KRYLON PAINT TEST

You might be onto something there. That pumpkin seems to be a winner! 3.5 hours is much longer than my trial time (30 minutes) even if color is transferring with rubbing, as long as it does not transfer with regular handling then I would say it is adequate.

You know the exhaust products prove a different problem, but I'll admit I don't test for exhaust.

Phil

pkrankow wrote:You might be onto something there.  That pumpkin seems to be a winner!  3.5 hours is much longer than my trial time (30 minutes) even if color is transferring with rubbing, as long as it does not transfer with regular handling then I would say it is adequate.  

You know the exhaust products prove a different problem, but I'll admit I don't test for exhaust.  

Phil

It would be worth it to test the effect of exhaust on a finish by adding a bendable solid copper wire/alligator clip to your engine test stand.. so when you run engines you can put a small painted piece of scrap-wood in the clip and position it behind the engine in the prop-blast as sort of a "real-world" test.

If I hadn't seen it here, I would have said to let the paint gas off for a long week before applying the clear. But who knows, maybe the tender fresh paint and same brand clear mixed with each other and gassed off together??? Maybe we have a new method in the works. Rustoleum clear is said to not be fuel resistant like the colors are, But mixed together freshly??? More experimentation.
Rusty

Eric, you just saved me a bunch of work. I have been itching to try exactly what you just did. The local Walmart carries Krylon in many colors including the camos that I love. I don't like brushing on dope and enhaling the vapors, not that Krylons are that much better. But spray paints give a more uniform appearance and are easier to apply.

I would though seal bare balsa before applying.

I wonder how Krylon would work on silkspan........

I am using Dap Fast and Final spackling underneath Rustoleum to good effect on wood. The results I am seeing are good: a single round of sanding primer before going to color. I use film for open bays (Monokote)

Phil

Its not food, so the only need to list CAS ingredients.

I am using that exact red rustoleum on my last Flite Streak. I hope to get paint onto it this week. It will get a practical exhaust test in service.

Phil

We've got some cold air coming through Rhode Island over the next few days. I've got the urge to test one of my Golden Bee's that has a larger (.082") venturi, against another GB with the smaller (.062" standard) size, using cylinders having the same porting. I also want to taper-grind a plunger-needle (Ace style) to test in the larger air intake.. to see what kind of throttle-response I get. 5/64" (.078") music-wire would be the size to use.. and I have some. While (when) I'm at it.. I also plan to test an SPI/Tee Dee cylinder for throttle response using the Ace-style unit.. and report my results to Cox international.

It was near freezing last night. (tough.. if you're trying to harden-off seedlings..  ) How's your "maters" doing??

When I spray Rustoleum I always heat the can. Not too hot to touch, but probably about 220 degrees. I feel like it flows and covers better when hot.

That 2x might be heavier, but then you might not need as much. I've never tried it.
Rusty

I have yet to use a clear coat since the clears have been reported previously to NOT be fuel resistant. I have not tested any clear yet. I have a can of Rustoleum Painters Touch x2 clear to test, but haven't yet.

Phil

I was in the automotive section of Walmart recently and saw lacquer based Rustoleum clear. I think that's different from the Rusto clear at Lowes. If it doesn't craze the enamel Rustoleum colors it may very well be worth trying. I didn't see any Rusto colors next to it. "Rusto"...Mercy, I'm gettn' lazy.
Rusto

I've been wanting to experiment with Minwax rattle-can clear polyurethane. Has anyone tried it.. since we're on the discussion of clear-coats? I don't know how it would adhere to undercoats of other products.. but if the undercoats were "flat".. or de-glossed, it might make a difference. You'd get the gloss back.. if desired by using the clear-gloss .. correct?

I always understood polyurethane to be fuel-proof..   .. and I think most people overlook this product, because it's not generally found with the spray-paints.. but rather with the stains.

The Minwax is expensive at $7.77/11.5oz. can



Rustoleum also has polyurethane sprays. These are about $2.00 less for the same size can. These are all stated to be oil-based.

I have used Minwax Polyurethane (the rather stinky solvent based stuff). Very fuel proof! I used it over some lacquer, which is not fuel tolerant at all, and I used it over Rustoleum. I just shot it on the lacquer and it was fine. This was pretty recent lacquer.

It wanted to fisheye on the rustoleum, so I very lightly sanded, washed with denatured, dusted on a couple coats. I don't think the first coat even was a whole coat. The rustoleum was old so it might have been contaminated.

I also used it on an old flight box, which was definately oil contaminated. After cleaning it out, washing with a scrub brush, soap and water, letting it dry then attacking it with denatured I had no problems.

Phil

I brushed Minwax urethane on the Osprey for the bare wood look, and it's like Phil said, completely fuelproof, acetone won't even bother it. It doesn't even have to be the Spar, but either works fine, spray or brush-on is the same stuff I think.

The Minwax Polycrylic is not fuel proof at all, but it's good for laying tissue down on solid balsa like the fuselage for a nice glassy finish. I don't know about open bay wings, but I think it's heavier than you'd want in some cases. My Yak-9 was a big success with tissue and polycrylic on all the parts other than the wing. Then I sprayed it with flat white Rusto and wet sanded it. After the Lustrekote, it looked just like I'd used gloss white, and the flat seemd to cover with much less paint. I think I only used one coat.
Rusty

roddie wrote:I've been wanting to experiment with Minwax rattle-can clear polyurethane. Has anyone tried it.. since we're on the discussion of clear-coats? I don't know how it would adhere to undercoats of other products.. but if the undercoats were "flat".. or de-glossed, it might make a difference. You'd get the gloss back.. if desired by using the clear-gloss .. correct?

Hey Roddie, this is actually what I intended to answer in my post above, but forgot. Yes, you can get your shine back, but it probably will gradually yellow, or more like amber over time. It has sort of a faint yellowish color anyway. At least it looks that way on plain balsa. I think Phil pretty much covered what you can apply it to safely.

Back to another post I made in this thread regarding Lacquer based Rustoleum, Phil answered that too. I was mistaken in believing lacquer was fuel resistant. Glad I didn't waste money learning that.
Rusty

roddie wrote:I've been wanting to experiment with Minwax rattle-can clear polyurethane. Has anyone tried it.. since we're on the discussion of clear-coats? I don't know how it would adhere to undercoats of other products.. but if the undercoats were "flat".. or de-glossed, it might make a difference. You'd get the gloss back.. if desired by using the clear-gloss .. correct?

I always understood polyurethane to be fuel-proof..   .. and I think most people overlook this product, because it's not generally found with the spray-paints.. but rather with the stains.

The Minwax is expensive at $7.77/11.5oz. can

Rustoleum also has polyurethane sprays. These are about $2.00 less for the same size can. These are all stated to be oil-based.

I've always (well, over 50 years now) used single pack polyurethanes.  They're completely fuel and exhaust proof, including in one of my boats which ran 50% nitro.  I used to use expensive stuff (Feast Watson's "Proof") but have discovered over the years that cheap stuff works just as well.  If I'm using the bulk stuff (ie a paint can from which one might brush it on) I thin it with mineral turps - coz it's cheap and it works!

It never gets really cold where I live (there's never been a 0°C recorded here) but I did find that on my full size sailing dinghies (very high performance) that heating the can, as said above, and applying the finish on what we would call a bitterly cold Winter's night (about 10 or 12°C) worked a-treat.  The warm varnish would flow beautifully, and the cold air slowed the drying, ensuring that all imperfections had ample time to flow out.  Using this method can produce a brushed finish at least as good as any sprayed finish.  I preferred brushing in fact.

I was in Oz, Commonwealth and world contention in my younger days, so i required an absolutely blemish-free finish - and this gave it.

dinsdale wrote:......applying the finish on what we would call a bitterly cold Winter's night (about 10 or 12°C) worked a-treat.

LOL -- what we would call a bitterly cold winter's night would be about -29C

dinsdale wrote:applying the finish on what we would call a bitterly cold Winter's night (about 10 or 12°C) worked a-treat.

While over here on the east side it gets a little colder than Perth, anything cold enough to freeze water is too cold for a human body to bear. Don't know how you northerners do it.
Dinsdale, I'd be interested to know what brands of finishes you use. It's all well & good for our US friends to quote Rustoleum & Krylon & Lustrecoat etc, but I've never seen any of them out here. Some local Oz formulas would be handy. How about Estapol? I do have a can of Plasticoat clear but don't know how that would go.

Rod.

Rustoleum, Krylon, and several others are basic spray enamels.  The formulas change between products and even colors and gloss levels, so some testing is in order.  

The basic test is to apply the paint, wait about 14 days to allow the paint to fully cure, then apply a paper towel with some high nitro fuel (the highest you run) on it to the sample, and cover the paper towel to limit evaporation.  After 30 minutes uncover the sample and inspect it.  Suitable fuel resistance does not transfer color or fingerprints when touched, does not wrinkle, blister, or any other type of "coating failure" but may transfer color with light rubbing. There also may be slight discoloration (lighter or darker) but this should go away after sitting overnight.

If the sample passes the fuel test, you may choose to do an exhaust test.  Run an engine and gather exhaust "slime" on the sample.  Put the sample up overnight.  The next day inspect for coating failure.  Clean only a portion of the sample during inspection.  Put the sample up for a week and inspect the whole sample.  If it cleans up it is good.  

Frequently the exhaust oils will strip Rustoleum and other enamels over a period of several weeks or months IF the oils are not at least wiped off.  Many people use window cleaning fluid to clean the models with as necessary.  Both ammonia based household cleaners, and alcohol based automotive windshield washer fluid has been reported out of spray bottles.

I am sure there is a suitable product easily purchased local to you.

Phil

I have always just used ordinary oil based gloss enamels, but have had to tolerate a very quick deterioration of the finish. I basically accepted this as normal. Some have told me that sealing enamel with clear furniture varnish can help. I have recently had some dope tinted with acrylic automotive tinters- I was told this would work by the manufacturer of the tinter. Yet to try.

Rod.