Why can't I airbrush clear coat?

[SirFrancis]

Hey people, just started using my air brush again after a few years. Sprayed the camo coat on and the yellow cowl no problems. Now I thought I'd hit it with clear gloss before decals. I have a new Tamiya X-22 Clear. I actually tried hand brushing it on at first but it stripped the camo paint off. It was glossy so that part worked. I had to sand it off and respray the camo. So then I tried to airbrush the clear but after two attempts one with 50% thinners and 2nd go with maybe 10% thinners, it left a course speckle matt-satin coat. What's the go here? What am I doing wrong?
PS why does hand brushing it on strip the camo like a paint stripper? No other acrylic paint I have does that. My matt clear also does that.

Ok cheers

 

[Crimea_River]

No idea why it's stripping your paint but you didn't say what paint you used.

The clear coat should spray with some thinning. It looks like you are shooting at too high a pressure and from too far away so what is happening is that the droplets are drying in the air before they hit the model. Use a low pressure, get closer and move slower. It's tricky because this can cause pooling and so it will take some practice.

 

[fubar57]

Andy, I've tried brush coating Tamiya Clear over Tamiya paint and had the same paint stripping reaction. Tamiya Clear seems thicker than colours so that's probably the cause. I strictly use Future now until I can try me some Mr Color or whatever its called like Wayne uses

 

[Crimea_River]

Weird. I've sprayed the Tamiya stuff and had no issues. Never tried brushing though and won't now.

 

[SirFrancis]

No idea why it's stripping your paint but you didn't say what paint you used.

The clear coat should spray with some thinning. It looks like you are shooting at too high a pressure and from too far away so what is happening is that the droplets are drying in the air before they hit the model. Use a low pressure, get closer and move slower. It's tricky because this can cause pooling and so it will take some practice.

My camo coat is Tamiya XF-62 Olive Drab. I will give up brushing Tamiya clear coat on, too many disasters. The second go with the airbrush I think u are right too much pressure / too far away. But the first go was much closer and low pressure. Maybe with the first go being 50/50 thinners it was too thinned?

I've never used this Futures stuff I keep hearing about. A quick search online comes up with Pledge floor finish. Is that the same? Can I also airbrush that? It only comes in a 798ml bottle so it's about AUD$35.

 

[Crimea_River]

Yeah, Future used to be available but it's been replaced by Pledge. Some say the formula has changed and it's not as good as the old stuff. I have no experience with that as I still have my old bottle of Future which must be getting on 15 years now.

My preferred gloss coat is Alclad II Aqua Gloss which for a 4 oz container may set you back 20 bucks in Oz but it will last you a long time.

 

[Vic Balshaw]

I've never used this Futures stuff I keep hearing about. A quick search online comes up with Pledge floor finish. Is that the same? Can I also airbrush that? It only comes in a 798ml bottle so it's about AUD$35.

Butting in if I may with this floor polish thing. Us poor folks down under seem to get the rough end of the stick with this product, no sooner is a new product line introduced then it will disappear from the shelves only to be replaced by yet another product. Rather than paying top $ for Pledge floor finish on line I use Long Life floor polish as a sealer over hardened paint to help protect against marking and it can be used to prime the surface for decal application, a 1lt bottle from Bunnings will set you back A$14.00 and last a long time. It can be brushed or sprayed direct from the bottle without dilution and is water washable. Having said that I agree with Andy, a bottle of Alclad II Aqua Gloss is best particularly for decal application.

 

[SirFrancis]

Ok thanks guys, I'll check out how much the Alclad is here and the Long Life might be worth a look also.
A quick google suggests that a 50/50 ratio is ok with the Tamiya clear so I don't know what went wrong on the first attempt as I believe I did everything right. Grrrrr

 

[TheRealMrEd]

+1 on the Aqua Gloss Clear. Caution, do not shake or thin it! Spray right out of the bottle. It will also NOT mess up bare metal finishes!

Ed

 

[Stosser]

As a rule of thumb, you never brush a coat of paint with the same or powerfull solvent on a previous coat of fresh paint. Most paints are hardening by loosing the solvent (which evaporates) and just a few by chemical polimerisation. Althought it will look dry, the process of drying may take a few days to end. To avoid this one should use solvent based varnishes over water based paints and viceversa.
Not all acryllics are waterbased. There are automotive acrylic paints that are thinned by solvents. It is also the case with Tamiya and Gunze which are containing a thinner that contains izopropylic alcohol (a thiner is a mix of solvents, while a solvent is is a chemical formula per se - like an alcohol or a hidrocarbure (toluen)).
So, if you want to avoid any problems you should follow a simple rule. If you have painted with water based paints (non etheric smell - Valejo, Ak interactive, even Humbrol acryllics) the varnish should be solvent based. If the paints are smelling, (laquers, enamels or solvent based acryllics), than the varnish should be water based (Future, Pledge, Valejo, Ak interactive etc).
Always thin down the varnish till it flows easy and give a wet surface when sprayed and make several passes to achieve a good and even coverage.