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Nov 26, 2021, 08:03 PM
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3David's Avatar
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So Bob, you differ from previous posts that said I should sand most of my primer to the resin layer and then paint.
I guess there many ways for a paint job…
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Nov 27, 2021, 12:56 AM
San Antonio TX.
sensei's Avatar
Quote:
Originally Posted by 3David
So Bob, you differ from previous posts that said I should sand most of my primer to the resin layer and then paint.
I guess there many ways for a paint jobÖ
It all depends on what your base coat is, in both color and brand, I always start with solid coverage for the reason of seeing irregularities through the base color

At this point if you are still worried about weight you can spray a sealer down instead of thinned down primer, it goes on as wash prime that weighs very little.

If you prime fill and sand the surface as I described, it wonít be an issue to put just enough prime or sealer to make the the surface a solid color, but you need to do whatís right for you.

Bob
Nov 27, 2021, 10:11 AM
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exf3bguy's Avatar
If I’m not mistaken the fuselage was molded with a primer coat. All it requires is a scuff and some attention to the seam. When I prep my molds I use a total of 100 grams of mixed primer for both molds. After it flashes off it’s more like 50-60 grams. I see no need to remove any.
Nov 27, 2021, 11:00 AM
Scott
Pylonracr's Avatar
If your mold is smooth and you primed in the mold, do as Shawn says and scuff the surface and paint.
While Bob lays down a light coat of primer for a continuous base color, I usually lay down a coat of white paint and put my graphics on top of that. My reasoning is that by using lacquer color the white paint is slightly lighter than primer and much of the white paint will be the final color anyway. A top coat of urethane makes the surface fuel proof (I fly glow). It doesn't have to be white, whatever the predominant color is, preferably the lightest color in the overall scheme.

You are correct in that there are many ways to paint a plane. The thing to remember - Everything you spray on the plane adds weight.

Scott
Nov 27, 2021, 11:06 AM
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exf3bguy's Avatar
Scott is absolutely correct. White covers well, add a few trim colors and that will be as light as you can get. I have found that it’s best to start in all white regardless of what your main color will be. A good example would be yellow. You can go straight to yellow but it could take several additional coats to get good coverage. If you start off with white you could save 1 or 2 coats of yellow.
Nov 27, 2021, 02:09 PM
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3David's Avatar
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Thanks you guys for all to good ideas
Yes, I do want lots of bright yellow to contrast against blue and green. In this case I should have painted a white primer. Unfortunately I did lots of surface damage trying to demold the fuselage sides. I was scared of damaging it totally. So I believe my finishing process will go something like.:
Sand as much as posible
Use filler for bigger damaged areas and the seam
Spray very thinned white Primer one coat
Spray yellow two thin coats and mask
Spray blue two thin coats and mask
Spray red two thin coats and mask
Spray clear, varnish. One almost wet coat coat
Dec 15, 2021, 09:54 PM
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3David's Avatar
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I’m no painter and I have had lots of trouble
Dec 15, 2021, 10:02 PM
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3David's Avatar
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Painting difficulties


I spent many days prepping for paint. Filler, sanding, washing, primer, sanding washing, filler, so on and so on. Once I finally got to an ok state with how the fuselage looked I sprayed yellow first. Sanded then washed. Then masked the areas for green. Sprayed green, then sanded, then washed. Up to now I was very happy for the results where looking good and light. Since I went as light as posible with primer and my colors to. Now the only thing left was give it the shine with varnishÖ
Dec 15, 2021, 10:22 PM
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3David's Avatar
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Why why varnish you do that ?


Ok from the beginning:
We have to remember that I had no issues with the primer nor the two colors applied.
Air pressure good
Air supply more than needed, checked
Three water separators drained and checked
Spray surface cleaned and degreased
Spray gun, tools, mixing gear everything well cleaned and washed
Prepped the spray gun to full air, one turn less than full liquid, and calibrated spray width of nozzle.
Prepped the varnish as instructed by the seller. 1 part varnish, 0.5 parts hardener and 10% thinner
Spray at 90 degrees to the surface and about 4-5 inches away
But as soon as I start spraying itís like the varnish spray droplets dislike each other and repell. And you see craters forming so to force the droplets to become a wet looking I had to apply much to much varnish. Very thick and very heavy. But still I had craters all over the surface. So sad.
Dec 15, 2021, 10:26 PM
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3David's Avatar
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First I need to solve my varnish clear system.
Then with what is done already I guess I’ll just have to sand it down and start again.
It’s going to be imposible to sand just the clear coat off because the clear is so thick and the colors beneath it are so thin and light. Or just scuff it and apply more clear on top and make it even heavier.
Dec 16, 2021, 02:28 AM
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Quote:
Originally Posted by 3David
First I need to solve my varnish clear system.
Then with what is done already I guess Iíll just have to sand it down and start again.
Itís going to be imposible to sand just the clear coat off because the clear is so thick and the colors beneath it are so thin and light. Or just scuff it and apply more clear on top and make it even heavier.
Hard to say if this idea would work, but since you say you put a lot of clear on, it may be worth a shot.

I would block wet sand the clear with 600 grit until most of the dimples are gone. If you still have clear, then block wet sand with 1000 or 1500 grit. If you can find it - a follow up with 2000 or 4000 grit will almost make it shine.

Wet sand with a sanding block is the key.

If it comes out smooth, then polish with some rubbing compound and wax.

That's basically how all high end car paint jobs are finished.
Dec 16, 2021, 07:13 AM
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Thank you for your ideas Blewis.
Should I use a block to try to sand or just my finger tips ?
Should it be in a circular manner or try length wise?
At the stage of polishing with polishing compound can it be done by hand, or do I need to purchase machinery?
Dec 16, 2021, 10:51 AM
Scott
Pylonracr's Avatar
I was going to recommend the same thing. Wet sand until all of the imperfections are gone. Since the clear coat is quite fresh and very thick, it will continue to shrink as it cures. Use this to your advantage, sand it now and let it cure another week before you polish it. The sanding scratches will shrink part way out on their own. A 3" orbital buffer would be best, but you can polish by hand if necessary. Sand lengthwise down the fuselage, never in circles.

Scott
Dec 16, 2021, 11:20 AM
San Antonio TX.
sensei's Avatar
I believe you had a contaminated surface to start with, what I am seeing in your pictures are called fish eyes.

Are you spraying clear varnish or urethane?

A basic way to hold down the beginning of fisheyes is first make certain the the surface is contamination free by washing the entire surface with Ajax or Comet powder using a gray scotch bright pad and plenty of clean flush water.

Next when spraying your first and maybe even second dust coats, don’t allow the surface to become very wet, and allow good tack time.

Now that you have what appears to a very wet coat of varnish/urethane clear on it you don’t have much choice but to either sand the surface to prep re-clearing, or for cut and buff, or sand to near prime and re-base coat.

If you are fortunate enough to sand enough for re-clearing, wash the surface as I have stated and spray a dust coat or two as stated prior to your shine coats.

Bob
Dec 16, 2021, 11:45 AM
Registered User
Quote:
Originally Posted by 3David
Thank you for your ideas Blewis.
Should I use a block to try to sand or just my finger tips ?
Should it be in a circular manner or try length wise?
At the stage of polishing with polishing compound can it be done by hand, or do I need to purchase machinery?
Never use your fingertips - a block would be best. If you have an automotive paint store available, they should have small blocks, or make your own.

I would go predominately lengthwise, although occasionally switching up the angles from lengthwise to 45 degrees is recommended.

I have polished a lot of parts by hand ( this is where circular motion works ), but a small buffer would work as well - just be very careful if you have never done this before.

Check out You Tube for videos on how to sand clear coat. Here's one to get you started.

How To Sand ClearCoat Safely - Orange Peel Removal (19 min 14 sec)


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