Finally got around to priming a few parts this weekend. Seems like the K38 I have is reallllly thick. I have had to paint for a few years and it's sat on the shelf in the original can. I had to reduce it to get it from spitting out of the gun, it seemed way to thick. As soon as I reduded it a little it sprayed much better. Is this the nature of spraying k38? or is my paint just too old? Seemed to cure and sand really good, not sure if I should keep using it or pitch it...

We use alot of K38 and spray it out of a Sata KLC P gun with a 2.5 tip, we use it for the K38 and the U-POL spray poly it lays it out very nice with the big tip, then we block it with 320, 400, 600 and finish with 800 so if its a metallic they will not stand up in the deep scratches. If you use a 1.3 or 1.4 gun it chokes and will not spray out of the gun. If you reduce it you are not getting the mil thickness you need, and the shelf life is not that long.

I use a 1.7 sata LMC2000 with K38 and don't reduce it.

One thing with k38 and k36 is ONLY mix up enough to spray 1 coat. Because the pot life on those products is like 30 mins it kicks over darn fast changing how it sprays. Also a large quantity of mixed K38 will kick faster then a small quantity of mixed product.
Meaning if you mixed up enough k38 for two coats, by the time the next coat came around the k38 would be starting to kick changing how it sprays. So you only mix enough for one coat.

That's interesting since they say to spray it with a 1.4-1.6 tip. I used a 1.6 tip and it spit like crazy and was really dry. So is K38 normally very thick? and why would they say to spray through a 1.4-1.6 tip?

What kind of gun are you spraying with ? How far do you have the fluid knob screwed out ? I screw mine all the way out (be careful, if you do it too far the knob and spring will fall out) and then pull the trigger, then screw it in until I feel the trigger move, then stop. I used a 1.5 tip in a FLG3 Devilbriss but was spraying the K36. Mixed and used it at 5 to 1 (23 to 24 PSI) and it had a buildup on tip after spraying a while which then spit it onto car (was very thick). After talking to someone they told me to thin it down 10% and increase air pressure to 28 to 30 PSI with trigger pulled. This solved my problem and it came out real well, move fast thou because alot of primer will come out. I also used a 1.4 tip with a cheap HVLP gun from Menards with the same settings and it work just as good. Hope this helps.

I've got to give my 2cents after being in an autobody program and hearing all this hoopla about PPG. I was (key word "was") a pro-PPG and still think they have a high quality product (maybe except the Omni line) but must say that there are the same (if not better products out there) for at least 1/2 the cost of PPG.

Check SPI, Kar Kolor, Standox, etc.... You will see when you price their epoxy primers (and contrary to some opinions, especially PPG's), you don't need to spend that much. I shot PPG's DP40LF because it was supposed to be the best for adhesion to bare metal. BS....there are so many other choices (plus to boot DP40 is NOT sandable)...

Boy, I'm learning a lot but mostly there are other quality choices for less than PPG (and you might as well through in Dupont)

Hope this helps you think more before you spend your hard earned ca$h.....

The Duff

Trust me, I think SPI are one of the best for the money.. To bad I already bought the K38. Barry's products are awesome. His epoxy is the best!