OldschoolTrek

So I'm planning on repainting my 91 trek 2300 pro. I have been researching different spray guns and various compressors. So, my question is how powerful of a compressor do I need to use a HPLV spray gun? I have seen sites that rate the compressors with a horsepower rating and I see that spray guns that require x amt of PSI, but the site doesn't list which is compatible with which.

What I really need to know is can I just use my old air compressor that works great with my Iwata gravity feed airbrush? Any help is much appreciated!

Nessism

Most spray guns will have a cfm rating @ some particular psi. Your compressor will need to supply this amount of air in order to drive the gun. My compressor is a very old 2 hp 20 gallon job that works great for home painting (bicycles and motorcycles). I think you could get away with even less power than I have although I'm not sure where the minimum would be.

One key to home spraying (or any spraying for that matter) is to keep the water out of the supply air. I've got a couple of cheap water separators that get the job done but a properly larger separator is recommended.

Hope this info helps.

Good luck.

OldschoolTrek

I guess I'm not familiar with the different types of compressors. All I know is the ones that you plug into the wall and hook up to an airbrush.

OldschoolTrek

I also wonder if I would save a bunch of money by buying a brush and renting the compressor to paint my frame, since I'm only planning on painting the frame this one time? But that doesn't include the time I need to primer the frame. Any advice for doing this cheaply, but getting a quality paint job out of it?

j0e_bik3

ok here ya go (and when you speak of me, speak well )

the trick is to get a gun that has a CFM rating that the compressor will handle, for a bicycle you don't need a super output compressor, or anything larger than a detail gun (yes even for the clearcoat)

newer LVLP (low volume low pressure) guns run at about 20-40lbs at the gun regulator, and usually sip air at 3 to 9 cfm.

harbor freight actually makes TWO guns that are noteworthy for the home painting enthusiast:

this detail gun:
https://www.harborfreight.com/cpi/cta...emnumber=46719
only needs 43 psi, and only uses 3.7cfm! you could run that on a 5 gallon compressor! and that gun will do a great job of finely atomizing even thick clearcoats, as it has a 1mm fluid tip, which is on the large side for a detail gun.

and this full size LVLP gun: (it's incorrectly labeled as a HVLP gun)
https://www.harborfreight.com/cpi/cta...emnumber=90977
notice it only needs 29psi, and uses 5.91cfm! thats just crazy low air consumption, and will run BEAUTIFULLY on a 20 or 33 gallon compressor

now before some of you paint jockeys get all in a stink about harbor freight stuff,...I own just about every gun type, detail gun, and airbrush that IWATA makes, and I will swear an oath to the late ed big daddy roth himself, that BOTH these guns will shoot right along side the equivalent IWATA gun.
now you can't run over them with a pickup truck, and have it shoot just perfectly still, like an IWATA, and they don't have IWATA'S patented "tulip shaped fan" pattern, but like I said they will produce JUST as fine a quality paint finish as MUCH more expensive guns.

now to be fair, these also have very low air consumption requirements:
https://www.spraygunworld.com/product...%20EVO4014.htm

https://www.spraygunworld.com/product...-%20AP4020.htm

https://www.spraygunworld.com/product...ex%203000.html

https://www.spraygunworld.com/product...ex%201000.html

and again all those will shoot right alongside sata's, better devilbiss, and iwata.

there is one other gun that is just so unique, and has such unique features it bears mention, even though it's an air hog, and needs a full size 15+cfm compressor to run:
https://www.spraygunworld.com/product...DEVSRI630W.htm

it has a tulip shaped fan pattern (very accurate control) and the pattern is adustable down to a tiny 1/4", and all the way up to a full size 8" fan! usually a detail gun is limited to about a 3" to 4" pattern, and will only run down to about an inch, before they start getting "runny"

a very unique gun, and nothing else does what it does, all in one gun.

for standard size paint guns, use a 1.3mm-1.4mm tip for best results, and for detail guns I like a 1.0mm with modern urethanes, but you'll need a big 1.8mm tip to shoot primer, but pro painters will NEVER put primer through a gun that is used to shoot clear, and I have a separate gun for each paint type: one for metallics, one for candies, one for flakes, two for primer, 3 for clear, 4 detail guns, yada yada.

so IF you put primer through your gun, you SHOULD tear it down and completely clean it, before shooting another type of paint through it or you WILL get a big ****er of primer come flying out right in the middle of your clearcoat (ask me how I found THAT out )

compressors are easy, just get the HYOOGEST one you can afford, and that you and your neighbors can deal with the noise (cheap $150 compressors are NOTORIOUSLY loud) and that wont pop the breaker on your house when you run it.
try and get the highest CFM in the pressure range YOU will be using, and again the better ones will be expensive (like $750+), and MUCH quieter, but remember, using any of the above guns, you CAN get a good home paint job, with what would ordinarily be much too small of a compressor.

the above idea of renting a BIG @$$ compressor, and then BUYING the paint gun is a very good idea, and one I use all the time. if you have the cash, I would buy a detail gun, and a full size gun, AND a cheap beater with a 1.8mm tip for primer.



peace, love, and isocyanates

Nessism

This compressor would be enough based on the cfm ratings https://www.harborfreight.com/cpi/cta...emnumber=90234

Water seperator
https://www.harborfreight.com/cpi/cta...emnumber=95439

Gun
https://www.harborfreight.com/cpi/cta...emnumber=47016

j0e_bik3

except that compressor is like DEAFENING!, and gets the air volume too hot after a few minutes (no good for painting) save that for air tools, or pressure washing.

the gun shoots like crap (yes, I had one of those too) save it for primer, it's NOT HVLP, or LVLP, so you'll waste 50% more paint sprayed into the air, and running at 50+ lbs, it has WAY too much "bounce" for shooting a tubular surface, like a bicycle.

and that water separator is just a frickin JOKE! (I tossed mine out after using it ONCE) there is NO filter inside, it's just an empty canister, and there are no cartridges available that will fit it.

I'm not trying to offend you, but I wouldn't recommend THOSE choices at harbor freight to anyone.

the guns I listed above I have personal experience with, and they are all reasonably priced, and will do what I said they would.
if you don't care how much a spray gun costs, or you want the BEST, choose anything by IWATA, or an FX geo, and be prepared to spend upwards of $600

ok water separator (this one is a CLASSIC, I have two) they sell cartridges to replace the filter, but every painter I know just uses a fresh roll of toilet paper for each paint job.(NOT CHARMIN:TOO MUCH LINT!) they cost about $75-$85 and are worth every last penny:
for the compressor: the Motor Guard M-60
https://www.ketone.com/proddetail.php...0bf9d24e824b2a

and on the gun regulator, these ACTUALLY WORK, and wont decrease your flow at all, the devillbis whirlwind:
https://www.autorefinishdevilbiss.com/products.php?pg=42

I write technical manuals for DeVilbiss, and Evercoat, and I am currently writing an article on painting bicycles for Urban Velo magazine based out of pittsburg pennsylvania.
I have been painting motorcycles, cars and bicycles for something like 34 years and I ran a very successful motorcycle restoration/custom painting business for well over 17 years, now retired and playing with my grandkids.

so it's pretty damn good advice, if I do say so myself

RCordone

I got very good results on two frames I repainted using my old 1.5 hp stapler compressor and a $20 8oz gravity feed gun from Harbor freight. I sprayed a base and 2 clear coats on each frame. Only thing I was warned about from the paint shop was that the cheap guns often times don't atomize the polyurethanes very well. When I sprayed the clear I had to spray two quick medium coats in succession so it would flow out and dry evenly.

Nessism

Two wet coats of clear typically works although it depends on the particular clear you are using.

Regarding what guns to use, I've heard good things about those $100 Astro knock offs of the Sata Mini jet. I've got a Sata myself and it shoots pretty well once I figured out it needs more pressure than one might think for a so called HVLP gun. Also have a DeVilbiss suction feed touch up gun that sprays nice as will. The Sata has a gravity feed cup so less paint is wasted but the overspray is about the same as the DeVilbiss which is not HVLP.

Regarding that water separator that takes toilet paper rolls, isn't there a generic equivalent that's cheaper than $80? We're talking about toilet paper rolls after all - the outer housing is just a casing of some sort.

At any rate, good info joe. Keep it coming.

j0e_bik3

no unfortunately harbor freight hasn't reverse engineered the motorguard filter (yet?), but I can tell you, I have had mine for 28 years, and have gone through 3 compressors, and that thing is still good as new.
I've dropped it, I forgot and left the compressor on with the drain valve open while I was on vacation for two weeks (the thing was running constantly for almost 13 days straight), and I used one with a line dryer for the entire 17 1/2 years I was in the painting business, and I still have them, and use them at the home(garage) shop.

so you buy one motorguard filter, and thats the last one you'll need, probably for the rest of your life.

they WORK too,...I take it with me when I have to go and shoot at some other shops (custom paint crap: ghost flames, tribals, yada yada) and some of the shops have THE DIRTIEST, WATER AND OIL laden compressors and lines, and one new roll of TP, and you get a perfect clean DRY paint job, everytime.


like I said, "worth every penny"

Nessism

Okay, think I'm going to order one. My water separators are pure crap - can't wait to throw them in the trash heap.

Compressor running for 13 days straight? That must have cost you some serious money. My cheap ass 2 hp compressor really sucks up the KW's; I can see it in the electric bill every time I really use the thing.