[November 16, 2005]

I did some research this morning on priming/painting guns. I did a quick search on Harbor Freight Tools and found a few HVLP (High Volume, Low Pressure) guns on sale. I figured that this whole topic had to be covered before, so I did a search on Yahoo's RV7and7A group. A lot of people recommended HFT's 43430 HVLP Gravity Feed Spray Gun. $64.99 on sale for $39.99. From what a lot of people said, HFT's stores don't necessarily know about the sales, so print out the page from their website and bring it to the store and they will honor the price.

Here are some people's opinion's on spray guns I found on yahoo:

I wouldn't suggest a siphon fed non-hvlp model, like your link, for shooting primer. I have a touch up gun exactly as like one you linked to, and an HVLP gravity fed gun. The HVLP gravity fed gun wins hands down in my book. The HVLP gravity fed gun will give you a much finer spray, and more control as compared the the siphon gun. You only need a thin layer of primer on internal parts, and the siphon guns spray A LOT of material (primer) and could lead to over coating (adds weight). I had used the siphon gun to do some touch up on my Citabria, and I bought the gravity fed HVLP for the RV. Recently, I was curious about the differences so I put some primer in both guns and sprayed away. I couldn't believe how much primer came out of the siphon gun compared to the HVLP. Even with the nozzle turned down, with the siphon gun there was almost a cloud of overspray blowing down the street, where with the HVLP there was very little overspray. Sure the HVLP gun is more expensive, but it might end up costing you less in the long run as you will get by using less primer.

This is a link I found with some more information:
HVLP Spray Gun

Please note: The #38308 gun I have is no longer sold by Harbor Freight. They have replaced it with a similar gun that uses a little more air and it's number is #43430. It sprays as good as the #38308 gun, but I haven't used it, but some others have and you can go to the next page for feedback on the new gun. It seems to respond well to the setup instructions I have below.
The Harbor Freight HVLP gun #38308 and the newer #43430 gun is a great gun to use for primers and will also do an excellent job with base color coats and high build clears.

It is a good gun for the part time painter as it puts on enough paint to do a good job, but not as much as an expensive production gun does that will get us novices in trouble. This is not a gun a professional would use for overall paint jobs, but I know a lot of pros use this gun for panel repair and primers. So if you are a part time painter who probably paints his rod in pieces and you need a gun that doesn't consume a lot of air I can recommend this gun. I spray with a 5 hp single stage compressor. This is probably the bare minimum you can get away with for an overall paint job (car in one piece).

For high build primers (mixed in highest build form) you might want to order their 1.7 Tip Kit for the gun from their service dept. (the gun comes with a 1.4 tip).

Setting up and spraying with the Harbor Freight HVLP gun #38308 and the 43430

Pressure Adjustment: Open your compressor regulator up so there is plenty of air pressure in the line to the gun (I set mine to about 90 psi). Next set the regulator on the gun handle to 50 psi (what I use for DP40 and K36) with the trigger pulled and leave it set there. Close the valve at the bottom of the handle (on the gun, not the regulator) and then with the trigger pulled, open it to the point where the air volume starts to stay the same (just listen to it) and leave it there (it should be pretty far open at this point). I never mess with this after this unless I think it has been changed.

Note: On my two year old gun they say the maximum pressure is 60 psi. On my new gun it says 40 psi. Instead of the 50 psi above you might try 40 psi if your gun says 40 psi max.

Fan Adjustment: Next open the fluid volume control about 3 turns for starters (at the back of the gun). Close the fan control down (on the left side of the gun behind the nozzle) so when you spray you only get small round circle. With the gun about 6 to 8 inches from a test surface (I use the garage door or better yet some sheet rock, or masking paper) move the gun across the surface (about 6 to 8 inches from the surface) and pull the trigger. As you are moving turn the fan control until you get the desired fan shape/width (about 5-6 inches wide top to bottom oval shape for overall painting) (remember if you are spraying up and down on a surface you can change the nozzle at the front of the gun 90 deg. so the fan is horizontal).

Fluid Control: Next after getting the fan the right size continue spraying and adjust the fluid volume at the back of the gun for the final adjustment to get the fluid right for the gun speed (how fast you sweep it across the work). You want to be laying on the paint at a pretty good volume, but not causing runs at a normal gun sweep speed.

Changing the pressure to match spec sheets: Now you're ready to paint and with 50 psi at the handle the gun is spraying about 10 psi at the cap. If you want 5 psi at the cap put 25 at the handle regulator (8 psi = 40 psi, 7 psi= 35 psi, etc.). You can't actually see the pressure at the cap which is what the spec sheets are referring to. The gun is internally regulating the pressure down based on the inlet pressure. Some expensive guns have a gauge off the back of the handle that tells you the cap pressure and then they also have a regulator and gauge at the bottom of the handle like this gun that regulates the pressure into the gun.

Painting: Look at what your painting and the way the paint is going on the surface right behind the gun and adjust from there. For instance if you want to spray some small areas/parts you can turn the fan down to a small round size. You will also have to greatly shut the fluid volume down at the back of the gun (clockwise) at the same time to avoid runs. usually turn the air pressure at the regulator on the handle down to around 25 to 35 psi to do spot work like this.

Proper Pressure: Remember you need a high air pressure (Set as the spec sheet calls for) so that you get proper atomization and so you can turn the volume up. The higher pressure will actually mean fewer runs since the atomization is better. This is not so critical with the primers, but you really need it with the sealer, base, and clear coats so you get good coverage without runs and with little orange peel.

Note: I'm not a professional painter, but the above is what works for me. If anyone else has anything they would like to add to the above or comment on please e-mail me.

Also, I found that sears has a good deal on their Professional tool storage chests this week . 8 Drawer top for $130 (was $190) and the bottom part for $170 (was $240). I am going with the black color only because all of my other tool storage chests are red now. This will make it easy to seperate the aircraft tools from my other tools. I just got back from sears and they had a free 4 drawer intermediate chest when you bought the top and bottom part!

Tonight I also went over to Harbor Freight Tools and picked up the HVLP sprayer. While I was there, they had a Air Filter/Regulator/Oiler combo for $40 on sale for $20. Its hard to find the individual components for $20. They are all seperate. The input to the filters is 3/8", output is 1/4". The regulator has a 1/4" input and output, and the oiler has a 1/4" input and 3/8" output. I do not know why they even bothered with the 3/8" fittings on this whole contraption since the least common fitting size is 1/4". I plan to put T fittings between all of the components with quick disconnect fittings so I can easily have a hose connected to a unregulated, regulated or regulated w/ oil output.

Finally, on a sour note, Aircraft Spruce charged me $70 (yes, seventy dollars) to ship the chemicals to me GROUND! How can Van's tell me that the empennage will cost $90 for 3-day FedEx and Aircraft Spruce is just less than that for GROUND?

HVLP Gravity Feed Spray Gun. From Harbor Freight Tools. part # 43430-8VGA. $39.99 on sale ($64.99 regularly).

Central Pneumatic 125 PSI FRL Air Regulator. This comes with an Air Cleaner, regulator and oiler. Harbor Freight part # 45009-2VGA. $19.99 on sale ($39.99 regularly).

Craftsman Professional tool chest. 9 drawer top, 4 drawer intermediate, 5 drawer bottom. Sears had a great deal on this. Normally for the top and bottom, it is $430. They had the top and bottom for $300 and a free intermediate section (no rebate!). I think the intermediate cabinet is worth $130 or so. My biggest problem with all of this is how tall it is. As you can see, the drop ceiling in my basement had to be lifted up so the top unit could open all the way (The top needs to be open to unlock the drawers).



Last Modified: September 4, 2017