Testing an HP-B+

is there any paint residue on the needle? do you use oil on the needle?

rolgan, i bought an HP-C and it came with a .3mm n/n combo. just reading about the HP-B+ on the iwata homepage i take it that it has a .2mm n/n combo. is this correct? what was the thinnest ratio of paint to thinner that you used? with the thinnest ratio, what psi did you use?

when i first got my hp-c, i had the same problems and converted my whole rig to a .4mm n/n combo and it worked like a charm. i've never had too much luck with the .3mm n/n combo and i think the problem lies in the pigment size of modelling paints. the hp-c and your hp-b+ is really overkill for modelling and is designed as an illustration brush using dyes, inks and urethanes. the n/n combo is just too small of an opening to spray consistantly with model paints. here is my suggestion:

1. get a moisture trap for sure

2. use a 70% tamiya thinner to 30% tamiya paint ratio and mix thoroughly

3. drop the psi to 10 psi and try the fine line, if 10 psi dont work, drop it even further and keep trying.

4. if you have to thin much beyond 70/30 then you're basically paddling upstream and may have to buy a larger needle/nozzle combo to enable you to spray model paints through the airbrush.

as far as iwata's and modelling go, the hp-cr and the hp-cs are the way to go. if you have your reciept, maybe return the hp-b+ and swap it with the hp-cs and then you're all set. unless your an art student or plan to do illustration with the brush, you're gonna have a very hard time fitting model paint through that fine of a nozzle. later.

rolgan, salty has the right idea. The nozzle might be too small and/or the model paint pigment might be too large.

You could trying spraying water through the airbrush and play with it for about 15 minutes to see if the problem is solved and you get a little practice with the airbrush. If you have to have color than put food coloring in the water. If the airbrush works then try a little model paint and a lot of thinner. Keep raising the amount of paint and see if the airbrush still sprays well.

I've sprayed with my HP-B and HP-C that both have the stock nozzles on them now and I haven't had any problems painting models with enamel paints. Except for Testors gold and silver enamel paint. But that paint has very large metallic particles.. In my Iwata collection the HP-CR is the best all around airbrush for model painting...including metallic gold and silver.

I agree with the guys here. You are going to struggle with a .2mm airbrush and model paints. Personally I would take the opportunity you have and swap for a CS (.35mm) or CR (.5mm). It's a hard call between these two brushes but the CR is the best all-rounder and with some practice in capable hands you will be able to do detail work almost as well as the CS. On the other hand the CS handles detail a little better, is almost as versatile but I find it does struggle a little with metallics. You can solve this by getting the optional .5mm needle and nozzle for it later if you want or need to. It's really a toss-up and you won't go wrong either way. I would lean slightly in favour of the CS, as that way you have an easy option if you want to increase it's versatility to cover the CR's only advantage (spraying metallics). Good Luck!

Cheers...Snowy

maybe replace the nozzle with a cs one...

Thanks for the input, I really appreciate it.

I got moisture trap and filter system and my Puma is spraying like a dream, I am consistently getting good lines and feathering so I'll likely return the HP-B+ as it is overkill.

I got the Iwata working and the lines it's capable of are insane, but the nozzle is likely to small for model paints. I'm having trouble with paint drying on the tip, i've messed about with psi and thinning ratio. I think I'll take everyones advice and possibly exchange it for an eclipse.

As I mentioned earlier, I appreciate the help and you'll likely hear more from me in the future as problems/successes arise.

regards,

Cory

what about putting in a larger nozzle? try that.