. There were some patches of hazy whitish residue on the finish, but they wiped off easily with a cloth. There were no marks in the surface of the finish. There didn't seem to be any chemical reaction going on with the EM9300. Some goop from the foam had stuck lightly to the EM9300, but it didn't harm it.

The mark on that neck of Jeremy's that was in the guitar stand was on there tighter. It didn't wipe off. I wanted to see if buffing would take it off. But before I got to it, Jeremy had sanded that neck back down to the wood and repainted it with Varathane Ultimate (for other reasons). And he notes that he's never seen marks from that guitar stand on necks finished in VU.

Also, I worked on those spots under the pickguard on my Scroll Bass. In that case, the whitish discoloring didn't just wipe off. But I was able to clean it off with a few seconds of buffing; a drop of liquid compound and a cotton buffing wheel.

So, my conclusion at this point is that these discoloration marks are definitely residue from the foam/vinyl which is sticking to the surface of the EM9300. The residue isn't chemically digging into the EM9300. It's just stuck on the surface.

The mystery is why I'm seeing these marks on the EM9300, but not on the VU? I'm thinking that the difference is in the buffing. Or lack of. The VU almost always gets a final wet-sanding and buffing of the top coat. With the EM9300, we're doing very little buffing of the top coat. That's one of the things I like about it. Maybe the buffing itself is leaving a protective coat of wax or something on the surface, which is keeping the foam residue from bonding to the VU? Maybe the solution is to always lightly buff or wax the EM9300 before leaning it against a foam-lined holder or case lining?

I'm going to be partially repainting that Scroll Bass in the next week, and I'm going to continue using the EM9300 on it. I'll try some more experiments with the final coat buffing and waxing, to see if that makes a difference.

Jeremy was pretty discouraged by this marking situation. He's stopped using EM9300 and continuing on using VU on his instruments. I'm going to keep working with the EM9300 on my basses. We'll have examples of both to compare. And we'll keep experimenting and learning.

 

[ardgedee]

This makes me think of fine oil paint which will continue outgassing for decades after it's no longer workable -- it's why you shouldn't frame oil paints under glass. Maybe the EM9300 also continues curing after it's hardened?

 

[Bruce Johnson]

This makes me think of fine oil paint which will continue outgassing for decades after it's no longer workable -- it's why you shouldn't frame oil paints under glass. Maybe the EM9300 also continues curing after it's hardened?

No, I don't think that's what's going on here at all. The EM9300 is fully cured and hardened. These water-base polyurethanes don't really have any outgassing. The water evaporates out fairly quickly, and then the two parts of the polyurethane chemically mix and harden, without giving off any gas.

Oil-base polyurethanes, particularly the one-part type, do have a problem with outgassing. They often take several weeks to fully cure, outgassing solvent during that time. That solvent outgassing would be more likely to chemically damage the foam.

As you say, fine oil paints, as used in paintings, can continue outgassing for decades.

 

[HMH]

I just got saw that Target Coatings is releasing a new water based 2k finish with no Isocyanates or aziridine. Hopefully it delivers.

 

[Bruce Johnson]

I just got saw that Target Coatings is releasing a new water based 2k finish with no Isocyanates or aziridine. Hopefully it delivers.

That's interesting. I get their weekly e-mails, and didn't notice that. And I don't see it on their site. Do you remember what the product name/number is?

 

[HMH]

That's interesting. I get their weekly e-mails, and didn't notice that. And I don't see it on their site. Do you remember what the product name/number is?

Hey Bruce, I saw it on their Instagram feed. It's called Emcat+

Introducing EMCAT+® | Target Coatings

Introducing EMCAT+® – See the Video and Press Release Below FOR IMMEDIATE RELEASE Contact: Jeff Weiss Target Coatings, Inc. (201) 821-0150 [email protected] Target Coatings Introduces New EMCAT+® System of Water-Based Wood Finishes 1K and 2K Finishes Excel on Challenging Substrates...

www.targetcoatings.com

 

[Bruce Johnson]

Hey Bruce, I saw it on their Instagram feed. It's called Emcat+

Introducing EMCAT+® | Target Coatings

Introducing EMCAT+® – See the Video and Press Release Below FOR IMMEDIATE RELEASE Contact: Jeff Weiss Target Coatings, Inc. (201) 821-0150 [email protected] Target Coatings Introduces New EMCAT+® System of Water-Based Wood Finishes 1K and 2K Finishes Excel on Challenging Substrates...

www.targetcoatings.com

Hmmm...Okay. I guess it will be in next week's e-mail. I'm not sure if I'm interested in it myself. I generally don't want to work with 2 part finishes. Too much process hassle. But maybe, just for a last top coat?

 

[HMH]

Hmmm...Okay. I guess it will be in next week's e-mail. I'm not sure if I'm interested in it myself. I generally don't want to work with 2 part finishes. Too much process hassle. But maybe, just for a last top coat?

That is what I was thinking as well. If it outperforms Varathane for top coat purposes and easily accepts pigments/dyes, then it may be worth having on hand.

 

[Jamie Hayes]

So, this thread has been a great resource, and overall I've been liking VU for its fast drying and low toxicity, but I just can't get it to flow out glassy like I've seen others on here achieve. That's leading to a lot more sanding and headaches. It seems like no matter how I set up my gun I get little specks of dried finish, even laying it on thick at very low pressure. I'm using an lvlp gun with a 1.7 tip, using Bruce's settings as a guideline (fan off, gun air open, 10-13psi, 4-5 half turns needle adjustment) but I've also experimented a lot with various adjustments. I can get it somewhat smooth if I do pretty wet coats, but I've never been able to avoid those little hard bits, and they just compound over multiple coats.

Any advice or other variables to eliminate would be greatly appreciated. I really covet the painless finishing process I've seen is doable with this stuff.

 

[Bruce Johnson]

So, this thread has been a great resource, and overall I've been liking VU for its fast drying and low toxicity, but I just can't get it to flow out glassy like I've seen others on here achieve. That's leading to a lot more sanding and headaches. It seems like no matter how I set up my gun I get little specks of dried finish, even laying it on thick at very low pressure. I'm using an lvlp gun with a 1.7 tip, using Bruce's settings as a guideline (fan off, gun air open, 10-13psi, 4-5 half turns needle adjustment) but I've also experimented a lot with various adjustments. I can get it somewhat smooth if I do pretty wet coats, but I've never been able to avoid those little hard bits, and they just compound over multiple coats.

Any advice or other variables to eliminate would be greatly appreciated. I really covet the painless finishing process I've seen is doable with this stuff.

Hello Jamie;

Okay, in your spraying environment, it may be evaporating the water too quickly. Try thinning it just a little bit with water, or General's Water-Base Dye Stain reducer. Just a little bit, like less than 5%. That will slow down the initial chemical mix and give it more time to flow out. But be careful, because it will be easier to get sags or runs.

Also, from your description, be careful not to lightly dust over an area that you just sprayed. That may be where you are adding those extra hard pebbles. Try to get it set so you are spraying over an area in one pass, to the full thickness that you want.

 

[byacey]

Today was the day I decided to also finish my adhesion test with the wood sample plates. I decided not to buff these plates out to a high gloss sheen as I don't do that finish very often. So these samples are not sanded level as you can see and look kind of crusty. I wanted the finish to be as clear as possible for the test and not abraded. The samples would look better if I was to level and buff but I don't have the time for all of that.

I really have to apologize at the poor quality of the pictures but my camera is a POS for up close shots. You can still see the results.

Some damage testing first......

View attachment 2340008
I first used my burnishing tool to press against the sides of each sample to simulate a neck or cover plate going into a tight pocket. The only sign of delamination was on the Cocobolo that had oil under the shellac and topcoats. It was minor.

Next I struck each sample with a hammer to see what would happen from the finish taking a hit. The finish on the Redwood and Cocobolo samples with oil sealer coats showed some lifting. Now see the second picture...the Redwood sample here was the non-oil sealer, shellac base coat panel. It did not have any delamination from the hit. I did it a few times to make sure.
View attachment 2340009
View attachment 2340010
The light spots are just the light reflections around the dents, not the finish pulling up.
View attachment 2340011
The cocobolo with the oil sealer lifted but the non-oil coat did not.

I am getting the impression that the Shellac is fine for popping the grain and the sealer oil should not be used on resinous woods like Cocobolo. I have always had issues with Redwood as well. So for now I have two woods that will not get any oil sealer for now on. Remember, the tinted shellac samples looked very much like the samples that had the oil sealer coats under the finish. So I guess I will be dropping the oil sealer from most operations.

Now the test for delamination from tape. After the slicing with a razor blade, I place a piece of carpet tape to each sample and waited two hours to pull it off.

View attachment 2340012
View attachment 2340013
You can see some lifting on the Cocolbolo with the oil sealer under the finish. Cocobolo with only the shellac base coat was fine. Same with the Redwood sample that was sealed with oil. Every other sample was fine with no lifting.
View attachment 2340014
You can see the delamination around the slices from the tape pull. Not good. This is why I have been having some issues on a customization that I am working on. The finish on that instrument might have to just be stripped off and reworked. Just a coat of tinted shellac to pop the grain and then topcoats. 3rd time is a charm I guess.

Something I have found with these waterborne finishes is that the cured finish always loses transparency and optical depth compared to an oil based or laquer finish. I think the refractive index is farther away compared to an oil based finish.

 

[Bruce Johnson]

Something I have found with these waterborne finishes is that the cured finish always loses transparency and optical depth compared to an oil based or laquer finish. I think the refractive index is farther away compared to an oil based finish.

Maybe, but I think the finish isn't actually losing transparency. It's the top surface looking cloudy, because it wasn't fully buffed up to a high gloss. It initially looked high gloss and clear because of the wax residue in the buffing compound. When the wax dries out in a few months, the surface looks more whitish and less transparent. Buff it and/or wax it again and it goes back to being clear with optical depth.

Have you tried re-buffing your instruments when they've done this? Did it restore the clarity and depth?

Jeremy and I have noticed this and are experimenting with better buffing techniques and maybe better waxing.

 

[byacey]

Maybe, but I think the finish isn't actually losing transparency. It's the top surface looking cloudy, because it wasn't fully buffed up to a high gloss. It initially looked high gloss and clear because of the wax residue in the buffing compound. When the wax dries out in a few months, the surface looks more whitish and less transparent. Buff it and/or wax it again and it goes back to being clear with optical depth.

Have you tried re-buffing your instruments when they've done this? Did it restore the clarity and depth?

Jeremy and I have noticed this and are experimenting with better buffing techniques and maybe better waxing.

I haven't tried it on an instrument, just kitchen cabinets and test strips of maple and spruce.
On violins I always use oil varnishes, and they have very clear optics just the way they are applied to the wood.

What do you think is changing with the waterborne finish that it loses transparency until it gets rebuffed? Most plasrics that are polished remain glossy unless they are soft and in a constant state of cold flow.
I have used 2 part urethanes on basses and guitars with good success, however it has to be really well cured before it could be rubbed out to a high gloss.

 

[Bruce Johnson]

I haven't tried it on an instrument, just kitchen cabinets and test strips of maple and spruce.
On violins I always use oil varnishes, and they have very clear optics just the way they are applied to the wood.

What do you think is changing with the waterborne finish that it loses transparency until it gets rebuffed? Most plasrics that are polished remain glossy unless they are soft and in a constant state of cold flow.
I have used 2 part urethanes on basses and guitars with good success, however it has to be really well cured before it could be rubbed out to a high gloss.

Hey Bill;

The water-base one-part polyurethanes that we have been working with on this thread don't cure to as hard a surface as the 2-part oil-base polys. It's not that they haven't fully cured, it's just a softer mix of plastic. As I understand the chemistry, having the micro-beads of catalyst pre-mixed into the water of a one-part poly limits the hardness of the cured plastic. As compared to directly mixing in the catalyst right before spraying.

But there are differences in hardness between brands of one-part polys. Some of the older one-part polys were quite soft when fully cured. But they keep getting better year by year. The EM9300 that I'm working with now is getting close to the hardness of 2-part polys.

The final hardness is what causes the cloudiness and loss of transparency. Softer plastics are more difficult to polish up to a high gloss. It takes more work and care. And a wax coating can hide the less-than perfect buffing....for a while.

That's why I don't think your water-base finish is actually chemically getting cloudy over time.......Unless you are talking about a finish from 10 or more years ago?

 

[Jamie Hayes]

Hello Jamie;

Okay, in your spraying environment, it may be evaporating the water too quickly. Try thinning it just a little bit with water, or General's Water-Base Dye Stain reducer. Just a little bit, like less than 5%. That will slow down the initial chemical mix and give it more time to flow out. But be careful, because it will be easier to get sags or runs.

Also, from your description, be careful not to lightly dust over an area that you just sprayed. That may be where you are adding those extra hard pebbles. Try to get it set so you are spraying over an area in one pass, to the full thickness that you want.

Thanks for the ideas. I'm starting to lose it a bit with my inability to get a smooth coat on. I've tried just about every pressure, needle setting, thinned 5%, thinned 10% with water, with general finishes reducer, always laying it down in one pass. No matter what I do I get the little sandpaper-y bits. Even if I lay it on thick there are little dried bits throughout once it dries. I even picked up one of those cheap harbor freight guns just to try and rule out another variable. I'm in the bay area so it's 65-70 most days and like 45-50% humidity. Any other ideas for where I'm going wrong? I'm on the verge of throwing in the towel with VU -- maybe try one of the emtech products. As always, thanks for taking the time to try and help out!

 

[Matt Liebenau]

Thanks for the ideas. I'm starting to lose it a bit with my inability to get a smooth coat on. I've tried just about every pressure, needle setting, thinned 5%, thinned 10% with water, with general finishes reducer, always laying it down in one pass. No matter what I do I get the little sandpaper-y bits. Even if I lay it on thick there are little dried bits throughout once it dries. I even picked up one of those cheap harbor freight guns just to try and rule out another variable. I'm in the bay area so it's 65-70 most days and like 45-50% humidity. Any other ideas for where I'm going wrong? I'm on the verge of throwing in the towel with VU -- maybe try one of the emtech products. As always, thanks for taking the time to try and help out!

You may have mentioned earlier but are you filtering the VU before you pour it in the paint gun hopper? Also, and I’m sure you did, but did you thoroughly clean the gun when you first got it? They typically ship with a preservative oil or something that paint doesn’t always like.

 

[Jamie Hayes]

You may have mentioned earlier but are you filtering the VU before you pour it in the paint gun hopper? Also, and I’m sure you did, but did you thoroughly clean the gun when you first got it? They typically ship with a preservative oil or something that paint doesn’t always like.

Good thoughts. Ya, I cleaned the gun when I got it and many times since. I am filtering it, but that is a variable I haven't tested -- maybe cheap filters are letting me down? But I wouldn't think there would be that many clumps in a fresh can and there's a second filter in the gun as well...

 

[Matt Liebenau]

Good thoughts. Ya, I cleaned the gun when I got it and many times since. I am filtering it, but that is a variable I haven't tested -- maybe cheap filters are letting me down? But I wouldn't think there would be that many clumps in a fresh can and there's a second filter in the gun as well...

The 3M PPS cups I have that are supposed to be for water based finishes have a 125 micron filter built in. The HF Spectrum knock offs that are larger don’t say on the box. I don’t know what size filter the Home Depot cone shaped paint filters are. If the specks are big enough to pick out by hand though I’d imagine they’d get caught in most filters.

 

[Bruce Johnson]

Yes, some filtering is important with these water-base polyurethanes. The cheap HVLP guns that I use all have those little white plastic filters down in the bottom of the spray cup. I buy the filters by the bag and change them out about every paint job. I also clean my guns pretty carefully about once a week. When I'm doing an instrument, I'll normally have 2 or 3 guns in the rack, with paint in them, for the duration of that paint job. That way, I can walk over, open the air valve for the spray bench, plug in the gun of choice, and spray a coat any time. I'm not filling and cleaning the gun with every coat.