Just need verification that my ospho process is corect.

Y

y5mgisi

I just stripped the roof of the truck i am painting which was heavily surface rusted. Thousands of very very shallow pits. I think the best way to "fix" this issue is as follows, and please correct me if any of it is incorrect at all.

1. Apply oshpo and work it in and around with a red scotchbrite pad ensuring it does not dry.
2. Hose off the surface with water.
3. Blow dry with leaf blower/compressed air.
4. Sand with 180 on a DA.
5. Solvent W&G remover.
6. Waterborn W&G remover
7. Apply Epoxy.

Does that sound accurate?

Thank you!
 
Oops! Yes, 80 on the metal. 180 after epoxy for the 2k. Other than that it sounds good?
 
There seems to be some controversy about using the waterborne first vs the solvent based. What are the reasons for using one before the other? Thanks!
 
y5mgisi;n75048 said:
There seems to be some controversy about using the waterborne first vs the solvent based. What are the reasons for using one before the other? Thanks!
Click to expand...

The waterborne takes longer to evaporate, using the solvent after it helps with the evaporation.

I don't know the chemical process behind it, but I do remember Barry talking about it in one post years back. So water first, then solvent = faster and safer.
 
We don't normally use solvent base at all unless there has been some kind of contamination that it is better at removing. Water base is all we need for clean sanded metal.
 
Interesting. So basically I could do it in either order and be fine so long as I let it dry/evaporate long enough?
 
How long should I leave the ospho on the surface? Like spray it on, scrub with Scotch Brite then hose off? Or leave it for several hours?
 
After scrubbing with scotch brite, then brush on more clean Ospho a couple times to see if all the dark spots (rust) are gone. You used it to get rid of rust, so when the rust is gone, rinse good and dry---use air to blow out the pits and seams.
 
So the rust isn't gone until all the metal is Brite like blasted steel? I have a couple areas that have heavy pitting and I applied the ospho several times over a few hours and scrubbed with a wire brush. Never let it dry. When I rinsed it with water, I still had mostly black everywhere and also was left with a white residue on the non rusted metal around it.
 
y5mgisi;n75032 said:
I just stripped the roof of the truck i am painting which was heavily surface rusted. Thousands of very very shallow pits. I think the best way to "fix" this issue is as follows, and please correct me if any of it is incorrect at all.
Click to expand...

Everyone's opinion of surface rust seems to be different, but it sounds like you need to have someone with experience blasting sheet metal to clean it up for you. The white residue is dried Ospho, it has to be thoroughly wet before rinsing.
 
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