Regarding ospho and epoxy primer...

[Yotabldr]

I've read plenty of threads here on neutralizing ospho before laying down E/P but haven't seen anything that really addresses my following question.

When it comes to a lap joint where ospho has creeped into and completely dried and can't be neutralized and stripped between the layers, can epoxy be applied over the entire joint without issues? Blasting will take place beforehand so any exposed metal will be stripped completely of any ospho, but "some" will obviously remain in whatever is trapped between two layers. Ospho will have easily had 3 months or more dry time.

This pertains solely to understructure stuff like the two L brackets in below pic. Just getting hit with a few coats of epoxy and done.





Thanks for any input.

 

[fakky]

following .....

 

[RenewAP]

I think the best you can do there is flood the area with water while the Ospho is still wet, then blow air into the seams to dry them. You can then do the same to the epoxy while it is wet to force it into the gap. Any epoxy the comes out the other side of the seam can be brushed smooth, or just wait until it is dry, lightly sand the excess smooth, then recoat with more epoxy if looks matter to you.

 

[Chris_Hamilton]

The epoxy if you spray it will go as far as the neutralized Ospho. Nothing is really going to get into any tight flanges. If some Ospho does then so be it, you aren't getting epoxy in there from spraying. Flooding the seams may be a good idea but how often does anyone do it? Getting a proper coat on the exterior (meaning not the insides of flanges) is enough and seals things fine. And if you are blasting then it's really nothing at all to worry about. Non-issue.

 

[dhutton01]

My understanding is the issue with ospho is it can cause poor adhesion if not properly neutralized. Adhesion inside a pinch weld isn’t a big concern imo.

Don

 

[Treeslayer]

i have read enough on here, im afraid to use any of that stuff. i have had paint fail and peel before, idk if i did some thing wrong or if some of these other products caused it, or if i just used cheap paint. i aint taking any chances.

 

[Yotabldr]

Appreciate everyone's thoughts on the matter.

If I had epoxy here ATM, I'd lay some down in these spots before I reposition the 2 tabs of subject but I'm wanting to hold off on getting the shelf-life clock started. I'm still a good 4 to 6 months out before I'm ready to do any real spraying.

For now, I'll delay on moving these tabs in hope I'll have epoxy here by then. If not, looks like I'm safe letting some ospho wick in there for the time being. Rust happens quick here in Florida.

Thanks again.