Official Luthiers Forum!

Hello all! I was looking in the archives and found a few things but was
wondering if anyone is using or has used a Preval with nitro lacquer. I know
JJ had some problems with some lacquer that he sprayed using one but was
wondering if that was the problem or not. JJ? Thanks.

Less than useless...

I actually finished my #1 completely with nitro using a Preval unit, so it CAN be done. Expect to have more material waste and more sanding. Actually, I was surprised at how uniform a coat you can get with one of these...if you've got the patience.

Having said that, I bought a spray gun for #2 on. Especially if you've already got a compressor, it's a no-brainer. If you don't, you may consider one of the HVLP turbine rigs.

Here's that Preval finish.

_________________
Wes McMillian
Santo, TX
http://www.wesmcmillian.com

The final finish is a matter of finishing the finish. How it was applied doesn't matter.

The PreVal is less than useless...

 for the same price, you can buy a cheap, but real, gun. Don't have a compressor? Use a spare tire and a home made hose assembly. Go to the filling station and put 40 lbs of air on a big truck tire and you can spray a guitar. Drop the gun in a pail of acetone between coats/sessions so you don't have to clean it and waste air.

[quote=Grumpy]The PreVal is less than useless...[/quote]


Yep. Better to get a rattle-can of lacquer.

_________________
"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."

OK Mario and Don, I'll take the other side on this one...

I've used Preval sprayers with both solvent and water-based products with great results.  I use it regularly on touch-ups and small detail items.  I agree with Don, that if I'm spraying clears, a rattle can would be better, but sometimes I mix up toners and spray some color or some dye, and the preval works great for me in those applications. 

I wouldn't try to finish a kitchen table with one, just because it would take forever, but I have had excellent results with a Preval as just another tool in the arsenal...

Mitch

A Pre-Val is an ok stop-gap measure for a small project and touch-up work, (I'll give you that) but it has no real value to someone who builds consistently who wants to use it for spraying an entire guitar finish.

I've tried using them with waterbornes to spray a guitar, and found they constantly clogged, left air bubbles in the finish, and got pretty expensive very quickly. It would have been cheaper to buy a small airbrush or a cheap spray gun. That's the primary reason I eventually broke down and bought a compressor and spray gun.

_________________
"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."

I used to use the Pre-val and Jetpack style sprayers and they do work. I have mixed feelings about them since you can just buy the rattle cans and get the same results with less cost and effort. I think I would push for a cheap sprayer and a compressor. If you can't afford the compressor then I know you can buy compressor tanks for not too much money.

_________________
Brad
Avon, OH

You can't mix dyes into rattle cans, this is where Prevals are useful.  However....



IMO there is a natural evolution that all serious finishers tend to
take...brush-on or rattle-can, then Preval, then compressor+HPLV guns.



A Porter-Cable 10-gal compressor and pair of Grizzly HVLP guns will set
you back <$500 including hoses, quick-connects and water
traps.  If you are serious about doing your own quality finishes
then I'd just save my pennies and take the plunge.  You'll wonder
why you didn't sooner (at least I did).

What Erik said...

Mitch

 

Thanks everyone. I never planned to check into Preval for the long term, but
exactly as a "stop gap" until I can get a HVLP system. Thanks again.

You can't mix dyes into rattle cans, this is where Prevals are useful.  However....

There are so many better ways! For half the cost of the preval system, you can buy a cheap airbrush, and a length of hose. Go to the hardware store and buy a replacement hose for a bicycle pump. The one with the flip-on lock lever. Cut the other end off, and connect this to the airbrush's hose. Head to the filling station and fill a spare tire with 40 lbs of air. better yet, go by a scrapyard, and tell them what you're doing, and ask them if they'd give yo a couple junk tires, the largest ones they have. They'll happily give you a couple as they're worthless to them...

You now have a lifetime's worth of PreVal sprayers that will never cost anything to refill or run, can spray anything you wish, and do a decent job of it.

It's like you guy WANT to line up to throw good money after bad ideas.... I don't get it? Does everything HAVE to come in a kit, wit a name brand on it? Can you NOT improvise, even a bit? I made the above system when I was a teenager, spraying models, then helmets, then doing graphics on race cars and what not. I could do a touch up at the track using the car's own tires for air..... I still have that hose, and recently used it  with my improvised vacuum system. Oh yeah, still have the airbrush, too.

B. Bubba. IMPROVISE!!!!

And by the way, I DO have a Preval unit. I DID try it.


Free to the first OLF-er to visit.

Mario-
I'm impressed that you can put a nitro finish on a guitar with an airbrush.
Instead of messing around with an airbrush and a tire for air supply, perhaps a cheap jamb gun and a cheap compressor would be a better stopgap measure. Trying to run any gun but an airbrush from a tire- even a truck tire- would be a short-lived and frustrating experience, particularly for a beginner, who would probably empty a tire just getting the controls set on a gun. That said, I do agree with the 'make-do' attitude you espouse. Believe it or not, you don't have to jump to a 5HP 60gal compressor as the first step.

I've finished a guitar with nitro (I wanted to add some 'vintage' tint) and Prevals- it takes a lot more than one 'unit' (so the cost starts to add up), and the Preval won't atomize most nitros unless they are thinned quite a bit. Also, the propellant can cools down as you spray, so you have to try to keep it warm or you lose pressure, and get sputtering. So, it was a less-than-satisfactory method for me. I ended up with a bunch of empty Preval canisters at the end, when for the same money I could have had a cheap jamb gun and a hose or two, which I could use for years.

Cheers
John

Have you ever tried a tire? It'll go an hour with an airbrush...

The cheap airbrushes can shoot a 2" wide pattern, and not need to be thinned to the level you have to thin for the Preval to work. And as you noted, it takes many cans, and I'd also forgotten about the cooling part of the equation.

My whole point is that there are so many better ways(including brushing if it's a clear) to go than the Preval. Hopefully I got y'all to think outside the box a bit. That's all I ever try to do.

[QUOTE=grumpy] My whole point is that there are so many better ways(including brushing if it's a clear) to go than the Preval. Hopefully I got y'all to think outside the box a bit. [/QUOTE]

Agreed.
I'd put most of the hand-applied finishes (Deft brushing nitro, Oil, wipe on varnish like Tru-Oil, varnish, FP with Behlens/LeeValley pre-mix, trad shellac FP, etc etc) all above nitro and Prevals...it's about at the bottom of my list now.

Cheers
John

[QUOTE=TommyC] Hello all! I was looking in the archives and found a few things but was
wondering if anyone is using or has used a Preval with nitro lacquer. I know
JJ had some problems with some lacquer that he sprayed using one but was
wondering if that was the problem or not. JJ? Thanks.[/QUOTE]

It was bad lacquer!

I bought 4 cans of Preval Air some years ago and still have 3 left. After the unsuccessful lacquer trials, I occasionally used it to spray shellac over large areas but now find it easier to wipe or brush on. I bought an inexpensive HVLP spray unit from Rockler and that seems to suit my declining spraying needs for now.

I have fallen in love with FP shellac over the past year and do very little spraying anymore. Any future major spraying needs will be handled by my fellow Hoosier, OLFer and neighbor...Joe White.

I may use the remaining Preval cans to spray insecticide for Canadian mosquitos and flies next summer if I visit Mario!

_________________
JJ
Napa, CA
http://www.DonohueGuitars.com

The only way those cans will help up here is if you hold a lighter to them while pressing the nozzle, and burn the bugs' wings before they can land...

[QUOTE=grumpy]The only way those cans will help up here is if you hold a lighter to them while pressing the nozzle, and burn the bugs' wings before they can land...

[/QUOTE]