Best spray can lacquer for refinishing?

[ghmerrill]

What is the best and easiest spray can lacquer, for amateur/home use, in refinishing a brass instrument? I want to refinish the slide on my Olds 1947 trombone. I have tried Deft (nitro) semi-gloss. The result on portions of the horn (tuning slide and bell section) was great. But the slide didn't come out so well (patchy, uneven, "orange peel" kind of effect, etc.). I'm going to strip it down and try again, but I'm thinking that a non-nitro lacquer would be better for several reasons. It's not worth it to me to have this professionally done, and I don't want to get involved in renting a a real spray outfit and booth (which probably wouldn't be any better/cheaper than taking it to a pro to do it). The Deft actually came out very nicely on the other (smaller) sections of the horn. I was just somewhat inept in doing the handslide tubes.

I've seen a recommendation for Mohawk "Lacquer for Brass", particularly Satin or Matte (which is the direction I want to go in). But its chemistry is something of a mystery. It's apparently not nitro, but it's not clear what it is. I'm assuming that since it's specifically for brass, it should work well. If it does, I may then strip the deft off the other surfaces and apply the Mohawk.

I'm not going to refinish the bell section. It's fine as-is, though with the usual imperfections owing to its age (the horn is exactly as old as I am ), and I just can't bring myself to refinish it.

Thoughts?

Also ... what humidity should I be looking for when I decide to apply it? Right now, the humidity around here is pretty dreadful (between 65% and 75% for the rest of the week), and I'm not sure I can get it down very far in my garage where I need to do the spraying. This may have to wait a month or two.

[gocsick]

The rule I learned back in my aircraft repair days for dope and lacquer was: Ideal humidity - 40-50% RH and an ambient temperature to dewpoint difference more than 20 degrees F. Anything more than that requires a blush retarder.. and never spray when the humidity is more than 65%.

All that being said @bloke has shown some blush free instruments that must have been sprayed outside that envelope given his location and time of the year.

Spray can is actually more susceptible to blushing.. since it has a higher solvent content that flash off and skin over faster.. Trapping the moisture.

I'll let someone more knowledge recommend different rattle can brands.. I've only ever used the cheap hardware store stuff.

[bloke]

never anything other than high gloss (unless you have some motive/tastes which I don't understand)

needs to state that it's formulated for spraying metals

one equipped with a fan nozzle is the easiest to use (I haven't found one I like which is equipped with that type of nozzle)

[LeMark]

I've used Mohawk, and it work very well, and the desciption says it's Nitro

[arpthark]

The rule I learned back in my aircraft repair days for dope and lacquer was: Ideal humidity - 40-50% RH and an ambient temperature to dewpoint difference more than 20 degrees F. Anything more than that requires a blush retarder.. and never spray when the humidity is more than 65%.

All that being said @bloke has shown some blush free instruments that must have been sprayed outside that envelope given his location and time of the year.

Spray can is actually more susceptible to blushing.. since it has a higher solvent content that flash off and skin over faster.. Trapping the moisture.

I'll let someone more knowledge recommend different rattle can brands.. I've only ever used the cheap hardware store stuff.

@bloke also uses the ol’ torch-and-blow method he’s detailed here in the past…!

[ghmerrill]

and never spray when the humidity is more than 65%.

That could have been my original problem with the slide. As I said, the other tubing came out great.

Spray can is actually more susceptible to blushing.. since it has a higher solvent content that flash off and skin over faster.. Trapping the moisture.

Yeah, I've seen that that's a downside of using the spray can stuff.

[bloke]

torch and blow

Make sure your lips are dry, so you don't spit on wet lacquer.

Run your propane torch over blushing lacquer to pull the humidity out of it, but (courage, brothers) stick your lips right up there close and blow on the area that you're running across with the torch to prevent it from catching on fire.

Sometimes, if you shoot out of a legitimate gun and it blushes, you can go back over with rattle can (because that junk is so thin) to rewet the lacquer and the moisture will evaporate through the re-wetted lacquer.

That said, if you shoot out of a real lacquer gun, you probably have lacquer, thinner, and drying retarder on hand. Though there is more risk of runs and bugs and dust, you can substitute up to 100% of the thinner for drying retarder and slow the drying process of the lacquer down enough whereby it won't blush even when humidity is absolutely ridiculous.

(which reminds me...the Miraphone 186 "twin spin"... Not only do I have to do a lot of relacquering on those (probably 75% of the surface area of those two instruments) I have to polish them in the wee hours, so I don't sweat like a pig and drip perspiration all over the areas I'm polishing.)
Even though we've hit September, the extended forecast is still showing crappy high temperatures for every afternoon.

Hey...
Suddenly September 7th is starting to show a little hope, and I'm not going to have either one of these ready to shoot by then anyway.

[ghmerrill]

torch and blow

Hey...
Suddenly September 7th is starting to show a little hope, and I'm not going to have either one of these ready to shoot by then anyway.

Yeah, it looks great. Around here the humidity is going to dip down to around 50% for about 5 hours. Otherwise, it will be trying to sustain its usual 94% level.

[ghmerrill]

I've used Mohawk, and it work very well, and the desciption says it's Nitro

I have not seen the Lacquer for Brass described as "nitro", but rather as a "modified cellulose-ester formula" -- which makes it a sort of "relative" of nitro, but not a "kind" of nitro. The point of the "modification" was to avoid certain detrimental features of nitro (such as yellowing/discoloration, brittleness, and volatility). I don't care too much about the differences there, but I also would rather use something other than nitro for longevity and wear issues.

[ghmerrill]

never anything other than high gloss (unless you have some motive/tastes which I don't understand)

Ummm .... It's probably just my sophisticated artistic taste concerning the finish on my ancient trombone. And I know that others may be insensitive to such a refined taste. But I guess my thinking was mostly that -- in the absence of buffing -- the non-gloss finish might hide various small imperfections (both in the brass and in the finish) better. Maybe not. I'll reconsider.

In terms of the torch and blow, I think I'd want a lot of practice before doing that for real -- although it does sound like a lot of fun. My wife reminds me that although I don't have a life insurance policy, she did take out an "accidental death" policy on me. So any problems should be covered by that.

[bloke]

There are actually some metallic paints (lacquers, since we all seem to think that we prefer lacquer to other types of paint on musical instruments, though clear epoxy really isn't a lacquer) that just about look like polished brass.

I think it's interesting how people turn their nose up at pigmented paints (lacquers) on their brass instruments, but view paint without a color added as acceptable.

There are all colors of lacquer (not saying anything that we don't all know). Clear (no pigment) is only one of the nearly infinite choices. (again: duh)

something else:
Fun colors on guitars and drums (priced at several thousand dollars) are just fine, but fun colors on brass instruments...

I know you were just having fun in this repartee, and I am too... I'm just thinking about perceptions, and how interesting and humorous they can be.

[ghmerrill]

I think it's interesting how people turn their nose up at pigmented paints (lacquers) on their brass instruments, but view paint without a color added as acceptable.

I do not turn my nose up at that -- but then I'm not very sophisticated.

Fun colors on guitars and drums (priced at several thousand dollars) are just fine, but fun colors on brass instruments...

For a while I considered stripping everything off it and creating a really "artistic" patina of some sort. Then I thought that was a stupid thing to do to an instrument that I just wanted to play.

I know you were just having fun in this repartee, and I am too... I'm just thinking about perceptions, and how interesting and humorous they can be.

What I've done now is to strip all the lacquer (or "coating" for a more general term) off the slide. I think I'll try Renaissance wax on it.