Painting help

[Chuck Feldman]

I am spraying Brodak dope thinned 50/50 and some retarder. I am getting blushing. The gun is the standard touch up gun. I know there are lots of variables in this process. I think the gun is not putting out enough paint andthe air to paint ratio is off. While spraying I found i had to increase the pressure to get the paint to spray. This morning I am going to take the gun appart and clean it. This may help. If you would please tell me what pressure you use and other details that might be important. The paint was applied outside with 50% humidity and the temperature was 75 degrees.
Thanks for your help ahead of time. Oh do you have any method to remove blushing? The blushing is uniform and has just made the finish flat. It was glossy when wet.

Chuck of Stuart, Fl.

[Rotten]

sounds like you have moisture in the compressor tank

[Will Hinton]

I run into blushing all the time since I can't decide to wait 'til the humidity goes down to spray when I have customers waiting.  (I spray mostly nitro-celulouse lacquer which has dope like properties.)  The first approach is to use 10% retarder when spraying, another thing I do is to spray the material as thick as my gun will allow, meaning less thinner when possible to slow the drying process.  (The blush is moisture trapped beneath the surface due to rapid drying.)
Now, when all that hasn't worked; (notice I said WHEN, not IF) let it dry an hour or so then spray it lightly with a coat of pure thinner.  This usually allows the trapped moisture to release and will cure the blush.  Sometimes I have to spray the thinner two or even three times, and once in a while I shoot it heavier if a light coat isn't working, but I've never had it not cure the problem eventually.  It takes patience, but is worth it.
There is also a product called Lacquer Melt available from the luthier suppliers that does a marvelous job on the nitro I spray on guitars, but I've yet to try it on dope, I'm a bit afraid of it for that because it is POTENT!  You have to spray it so that it really atomizes and it is really easy to shoot it with too much impact velocity on the surface.  It can introduce heartaches if not used carefully so I can't really recommend it here unless nothing else works.  Remember also that you can achieve a glossy finish when you spray the clear coats if it is your color that is now flat.  That doesn't help the white spots that blushing sometimes causes, but if it's only flat clear can cure.  Also, I have actually had times when I simply sanded and buffed the flat surface and achieved the desired gloss.  Yopu may want to play with a small area on the underside of the ship to see.
Take heart, the thinner will work for you.
Blessings,
Will

[Chuck Feldman]

Will,

That makes sense to me. I will do as you say. What pressure do you us on a touch up gun? The reason what you said made so much sense to me is this, as I was spraying I had a lot of trouble getting coverage.  This morning I took the gun appart. I found the two smallest holes each side of the fan nozzle to be restricked. A test spray after this has given much better results but I used thinner not paint. My previous spraying I was holding the gun about two inches away to get coverage. Adjusting the needle did not help. I sprayed on when i should have quit! Now i need to be 6 or so inches away this seems to do the job. The fanning spread is nice now also. I will not spray again until the lunch time has passed and it is the driest part of the day here on the east coast of Florida.

Thanks,

Chuck of Stuart, fl.

[Roger Vizioli]

Chuck,
Go easy on the retarder.
If applying on Polyspan. too much retarder seems to pull the famous "polyspan fuzzies" to the outer surface, even if polyspan applied correctly.
Also, if applied too heavy, small droplets penetrate the covering and form on the underside and are visible as dark "spots" if a translucent appearance is being sought (ie dyed clear coats).
Been there, done that! 
Roger V.

[Will Hinton]

Chuck,
I'm using a (gasp) Harbor Frieght touch up gravity fed gun for this and I set the air pressure up to around 25 to 30 lbs for the thinner only, but I spray from further away than usual to be sure and get a really thin/atomized spray.  Candle the ship as much as possible and go by what you see for a coverage and adjust your distance accordingly.  I go for full but light coverage at first.  If that isn't working then I soak 'er down but avoid putting so much on that it causes the thinner to run anywhere.
I your blush isn't the whitish color and only dull with no gloss, try the sanding and buffing on a spot first, it's much safer even though it's more work.  Also, if it can be cured that way you're likely to end up a tad lighter, always a bonus!
Good hunting!
Will

[Bill Little]

I accept blushing as a way of life around here using dope.  It's one of the main reasons I have gone to using automotive urethane 2 part clears!  Any lacquer that is sprayed almost anytime of year, here, blushes.

If it is an all dope finish, I spray the clear and rub it out.  I have never been hurt by the blushingi the colors once th eclear is aprayed on.  Evidently, the clear releases the moisture in the color coats and rubbing out the clear takes care of it all.

Actualy, I have sprayed the base coat/clear coat auto paints when it is raining!

[Will Hinton]

Coach,
There are many days when I spray nitro-celulouse lacquer when it's raining!  Have to or the customers get antsy.  Nitro is basically dope in a different can as far as I'm concerned, so the blush removing techniques I mentioned above get used a lot.  The two part stuff is so bloody expensive around here I have avoided it up to now.
Also, I used it once for the clear coat and felt it really added weight like crazy - have you been able to keep it really light?
Clue us in, my friend.  (By the way, merry CHRISTmas!)
Will

[Bill Little]

Hi Brother Will,

I have learned from Sparky to use some acrylic lacquer thinner to cut the clear automotive urethane when apraying it on our airplanes.  That really helps along with being *gentle* when spraying it!   It looks SO GOOD, that many people apply too much.  I remember Derek telling us that he sprayed th efirst coat on his Staris and it looked so great that he sprayed another, then another, then another.........  after four coats (and about 8 added ounces!) he realized he probably should have quit earlier!   One, *maybe* two coats is all that is usually needed, I found out.  As Sparky says, you just have to rub it out with in about 24 hours or it sets too hard.

I have known about the thinner spray to releive blushing on lacquers, but I was very hesitant to recommend since you can make a big mess real quick if you aren't careful. 

Clear coating and rubbing has always worked, just takes a while longer, but is a *little* safer.

And a Merry CHRISTmas to you, too.  May we all remember THE REASON for the season.

[Will Hinton]

Thanks Bill,
I would really like to try the two part stuff in colors because of the tremendous selection available!  What quantities have you found it in as far as not having a quart of the stuff in each color?  Man, would that cover a lot of ships!
Also, the very merriest of CHRISTmas to you and everyone!!!!
Blessings,
Will

[Keith Polzin]

   Two part auto clear, reasonable price.  Good stuff.

  http://www.southernpolyurethanes.com/homepage.htm

  I got some. I liked it.    Keith

[bruce malm]

Another problem I have found is the water filter is to close to the compressor. Especially if the compressor is used a lot. The air coming out of the tank will be to warm  if the filter is connected directly to the compressor and the water will not coalless. Add about 20>25 feet of hose, pipe, etc. between the compressor and the filter and you will be surprised how much better the filter works. A friend of mine was complaining about all the water they were getting out of their air tools at a high air usage shop.  I told him about this and they added about 40 feet of PVC to the main feed line and moved the filter and the problem disappeared.

Bruce

[Bill Little]

Thanks Bill,
I would really like to try the two part stuff in colors because of the tremendous selection available!  What quantities have you found it in as far as not having a quart of the stuff in each color?  Man, would that cover a lot of ships!
Also, the very merriest of CHRISTmas to you and everyone!!!!
Blessings,
Will

Brother Will,

The guys at the paint shop will usually mix it in as little as 8 oz. amounts.  I generally get a pint of a color I really like! I used 3 oz. of the base paint, equal amount of basemaker, and had some left over after I sprayed the Argus!  It only took a touch over 4 oz. of mixed paint to cover the entire plane, so a *little* goes a long way.

Merry Christmas!

[Will Hinton]

Thanks Coach,
I'll do some shopping here & see if I can find one of our suppliers that will do that for me.  I tried some time back at my local auto paint supply shop & they weren't interested.  I'll head for the "big city" of Toledo & track it down.
You & the family have a really blessed CHRISTmas too!
Blessings,
Will

[Chuck Feldman]

I am still in the painting process. I do not paint often. The weather being the major factor. I have applied the final coat of color and it is semi shiny. I think it would rub out quite nicely. But I have noticed that if I sand a spot it turns bright yellow? The paint is Brodak Piper Cream. I do not understand this but I can tell you I shake it and stir it over and over.

The tips that you all have provided have been good. I slowed the drying time by making the paint mixture thicker. Next step for me will be to get the tape on and shoot the trim color. Metallic green (brodak) that will cover fast. I have something else to pass on. I tried using brodak epoxy filler early in this build and it just wouldn't cure. I had a lot of trouble with this stuff and will never use it again. I mention this now as the areas where this stuff is on the model is a flaw area now. If not for that this model would get high points in appearance judging. I may try to re-sand it and level it off but have not decided yet. I mention this to caution everyone that if you want to make a front row model or a really nice one do not use products that you have no experience with.

Chuck of Stuart fl.