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I had a client who wanted a UV cured Polyester finish. I've done polyester (it's my regular finish for necks) but don't have or want expensive UV curing lamps. I don't lie to clients so that wasn't an option. I could have sent it out for finish, but I like to control everything. (even though there's some great finishers out there). I came across a UV cured polyester that cures in normal sunlight.
http://solarez.com/productsnew/gloss.html

I've done a bunch of experimenting with it, including testing a bunch of sealers. Here's a few pics of the guitar with it.









I'll assemble and clean up the guitar Monday and post better pictures.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

Woody - thanks for sharing this. I am very interested in your thoughts on this resin!

How fast did it cure? Looks great!

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http://www.CostaGuitars.com
PMoMC

Woody, you big tease, tell us more. The results look great but how is it for flexibility, hardness, resistance to scratching etc., etc., etc.? Also, are you able to compare it to catalyzed or light cured Poly finishes? Inquiring minds want to know. TIA

Cecil

Their site is less than instructive. Can you give a brief description of the method used? Brush, spray, how many coats, buffability etc.? This seems very intriguing indeed!

Looks good, Wood!

What is the back and side wood on that one? Cypress?

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

The final finish is the same reguardless of whether it's catalyzed or UV cured. I done a bunch of tests, and experiments to arrive at what I actually used. I'm an oil Varnish guy, but I've used (catalyzed) polyester on necks for a while. I'll try to answer everyones questions, but I'll probably leave some out.

I didn't time how long it takes to cure in the sun. The manufacturer says 3 minutes. It didn't seem like I was standing in the sun holding the guitar for a long time, so it's pretty quick. When exposed to the sun it starts curing. The part of the guitar underneath isn't curing, and it quits curing when it's no longer exposed. Pat Hawley started a thread a week or 2 ago about making a stand that rotates automatically (like a grill rotisserie). That would work great. You can tell by watching while it cures. It's pretty neat to watch it cure.

Warning: Polyester is dangerous. It contains vinyl benzene (styrene) There's ongoing arguments about whether or not it's a carcenigen. (sp) Reguardless, you need to use the proper safety gear. I use a hooded respirator, with gloves, and a tyvec suit.


Polyester needs some type of compatable sealer, at least on oily woods like Rosewood. I think a barrier coat/sealer is a good idea on any wood. I used ML Campbell Exotic Woods Sealer. There's similar 2k Urethane barrier coats available from several manufacturers. I can buy this stuff locally. The Osage Orange body didn't require pore filling, but I used the same filler I use with oil Varnish on the Rosewood cutaway and Mahogany neck. (CrystaLac waterbased grain filler from Rockler)

I sprayed 2 coats of the ML Campbell sealer, with 2 1/2 hours between coats. 3 hours after the last coat I sprayed the first coat of Polyester. I had to thin it alot to suit my equipment, and spraying style/preference. (thinned by adding 40% MEK) After 30 minutes I sprayed a second coat. 30 minutes after the second coat I cured it outside in the sun. After curing I checked the thickness. I had .0025" (2 1/2 mils) I level sanded with 320 grit. Thickness was right at 2 mils after sanding. I sprayed 2 more coats with 30 minutes between coats. 30 minutes after the second coat I cured it and let it sit overnight. The overnight wait wasn't necessary with my test pieces, but it seems strange to me to spray a finish, and be buffing a couple hours later. LOL The next day I sanded with 600 then 800 then 1200. I then buffed with menzerna medium, followed by fine. The final finish on this guitar was 4 mils thick. (.004, or 100 microns)

The beauty of this finish. If you get a run or sag just take a foam brush and brush it out. You can do that with any finish that doesn't dry/cure too fast, but this stuff will flow out to the point the mistake isn't noticable. If it gets any dust specs you can take some tweezers and remove them before curing. It would probably be a good finish to brush, but life's too short for me to brush finishes LOL. It builds really fast so you need to keep track of how much your putting on. My first (catalyzed) polyester finish, a few years ago ended up over 12 mils thick. (before the strip and re finish)

I deliver this guitar in early August. It's owner is a working musician, who'll beat the crap out of it. We'll see how it holds up.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

Thanks for the info Woody. I found out last night that I am going to have to find a new finish material because my the one I am using has been discontinued. This showed real promise.

Cecil

How can one compare a short oil varnish and a UV cured polyester one? The differences in toxicity, hardness and application are incommensurable.

Take note of Woody's use of gloves, tyvek suit and hooded respirator.

I wouldn't drink Rockhard, but I have no fear of brushing it without a respirator…

Woody, the finish looks great. So, is it as tough as, say, a urethane finish?

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

A point of confusion. Do you cure between coats? If it will not cure until exposed, how do you get a surface you can recoat? Also, if you do cure between coats, how do the layers bond? The surface should be inert after cure, no?

Thanks for the heads up Woody. Definitely interesting. Seems that an inexpensive UV lamp would then be sufficient for indoors, no? Seems I read somewhere that these finishes are wavelength dependent. One manufacturer's UV finish will not cure properly with another's lamp. But no one owns the sun, so it apears that the finish might be "broad spectrum". Meaning an inexpensive UV lamp might work as well.

Mike

Did you have to prep it with cobalt or anything?

Other than wearing the proper safety gear, was it generally easy to work with? Would you use it over your MEKP catalyzed stuff in the future?

It's at least as tough as catalyzed urethane. I've used catalyzed Polyester(first Mcfaddens, then Chemcraft Reslack) on necks for a while. I can't tell any difference in the finished product with any of these.

As said earlierPolyester is toxic stuff. Use the proper precautions,and safety equipment

For a closer substitute for Rockhard I'd recommend Sherwin Williams Fast Dry Oil Varnish, Ace Interior Oil Varnish, Pratt and Lambert #38 or Epifanes Clear Gloss Varnish. I use Sherwin Williams (on most bodies) Laurent uses Epifanes, Bruce Sexauer uses Aces, and I'm pretty sure Ken Miller uses Pratt and Lambert. The schedule would be different for each varnish, but the process would be similar to Rockhard. Mohawk has a "Exterior trim and door Varnish" Mohawk is owned by the same company as Behlens. It may be similar to Rockhard, (or it may be discontinued too)
Randy Muth uses KTM-SV, a waterborne urethane/varnish. I'm not a waterborne fan, but Randy's really smart, and builds great guitars. I suspect the SV is different than any of the waterbornes I've experimented with.


No cobalt to add. You have to add the photoinitiator, but there's no "ticking clock" as long as it isn't exposed to the Sun, or some form of UV. You can add MEKP for a chemical cure if it's night, or if for some reason you want a chemical cure.

I will continue to use this instead of catalyzed Polyester (on stuff I use Polyester on)

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

Woody - I have a couple more questions about this resin. I just ordered some to experiment with. There doesn't appear to be a lot of info about the UV cure polyester on the Solarez site, or on the Web in general. Most detailed info available seems to be in regards to other Solarez products, so I'm hoping I can pick your brain a little and benefit from some of the experience you have with it.

I got the impression from the limited material I've read that the resin is ready to use out of the bottle, but in the quote above you mention needing to add the photoinitiator. Am I understanding that correctly...that you added the photoinitiator, or is it already present in the resin when you get it? If you do add it yourself, does the photoinitiator come with resin when you purchase it, or do you order it separately? The only thing I ordered was the resin (the one from your link above), so I'm wondering if I need to place another order for the photoinitiator.

Also, how does this product buff compared to nitro? I don't think it is a thermoplastic, like nitro...please correct me if I'm wrong here. Does it buff as easily as nitro, and to as high a gloss?

Thanks again for sharing your experience with this stuff. I'm kind of excited about the prospect of a finish I can brush on (I have no spray equipment or facilities) and allow to self-level as long as necessary without worrying about it going off too soon, and about not having to wait weeks for it to cure before buffing.

I may have outsmarted myself with the photoinitiator. I can't find any documentation saying I had to add it, except on the bottle of photoinitiator. It's buffs really good. I'd compare it to well cured Nitro. It buffs a little easier than Oil Varnish.

Remember, polyester is toxic. Use the proper safety equipment.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

My quart arrived today, after I posted my questions. I slapped some on some scrap and headed out to the backyard and watched it set up. No photoinitiator required. I did read on the label where you can add 1% MEKP for "dual cure", but apparently it's not necessary.

Time to do some experimentin'.

PS - I do need to get some better safety equipment. Unfortunately, I learned to love the smell of polyester resin as a kid / teenager while patching dings in surfboards and spending too much time in surf shops and shaping rooms.

Anyone know whether polyester adheres well to shellac? And, does shellac adhere to polyester?

Polyester doesn't adhere to shellac, at least none I've ever tried. Gary Fisher from Solarez recommend I use their UV cured "Vinyl Ester" for a sealer. (He called it a primer) I used ML Campbell's "Exotic Woods Sealer", which is similar to Mcfaddens Rosewood Sealer.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

I'm also curious about UVP over shellac.

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"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

Interesting. Thanks for posting about this Woody.

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Formerly known as Adaboy.......

I'll try some solarez over shellac, but neither Mcfadden's polyester or Chemcraft adheres well to shellac.

Charlie, and anyone else who tries or uses a UV cured finish, reguardless of whether it's with the sun, or with lights. Let it sit 30to 45 minutes before curing. I doubt there's a big problems with trapped solvents, but it needs to flow out for a while to grab the surface you're putting it on.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

Thanks Woody - that sounds like good advice.

Hey Woody...

How much of the quart did it take to spray the guitar?
Trying to get some sense of cost to weigh options, and at $72/gal it's not to bad if the coats are few and the product goes a long way.

Thanks,

Don

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"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

What solvent do you clean your spray gun with? Does it require immediate cleaning of the gun?

After watching one of their videos you could get a partial cure at 45 seconds. With that in mind I wonder if you could spray the back, semi cure it for 45 seconds, spray a side, cure it for 45, spray the other side, cure for 45, etc... Assuming this would minimize and runs. Interesting finish. I think I'll order some to play around with.

Another question for the sprayers - what happens to the overspray? If you spray out of sunlight, does it take forever to cure? Is your whole shop sticky?

Super interested in this technology....

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