I am going to be undercoating my 2003 Chevrolet Silverado 1500 LS. I will use a hard type undercoating on frame and walls, as well as on the drive shaft and other areas that won't be affected or made unrepairable by being coated. I will use an oil type undercoating on areas with bolts, or parts that would be ruined/made unrepairable by being hard coated. I will also use the oil coat on the leafsprings, as I don't expect the hard coat would get distributed well, and would probably peel or crack off when the springs flex.

Before I actually start coating, I want to attack as much rust as possible, and clean all the surfaces as well as possible, to give a good bonding surface for my coatings.
I plan to remove the bed to give myself as much room to get as much rust as possible there.
My main concern is clean up prior to coating. I will have your usual dust dirt and grime. Then I will have rust powder from all the sanding/brushing/grinding I will do.

Should play it safe and use air and wipe down with thinner/cleaning agents? Or can I pressure wash and then attempt to dry in a quick manner? I know the last one is dangerous, as coating over moisture is deadly, and it could take forever to dry out. Washing would be more thorough, and my drying idea would be to get fans and heaters, and position them under the truck on a lift to blow hot air around to dry it out. However, my gut tells me I may still have trouble, and that maybe I should be content with air/wipe down, which I could do a reasonably good job with. What do you guys think?

it would be wise to do pressure washing,degreasing, and cleaning before any work starts.
then air and WAG to clean and prep after rust work.

jwheels17 wrote:......I will use a hard type undercoating on frame and walls, as well as on the drive shaft .....

Thick undercoating could put the driveshaft out of balance. For that reason,
I'd simply sand the existing rust off and wipe some type of rust converter on
it. Or you could paint it with a thin coat of epoxy.

Can you elaborate, tom? Not sure what WAG means

My question about using water at all is because a neighbor who has a shop expressed the concern that water will sit in nooks and crannies that you will never get to dry out in a reasonable time, and coating over that would just keep rust underneath the coating.

That's why I was wondering about just abrading rust, using air to blow away, and wiping with cleaner. Do you think that you could pressure wash and have it dry out completely? Might that mean an investment in heaters, fans?

I'll be careful around the shaft. Thx.

WAG,Wax and grease remover
Jay D.