Waterborne vs Solvent CV Finishing

[brycycle]

Paul,

in discussion with another Luthier, he informed me that he uses a waterborne CV (a Target Coatings product) as opposed to a solvent based product.

any notable differences in end product(s)?

thank you.

[jingle_jangle]

Could this have been Larry Davis, Bryce?

Larry has been testing waterborne CVs on some of his own guitars, and I've been waiting to hear from him on these. I've had Target in my sights for awhile, but, frankly, am quite hooked on my solvent-reduced CVs. I don't want to buy a salesman's rap about CVs, only to discover a failure a year or two down the line. My previous experience with waterborne primers and clearcoats was not a happy one. The primers are up to snuff, I've been told, but I'm also told by my friends in the automotive industry that the clears are not quite there yet.

I'm not resistant to change. I just do not want my customers to be doing a paint company's R&D.

[brycycle]

"Target in my sights" zing!

yes, i am infact referring to Larry. he has my 4002 in his possession at the moment and has been most impressivly thorough w/ the diagnosis of the issues, as well as keeping me well informed of his intended solutions - thanks for the referral!

it now appears that i landed the '66 4001s (RM?) from Montreal and am in discussion w/ Larry regarding a restoration. given the rarity of the bass, i obviously don't want it to be the subject of any issues down the road as you referred to...this one may be swapping places w/ that '68 in your line-up, i'll keep you posted via e-mail.

thanks, Paul.

[jingle_jangle]

I'll elaborate on this a bit:

Waterbornes do not take well to sanding, either dry or wet, in my past experience. I tried a waterborne primer when it was a new product, and it was sold as "easy sanding". It, in fact, sanded just like the latex paint that it resembled once applied. In other words, it was a failure in this category.

I've read up on several waterborne CV manufacturer's tech sheets, and they recommend a 2 mil (.002") film thickness. They say nothing about bonding between coats, or sanding either. This led me to believe that sanding was a no-no. That means (since you need a mechanical bond between subsequent coats) that re-coating is a no-no, too.

How am I ever to get a workable thickness for flatting and buffing, if my initial spray film is only .002" thick? My rule of thumb is that waterborne finishes lose 2/3 of their thickness in catalyzation. That leaves a bit less than .001" in cured film over the wood. When I spray solvent-reduced CV onto a Rickenbacker, I put on enough varnish to give me a wet film thickness of about (are you ready for this?) 30 mils. This yields a catalyzed film thickness of about 15 mils, which is cut by half in the flatting and buffing operations to .007", or 7 mils. I sure don't want to go thinner than this--it's about two human hairs in thickness.

The literature on waterbornes also recommends an elevated dry temperature, usually between 120°F and 140°F. I hesitate to put any wooden instrument into a drying oven, as heating to these sorts of temperatures can bring on another, entirely different, but equally daunting set of problems to the set encountered at room temp.

Waterbornes are in common use here and in Europe for fine cabinetwork and stuff like yacht interiors. But for really fine finishes, we're still not there technology-wise, I believe. As one furniture pro put it on a wood finisher's forum awhile back, "There is a fine line between good wood finishing and fine wood finishing. I have not seen or been able to produce fine wood finishing using water base finishes. I hope it is happening, but I haven't seen it. I have used European and American, small companies and the largest in the world. I have also had conversations with 400 + higher quality kitchen and furniture manufactures in the last three years, and only four or five were using water. I would certainly prefer to use water, but at this time I'm not satisfied with the results."

[dgwguitars]

Yes, Paul and I have been talking about finishes offline, and yes I'm doing some R&D on CV on a guitar right now, albeit the one from Target Coatings.

The subject of finishes is typically on that draws heated debate among guys who apply them, since most guys (and girls) typically have their favorite, and I'm as guilty as the next, since my current finish of choice is Target's Ultima Spray Lacquer (USL). Just to give you some history, I did my first few guitars long with nitro, and ultimately didn't like it for two reasons. One was the fragile nature of the finish, and the other the high VOC's. I went from there to a urethane, which worked reasonably well, but it had a problem with "witness lines", since there is no burn-in. It's also a bear to repair, and it just has a plastic look, which isn't surprising since it is plastic. At that time I was frequenting the Musical Instrument Makers Forum, and the buzz on the board at that time was Premium Spray Lacquet by Target Coatings, which is the predecessor to Ultima Spray Lacquer. PSL was highly regarded by those on that board, so I transitioned to it, and to Ultima, which I now use. In the time since USL was introduced, I've found that it sands (wet and dry) and buffs out well, has great clarity, lends itself to leveling well, has great burn-in, is easily repairable, etc, etc. The only exception I have to Target's recommendations is that they say that it can be wetsanded and buffed in 72 hours, which I've found isn't adequate to allow the finish to cure. I let a guitar hang for at least 10 days , and preferably two weeks, at room temperature and then do the final wetsanding (Micromesh) over a period of three days, and then buff it out. I have never had problems with PSL or USL, and no complaints from the guitars' owners, at least three of which frequent this board.

Thanks to prodding from Paul, I've been kicked into trying a new finish, and I'll probably start shooting the CV R&D guitar this weekend. More to follow as it progresses.

[johneek]

...I have never had problems with PSL or USL, and no complaints from the guitars' owners, at least three of which frequent this board....

As one of the 3....I've been very happy with the finish on my 350...visual evidence of which can be seen in the September photo in the RRF Calendar, and here:

viewtopic.php?f=1&t=377309&st=0&sk=t&sd ... y+finished

[dgwguitars]

Well, just today I finished shooting the test guitar with Target's CV, and while I can't make any definitive comments yet, in shooting (I use an HVLP system) it's a little different than the waterborne lacquer that I've been using - not better, not worse, just different. Visually, in the can it has a thinner appearance, and has a slight yellow cast. The PSL is very white looking in the can and goes on thicker, although I've found it necessary to add Target's additive to get it to flow out well, so in the end it's probably equal on both sides. In the process of shooting I flatted the finish twice, and found it equal to the PSL in that regard. The guitar is now hanging, as it will for at least a week. I'll chime in with more after I've started the wetsanding process.

[brycycle]

looking forward to seeing the results, Larry.

[dgwguitars]

I finished the wetsanding and buffing today, and am pleased with the results. There was nothing unusual in the process, except for a few witness lines along the way through the grits, but the end result is very pretty. Since it's just finished, I can't comment on long-term issues, but based on what I've read on Target's forum, it should work well. If someone can school me in how to post photos, I'll do so.

[johneek]

Larry,

Just below the area where you type your post are two tabs. One labeled "Options" the other "Upload attachment" Click on the "Upload attachment" tab and you should be ready to go. It's pretty self-explanatory after that, though there is a file size limit that I can't recall off the top of my head. If you run into problems a bunch of people on the Forum would be happy to upload them for you.

[dgwguitars]

Larry,

Just below the area where you type your post are two tabs. One labeled "Options" the other "Upload attachment" Click on the "Upload attachment" tab and you should be ready to go. It's pretty self-explanatory after that, though there is a file size limit that I can't recall off the top of my head. If you run into problems a bunch of people on the Forum would be happy to upload them for you.

Thanks, John.

After considering it further, I've decided to not post the photos at the suggestion of a learned member of this group since it's similar in shape to a well-known brand. For those who are interested in the results email me.