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Building Tips and technical articles. => Paint and finishing => Topic started by: RogerGreene on July 20, 2014, 02:32:01 PM

Title: Help-Paint problem
Post by: RogerGreene on July 20, 2014, 02:32:01 PM: Help,

I painted Rust-oleum color, two coats of heirloom white, over about five coats of SIG Supercoat clear. The wing was covered with silk filled with thinned 50/50 clear SIG. I waited three days to apply another rust-oleum and it wrinkled. >:( I prushed on some Brodak light blue and it wrinkled on the rust-oleum. >:( HB~> Any suggestions? (know now DON'T USE RUST-OLEUM its not lacquer). How do I get the rust-oleum off the plane.

Thanks,
Roger
Title: Re: Help-Paint problem
Post by: Avaiojet on July 20, 2014, 04:45:14 PM: Photos?
Title: Re: Help-Paint problem
Post by: RogerGreene on July 20, 2014, 05:29:11 PM: I have sanded the wrinkles, where they appeared, out of the rust-oleum second coat down to the SIG Supercoat. Where I did not apply a second coat of the rust-oleum I have applied minwax Polyurthane clear satin. And when that dries I will try the Brodak blue paint. Hopefully that will work, fingers crossed.
Title: Re: Help-Paint problem
Post by: RogerGreene on July 20, 2014, 05:30:51 PM: More photos.
Title: Re: Help-Paint problem
Post by: dennis lipsett on July 20, 2014, 05:54:22 PM: Rustoleum is not compatible with dope. It can literally never dry under certain circumstances. You have to use a primer before using Rustoleum and do not use a dope primer.
Title: Re: Help-Paint problem
Post by: RogerGreene on July 20, 2014, 07:01:31 PM: Yes, I know that now. I am hoping that the Polyurethane will cover the rustoleum so I can put some color over the mess. I don't want to take the rustoleum off if I don't need to.

Roger
Title: Re: Help-Paint problem
Post by: Avaiojet on July 20, 2014, 07:06:37 PM: Roger,

Looks like all your trouble is on top of the hard wood? Not sure?

I don't trust any dope over anything. But that's me.

My guess is the blue would be your second color? Again I'm guessing?

I would sand all those areas down flat and use Krylon aerosol can paint. You could sand the entire model and put on a coat of Krylon satin white or just over the areas needing repairs.

Do the model up with Krylon! I did a Flite Streak up with Krylon. First attempt with RRC, Rusty Rattle Cans, and it came out fine.

When done, I'd take the model to my local auto body shop for the auto two part clear.

I'm doing that. In fact, my local ABS just put two part clear over a Krylon story board with no issues.

Nice looking model from what can be seen of it.

Let us know how it all turns out.

Good luck!

Charles
Title: Re: Help-Paint problem
Post by: RC Storick on July 20, 2014, 11:25:11 PM: For sure you have a disaster on your hands. You could remove the RUST-OLEUM or you could top coat everything in Urethane when you get it close. Two parts (catalyzed urethane) and then sand it flat and buff. From now on stick with all like products.

You can paint RUST-OLEUM over lacquer but not lacquer over RUST-OLEUM. RUST-OLEUM is a enamel and is a mechanical bond type paint and Lacquer is a chemical bond type paint. Meaning the thinners in Lacquer's are too hot for mineral base paints.

Just as you can paint Sig dope over Aerogloss but not Aerogloss over anything but Aerogloss products. Aerogloss thinners are not just regular Lacquer thinners they are a mix of xylene and MEK. Way to hot for anything. I think (but have not tried) Aerogloss would wrinkle Ureathane.

This last bit is just a FYI and does not pertain to this issue

There is only one Ureathane impervious to NITRO and that is a Sherwin Williams Ureathane called Sunfire. Up to 60% Nitro is the claim.
SUNFIRE® Acrylic Urethane Basecoat System 365 Series http://apps.sherwin-automotive.com/help/popup/product_qualities.cfm#Sunfire_base
Title: Re: Help-Paint problem
Post by: RogerGreene on July 21, 2014, 07:56:06 AM: Thanks Guys, for your advice.

The Polyurethane over the rustoleum did not work, wrinkles appeared when brodak blue was lightly brushed applied to the polyurethane. >:( :( HB~>

So now I'll do the Krylon method as Charles suggested.

Thanks, what a learning experience....

Roger
Title: Re: Help-Paint problem
Post by: RC Storick on July 21, 2014, 10:03:23 AM: A lot of BS on this subject- as far as solvents go, MEK and acetone are on the safe side in spite of the fact that they both smell bad. Just use the correct glove materials for the solvent and don't drink or bathe in it.

I have searched the internet and compiled this about hot thinners. Disclaimer what works for some my not work for others. Do dissimilar paint jobs at your own risk. Remember DOPE is NOT Paint it's glue.

The bad actors are the solvents with a lot of chlorine (methylene chloride, trichloroethane, carbon tetrachloride) or benzine rings (benzene, toluene, zylene, etc) in the chemical structure. They cause cancer, can have low flash points, and they displace oxygen (because they have heavy molecules).

MEK ( methyl ethyl ketone ) is a straight solvent, where lacquer thinner is a blend that may include some xylene or acetate solvents. MEK is very soluable for lacquers and can be substituted for laquer thinner. Lacquer thinner is likely a little slower in evaporation, and is often a reclaim product. Reclaim lacquer solvent is used mostly for clean-up and is cheaper than MEK. Reclaim solvents may contain a very small amount of water, yet the solvent blend should be fine for reduction. Most lacquers are only soluable at a 28% volume solids, and this should be able to spray as supplied with the proper spray equipment.

If you spray any type of lacquer – nitrocellulose, CAB-acrylic, or catalyzed – you use lacquer thinner for thinning; and cleaning up. Of all thinners, lacquer thinner is the most versatile and also the most complex. Other thinners, such as mineral spirits (paint thinner), naphtha, acetone, and methanol, are simply the single solvent, so their characteristics don’t vary. Lacquer thinner is a combination of solvents chosen by manufacturers from different solvent families to give each thinner specific characteristics.

Since types and brands of lacquer thinner differ depending on how they’re made, you will gain much better control of your finishing, and experience fewer problems, if you know how to choose between lacquer thinners.
There are two key variables in the make up of lacquer thinner the amount of each type of solvent used (dissolving and diluting), and the evaporation rate of the particular solvents used.

Types of Solvents

As you’ve surely noticed, it doesn’t take much of the right solvent or solvents to soften or damage lacquer. But it takes a lot of solvent to thin lacquer. Manufacturers take advantage of this characteristic to keep down the price. They blend the expensive dissolving solvents with cheaper diluting solvents.
The only thing you really need to know about solvents is that within each family they differ in evaporation rate. Manufacturers choose between these solvents to control how fast the lacquer thinner evaporates out of the lacquer film.
To thin lacquer, lacquer thinner has to be formulated properly. It has to have enough dissolving solvent to put the lacquer totally into solution or the sprayed lacquer will resemble tiny pieces of white cotton. This is called “cotton blush” or “kick out.” Lacquer thinner sold for clean up usually has too low a percentage of dissolving solvent to put lacquer into solution.
Lacquer thinner made from reclaimed solvents is also risky to use for thinning lacquer. Since the reclaimed solvents vary from batch to batch, the thinner may work well one time and not well the next.

Speed of Evaporation

All lacquer thinners contain solvents with differing evaporation rates so that running and sagging are reduced. But lacquer thinners vary significantly in the time it takes for total evaporation depending on the particular dissolving solvents used.

Over-the-counter lacquer thinners are commonly divided into three groups: standard lacquer thinner which evaporates at “normal” speed, lacquer retarder which evaporates more slowly than standard lacquer thinner, and fast lacquer thinner which evaporates faster than standard lacquer thinner.
Standard lacquer thinner and lacquer retarder should be available from all lacquer suppliers. Fast lacquer thinner is not so widely used for wood finishing, and is usually carried by auto-body paint stores.

In normal weather (75°and 40% humidity), standard lacquer thinner evaporates about right. In very hot weather standard lacquer thinner won’t give lacquer time to flow out level before it dries. The lacquer may even dry in the air before it lands on the wood resulting in a sandy surface called “dry spray.” If the weather is humid, moisture becomes trapped in the lacquer causing it to appear milky. This is called “blushing.” You can solve all three problems (poor flow out, dry spray, and blushing) by using lacquer retarder or by blending lacquer retarder with standard lacquer thinner. (If you live in a very humid climate and the brand of lacquer retarder you are using isn’t slow evaporating enough to prevent blushing, switch to a brand, like M.L. Campbell’s C163 36 BC Super Retarder.)

No matter which type of lacquer thinner or blend of thinners you use, continue with the same ratio of thinner to lacquer. The amount of thinner required for optimum atomization is not affected by the speed the thinner evaporates from the applied film.
Title: Re: Help-Paint problem
Post by: RogerGreene on July 23, 2014, 08:11:40 AM: Charles,

The Krylon clear worked. :) It went on and NO wrinkles.. :) Now can I use Dupli-Color 'Protective Clear Coat Finish' as the last coat for a gloss and fuel proof coat??

Thanks,
Roger
Title: Re: Help-Paint problem
Post by: Avaiojet on July 23, 2014, 09:36:30 AM: Roger,

I didn't suggest Krylon clear. I suggested Krylon satin white.

I wouldn't use anything but Krulon colors. I don't mix brands.

I've said it 100 times. Go to your local auto body shop and have them spray the two part auto clear. I'm doing that with two models. The Flite Streak 007 and the P-40 Warhawk.

Most shops spray clear coat every day. Or wish they did. LL~

OR, Some guys use KSB clear out of a can. Say it's fuel proof and really shines! They have applied it with a foam brush.

I've never used it.

About clear coats.

Other than using dope to apply covering over open bays, as Robert said, clear dope is glue, not a bad thing to keep in mind, I see no reason to use any clear till the final fuel proof coat. I would never use dope for that final coat.

If you are doing a really complicated paint scheme and some airbrush work, a thin coat of clear can save your work if mistakes are made. You can remove the mistake to the clear and start again.

These are models and guys do try to keep weight down, so every bit of paint adds up.

I put some coats of dope over the open bays to fill the silkspan and the fuselage also, I was surprised at how much weight was added.

I guess my dope weighs more. LL~

This FS was painted with nothing but Krylon aerosol can paint. RRC.

However, the blue lettering and black outline is vinyl. You can apply clear over vinyl.

Edited to add photo.
Title: Re: Help-Paint problem
Post by: Phil Krankowski on July 24, 2014, 08:34:03 AM: At this point you have 2 failed layers of paint with respective tie-coats. I would really consider using a paint stripper and removing the paint to bare wood and neutralizing.

Yes, the silk will probably come off at the same time...

I have used rustoleum over dope, but the dope was very old (10+ years) I can also tell you that coating over enamel paints without waiting 2 weeks for full cure will cause problems. I have been there before on other projects.

Sometimes waiting can fix poor bonding when paints are still curing or off-gassing.

Phil
Title: Re: Help-Paint problem
Post by: FrankF on July 25, 2014, 04:46:02 AM: I used Rustoleum for the first time this month on a Streak RST. I used about 5 coats of NITRATE dope on wood surfaces and then painted on 2 coats of high gloss Rustoleum. Also, I used the Rustleoum on the wings which are first covered with the Mylar shrink film supplied in the kit. No problems detected - however, I'd wait at least a week for the paint to cure before flying.

I tested Rustoleum over Butyrate and vise-versa. It will krinkle - but Nitrate as a base coat seems to work well.
Title: Re: Help-Paint problem
Post by: Avaiojet on July 25, 2014, 07:22:57 AM: Quote from: Phil Krankowski on July 24, 2014, 08:34:03 AM
with respective tie-coats. I

Phil

Phil,

What is a "Tie-Coat"
Title: Re: Help-Paint problem
Post by: Phil Krankowski on July 25, 2014, 08:55:45 PM: Quote from: Avaiojet on July 25, 2014, 07:22:57 AM
Phil,

What is a "Tie-Coat"

A "tie-coat" should allow otherwise not very compatible products to be layered together. It should prevent the previous product from being affected by the next product. It is in principle compatible with both products.

I understood the polyurethane was used in this respect.

bare wood/silkspan
sig clear
rustoleum heirloom white
rustoleum heirloom white (failed)
Brodak light blue (failed)
Minwax polyurethane (tie coat attempt)
Brodak light blue (failed)
clear Krylon (tie coat attempt)
???

I see 7+ layers in places, with 3 layers failed...I may have misread some of how it is layered. Time to strip and start over I think...

Phil
Title: Re: Help-Paint problem
Post by: RogerGreene on August 16, 2014, 12:01:00 PM: I used KRYLON Ivory, Blue Ocean Breeze and Burgundy paint to cover up the rustoleum mess. Then I waited about three days to cover the plane with clear Minwax polyurethane to fuel proof. worked great. My Fox 35 Super Stunt with a G/S3 Series 11x5 prop pulls it around at 5 seconds per lap on 62' lines center to center. the plane weights too much at 55oz. Mostly the all the extra paint, but I need something to fly. Next one is in the works and it will be painted with either SIG or Brodaks.

Thanks for all your comments and help.
Title: Re: Help-Paint problem
Post by: Avaiojet on August 16, 2014, 02:40:02 PM: Roger,

I believe you have a fine looking model there.

About that clear Minwax polyurethane being fuel proof?

I'm not sure about that, please let us know.

Did you use the Miniwax from an aerosol can?
Title: Re: Help-Paint problem
Post by: RogerGreene on August 16, 2014, 07:42:35 PM: Thanks for your inquire.

The polyurethane, clear semi-gloss from an aerosol can, is fuel proof. I let it dry for a day and a half because of my work schedule. Follow the instruction on the can.

Roger
Title: Re: Help-Paint problem
Post by: RknRusty on August 16, 2014, 09:00:51 PM: Roger, that's a beautiful plane. For all the headaches ans elbow grease it caused you, I'm sure glad it turned out and flies so well. Thanks for posting about it.

Charles, I brushed(wiped with a bit of T-shirt rag) Minwax PU in the can on my new Skyray, the one that looks like a Streak. It's fuel proof, or at least very resistant. Early in the build, I put one protective coat on the fuse. Since then, I've cleaned epoxy drips, etc. with alcohol and it doesn't phase it. I also tried acetone and it ignores it too. It's very tolerant of being attacked by chemicals. It has the final coat on of Poly U it now that it's finished. I am impressed with it. I will not use it for clear over colors because I worry about yellowing. I'll use Lustrekote for that. My color is Krylon Metallic Aluminum. It has proven to agree with LKote.

Roger, I apologize for cutting off in another direction in your thread. We can take this discussion elsewhere if you wish.
Rusty
Title: Re: Help-Paint problem
Post by: RogerGreene on August 17, 2014, 03:03:17 PM: Hey Rusty,

No apologies needed. Thanks for the nice complement. The paint problem added some unwanted weight, but I now have a plane to fly.

Roger
Title: Re: Help-Paint problem
Post by: Avaiojet on August 17, 2014, 10:06:40 PM: Hey Roger!

Good lap time.

What about performance, I'll bet it's fine.

What is the span and what is that model?

Great looking, nice wing and all!
Title: Re: Help-Paint problem
Post by: RogerGreene on August 18, 2014, 08:36:48 AM: Charles,

Its an original design. 54 span and 507 square in area. The next one is to be built with lighter wood and LESS paint. max weight to be 43 oz. (I hope). Arion does fly good. Corners good, just the pilot needs to get use to it. I only have three flights on it. The first flight the engine was too rich. The next two the engine was fast 4 cycle. I do like the way it handles. I will be building another one this winter and not using the balsa wood from craft stores.

Roger