Tried spraying 2K epoxy and it didn't go well.

[jemmons]

I had completely stripped the engine compartment of paint with media blasting and sanding and throughly cleaned the bare metal to remove any grease or oils from hands, tools etc. As I sprayed the epoxy primer, mixed exactly as directed, it pitted or looked like moon craters as it sprayed on the metal. Anybody have any ideas as to what I may have missed or what went wrong? The temp was round 65-72 degrees, humidity around 50-60% Thanks everyone.

[Len]

It sounds like surface contamination to me. If there is the slightest amount of oil or grease on the surface it generates "fish eyes" that are craters where the paint won't flow evenly over the surface. In areas like the engine compartment you should use a pump sprayer to apply a solvent cleaner (grease and wax remover) to the surface to be painted or primed then wipe it off with paper towels. On the exterior of a car we usually do this several times to make sure the surface is clean but in the engine compartment you may need to clean it with solvent at least three or four times to insure a clean surface.

If you want to cure your present condition and end up with a smooth finish you're probably going to need to remove the primer and start over. If you don't care that the surface is smooth you may be able to sand the surface and dust a little more primer on until the craters are covered. Dusting the primer on will make it have less tendency to fish eye but you will still have a low spot in the finish when you're done.

You can use a sprayer like the one below or purchase a less expensive garden sprayer from a hardware store. Most Windex-type sprayers will only work once or twice before the solvent causes the seals to fail. Pouring the solvent on a cloth or paper towel and applying it will work but you'll need to go over the surface more than if the solvent is sprayed and it's more difficult to get the contaminants removed using the wipe-on/wipe-off method.


http://autobodystore.net/Merchant2/graphics/00000001/USCsprayer.jpg
USC Pressurized Sprayer Link (http://autobodystore.net/Merchant2/merchant.mvc?Screen=PROD&Product_Code=USC70305&Category_Code=PSH)

[trent]

In areas like the engine compartment you should use a pump sprayer to apply a solvent cleaner (grease and wax remover) to the surface to be painted or primed then wipe it off with paper towels.

I just pour grease and wax remover into my primer gun, and run at about 90psi. That a problem?

[Len]

I also tried spraying solvent cleaner out of a spray gun for a short time but it's so thin that a lot (if not most) of the solvent goes into the air. Not only do you waist half the solvent but, without breathing apparatus, you end up inhaling a lot more of the fumes. It would pay to go to Home Depot and purchase a pump sprayer for $6. or invest is a pressurized sprayer, they work great and you'll use a lot less solvent.