underbody primer

[FJ5WING]

getting the underside of the car blasted this week. I was wondering what to do with it once its naked.

I guess it needs to be wiped down ( I should use what?) and then I have a gallon of Omni 170 Epoxy primer with the 175 catalyst.

anything special I should know about thinning the primer. I never worked with epoxy primer before?

Thanks for any help.

Dave

[jerry]

first take time to blow it out , i use SPI waterborne wax & grease remover then 3 coats of SPI epoxy mixed to match original dark gray primer [dip] that came from factory. just read the sheet that came from primer manufacture and shoot.never had to do any blasting on my cars but i have seen some where guys spent 4-5 hrs blowing whatever out after blasting. i just used a 3M scratchy pad with warm soapy water ,let dry, wax & grease remover then shoot.most of the dark gray primer was still on bottom and in good shape.it helps to have car on rotisserie.

[Drop Top]

Depends on what kind of media your useing to blast your car. Sand, Plastic, Bakeing Soda, Walnuts? I could go on. If what is used to blast is an agresive material like garnet or sand, Then all you really need to do is blow out all of the sand out of all the nooks and cranies, then shoot the sealer. If you have had it done with Bakeing Soda. You will need to wash it down with vinager first and then with a metal etch or metal cleaner(PPG and DuPont both make this product). Fallow the instructions on the bottle. Then shoot your sealer. If you have used Plastic or Walnuts or someting not as agresive then do the same as Bakeing soda but skip the vinager step. For certain reasions I'm not a big fan of wax and grease remover. In my area its been outlawed anyway. After its been blasted it shouldn't have any wax or grease left on it anyway or anything else for that mater.

When useing Metal etch (metal cleaner), it is a mild acid so make shure you use the right safety precautions.

I never used Omni brand primers. Read the tec sheet and it will tell you how much to thin out. If it dosen't indicate how much thinner you can add and its too thick to come out of your gun or you don't like the way its laying down, Just add enough thinner to do the job. Usually all you may need is about 10% mixed by volume. Or what that meens. Mix the hardner and the primer then add about 10 of reducer to that.

[jerry]

i agree drop top. all my current project 69 b-body needed was a scratchy pad with soap and water.  to be sure i didn't miss anything i went over the under body with the water borne wax & grease remover i get from SPI.

[FJ5WING]

DROPTOP,

Thanks for the info!

I am having it soda blasted which im hearing is going to create a lot of clean up on my part. As far as your suggestion on the vinegar should I just use it straight or cut with water? Will the etch remove anything left behind by the vinegar?

Thanks again.

Dave