Paasche H airbrush

I'm not an aircraft builder but I do have a Paasche H that I use. It depends on whether or not you are painting a camo pattern. If so, use the #1, for just your base coats the #3 should be fine.
For pressure, between 15 & 20 PSI for base coating and a little lower for fine work.

I've used a Paasche H model for about 20 years now and build both 1/72 and 1/48 aircraft. For 90% of my work, I use the #3 combination which is a medium spray and works well with the types of paint used for model aiscraft. For finer detail such as mottling, I use the #1 but you need to thin your paint more and throttle back on the air pressure. I don't use Tamiya paints but the 15-20 psi setting is what I use for Model Master enamels.

Rick

the size of the needle doesnt neccesarily mean you can achieve a finer or broader spray pattern. the size of the needle allows you to spray different viscosities of paint through the same ab. if you have inks and such, or thin your paint like 70% thinner/ 30% paint, you can use the #1 needle with success. otherwise, youll have plenty of success with the #3. i personally have never owned a # 5 for my H. i use a #3 when i do use it. later.

Wow! Thanks to each of you for the quick and on target responses! Also, for the explanation of when to use each needle. I guess now I just need to bite the bullet and do it!

I have a question for you H model users: when replacing a needle, how far do you slide the needle into the body before tightening the screw? I usually align the forward sholder of the needle with the mounting portion of the body. Even though I really don't know if that's correct.

The needle should go all the way in, butting tagainst he body mount. Just make sure the needle orfice is facing upwards.

Rick