Hey all. I have posted a few times in here and I am so grateful for all the help as I navigate my first build. I am nearing be able to prime my car but unsure of the next steps. So far I have stripped it to bare metal, welded in a few patch panels, and removed all old bondo. I also made the decision to apply OSPHO to every inch of metal on the car as I was doing work inside and outside in the Michigan winter. I applied OSPHO to a Scotchbrite and then used that to scrub it onto the car and then just left it. I didn't take a rag and wipe behind it much, just the heavy excess, so I feel like my OSPHO is on thick if that makes sense. I am applying Kirker 2K Epoxy Enduro Primer. I have few questions before proceeding though: 1 - Prime or filler first? I have seen both. I was planning to prime first 2 - Neutralize and remove OSPHO, or prime over it? I have heard of people doing both. Anyone with actual experience of applying Kirker over OSPHO? 3 - 2 coats of primer? 4 - Any other tips or tricks for a first timer would be greatly appreciated!
I did this last year, I used ospho on several area, I scrubbed it afterwards with soap and water and dried it off. I sprayed it with two coats of Kirker Enduro prime. I lightly sanded the epoxy areas I wanted to fill just to rough it up. Applied rage gold over it, sanded it all out and then put another 2 coats of Enduro prime. Then I did several coats of feather fill. It’s been sitting like that since fall.
Thanks for this! So you let the OSPHO dry completely? When you did soap and water, What did you scrub it with? Mine has been on for upwards of a month. I took a couple pics to show just how much OSPHO is on there. I feel like a sander may be in order to knock some of it down.
I let it sit on there a good week or so, then used a green Scotch bright pad. On the insides of the doors, I sand blasted what I could get to, then brushed Ospho over everything including the lower inside seams, let it sit for a week or so and then painted it all with rustoleum rusty metal primer. Bonded well. This is on my A coupe.
Interesting. I have a rear fender off, maybe I will just test on that panel before I get into the whole car
When you have an excess on the panel of Ospho or any other metal prep re wet the surface with the acid soak a Scotch-Brite pad in water scrub it and then dry it off. Humid climates where there's a danger of flash rust occurring wipe it down with denatured alcohol Ospho isa converter it's got a high acid content Metal preps have less acid content. .
Ospho has to be completely neutralized prior to applying epoxy primer. Otherwise, the acid residue from ospho or any similar acid based product will interfere with with the setting reaction of the epoxy at the metal surface and the epoxy ends up not bonded to the metal even though it may appear to be fully cured at the outer surface. Same thing goes for etching primer under epoxy, except for the fact that etching primer can't be neutralized. On the SPI forum,the owner of SPI says if you want to use etch primer then don't buy his epoxy primer. Buy someone else's and you can blame them rather than him when your paint job fails because of the acid in the etch primer.
Honestly with the really high quality DTM/DTR primers like the ones Tamco sells, I would not take the chance using OSPHO at all, but you deal with what you have to now. Just make sure it is completely neutralized or you will have pieces of paint right down to the metal blowing off your car a few weeks after it is finished! God Bless Bill https://www.jalopyjournal.com/forum...ar-transport-hauling-open-or-enclosed.614419/
I have a dustless blasting bis. after blasting I wipe , scrub it down with ospho never letting the ospho dry if it does dry i just wet it again then wipe it off with a damp rag then wipe it with lacquer thinner . Like other have said if you leave dried ospho the epoxy will fail .
I am testing a panel this morning. I re-wet the OSPHO with more OSPHO. Wiped it all around, and then poured soap/water on the panel and wiped it dry with a new clean rag. Then I went behind it with wax and grease remover. How do I tell if I got all the Ospho off?
It says on the Ospho web sight to paint rite over it, no wash necessary. Yet if you search here, or google you will find enough differing opinions to make your head spin. I once put it on too thick, and it would never dry so I wiped it down with a damp towel, then sprayed DP primer. 6 months later, some spots where it must not have been cleaned enough there is whitish spots in some area's of the red DP.
If there's no white residue left we should be good to go. Like I said earlier in my post scrub it good to Scotch-Brite pad and plenty of water . Water neutralizes the acid. You could do a little spot test too, afterwards thoroughly dry mix up a little bit of your epoxy and do a small piece give it a week slide a razor blade under it and see if it comes off. Anytime you go into unchartered territory it's always good to do a spot test . I hope this helps
Exactly! That’s why I was fishing for real life experience haha. I think I’m just going neutralize and use a ton of water and hope like hell I get it all haha!
Agreed. I cleaned and then primed my rear quarter today. So I’ll see how it comes out! i have been reapplying the Ospho first because I read that neutralizes it. Then as it’s still wet I am dousing with soap and water and wiping that off. Then I hit it with wax and grease remover. Let that dry and then primed. Does that sound like a solid plan of action? Thanks!
Hello 41 Helen I think you should be fine. Some epoxies want you to use a prep and some don't. Always consult the product data sheet for the product you're using. what primer are you using ? .
Ospho is a rust remover and converter and has a good amount of phosphoric acid ,wettng agents and detergent If you leave it on the surface and let it harden it turns the rust black . A lot of Automotive epoxies discourage this black primer is it will create adhesion problems. I have a home built salt fog chamber I copied off the internet to test things. I did a salt fog test using a popular Automotive epoxy over metal prep. When I took the Q panels out of the chamber the epoxy HAD rustic creepage along the edges I took a sheetrock knife and I was amazed how easy epoxy came off. Read the product data sheets before you do anything. Years ago when you painted a car with lacquer if you did not use a phosphoric acid prep you could expect problems not too far down the road . The product data sheet will tell you how to prepare the surface.
Kirker Enduroprime stated that metal prep products can be used with it, SPI epoxy states that Ospho can be used but should be cleaned as mentioned above. You are good to go, as previously noted I did that with the Enduroprime and everything has bonded well.
I know this is an old thread, but I have been reading about epoxy and Ospho for a while - finally ready to epoxy my car that has sat in Ospho for years. I really didn't want to to rewet and wash down. One guy did a SPI and Ospho video and shows SPI failing to adhere to Ospho metal - I decided to test this with Kirker, as Kirker says Ospho promotes adhesion. I can't confirm that Ospho makes it better, but I did confirm that Ospho and Kirker primer work fine together - no adhesion problems compared to SPI over Ospho. Some differences I have noticed - SPI requires at least a 30 minute induction time, and is sprayable for a long time (48 hours I think). Kirker requires no induction and instructions say to use within in 90 minutes. SPI has UV inhibitors, Kirker does not. My adhesion test that mimics what the SPI tester did is here if anyone cares to take a look - I did this for me, and I am happy to spray Kirker over Ospho as is (degrease and scuff as Kirker recommends).
I don't understand the aversion to removing ospho. Why leave anything on the metal that has any chance of causing a paint adhesion issue.
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