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I have been reading up on EmTech, and when I got to the water bourne shellacs, it hit me (I think). If they call it shellac, then it is shellac. Some how emulsified in water. But shellac does not melt in water, it melts in alcohol. So do they melt it in alcohol and then mix it with water? Same with lacquer. The base component is nitro cellulose. Do they "melt" nitro cellulose in a solvent (acetone?) and then somehow mix that with water?

In the end, with something like EmTech 6000, is the finish really nitro cellulose? I really believe that with the WB shellac, in the end, it is a shellac finish.

Mike

I could be wrong, but neither are the same as the real thing, ie, true shellac, made the from lac bug, or nitro lacquer .. water base lacquer likely has nothing like nitro in it. I am guessing they are close chemical equivalents that are water soluble.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

I'm no chemist but water borne and solvent born finishes have similarities. They both use semisolid "cellulose" or other compounds like 'lac" which are solutes suspended in the liquid solvent which evaporates. Some catalysed finishes involve a chemical reaction to set the finish. The semisolids then bind to each other creating the finish. The trick is getting the solid bits to suspend and then bind. Much easier with hydrocarbon/acetone type solvents than water. This what i have been told but I beleive that it is just magic.

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Greg
http://garibaldiinstruments.com/

This quote from EmTech was what got me going:

UltraSeal-WB Shellac Sealer

UltraSeal-WB™ is a water-based dewaxed shellac finish designed to function as a sealer and barrier coating for use on wood construction and restoration applications. UltraSeal-WB™ is made from the highest grade of dewaxed shellac available, dispersed into a water phase through our unique Emulsion Technology Chemistries (EmTech™) process.

Mike

Like I said .. I could be wrong !!!! The trick obviously is to first get the material to disolve in water, and then to have it act as shellac once the water is gone. If the process were that easy, we would all be using waterbase lacquers.

It may start with real shellac, but what do they add/do to it to get it to dissolve and stay disolved in water ???

Kinda like powdered milk .. you cant just take the water out of fresh milk, then add it back in a month later, and expect it to be like fresh milk ....

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Target USL and EM 6000 are Acrylic Lacquers. To paraphrase Alan Carruth, these products are an emulsification of the Acrylic Lacquer in water i.e. the lacquer and lacquer solvents are not soluble in water so they're somehow whipped up into a stable emulsion in water, kind of like hollandaise sauce. The plus is that it doesn't take a lot of solvent to keep the lacquer dissolved when it's in the emulsion so the volatile content is very low.

They must use some similar trick with the water based shellac stuff. While I use the WBAL stuff all the time, alcohol based shellac is so darn easy to use I'm not sure why one would want to.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Andy, I agree with you on shellac. The one thing I do not like (about WB shellac) is the fact that one is spraying water onto raw wood. Normal shellac is alcohol based, so it will not raise the grain. I am only guessing here, but perhaps raising the grain can be a problem with WB shellac?

The thing I like about the WB shellac, then WB filler, then WB top coat, is that they all will "melt" into each other. Absolutely no interface issues. At least, that is my take on it from reading posts at Target.

Mike

I am just trying the Target WB Shellac Sealer for the first time. It seems to work fine. It does raise the grain as Mike suspected, but I say no big deal for a sealer, I sprayed a couple of coats, knocked it down with 320 and moved on to the pore filler or laquer.

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David White, Toronto

"All my favourite singers can't sing."

David, are you using the high solids stuff from Target for pore filling? If so, can you relate your experiences?

To others reading this, one of my reasons for interest in a complete waterborne solution is to avoid toxic chemicals (epoxy, nitro). I have zero issues with standard shellac. The nice thing about the Target materials is they dry fast, shrink fast, and sand easy. Hand sanding is all you need or should use. And they really buff out nicely too! No risk of explosions.

Mike

Mike, I posted in this thread.

http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=22392

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David White, Toronto

"All my favourite singers can't sing."

Actually I am a chemist. The EM6000 is not nitro, but is an acrylic based finish emulsified in water. Various cosolvents are used such as polyethers and/or dialkyl amides. These cosolvents are not innocuous, so proper respiration gear is needed. They are used in small amounts and are not particularly flammable, though. Also pH is important and ammonia is used to help emulsify acrylics. You can smell it, just like you do for a quality acrylic paint.

The waterborne shellac is real shellac. Shellac will dissolve in water is the pH is high enough. If you took the pH of Target's waterborne shellac, you will see that the solution has a high pH. I would bet cosolvents are used as well. While Target's MSDS sheets aren't very descriptive, if you look at them you will see references to some of these cosolvents. Dissolving shellac in aqueous solutions at high pH is not new at all. Shellac chemistry is very old.

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Randy Muth
RS Muth Guitars Website
RS Muth Guitars Blog
Facebook Fan Page

Randy, thanks for that info! I always wear a mask when working with these products. Yup, ammonia...most def knew that was in there. Never knew that about PH and shellac! How cool. Thanks for the tidbit about nitro vs acrylic lacquer.

Lacquer seems to be a "catch all" phrase.What exactly defines a "lacquer"?

Mike

Lacquer is an arbitrary term. I always think of lacquer as a finish that that does not cure (crosslink), but just lays down as the solvent evaporates. The beauty of this is that each coat melts into the next since the solvent redissolves the previous coat. It is also repairable for this same reason. Shellac is a lacquer, since it will redissolve in alcohol. However, over a long period of time, shellac and perhaps other lacquers may cure and not be as repairable. Another term that use to be used is spirit varnish. The spirit (solvent) evaporates to leave the coating.

Varnish such as oil/resin varnishes typically dry much slower and cure (crosslink) to give a very durable finish. However, since each coat is cured, the next coat does not melt into the previous coat and witness lines can show up upon sanding. It also is not as repairable for this same reason. This is true whether it is an oil/resin, polyester, or urethane product.

The thing is, there has been a lot of work in finishes, particularly with varnishes. In particular, the waterborne varnishes dry much faster to the touch while still curing slowly. What this means is that the next coat will melt in if if is applied within a certain time window.

This is how I always defined the words lacquer and varnish, but this is not standard anymore. So these terms have become pretty much meaningless. I would like to go back to the term, spirit varnish.

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Randy Muth
RS Muth Guitars Website
RS Muth Guitars Blog
Facebook Fan Page

I hadn't really thought about that before, but it seems that the 'melting' thing is what's causing problems in the topcoat for some people. I guess that's why we typically call it a 'sealcoat'.

Knowing what I know now, it seems that the best is to have a sealcoat which does not melt into the topcoat but has no adhesion problems.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Very good point! I have read about the topcoat problems as well (with WB sealer). Think I will stick with standard shellac for now. But, I am going to order some of that "high solids" stuff to test as a pore filler.

Mike

I prefer alcohol dissolved shellac better than WB shellac as well, since I see no advantage in using the WB stuff. However, I wouldn't expect a difference in behavior as a sealer once it is applied since they are both shellac. It is possible that the alkaline aqueous solution of the WB finish is redissolving the shellac to some extent, but this would occur with any shellac. I use KTM-SV as a finish and it is very sensitive to rosewood oils. Two coats of shellac, either WB or alcohol, did not effectively seal the wood. I now use a catalyzed urethane as a sealer and have had no problems. So I agree that it is best to have an inert seal coat with great adhesion. Rolf Gerhardt uses the same finish as I do and does use shellac as a sealer, but I think he uses multiple coats. Of course the adhesion of shellac is great.

On another note, I tried the Target high solids filler once and did not like it at all. I currently use System 3 SB112 epoxy which works well, although I'm tempted to try egg glare.

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Randy Muth
RS Muth Guitars Website
RS Muth Guitars Blog
Facebook Fan Page

Thanks for your posts muthrs........nice to hear from someone with your experience.

I thought I would pass this info along from the Target coatings forum about the differences between USl and EM6000 in case you aren't aware of the differences:

Quote from Jeff Weiss


The folks that have used EM6000 seem to like the feel of it on the neck better than USL from what I've read.

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Formerly known as Adaboy.......

Darryl,

Thanks for that info, that's good to know. I dealt with Jeff for several years. If it works for you go for it. For me, it's still acrylic so it can only be so hard and will have the dreaded blue cast. I really like the KTM-SV, which is a totally different product than the KTM-9 that everyone talks about. Honestly, I think too much is made of the repairability thing. If I burn through a finish, which I try not to do anymore, I just sand and rub the old finish vigorously with actone and then apply new finish.

Also, I would not recommend wet sanding the EM6000.

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Randy Muth
RS Muth Guitars Website
RS Muth Guitars Blog
Facebook Fan Page

The KTM-SV sounds interesting Randy. Thanks again for your post.

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Formerly known as Adaboy.......