Doright wrote:Hi Stangman66
Welcome to the forum.

Stangman66 wrote:Sprayed my basecoat racing stripes and it looks like sandpaper on the roof, hood, and is barely rough on the trunk in a few spots... valances came out nice.

The places that came out nice were these the areas you sprayed first?
Did you spray this all in one shot or did you spray it 1 panel at a time ? allowing Air compressor to Catch up and shut off before continuing to spray?

I ask because many try using too small of a compressor (Thinking they will stop spraying when compressor kicks on too avoid pressure fluctuation's).
A perfectly adjusted gun will start doing funny things IF The Air flow falls below what it was originally set for, the gun can not sense this OR adjust itself too compensate for a loss in air flow or pressure, As a painter you would not be able to sense the drop in air flow or pressure either BUT you should SEE it in the spray Fan as its laying down on the panel if it looks grainy or is not slick stop! Just falling a few CFM will cause problems.

Just out of curiosity how many CFM pump is on your compressor?

Thank you! Been lurking for a few months reading, trying to learn as much as I can.

I think the at the gun pressure regulator I was using is no good, wasn't the same one I used when I sprayed the doors and under the deck lid. I sprayed front to back, with the exhaust fans being at the rear of the car. Seems the top surfaces came out the worst, with the best places being on the front and rear valance and decklid and I believe too much air pressure was the cause (but cannot deny I'm a newb spraying...) There was metallic 'glitter' in the air while spraying and is all over the car right now.

I know the compressor is not recommended, it's a 33 gal 1.6hp, 6.3 @ 40, 5.1 @ 90, and I did try and let it catch up. I'll remember what you recommend this next go-around and be sure to let the compressor catch up for my LVLP gun. Thanks!

Ouch!
That compressor is way too small to handle a spray gun. And I highly doubt it actually puts out 6 CFM. Compressor manufacturers are notorious for overrating their smaller compressors.

What are your spray gun specs?

My Iwata LPH400 takes 9.5 CFM at 16 PSI to properly atomize the paint. I generally spray at 20-22 PSI for epoxy and base coat.

Stangman66 wrote:Thank you! Been lurking for a few months reading, trying to learn as much as I can.

I think the at the gun pressure regulator I was using is no good,

I know the compressor is not recommended, it's a 33 gal 1.6hp, 6.3 @ 40, 5.1 @ 90, and I did try and let it catch up. I'll remember what you recommend this next go-around and be sure to let the compressor catch up for my LVLP gun. Thanks!

Hey Stangman
Unfortunately the idea of waiting for pressure to build is not the correct answer to the problem. As you already know as you state you know your compressor is not recommended.
In theory your Paint gun and compressor spec numbers are really close and should work but Your gun needs 4.5 CFM to operate correctly so Eastwood claims! the Truth is ALL air tools are grossly under rated in CFM requirements to add to it Air compressors are Grossly Over rated in their CFM performance.

Your pump makes 6.3 CFM in Free air (which means it makes that amount of CFM with no air tank at all with no air pressure, As your pump runs it builds pressure in the air Tank, As that Pressure Builds to 90 PSI the amount of CFM the pump can put in the air tank drops to 5.1 at 90 PSI and as the pressure further builds further above that 90 PSI the CFM drops even more linearly against the Tank pressure!!!!

That said now you have the problem with the 33 Gallon air Tank.
I am not gonna get into the Math that covers how many square feet of air is in that 33 gallon air tank BUT your depleting it in about 1-1.5 Minutes of spraying! IF your lucky!
You just don't have enough CUBIC FEET OF AIR in that little air Tank to keep up with the Gun even with the pump running full blast.

NOW if you had say pump that made 12 CFM you wouldn't have a problem because the Pump would make enough air WITHOUT an Air tank in theory.
(Don't do that! Pressure fluctuations)

When thinking of air tools or Air compressors think about Electricity
Where PSI is = Voltage (Difference of potential)
Where CFM is = Current or AMPS (Ability to do work)
They are totally different things!
Air tools are just like Electric tools, You need the Amps to do the work.

Paint gun :
Think of A Paint gun as nothing more than a Carburetor on an engine.
All it does is atomize liquid fuel into a Vapor, It has a set amount of air you can put through it I.E 450 CFM, 600 CFM 900 CFM 1050 CFM etc.... Now the fuel can be increased or decreased by Jet size and Throttle opening but the CFM of the Carburetor is still the same size its still only letting a set amount of CFM air through the Throttle opening till it reaches its peak amount of air that can get through it.

Your Eastwood guns specks of requiring 4.5 CFM is more than likely understated and your compressor is over rated in my opinion.
Still your problem was Nice areas and dry spray which means.
The Gun was not adjusted properly before painting and or You were holding the Gun too far away from the surface being painted or too fast of activator/reducer.
As you painted your Air pressure and air flow were fluctuating which would cause you to have to move in or away from the panel to get paint to lay out nice. As a new Painter you want to Hold your gun a set amount off the panel 4-6 inches and hold it Robot perfect Never moving in or out from the panel.

If you look at new compressors look at the CFM numbers at 90 PSI forget the @ 40 ! its meaningless! the only number that means anything is how much CFM it makes at 90 PSI thats because most all air tools operate at 90 PSI you do not need a huge or a Million dollar compressor BUT you do need one rated hi enough to power you biggest air hog tool + some.