house primer

[limd21]

I airbrush my models, and use waterbased acrylics exclusively. I prime all my models (primer makes an excellent sanding guide and it gives a great undercoat for light colors like yellow) but hated using the typical rattle can primers because they're all organic solvent based and I'm trying to get away from those.

Recently, I've used regular "latex" (most of what we call "latex" housepaint is generally acrylic) primer that's intended for house painting. I thin it about 50/50 and it makes for an excellent, high build, easily sanded primer. I even tint it a bit with some black paint to make it light gray so it's more easily seen in contrast to a white body tube.

I've used both Sherwin Williams "PrepRite Pro Block" and Benjamin Moore "Fresh Start". Both are 100% acrylic, interior/exterior primers (which is good, since I don't fly my rockets inside!) Both work great! (BTW, they work really well to fill in BT spirals - paint 2/3 coats on just the spirals, sand flush, reprime to a perflectly smooth tube).
Needless to say, it's cheaper, too!

 

[jetra2]

What do you thin it with?

This sounds quite interesting - I've heard that you can use a roller and a can of Kilz or prime rockets, but I've never heard of using an airbrush...kewl!

Jason

 

[limd21]

I thin with either windex or windshield washer fluid - results seem about the same. Straight of the can it's way too thick to spray through an airbrush, so I thin it down to the consistency of coffee cream. The paint can instructions generally warn to not thin as it detracts from its ability to seal, etc. But the way I look at it, this is a model rocket, not the walls of my house that I expect to hold up to years of south-facing sun exposure. The proof is in the pudding, it works great.

 

[Rocketman35]

why windex or windsheild washing fluid? I know nothing of air brushing but it just seems like an odd thinning agent.

 

[limd21]

They also seemed odd to me when I first learned about them but Windex and WW fluid are commonly used as "thinners" by those spraying acrylics in the scale modeling community. Do a search for "windex" or "windshield" over on groups.google.com in newsgroups rec.models.railroad and rec.models.scale and you'll find tons of stuff. Isopropyl alcohol is also used, and some even just use plain distilled water. Anyway, in keeping from what I've learned from folks in those forums, I just extended the idea to using it to thin the primer. After all, house paint is another form of acrylic paint, so the experiment was worth trying.

I think the theory is that these fluids have more ability to "wet" or "flow" more easily than does plain water.

 

[Rockhiittman]

What do you use for the finish coat?

 

[limd21]

Originally posted by Rockhiittman
What do you use for the finish coat?

I've used lots of stuff. When I started shooting water-based acrylics, I got a couple of jars of "model specific" paint from the hobby shop. Stuff like Tamiya and Model Master. Cost is about $3-$4 per bottle.

Again, over in the scale modelling community, there's lots of people who found that the "craft" paints like Delta Ceramcoat, Apple Barrel, Folk Art, etc... work great when thinned. The biggest thing is that they come in a zillions of colors and only cost between 50cents and a buck per 2oz bottle. I gave it a try, too, and haven't looked back. Available at WalMart, Hobby Lobby, Michaels, etc...

My wife does painting with acrylic tube paint and I've even thinned these down to sprayable consistencies (milk/coffee cream) with great success.

Most of these craft paints dry to a dead flat surface. For gloss, Future floor "wax" (really, a clear acrylic paint), works nice as a shiny top coat.

 

[tbzep]

I've been debating on getting an air brush for a while. One reason I haven't already is because of the single vs. double, Pasche vs. (insert your favorite competitor here) arguments. The research I did confused me more than helped me.

What airbrush, tips, etc. would you recommend for rockets?

 

[limd21]

By no means am I an airbrushing expert - I'm relatively new to it compared to others, but here's what I use: Paasche "H" - which is a basic, single-action, external mix unit. It's dead reliable, easy to clean, and is built like a tank. Others with this brush have used theirs for decades (the H has been around for eons), and they're still going strong. It's relatively cheap, too.

Paasche sells this airbrush in a lot of different configurations, some with just a single tip (usually the middle #3 size). My particular kit was the "full blown" one with the small (#1), med (#3) and large (#5) tips, 3 siphon jars and the braided air hose. I'd recommend those looking at this airbrush get the full kit as it give you the most versatile system.

I do almost no fine-line work and actually use the large #5 tip the most since I'm generally covering large areas and work with relatively thicker paints. With this, I can comfortably cover BT-80 size tubes with no problem. I'll use the #3 for smaller jobs. If I do find a need for fine line work, I make sure my paint is thin enough, turn the pressure down to the 10-15 psi range, and I can get a pretty thin line - certainly to about 1/16" or a bit less. For rockets, this is going to be pretty rare.

As to double v. single, internal v. external, I think this airbrush wins hands down for 99% of what a rocket modeler would ever need. We're generally not doing the same things the scale modelers are, so our needs are different. I'm not particularly tied to Paacsche, as I think other companies (like Badger) would also make units that I'd be really happy with. I'm just thrilled to be able to use safe paints that are cheap and easy to handle.

 

[tbzep]

My biggest worry was that even the larger nozzles wouldn't be big enough for covering 2" to 4" diameter rockets.

Would you (or anyone else) recommend the airbrush over a cheap automotive detail gun? I haven't flown any HPR stuff in a few years and don't plan to in the future, so I won't be painting anything any bigger than 4" dia.

BTW, does the Paasche H kit come with an adapter to hook to a regular air compressor or any type of moisture trap?

 

[limd21]

Sure, for bigger jobs a detail gun would be great. I hear Harbor Freight's "cheapie" models actually work pretty good. But I've just not had the need.

I've not done 4", just BT-80 which is 2.6" and have had no problems. To get good wide coverage, I mix the paint a bit thicker (cream, not milk), turn up the pressure to 30psi, open the #5 tip up pretty good and fire away. I get coverage at least as good as (probably better than) the typical spray can. Certainly a lot more control and lot less "fogging" and wasted overspray.

The Paasche air hoses are all threaded on the air source end to 1/4" female NPT (some call this FPT). This is standard for air hose fittings you can find at your local hardware or big-orange home improvement store. All you need is one quick connect fitting which is probably <$2, and some teflon tape to seal the threads.

No moisture trap or regulator is included with the airbrush. I use the regulator on my compressor (shop type). I do have a "disposable" inline filter moisture trap at the end of my airbrush hose, but here in dry Colorado, the filter never has any accumulated moisture, so I've never had a need to "dispose" of it. In a humid climate, I'd get a real moisture trap, again, they sell these at hardware/home-impr stores. I hear others simply splice in a automotive fuel filter.

 

[tbzep]

If it covers as good as cans with less overspray, then it sounds like the Paasche H is exactly what I'm looking for.

Thanks!