RandyS

I have begun to spray Eastwood Urethane 4:1 Primer on my 66 project. It is being applied over Eastwood Epoxy Primer (which went on great). Spraying in controlled temp workshop @ 72 deg. I am using an inexpensive HVLP gun with a 1.7 tip @ 30 lbs., and having poor results. Applied two coats as recommended, but after drying the surface is very grainy. It will sand smooth pretty quickly with 320 grit. Other than buying a more expensive gun, what suggestions do you have to get better/smoother results. I do have a 2.0 tip coming.

Jetstarjim

Could be your air cap, they tend to be a little too universal on cheap guns. Definitely try a 2.0, or even 2.2. Some of those 4:1's are pretty heavy. Try narrowing your pattern as well, if you haven't already. Too wide, and it has a tendency to hit the car dry. Maybe a hotter activator might help too. I usually put down one heavy coat, let it dry and knock the orange peel down, then recoat. What I see often is 2 coats, the peel knocked off the second coat, and eventual shrinkage that looks like giant orange peel of the first coat. Don't let the primer be a crutch for improperly finished bodywork.

RandyS

I have the pattern closed down all the way, and it looks like it is going on wet. The instructions mention that it can be reduced up to 20%, should I try that after I get the 2.0 tip?

I have tried my best to get all the panels smooth using guide coat, but body work is not my forte by any means.......

Jetstarjim

The 2.0 tip, and reducing it, should help you quite a bit. I would start out at about 10% reduction, and go from there.


As far as bodywork, I've seen a lot of folks try to cheat a little by trying to fill 80, or even 40 grit sand scratches on their filler work with primer. I usually finish it out in 220 or finer, spot prime and block, then prime the whole panel. Less is usually more, in terms of under paint build, to help eliminate scratch and feather edge swells. It also helps with the longevity of your final finish.

coppercutlass

I use heavy primers and usually like to spray with a 1.5 or bigger . I always reduce the primer which most primers you can reduce . I usually reduce 10 percent for the first coats usually 2 or 3 then the last 2 I reduce 20 precent to lay it on smoother for easier blocking. I usually dry block with 180 then re primer then block with 180 again then 400 wet on a hard block . I only primer over 180 - 320 enything finer and I feel there is not enough bite for the primer. Fwiw I don't like to spot prime because it creates a lot of uneveness. I like to do my body work as straight as possible first and if need be spray a poly primer surfacer to really make it straight then I folow it with urethane primer . Same thing for filling low spots within filler I never do smal spots I always end with a light skim because sanding spots within the filler will make waves and leave an uneven un uniform surface. For everyday collision jobs I spot prime as is standard procedure but on resto work uniformness is key to straight panels . I do a lot of light skim coats lots of long board blocking and religiously use guide coat . Just my .02

RandyS

All of my final sanding on any filler or glaze was done at 220. No visible scratches. I plan to block with 320.

DFitz

Primers respond really well with reducer. Much flatter and flows much better, also easier to get runs, but overall I've had good luck with that. PPG at least up to 25%. Yeah, that's a lot more than they recommend, but I figure that's CA emissions controls....do what works.

Rocketguy

This is characteristic of a 2K primer surfacer. From dozens of years experience I recommend:

1. Prepare the job 100% before adding the hardener; i.e. wait until the very moment you are ready to spray it.

2. Yes reduce it, but only as much as needed. Also, the more time that passes after the hardener is added the more reduction will be necessary.