Airbrush Difficulty

DHM wrote:

Pulsing isn't a problem for everyone.  Many people who use tankless compressors have absolutly no problems with pulsing.  The tank is just an extra measure to ensure a consistant air flow.

Are they using a diaphragm compressor? They are the ones that pulsate, piston ones don't.  

Bgrigg wrote:

It's not just tanks that cause moisture, it's compressing the air. Tanks are just really good at collecting it.

yep exactly like I said!

me also...never had a tank, never had a pulse problem.  I have a cheap old (I can't even remember when I bought it) harbour frieght compressor with moister trap an a regulator.  If I remember correctly my whole set up cost about $90.

Be aware that if you do get a tank...you MUST get a moister trap, as the compression of the air into the tank causes moister build-up!

Adriaran wrote:

But I mean what does the pulsing of an air compressor cause?

I used on old paache blue comp until I wore it out. The bushing on the rod journal got sloppy and made a horrible racket but it still worked. I used a paache VL for ten years with that comp painting everything from broad strokes to fine lines, good enough for german mottle in 1/72. I never had a "pulse" problem. The only thing I used on my comp was a moisture trap and it was enough to absorb and pulse. YOu don't need a tank though they are nice. Later, after one gains some experiance one might realize the true advantages of a tank but for a beginner I don't think is neccesary.

Some people find that the pulsing can cause inconsistent results. 

The airflow from a tankless compressor pulses because of the cyclic nature of the compressor - air is compressed and expelled during the compression stroke, then the airflow stops momentarily while the piston returns to the "starting" position for the next stroke. So instead of a smooth continuous flow, it's more like a lot of quick "on/off" cycles.  

Bill, I have the first compressor you mentioned and it works quite well for airbrushing.  It's loud, but nowhere near as loud as some of the other (and by other I mean MUCH bigger) compressors I've seen. 

Compressors work by pushing air into a smaller space.  The air flow is pulsated, with points of higher and lower pressure.  Compressors with a tank don't have this prblem because the air can "sit still" for an even pressure.  This is why I would suggest a tanked compressor. 

Yes, I have a Badger 360.

What do you mean by causing pulsing? Does it mean the compressor will suddenly jump in pressure for a moment? 

Your airbrush sounds like the Badger 360. Can you confirm this?  Here's a pic:

Almost any dual action can spray a fairly fine line, but the 360 offers some challenges because of its dual gravity/siphon design.

It won't be able to spray as fine a line in siphon mode as that requires greater air pressure just to pick up the paint, so only use it in gravity mode.

To spray fine lines you need to lower your air pressure and get up close to the model. Don’t try to pull the needle all the way back, you’ll only want to do a very short travel. Practice on a scrap model, and practice lots!

It's difficult to control the air pressure with propellant cans. You might be able to fit a regulator inline, but they won’t keep the pressure as the can empties, and I strongly recommend saving up for a “real” compressor. They don’t have to be really expensive. I use a 3gallon pancake “garage” style compressor that was well less then $100. This is similar to mine:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95275

It’s loud, so if you live in an apartment you’ll need a quieter one, or really understanding neighbors! Here’s another that’s a bit quieter:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92403

The problem with this style is the single piston action can cause pulsing. One with a tank is better, but they tend to be over $100:

http://www.airbrushcity.com/comp45/ and see the second compressor on this page. The tank settles the airflow and eliminates the pulsing action.

The width of a line is usually more a function of how much paint is getting through the brush combined with how far from the object you are painting, more than air pressure. Example, with a double action AB, set the air to 10psi and pull back the trigger all the way you will still get a wide line. Set the air to 15psi and do the same you will get a wider line with more paint in it. The best way to get a fine line in my experiance is to limit the amount of paint coming out of the AB and use very low pressure. I use about 10psi, very thin paint, barely pull back the tigger, and spray about 1/4 inch away from the surface.

A regulator will help you monitor your pressure which will help some BUT, I have a friend who shoots nearly everything with 20psi, including fine lines. He uses paint viscosity and trigger control to do everything. He insists that the higher pressure is required to get the paint to atomize well enough for fine lines.

Experiment. One must be very, very close to the work for fine lines which means that very little paint is required or it will splatter and blow everywhere. This is another reason I use very little pressure, so I don't blow excess paint everywhere and put crows feet on my work. I tend to be a little ham-handed with the trigger.

EDIT: Want to add that if you try these things and still can't get a finer line check the AB needle. It's removable so that means it can be reinstalled incorrectly. Loosen the nut that holds it and push it forward gently until it bottoms. Not to hard or you can damage the tip. If the needle doesn't seat properly you will get way to much paint no matter what you do and the AB will still spray paint even thought the trigger is not pulled back.

Ok, because I bought my airbrush for only $90 on eBay. It's a dual-action, gravity and bottle feed, inner mixing airbrush, apparently retail going for well over $120 to $150. But I'm sitting there using it and going like, "Why can't I get a smaller line?" Because the airbrush says it's supposed to make lines as fine as the tip of a pencil but I can't seem to get it to go less than 2 inches. Would that in-line pressure regulator allow me to make pencil lines with my airbrush?

The biggest jump my skills made was right after I got a compressor, with regulator, and a moister trap.

Do the math you'll save money...like was already mentioned.

When shopping, don't skimp...get a nice one.

I use to use the can air too in the beginning. Keep in mind that later down the line, it will be much more cost effective to buy a compressor. Plus, it will be much easier to work with. I would spend about $14 on a can. I ended up buying an $88 compressor. After you buy 6-7 cans, you have paid for a compressor.

Andy

Only thing you could do would be to add an in-line pressure regulator, like this one from amazon  http://www.amazon.com/Inline-Air-Regulator-Easy-Read-Gauge/dp/B000U20CG0/ref=pd_lpo_k2_dp_k2a_2_txt/002-9149762-6144020?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=lpo-top-stripe-2&pf_rd_r=1XJCZ85BNKVJEAZ4D3HV&pf_rd_t=201&pf_rd_p=304485601&pf_rd_i=B000HI9COK

You'd need to get a second air hose, though.  The setup would then be something like this:  Air can --> hose --> regulator --> hose --> airbrush.

-Fred