Trouble spraying Lacquer

KingCavalier · #1 07-23-2014, 05:37 AM

Hi all,

I just started my first attempt at spraying NC Lacquer. For those of you who can do my hats off to you, this isn't easy. I'm using a HVLP conversion gun and it's taking some time to try and dial it in.

My problem is that I'm spraying outside and I had to stop because the humidity went up too high. My question is how long can I wait before I get started again. I'm using Cardinal Lacquer and they say it's ready to buff after around 10 days. I'm looking at around 3 days of down time, do you see any problem with that.

I have 4 coats on so far, I need to sand level and I want to shoot around 4 more.

Thanks.

SA

Brhibler1 · #2 07-23-2014, 06:44 AM

That's the down fall of shooting outside.
Conditions have to be just right.

I've sprayed outside and it was humid. The finish blushed a little, but as long as it was light coats it went away.

Also, never spray in direct sunlight, you'll get bubbles.

Almost any minor issue, blushing, bubbles, orange peel, can be fixed by spraying thinner over your flawed coat.

Good luck and may the weather be with you.

LouieAtienza · #3 07-23-2014, 06:50 AM

If you must spray outside with humidity, try to find a shaded area or create one. Retarder can help as well. You don`t say your exact probkem, but most of the time it is getting the proper viscosity for your gun. Outside, I would probably go for a slightly coarser atomization, and deal with a little orange peel, than try to build.up a `dry` coat.

LouieAtienza · #4 07-23-2014, 07:05 AM

I should add that HVLP would atomize a little coarser than a conventional gun, so you have to lay the finish down a little differently. Almost looks like orange peel.until it floats out; it takes a little practice to get it all right, and even the you have to adjust depending in the temp and humidity.

KingCavalier · #5 07-23-2014, 10:35 AM

Thanks Guys,

The thing that worries me is the down time. I wanted to spray on consecutive days but I had to stop because of the humidity. Is it okay to stop the process halfway through, wait a few days and then start again. Will I have any trouble with the next coats adhering to the first coats.

Thanks again,

SA

gpj1136 · #6 07-23-2014, 11:27 AM

One of the main reasons for using NC lacquer is that it re-emulsifies the original coats when you spray allowing the new coats to adhere. Just make sure there are no contaminates. I have had trouble from finger prints after a door knob was sprayed with a silicon graphite spray and not cleaning my hands before going back to spraying.

LouieAtienza · #7 07-23-2014, 11:47 AM

Quote:

Originally Posted by KingCavalier

Thanks Guys,

The thing that worries me is the down time. I wanted to spray on consecutive days but I had to stop because of the humidity. Is it okay to stop the process halfway through, wait a few days and then start again. Will I have any trouble with the next coats adhering to the first coats.

Thanks again,

SA

You`d only need to stop if the humidity causes the finish to cloud up; then you nees to see if it clears up or you have to sand it out...

Howard Klepper · #8 07-23-2014, 12:04 PM

Wait as long as you want. There is no time pressure with nitro lacquer. The lacquer will burn in to the previous coats so long as they don't get dirty.

KingCavalier · #9 07-23-2014, 03:23 PM

Thanks all, I appreciate the help

SA

viento · #10 07-23-2014, 04:55 PM

I´ve sprayed NC lacquer in my garage and have used a HVLP gun. I bought it as a double set
with a big one and a small one for about 25$. I waited until the humidity was below 75% to avoid white shades.
I did the spraying on three consecutive afternoons until I had the different layers of the burst I wanted.
Important for me was practicing before on a sheet of plywood and tilting the guitar somewhat to avoid paint run.

Birdman14 · #11 07-23-2014, 08:27 PM

Like it was said before, if it's not clouding up (turning the color hazey) I wouldn't worry too much about humidity. We spray a lacquer finish at the cabinet shop I work at all the time. If it clouds up you'll have to sand it out a bit.. But you can use a retarder to slow down the dry time which should get rid of the clouding up problem. As for time in between coats, it shouldn't matter. Best of luck getting it dialed in!

B. Howard · #12 07-24-2014, 06:19 AM

If you do get blush ( cloudy spots) from humidity don't panic. Spray a coat of retarder on the surface after it has flashed and the blush will come out. You can wait as long as you like between coats but if more than a week I would tooth the surface with some 320 grit paper to promote burn in of the new coat.