[Mkulikow]

So,

After much deliberation on stripping this powder coat off my '91 420 all the pieces went to the sandblaster. He dipped the ones he could fit and sandblasted everything. My next steps are going to be a coat of primer on the bare metal, glaze putty/filler for dents/dings, 2nd coat of primer. A 3rd coat of primer if the surface is not like glass before 2 coats of green.

This is my first time with an HVLP gun and the bottom sides went great, I built a 1-1/2 pvc booth with a fan blowing in through a filter with a static exhaust through another filter. I am now primering the top of the fender deck and I got these boogers/strings in the primer, it looks like paper fibers, any ideas? I am using cardboard in the booth but any input on the following pictures would be GREATLY appreciated.

Settings: thinned 10:1 per can (half pint mixing cup) with JD thinnner, primer added to thinner, gun at ~20psi with trigger pulled, material ~2 turns out, fan wide open. Sprayed on masking paper per Mark777s AWESOME posts over at mytractorforum and all should of gone well. The gun did sit for a few minutes after straining in primer while I put the door together and got my respirator on

Bigger picture;

http://picasaweb.google.com/Mkulikow/Tractor#5376164509394544674

- Mike

 

[Mkulikow]

More pics:

 

[Mkulikow]

Not thinned enough? Based on it not being spit everywhere any chance there was separation happening?

 

[dquandt]

Did you have a dryer between the gun and compressor?

 

[mrmondo]

Just wondering, I had a similar problem with mine when priming my Impala. The gun had a regulator on it and once I boosted the pressure on the compressor and adjusted it on the gun it came out better. It was the first time I used a HVLP gun so I had no idea what was going on. It still went on a little rough but not like before. Maybe not thinned enough.

 

[Mkulikow]

There is a filter/dryer between 2x 50' hoses. There is a desiccant filter and regulator on the gun. Pressure at compressor is 90 and pressure at gun is ~20 with trigger pulled. Luckily it looks like it is paint so I can sand it, does not appear to be contaminated but is gobs of paint.

- Mike

 

[Mkulikow]

I will try again with higher pressure (25 psi and less fluid) and thinned to 9 or 8 to 1...

 

[lodogg2221]

My guess would be to try higher pressures...I dont think the thinning is the trouble, unless its a guess and your guess is a bit shy of 10:1, which happened to me before!

BTW, thats a pretty neat spray booth you have going there!

 

[Mkulikow]

Non glued pvc with electric fence wire crossing on all 8 sides. Where the 2 diagonals cross you tighten it with a screwdriver, tightens the entire structure

I am using mixing cups that spell out 10:1 but my pressure may of dropped, you can easily hit the knob, need to get a good mini-regulator or be more careful!!!

 

[Mkulikow]

Well,

I hit the parts with maroon scotch brite and the threads came right off. There are no pinholes so this first coat is perfectly salvageable.

I will do the required body work and then it's 1-2 more coats to fill the sandblasting marks before green.

I still wish I could of seen this coming somehow on my masking paper during setup

If this happens on the color coats I'd be in deep $5^&...

One thing I am wondering, do you guys leave air flowing the ENTIRE time and only use the fluid control or are you releasing the trigger fully after the passes?

- Mike

 

[lodogg2221]

Air the whole time...that could be it if you let off. Thats why most guns allow that, because if paint builds up, or drips down into the air flow, then you hit the trigger, you will get splatters.
With the air always flowing, it draws the paint out more evenly as well, to prevent splatters from that as well.
Might not be the best description, but in a nutshell, keep the air flowing the whole time. If you do stop it, start it again before the gun is over the piece...

 

[mike_l]

I had a similar problem with my HVLP gun. Mine is a cheap HF one but it works pretty good once I got use to it. The cap on the paint cup did not have the vent hole completely open. It would spray fine and then start sputtering and spitting paint. After drilling the hole out with a wire drill that eliminated most of the problem. The other issues were properly thinning and straining the THINNED mixture. Thinning was trial and error. At home in the garage I needed more thinner, but when I painted the larger parts at work in a real paint booth the same mix ratio would produce runs.

 

[Johnod]

I had the same problem with a new HVLP gun I bought. The problem was the tiny screen you drop in before you screw in the paint reservoir. More pressure didn't help. I discarded the screen and it worked perfectly.
One of my favorite guns now.

John O'D