Airbrush Beginner - A few questions

First I would recommend practice, practice, practice! If you have an old kit, that is best. Are you solvent based paints or acrylics? I usually only use the enamels, so water-based paints, I don't know. As far as thinning, this is not an exact science! I have opened 2 bottles of MM enamels, and found one to be very thick, requiring more of the thinner and the other so thin, I could almost use it straight from the bottle. Testors isn't known for being consistent and can vary in this and shade as well, I have found. The best guide is thinning to about the consistency of milk.

there is no such thing as thinning ratio in my opinion. should be thinned to the consistency of milk. 

All good advice so far.

As for laying down a thin layer first - i used to lay down, essentially, a full layer of gray paint as a primer.

I've now switched to super fine tamiya primer from a spray can as i find it's much easier to use and goes down beautifully.

In terms of how many layers you can put down and drying time - that's up to the paint.  I use acrylics which have alcohol in the thinners, so they are touch dry in a matter of minutes, however, i normally wait 24 hours before putting anything over them - there is a difference between a paint drying and paint curing - i'm not sure of the chemcal reactions etc, but to be safe, i wait 24 hours.

The same with tamiya primer - i think it's lacquer based and it take a bit longer to dry than acrylic paint.  I'll let it dry for 24-48 hours before painting over it.

When you're painting with a colour (once all priming down), i'll normally build up slowly, in that, i paint the area with multiple passes all in the one session.  Ie, i don't do a single pass, wait for it to dry, come back for another single pass etc.  Normally, it could take 4-6 passes to build up a sufficient layer that i'm happy with.

Whatever you do though, keep the brush moving to avoid puddles and runs. 

Any other questions, feel free to ask away.

Good luck and have fun!

Testors tends to harden in the bottle every time it is exposed to air.  At first you can compensate for this by adding more thinner.  I'd say thin to 2% or 1% rather than normal milk. I never use it straight from bottle, even a new bottle- it is way to thick for that.

Yes, I am a proponent of the thin first coat to aid adhesion.  This can be followed up almost immediately, within a minute or two, with a heavier coat.  If I am painting several parts at same time, by time I have painted all parts I can come back and do the second coat on everything.

Excellent advice.  You can also switch paint to a smaller container once you start to run out, that way there's less air to dry it out.  I saved a lot of the 1/4 oz. Testor's bottles from years ago and use those for mixing and transferring paint from near-empty 1/2 oz. bottles.

OP:  Other than that just practice on a scrap model or just get some cheap ones and start using that AB.  Experiment with different paint/thinner ratio's as well, and Testor's MM paints are very forgiving.  I use hardware store thinner with mine and the results are great and its a lot cheaper to buy a quart or gallon as well.

As far as coatings, I put down a lot of thin coatings, and if I don't think it covered well, I will come back an hour or 2 later and coat it again, if possible - sometimes its longer.  If I am doing fine lines I will switch back and forth between the colors until it's right - and sometimes its taken 7 or 8 color changes to get it right.

Great advice, guys.  Thanks.

Bob

I use an autobody repainting technique called "Edging"... I paint the outline of the area first, then shoot it in 1/2 spray-width over-lapping passes...

Generally get it done in one coat that way...

Hans von Hammer

I use an autobody repainting technique called "Edging"... I paint the outline of the area first, then shoot it in 1/2 spray-width over-lapping passes...

Generally get it done in one coat that way...

Yes, if I have masking tape masking any edge on the part, that is where I start.  A light coat on all masked edges first.  Then I expand it to a light "adhesion" coat on the whole surface.  Later I will go back for the heavy coats.