Prep for Epoxy over sandblasted steel?

B

black88coupe

I am getting ready to sandblast a floor pan that will be going into my car. Can I go straight to Epoxy from there? I have looked around on here and didn't see anything about this. Did I miss the post?

Thank you.
 
This is all I have found so far. Thank you.

"NEVER use SPI Epoxy over a Soda Blasted vehicle unless you call us first for proper neutralizing instructions."
 
I've been told it is fine to shoot freshly blasted metal. (as long as your sand was clean to start with) I would use 700 just to be sure.
 
Couple of different (slightly) schools of thought:

You can wash the surface with Dawn, blow it off and shoot it when dry.

You can scuff sand it with a red scotchbrite pad , which knocks a little tooth off and releases any trapped residue, wash with Dawn, blow it off and shoot when dry.

Personally, I like to scuff it up a bit. Depending on the blasting media, the metal can be rather "sharp". If you decide to wipe it down with W & G remover and not scuff it, the toothiness of the metal tends to collect lint. Fuzzy city.
 
. If you decide to wipe it down with W & G remover and not scuff it, the toothiness of the metal tends to collect lint. Fuzzy city.[/QUOTE]

this is why ppg use to recommend not wiping down a blasted car . rags or paper towels will do this. i use dawn soap and water with a white brush then bring it in and blow dry . then epoxy .
 
I have always sanded with 80 grit or 100 then wiped with final prep. I have always believed that the blast media will leave particles imbedded in the metal that should be removed prior to painting. Try it yourself after you have blasted. Scuff it with some sandpaper, the residue that comes off can cause a failure in your coating system
 
It don't get any better than a basted surface that's been properly cleaned IMO.
 
I usually blow it off, and then hit it with 80 grit on a d/a. I then clean with 700 thoroughly. You guys don't get flash rust washing with soap and water?
 
Lotta great responses- thanks. I was also thinking about sanding and washing it with Dawn and then blow it dry. I was concerned about flash rust but my thought was that it would be minimal and the epoxy would seal it from the atmosphere so overall it wouldn't be a huge concern. Am I wrong on that? Mitch
 
if you wash it and blow it dry there is nothing to flash unless it is really humid . most flash is iron in the water . buzzing it with 80 is fine .
 
danp76;29085 said:
I usually blow it off, and then hit it with 80 grit on a d/a. I then clean with 700 thoroughly. You guys don't get flash rust washing with soap and water?


No, I've never had a problem with flash rust unless you let the water pool and don't blow it off, like in a trunk pan for example.
 
If you want to limit the flash rusting load up a spray bottle with straight isopropyl alcohol and spray the panel down after the rinse stage while it's still wet-this will help dry the surface while your drying it off and limit flash rusting. Waterborne wax and grease remover works good too.
 
Thanks for all the great info guys. Much appreciated. Ordered my SPI epoxy yesterday and sending the pan out in two weeks for blasting. I'll let you guys know how it works out. Mitch
 
Didn't get the pan sent out as soon as I had hoped. Most likely going out today or tomorrow at the latest. Will hopefully have an update by the middle of next week.
 
After washing with Dawn and rinsing with the garden hose I have taken a "garden sprayer" and rinsed the clean rinse water off with distilled water, then blown dry with the leaf blower. Works quite well, but I live in a lower humidity region so I can't say what the results will be when the humidity is high.
 
Senile Old Fart;29777 said:
After washing with Dawn and rinsing with the garden hose I have taken a "garden sprayer" and rinsed the clean rinse water off with distilled water, then blown dry with the leaf blower. Works quite well, but I live in a lower humidity region so I can't say what the results will be when the humidity is high.
Thanks SOF. Tried to take the pan in today after work but a storm rolled through and knocked out the power. Should be tomorrow for sure now.
 
OK time for a long overdue update. I prepped and painted the pan today. Had to call Barry for some last minute advice before I shot the epoxy. He got me going in the right direction and away I went. Thanks Barry. I did lay down a heavier coat than I probably should have but it layed down well with an almost completely flat surface with no runs. Gonna let it sit overnight and hit the other side tomorrow with any luck. Overall Im VERY pleased. Thanks again Barry.
 
Painted what would be the bottom side of the floorpan today. Came out pretty good overall. I was messing with my gun settings a bit so I got some dry spray in a few spots. Still pretty darn happy with how its going. Mitch.
 
I'm in the same boat. I had my entire car blasted and now I am going over everything with a da sander and 80 grit to knock off the loose metal.
I plan on washing it all with dawn and a white bristle brush then completely dry. Then I will wipe it all down with the water and grease remover right before we epoxy prime next week!!

Question: does epoxy "shrink" in the sun or when it gets hot? I'm wondering if etching primer or epoxy primer shrinks when in the sun......if it does, then I guess you cannot have TOO corse of a surface when you spray it, right?

- - - Updated - - -

I'm in the same boat. I had my entire car blasted and now I am going over everything with a da sander and 80 grit to knock off the loose metal.
I plan on washing it all with dawn and a white bristle brush then completely dry. Then I will wipe it all down with the water and grease remover right before we epoxy prime next week!!

Question: does epoxy "shrink" in the sun or when it gets hot? I'm wondering if etching primer or epoxy primer shrinks when in the sun......if it does, then I guess you cannot have TOO corse of a surface when you spray it, right?
 
Back
Top