Paint stuff

[Terry, NJ]

Don't really care too much now, cause it all gets sanded off any way, BUT! At some time in the future I'll want tho paint the body and that doesn't get sanded! I just spent my 60th or 70th hour on that &%#$@ ING coupe fender. and I wanted to prime it and let it dry over night. I'm using a Harbor Freight "Purple Gun" (Which is bound to get a reaction from the Iwata crowd) That Stoopit gun is probably one of the best things HF sells. And I'm using PPG Shop Line, sandable primer ( 4-1-1) (506 I think) Line pressure is around 50 lbs. Pressure Regulator at the gun drops to about10-20 Lbs. As I have said before, I'm the worlds 2nd worst painter! So the problem is that the paint is not misting, It come out like some kind of old, dry spray can, or like a can of starting fluid. Then it hits the work and it's like a sand finish. I was turning the screws to no avail. What am i doing wrong? I suspect too high a gun pressure. TIA
Terry

[RAS]

My first thought is the product you are spraying has outlived its shelf life. I know for my self it's rare that I still have good spray able hardner/activator by the time I get back to a project a second or third time. I'm not familiar with the "Purple Gun" but use the cheap ($20) Harbour freight many times. Since my tools or product set, I always spray some thinner or reducer through the gun first to make sure its working. Usually I just spray against a piece of paper or cardboard for a test pattern. Only after I'm confident in my spray gun do I mix product. It's very difficult to seal up a can well enough to save it for another day. Here in Indiana if evaporation doesn't ruin it the humidity can. In the old days you could just add a little thinner/reducer to make it spray able again. But now days the products need to dry chemically instead of air dry so I don't think that works. I hope this helps.

Rick

[Tinbasher]

Well it could be a couple of things. One the product is too thick. You may need to reduce it. Of that's not it, it could be too little air pressure. Usually you need between 20 -30 lbs at the gun for primer. If you still not having any luck check and see what size of fluid tip is need for the product your spraying. Most primers today need at least a 1.4mm. I have one primer I spray and it requires a 2.5mm tip. It's like spraying with a garden hose!! But it does put on a heavy product. See if you can get the Tech Sheet for the primer your using it may answer a lot of questions.

John Poole

[Terry, NJ]

Rick and John, Thanks for your input! The hardner/activator is old! I never considered that possibility. I have newer and from now on, I will use that. The "Purple Gun" is the $12 gun. (how they can produce that gun for $12 is beyond me!) Google it on youtube. OK, I will bump the pressure up to 25Lbs. It seems that I read somewhere that the Purple Gun needs higher pressure to operate properly. I believe that the tip size is 1.4 mm or about .056".
Terry

[Terry, NJ]

FWIW.I reamed the tip size to about 1.5 mm (Was .055, I reamed it to .0625, 1/16) Then I reamed two of the small holes (.020) to .025, I just cleared out the other two. It's no fun reaming a .020 hole. It's done with a .025 drill in a pin vice. Not under power. I think there was some improvement in the cone of the spray. I put a coat of Transtar Black primer for a guide coat.Next, I'll put a coat of Shopline filler primer on that.
Terry

[midgetracer]

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Even a 1.5mm tip is small for high build primer. I agree that more air pressure is necessary to avoid the dry application. Also move slower when spraying. Try on a piece of cardboard and make sure you have a good wet coat.

[Logan]

Spray your primer at 25 pounds of pressure and turn your fan patter back a quarter turn and slow down your travel speed. Your gap should be 5-6 inches from the panel, and do a 50/50 over lap. 1.3-1.4 tip should be plenty big for high build primers and sealers. The only time you go bigger is for a polyester primer. For that use a 2.0. If it's gravely looking, your to far away and air pressure is to low. Don't be confused by HVLP, the "low pressure" guns still like a decent amount of air pressure. My SATA's and Devilbiss guns love 23-25 pounds for primer and base. Then I crank it up to 26-28 for my clear or if I spray a single stage eurethane. And iwatas like about the same. I've sprayed out of almost every gun made (major manufactures) and I've always preferred the sata's. The iwata throws out a lot of material which therefor uses more material... that all being said, the HF guns work just fine. They're a shorter life gun, but they lay out primer and solid color base just fine. Blending Metallics and laying down clear coat is when the nicer guns really come in handy, besides the longer lifetime and the ability to actually rebuild the guns. Good luck, even with the old hardner and reduced it should still lay out pretty good if all of your settings are correct. You just might have a shrinkage issue using old material as it cures. Don't be afraid to lay down 2-3 wet coats of primer. If you run it, it will sand off. Primer and clear both like to be sprayed right on the verge of running. It's a fine line between a slick coat and a "curtain" run.

[Terry, NJ]

I raised the pressure at the gun to about 25 to 30 Lbs, I got the fan wider and it seems a lot better. I also experimented with my sorta "Brewster Green" on the back of the hood panels just to see how it will look. It's like a dark forest green, whether it dark enough to be Brewster green or not, I wonder. I wanted kind of a "light" Brewster. Brewster Green can be mistaken for black in the right light. I didn't want that. So I told him one shade lighter on the scale, No more! I think he did more. It's not bad! And I Think it will darken with a second coat.
Terry

[Ed in Maine]

For what it is worth I just used TCP Global epoxy and high build urthane primers and hardeners. The job went perfectly. I would highly recommend them. Their prices were half the cost of PPG Shop Line. I plan to spray the top coats next year. Ed

[mike657894]

i have used he HF guns and it needs 40 psi and a thinner mix to get a good paint going. I paint and just light sand between coats or dont sand at all. I am painting without a booth so a little dirt and maybe a bug or two will get in the paint. If you can use a down draft booth that helps imensly. look at the devill biss starting line gun set. I just upgraded to that and it uses the pressure it says it should. the HF gun will orange peel no matter what you do or it will speckle. great for $12 bucks but only good enough for farm trucks or trailers or equipment. the starting line kit is 150 I think two guns three tips and needles.

[mike657894]

the kit that is slightly cheaper is a mini gun and regular. I find the mini guns to be completely useless.
http://www.ebay.com/itm/Devilbiss-St...AAAOSwDiBZNuvy

[holdover]

A quality spray gun might work better for you, but if you don't do this on a regular basis it might be a tough sell. I pay too much for the paint to use something that doesn't deliver a great spray pattern every time. Your comment " it's like a sand finish" seems to say not enough thinner, or it was super hot when you were spraying it, or you used a fast dry thinner or a combination of these and some other variables, or as said some of your product may be old and not working correctly. Might you check around with your local club and ask if you can borrow a gun, or have a member spray it for you. (many of us are pretty protective with our equipment) Anyway best of luck with your project.