rebells_McLaren

Does anyone have any good advice regarding putting topcoat on latex paint ?
I tried it on the first wing I completed on my Fokker DR1, but with a very poor result. It looked like sandpaper. Almost like the paint dried out before it landed on the covering(Solartex).
I`m using waterbased polyeritan clearcoat.
I didn`t thin the clearcoat since the manual tells me to use white spirit. Not sure if the latexpaint will take that.
Attaching a image showing how the clearcoat looked like.
Has anyone else experienced this ?

Trond.

rebells_McLaren

Sorry , here is the image.

Trond.

BobH

My Feedback: (2)

Trond, I am just having my first experience with latex paint and models. I bought some RAF color paint from Clark Industries.. It shot pretty well but it still (after 1 week) feels not completely cured/dry. Im not sure if its because I used windshield washer for thinner or not?.. I plan to over coat the latex with Nelson's clear. The only reason I am clearing over the latex is because of the application of dry transfers that must be cleared. Looks like you have an imcompatibility issue with your top coat and the latex.. BobH.

rebells_McLaren

I tried to spray the second wing today. With the same result. I opened as much as possible on the spraygun. The result was a bit better. but not good.
It looks as if the air dries out some of the paint and blows it down on the surfase.

After I had painted the wing I did a test. I thinned the clearcoat with white spirit. The result was very good. It came on like a dream, and the paint looked like it was covering a larger area.
Tomorrow I will try to put a coat on the underside of the wing.
I am a bit worried about the white spirit/latex paint thing, but I`m hoping it will work out ok.
I did a test yesterday with whitespirit over latexpaint and it looks ok today.

About the latexpaint drying slow. I have read that it takes some time to cure it. Some saids letting the paint dry outside in the sun is a good way to cure it. Not much sun where I live so I will have to be patient lol.

Trond.

azhar

My Feedback: (19)

Trond,

Why don't you build a 'hotbox'. You can use foam and place a 40W bulb inside. It creates a nice environment for drying. It also speeds up the process. Works great. You do not need the sun.

Azhar

Tec

My Feedback: (5)

Mclaren, It looks like you shook the paint can? from what i can see there is alot of air bubbles. What is the clearcoat base (water based, oil, solvent) Just keep in mind you can't put oil or solvent based products over latex. also how are you applying the product?

Ed

Trond:

I don't know what White Spirt is, unless it's similar to our Mineral Spirits. Ideally, you should stay with a water based clearcoat. We use Carver Tripp Super Poly here in the states.
But, maybe you have stumbled on to something really good. Let us know how it turns out ?

snoopys copilot

My Feedback: (3)

Go to Home Depotand buy ( Minwax indoor/outdoor Helmsman Spar Urethane in a spray can). I just resprayed over an area that I repaired . It works great. I usually just clear coat over latex with Perfect clear satin. which is thinned with mineral sprits......

TY

rebells_McLaren

No sure what mineral spirit is. I will check if it is the same as white spirit as we call it in Norway. And yes I use waterbaset clear coat.

And no. I haven`t thought about building me a hot box. Not a bad idea.

It`s not air bubbles from the can. The picture didn`t show how it lokked properly. It`s like the airflow dries out the paint in the outer areas of the spray and it comes down almost like tiny pieces of cotton strings. Then it melts halfway into the paint. Giving the paint small dents.
I willl try to thin the waterbased clearcoat with whitespirit (mineralspirit ?)

Trond.
BTW. Crashed my trainer today....Again lol.

rebells_McLaren

well been outside and experimenting with the clearcoat. First of all. Mineralspirit is the same as whitespirit. Also, on the box with the clearcoat it saids it contains 30-60% mineralspirit .

I am using a spraygun with 12 psi pressure. tried up to 30 with the same result.

So I thinned it out with 15-20% mineralspirit. Tried it on a painted wooden door I have. The result was superb.
Here we go I thought and started to spray on the wing.
The result was a bit better but not good. Same thing happened. Maybe I sprayed a too thin layer I thought,and sprayed on more . It got worse !
I am not going to tell you what I said in this forum, but it wasn`t nice. The I pointed the spraygun towards a painted metal plate. And the paint came on just fine.

It must be something about the latexpaint on my wing I thought then.
So I took the wing I had sprayed some weeks ago and rubbed it with sandpaper. And applied the clearcoat on top of that. Now it shouldn`t react with the latexpaint underneath since I had a coat with waterbased polyuerethan clearcoat over it.
But the same thing happened again.
This is really starting to trouble me.

I will go to the paintstore tomorrow and see if I can get my hands on something that is similar to the clearcoat I am using now execpt that it comes in a spraycan.
Hope that will solve my problem, sigh.......

BobH

My Feedback: (2)

Rebels.. let us know what you find out. It still looks like incompatibility to me. When paint bubbles over other paint its typically a chemical raction taking place between the two. I would find a water based clear and experiment with that.... Bob H.

Ed

Trond: If you are using a spray can, then it probably contains a "solvent" that is not compatable with waterbased latex. I don't know of any waterbased spray cans.

Also, if it looks bumpy, it needs to be thinned further to permit the material to flow. Air pressure should be held to 20 PSI.

rebells_McLaren

I thought I was using waterbased clear ?
It is a polyurethan containing mineralspirit. Is that waterbased ?
I asked for waterbased when I bought it, so it should be right.
I thinned it 25% the last time I tried. It should be enough .....
But I will keep trying.

Trond.

rebells_McLaren

Ok. I have talked to to the paintstore and it seems that I am using oilbased clearcoat.
It shouldn`t be any problem with the latexpaint, but I am going to buy a can with waterbased clearcoat . Rub down the old paint a bit and hope for the best.
This morning I tried spraying with mineralbased paint thinned with 30% mineralspirit. It came on to thick, got yellow and the same bumps and dents appeared. I took a rag and whipet it all of ......

I really hope that the waterbased clearcoat will solve the problem.
It is fuelproof isn`t it ?

Trond.

rebells_McLaren

What do you use to thin the waterbased clearcoat ?
Do you use only water, or is it possible to use the same windshield fluid that I use with the latexpaint.

Trond.

Tec

My Feedback: (5)

To thin waterbase poly add some water You need to apply thin coats and DO NOT SHAKE the can, Poly of any base will have airbubbles in your finish. Make sure you get all the oil based producy off your plane before you spray the new poly! Spray a light coat and let it flash completly before the next coat, you can also sand with 320-400 grit paper between coats to remove any dust that has fallen into the finish as it was drying.

rebells_McLaren

I tried the water based poly today. It worked pretty nice. I did shake the can, and yes. Some airbubbles did appear.
I didn`t use any thinner. I put only one coat on. A thick one. I will try to put two coats on the next wing.
But isn`t it so that if you put a thin coat on first, you will get a very course surface ? In that case, will it disappear when I put on the second coat.
Anyway. Thanks for all the input I have recieved from this forum.

Trond.

Tec

My Feedback: (5)

Thin coats will dry faster, and have a nice build and even sheen. You can control the finish more buy sanding between coats. Think like your painting your car! There is 3-4 coats of color, and 3-4 coats of clear. Everyone has there own way of painting, I'm a professional painting contractor and i get my best work this way. Good luck, just don't rush your job

rebells_McLaren

Thanks for the tip. I will paint the topwing this evening.

Attaching a picture showing it. Not a typical paintscheme from ww1 lol.
It is the same paintscheme I am using on the internett when I fly the Red Baron 3D flightsim. Me and my buddies in REBELLS .

Goggles

My Feedback: (4)

Will water based poly 'yellow' over time?

jimcork1

My Feedback: (4)

Thanks for the info on Latex. I am currently paint a very large model using Latex. I am learning as I go. currently used Behr white exterior latex primer on the fiberglas. (F/G fuse and sheeted Glassed wing). I did lightly scuff/sand the surface prior to application. I shot the paint from an automotive sprayer at 45 psi with inline filter. The primer was thinned with water. (water base). The higher pressure allowed me to get a fine atomization spray to cover. This worked well,, however I agree with long dry time. We have 100% humidity and I keep fans blowing on the parts. It takes about 3 days to really harden. I have sanded lightly w/320 grit w/dry paper and got a smooth finish. I plan to coat w/latex in 4 different colors as scale. I have emailed and worked with Behr mfg on this combo. They reco sand rough w/120 prior to priming. They also stated they think this "should" work. I am still concerned and reading other post helps. I also plan to clear coat and am concerned about blistering and compatability issues. Minwax indoor/outdoor Helmsman Spar Urethane in a spray can mentioned above will be tested to see what problem it causes in my witches brew. So far it is working well but I am "still watching paint dry". If there is any advise on this project,, as Scottie would say.. "Captian,, now is a good time". We haven't reached the no return point but should be there in 48 hrs for the first color coat. Behr paint had the exact color matches needed and custom mixing for this project. So thanks for any help in advance. Jim