Official Luthiers Forum!

Okay, so I got this nifty Fuji mini-mite 4 hvlp system.
Now I need to decide what ultimately to use on my acoustics.
Besides the obvious nitro lacquer and shellac, what experiences have y'all had with acrylics, urethanes, and what not? I like laquer, but I'm not excited about the hardening time. My previous experience has mainly been with the rattle cans, but I was able to obtain professional quality finishes with them.
Now that I have a sprayer, my options are wider.
Anybody care to comment?

_________________
Old growth, shmold growth!

If you want quick cure time, you will have to go with catalyzed systems, or use what Taylor uses, which is a UV catalyzed varnish.

I have never seen any acrylic lacquer I liked, the cure time is the same as nitro except it never gets anywhere near as hard as nitro. I've seen a furniture finished with acrylic that still hasn't hardened enough for everyday handling, years later. Hardware store polyurethane doesn't get very hard, at least not right away, but they take a while for it to cure. Waterbased will cure a little faster but then again I've never seen any waterbased finish I like, when they dry they don't get that hard, plus if you let it soak in water a little too long (like a cold drink on a table) then the water will turn it permanently white, it's also picky about what can go under it, any oil and the finish may not adhere to the surface.

Nitro and french polish is about the only forgiving finish out there.

Then there are Alkyds, the problem with them is usually the can says "recoat in one hour or two weeks", take that seriously, because if you don't, the finish will wrinkle on you.

_________________
Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

I could be wrong but I had in mind that Taylor uses UV polyester.

I think all finishes take a while to harden.
Nitro is very easy to use.
Dries fast, so multiple coats in a day, with not much sanding.
Water based lacquers (?) dry fast, multiple coats in a day, more sanding than nitro,
and I don't like the way they look.
User friendly though,
and pretty good for some woods.
Varnish is the bomb for spraying.
Look fantastic, and brands vary a LOT.
Very slow drying,
1 coat a day,
but worth it IMO.
Sher Williams makes a fast dry varnish that dries really fast,
but doesn't look as good as some of the slower drying varnishes,
IMO.
Maybe I'll try spraying shellac next time.....
Never sprayed shellac.
Dries fast and would probably look great.
Fumes aren't bad either,
just don't drink the solvent,
unless you are using Everclear.

Alan you should give Target Coatings Water base shellac a try. Nice stuff. Sprays nice too.

_________________
Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

Thanks Bob.
I'll look into that.
I'm trying to find a finish that I like,
and it ain't easy.

What about the catalyzed stuff? Anybody use that on their guitars?
Does catalyzed nitro cure faster and harder than non-cat?
What about non-yellowing laquers? What are those?

_________________
Old growth, shmold growth!

Cardinal lacquer claims 7 -10 days cure before buffing. I just sprayed the final coats yesterday on a guitar with Cardinal, so cannot report about curing time. It is water clear and sprays like any other lacquer. LMI stocks it and has the data sheets .

Chuck

_________________
_________________

One thing - with the catalyzed poly finishes, waterborne, and anything that's polymerizing - you better have a good way to ensure your gun is 100% squeaky clean and totally rid of every last spec of that stuff... or you go buy a new gun.... Once it kicks and sets - it's there...

This is particularly important with the UV cure stuff - shoot it outdoors and you may end up with a nice skin of hard material inside the gun from sunlight... It cures pretty quick in contact with UV/Sunlight....

Thanks

Which is why I won't shoot catalyzed anything through my spray guns... I wish they sell preval units in Taiwan though, so I can shoot catalyzed stuff through something disposable.

_________________
Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

Are you using one Todd? I assume you would have some sort of heat source and humidity control? Airflow? Ventilation? I can see if you were to get the temp. up a bit it would speed things along.

Thanks,
Danny

In my own feeble way I'll try to add th this conversation... As a cabinet finisher for many years, my mind is split on this issue. Nitro is only surpassed in obsolescence by shellac in the cabinet finishing industry (which makes sense when you think of moisture exposure).

So why then is it a favorite of luthiers everywhere??? One major reason is ease of use/ease of repair. Nitro and shellac fit into the category of "burn in" finishes. Even after a finished piece has fully cured subsequent coats chemically bond together (likewise many minor finish repairs can be performed using only the appropriate solvent). Another major consideration is the fact that these finished "stick" to an awful lot of the "less desirable substrate conditions".

I guess I would emplore you to add some of those considerations to the equation when evaluating pros and cons of a finish and it's dry time.

On a side note- catalyzed finished are getting very user friendly. There is plenty of time to clean the cup of your gun, and with the correct solvent it can be done in minutes. The 3m pps system is well worth the investment for spraying and cleanup.

Interesting. I wonder why the Transstar hardeners have pictures of scantily clad women on them.

_________________
Old growth, shmold growth!

Well, apparently I can't get catalyzed or pre-cat in anything less than 5 gallons. No way I cn use that in 6 months (or maybe even six years...). So it's standard laquer or water based for me. I hear tons of horror stories with the waterbased stuff, but is it really that bad? How hard does it actually get after how long?
I can't help but suspect user-error in some of these horror stories, but I dunno. I've never used the stuff.

_________________
Old growth, shmold growth!

Find your local M L Campbell dealer. They sell in 1 gallon cans. You'll need to open a business account most likely as these are not consumer products. They sell a variety of different types of coatings from nitro on up and water base too. Their Krystal high solids conversion varnish is tough as nails and quick, something like 8 hrs. to stack and pack after final coat. I know from talking to Pat DiBurro that some manufacturers are using this on guitars, I can't recall who at the moment. And as mentioned Taylor uses UV polyester so almost anything can be made to work fairly well. Be warned about conversion coatings though, the chemistry has to be accurate and if you don't like lacquer fumes you're really not going to like this stuff.

_________________
Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

Todd,
What do you recommend on wait time. I just finished spraying a guitar with 9 coats of rattle can lacquer two days ago. Dan Erlewine's dvd say to wait a week before sanding and buffing. What do you recommend? I've never used aerosol cans before.

Hutch

_________________
"After forty-nine years of violin building, I have decided that the search for a varnish is similar to the fox hunt. The fun is in the hunt."
Jack Batts Maker and Repairer of Fine Violins

Water based and water bourne finishes have come a long way, but (and this is a large posterior) some of these finishes don't impart the rich ambering that you would get from other finishes. This is where a slight bit of toning can really help, a tiny bit of color in the finish will go a long way. Either that or you could apply a shellac barrier coat and a WB finish...

As mentioned, ML Campbell has a full product line that comes in gal. quantities, and they are great finishes. Targets product line is great also... there are a lot of great coatings out there.

Good luck

Last time I used rattle-can lacquer I waited 4 weeks before final sand and buff. May have been overkill though.

_________________
Steve Smith
"Music is what feelings sound like"

Putting a fan on lacquer will speed up the hardening process exponentially. I use a box fan on the slowest setting, and have buffed after two days.
The spraying schedule is also very important. I take 2 or 3 days to spray lacquer, consisting of 9 or 10 very light coats on the back and sides, and 4 or 5 on the top.

Wayne Henderson uses it. I have not been that impressed with the look. It seems to appear cloudy, especially in direct sunlight. And on some BR, it can turn parts of the wood bright green after a few months.
The big advantages over lacquer are that it hardens quickly, shrinkage is much less, and it is easy to buff to a brilliant shine.

_________________
John

Sherwin Williams owns ML Campbell. I don't know if that means changes to ML Cambell conversion varnish, or if there's already been changes. I have no expereince with conversion varnish.

For a "traditional finish" I use Sherwin Williams fast dry oil varnish. Under the right conditions you can buff in a few days. It takes it quite a while to fully harden.

For a more durable finish I use Axon Polyester. I use it on all my necks. I can buff the next day but usually wait 72 hours. It's hazardous, so proper safety equipment and precautions are needed. Most finishes carry a certain level of danger with them, even waterborne.

I buy both products locally. Axon has a $350 minimum purchase.

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

I'm looking into the Axon polyester formulations.

They said their minimum is $250. However, my first order to get into it would be $350, plus shipping, which is expensive 'cuz there's a hazmat charge.

I wasn't thinking I'd get into the polyesters, but I dunno. I might give it a try.

If I can get a thin enough coat then polyester might make a nice acoustic finish.

_________________
Old growth, shmold growth!

I suppose I got confused about the minimum. When I buy a batch it's $350. They're 65 miles from me, but I go pick it up to save on the haz mat charges. It's really easy to get polyester too thick. It doesn't shrink near as much as most other finishes, so it builds faster. I get ~3 mils with 4 coats, after buffing. This is over 2 coats of sealer, but the sealer doesn't build much at all. Do your homework, and use the proper equipment to protect yourself especially with polyester, but with any finish.

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