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Steve vanPelt
09-15-2011, 07:12 PM
A couple months ago I decided to give the UV finish thing a try. I was pretty impressed with the finishes Mike DaSilva and Joe Souza are getting with the stuff. Plus it's plenty hard and tough. And goes on thin. The topper was that, being pretty new to this craft, I wanted to be able to string one up and hear it, before starting the next one, instead of the 6 weeks it takes me to do a lacquer finish. Last year I made one change, and built that mistake into four ukes before I realized it. I figured UV would be a great finish, and fast, and easy. You know, like *the* answer.

So I ordered the CureUV system, with the light, filler, gloss and safety equipment. I followed their directions to the letter, but just couldn't get it to work for me. I tried a few suggestions from the interwebs, they didn't work for me either. I set the light aside for the time being until I felt like really getting into the learning curve.

Fast forward about a month to the Healdsburg Guitar Festival. Cardinal had a booth there and I stopped by and talked to their chemist, Mac, for about an hour. Mostly about their UV finish. He told me they formulate theirs with a solvent base so it would flash over and you could spray several coats before hitting it with the light. They use a pre cat vinyl sealer so the gel filler doesn't seep in farther than the light can reach. Then he told me they were offering free samples if I signed up for them at the show. So of course I signed up.

After a few emails and phone calls over the last week or two, when I got home this afternoon there was the box from Cardinal on my front porch. I built a little concert pineapple out of sapele and spruce to use as a platform to try this stuff out, and it was ready for finish. Oh, and he threw in a trial size of their lacquer, too. I like this company already.

I sprayed two coats of precat about a half hour apart and let it dry for an hour or so. Wiped on the filler and lit it up. Leveled it with 220. sprayed 2 coats of gloss on the top and 3 on the back and sides, lit and leveled it. Sprayed one more coat on the whole thing. Spent less than a half hour to wetsand with micromesh from 1500 to 6000. Then buffed it with Mezerna medium and fine. The cheap Chinese belt on my buffer has stretched a bunch so I couldn't really put much pressure on it before it slips. I'll fix that tomorrow and rebuff.

This stuff sprays so well, so easily. No dust or nibs stuck in the uncured finish. It's like what I had hoped UV would be like. :) I can't think of words to describe how happy I am with this. I have all day tomorrow to finish a koa tenor that was going to get lacquered.

I put 2 ounces of finish in the cup, and with overspray and solvent gassing, I'd guess maybe 15 grams tops of finish before sanding, and I'd bet the top has no more than .002 on it. I'll weigh and try to measure it tomorrow.

No dust, no nibs, no learning curve..... here's a couple pics.... four hours from box to buffer
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Sven
09-15-2011, 08:32 PM
Sheesh..! That's fast! And a good company it seems, and a good result!

But that ruler with the reverse numbers, is it especially made for that corny backward inch nonsense?

Pete Howlett
09-15-2011, 11:27 PM
It's a pity companies like Cardinal have such a huge internal market in the US that they have no need to look abroad for business. My only reservation with UV is its repairability... great result though ;)

Steve vanPelt
09-16-2011, 07:56 AM
Hey Pete, I'm not even sure what their home country is. I know they're a multi national company that has been doing automotive and industrial coatings, liquid and powder, for a long time. I've heard that at least one luthier (I forget if it's Ryan or Olson) says they can do an invisible repair on UV poly. It's kinda soon to tell, but I think there is a good chance it's less likely to need a repair as well.

I haven't given up on lacquer just yet though and am looking forward to giving the Cardinal nitro a try. It really sounds impressive from what you and Eric are saying about it. I just found out that it's compatible with the UV pore filler as well.

Steve

DeVineGuitars
09-16-2011, 08:12 AM
One other thing to mention about the Cardinal nitro has to do with adhesion. Steve grimes told me he had some adhesion issues with it, that he latter figured out was the fault of his sanding sealer. I for one have never used sanding sealer, and don't plan to. I use a shellac base before and after pore filling and the lacquer bonded very well to it! So be warned that if you use sanding sealer, you need to contact Cardinal to check comparability.

Steve vanPelt
09-18-2011, 08:04 PM
Thanks for the tip, Eric. When I talked to Mac at Cardinal, he said to be sure to use their precat sealer, then the UV filler and spray the lacquer right on top. I've always used shellac as a bond coat under nitro, so thanks, I will continue to do so.

I've had a chance to finish another couple of instruments and wanted to update this thread. I have been doing my homework, and my finishing technique has improved dramatically over the last year. Basically follow the advice from Chuck and Allen, as posted in these boards. Spent many hours preparing the instruments for finish and they were well blocked and well prepped before I started the finish process.

On one tenor uke with three coats of Cardinal UV Poly gloss I measured a film thickness of .003 at the sound hole and the total weight of filler and finish at 11 grams. The two I'll show here have 4 coats on the top and 5 on the back and sides.

I've found the results to be quite frankly, unreal. To quote Eric, "it's that good." What I like about it is it is thin and hard, durable, easy to wet sand, easy to buff right on out to the edges. It has the clarity of nitro, but seems like a slightly different level of refractiveness. Very user friendly and glosses to a literally mirror shine with less effort than nitro.

Regarding the thread on finished for new work, this definitely deserves a look. I think the initial investment could be made up quickly by an active pro in the form of additional time to build more instruments. Just my .02 cents.

Rick, if you read this, I'm curious as to what poly you're using...2 part, UV, Cardinal?

The biggest drawbacks I've found so far is the necessity to wear long pants and shoes while using the light (slippahs are out) and that it's screwed up my building schedule. Usually at this point I hang the ukes for month and have plenty of time to fab the necks. Now I feel behind.

Steve
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Rick Turner
09-19-2011, 04:09 AM
I'm using the same Cardinal poly but without the UV initiator in it. I'm mixing in 2% cobalt, letting it sit for 30 minutes, then 2% MEKP. I don't get the instant cure, but we can sand and rub out in 24 hours which is plenty fast enough for me. Frankly, I think that UV has been oversold because of the whiz-bang appeal. MEKP cured poly is plenty fast unless you're doing a hundred instruments a month or more...that was Bob Taylor's advice to me. The UV thing is expensive and cumbersome, and as I said, finish cure is not my bottleneck.

Steve vanPelt
09-19-2011, 05:59 AM
24 hours doesn't sound too bad at all. Same great finish without the initial investment. Looks like my homework fell short this go round and it cost me. The instant cure is not my most favorite feature of the product. And it seems like a good idea to let it rest overnight, before sanding, anyway because the heat of the light drives out a bit of moisture from even the driest of wood. I let it equalize overnight before wet sanding.

How many coats do you apply?

thanks, Steve

Rick Turner
09-19-2011, 06:50 AM
Steve, right now it's two coats of epoxy, light scuff, two thin coats of isolator, light scuff, three coats of Simtec polyester sanding sealer, sand dead flat, three (but maybe should be four) coats of Cardinal polyester topcoat. All polyester 2% MEKP catalyzed, Cardinal also with 2% cobalt drier allowed to sit for 30 minutes or more before adding MEKP.

I understand the appeal of the quick cure, but as I said, the guru of this whole thing...Bob Taylor...was the guy who told me not to bother, and I'm glad I took his advice.

The single biggest "breakthrough" for me in finish over the past few years has been the epoxy sealer thing. It's fantastic, and I see it working under everything from oil finishes with a more open pored look to varnish to French polish, to nitro, to dead flat gloss polyester. The great thing is that it's almost as low tech as wiping on tung oil. We use foam brushes, and then wipe down with blue shop towels.

Allen
09-19-2011, 10:19 AM
So you're not using the epoxy for pore filling Rick? Just as a sealer?

Rick Turner
09-19-2011, 10:47 AM
Well, it's a sealer that helps fill pores! I guess I could do one thin coat and then follow that up with a coat of thicker epoxy squeegeed off, but for now I think the distinction between sealer and pore filler is more in spelling than in the reality.