Tam. Acrylics thinning ratio?

OK, I painted my Firebird last night using the technique suggested in an earlier thread (well-thinned paint, 15 psi). This produced a mostly smooth, orange-peel free finish, but I felt that the paint was a little too thin. Then, I used the same technique with a lighter color and it immediately pooled in the low spots on the first coat. I was thinning 50:50 with X20-A; what is the proper ratio to ensure smooth application while still allowing the paint to stick to the edges and high spots?

Alex

There is no such thing as a thinning ratio!! Thinning can only be determined by test spraying and adjusting, and it is variable based on abmient conditions (as I was reminded again last night by spraying in 87% humidity :disappoin).

That having been said, 50/50 is probably too much for Tamiya acrylics. Really the only way to tell is to mix some, test spray and adjust. Always always always test spray. Always.

To oversimplify it, too much thinner is when the paint pools/runs, and just right is just before the paint pools/runs.

And obviously you can thin it more if you're only applying light coats. Heavy wet coats can't be thinned as much, which is part of why I never use them.

OK, I painted my Firebird last night using the technique suggested in an earlier thread (well-thinned paint, 15 psi). This produced a mostly smooth, orange-peel free finish, but I felt that the paint was a little too thin. Then, I used the same technique with a lighter color and it immediately pooled in the low spots on the first coat. I was thinning 50:50 with X20-A; what is the proper ratio to ensure smooth application while still allowing the paint to stick to the edges and high spots?

A related question: Does the type of airbrush matter? Fifteen psi seems to get a splattery result with my Paashe Type H. I've had fairly good results with Tamiya acrylic 50-50 at 23 psi. It does seem a bit too easy to apply too much and get sags, but I've assumed the problem is with my eyes and with the Tamiya acrylic.

In any case, it seems like a different nozzle system could produce different results, yes?

Didymus
Didy

On my Iwata, I thin Tamiya acrylics pretty thinly; but just as MPWR said, there is no set ratio! I too set the compressor at 12-15 psi. Didymus, I have always had to use my Paasche at a higher psi than the Iwata, it may be the design or the nozzle size.

Yeah, airbrush design will effect what pressures will work best for you, together with nozzle size, feed mode, etc. My Badgers generally behave well at 15 for highly reduced laquers and 20-25 for acrylics. Ideally you want to spray as low as possible, but splattering is of course bad- so that usually is the limiting factor to how low you can go.

It's possible to spray Tamiya acrylic at 50/50. But to avoid runs you really have to be on top of things- thin coats, good light and good consistent technique.

OK... all that said, is it even possible to cover a darker base coat/primer with Tamiya acrylics like white or yellow? The lighter color I mentioned was yellow, covering dark brown primer. Can this be done, or do you need a white base coat?

I didn't have a problem with splattering, but the paint seemed to apply weirdly. It seemed to "rain" onto the surface and then smooth out, but it had a few tiny bubbles in it as it did so. Nothing like I've ever seen before... Overall the results were good (on the Firebird), but I think I applied too much paint in an attempt to "fix" the discoloration that had occurred due to the paint's runniness. Once dry, that discoloration disappeared, but I ended up with a lot of paint. And it didn't want to cover the edges.

Alex

OK... all that said, is it even possible to cover a darker base coat/primer with Tamiya acrylics like white or yellow? The lighter color I mentioned was yellow, covering dark brown primer. Can this be done, or do you need a white base coat?


No, it's not possible to cover a dark color with a light color (except in remote times when you're spraying a flat color), you should always use white primer under white and yellow preferably, it's also recommended under red.