Are the dark spots ok to epoxy primer over or do I have to get more aggressive and remove them too?
CK5
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Surface prep before epoxy primer
- Thread starter LVJimmy
- Start date
Well I guess since there hasn’t been any guidance I’ll have to play it safe and keep sanding
i would shoot that but im no expert. Epoxy primer if mixed right is pretty great. I spilled this on my shop floor 10 years ago and covered with a rag and forgot about it. Pretty sure ill never be able to get this rag back off the floor,lol.
The surface needs to be free from rust and prepped for mechanical adhesion. Cleaning w wax and grease remover (my favorite is DAWN dishsoap a couple ounces in a gallon of water, wash the surface well, then wipe clean with a water wash and dry thoroughly. Coarse grit 80-100 should work fine for prep. Are those “spots” the same as the original substrate coating? Are they flaking or questionable for adhesion? If so they need to be removed. Now is the time!
Thanks. They seem to be well adhered but better safe than sorry.
I wouldn't sand any deeper to get those marks out. that's most likely the debris from the sand paper getting packed in there. when you get down to bare metal, before you prime you should do an acid bath. phospho, kleen strip or something of the like, to kill any micro rust and remove the stuff that's packed into to grind marks. if it survives the acid then I'm sure your good to go. you could always try a paint stripper if you thinks its old primer.
Thanks. I sanded again with 120 and 180 grit cleaned with fast etch. Cleaned again and used epoxy primer
