A couple questions regarding SPI Epoxy

  • Thread starter hudson hornet !
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hudson hornet !

I have been using SPI epoxy fr a while now, and I read a couple things tonight that I would like clarified if possible.

1. I read tonight that SPI has some form of acid mixed in to help prevent corrosion. This was in the comment section of the famous SPI torture test video on youtube. Is this true?

2. After the primer has cured, how hard should it be to scrape off with the tip of a flat head screwdriver? Consider this a destructive test for adhesion.

Thank you folks for your time, and I appreciate the good advice on this forum.
 
I don't think there's any acid in the epoxy at all, I'm too lazy to look up the post where Barry definitely said no to that one. Some confusion may have led to misinformation is my guess.


The answer to your second question is sort of answered on the YouTube video, no? It shows how good it sticks after so many days and the difference between the ospho and with out.

I think depending on how heavy you spray, metal temperature, flash times, those variables make it harder to know when the epoxy will reach full cure and how hard it will be to scrape.

Would be interesting to spray multiple test panels sanded with 80 grit on a DA on different days and see how it turns out after 48-72-96 hrs and so on.
 
I used SPI epoxy on my horse trailer frame, applied two coats with a paint brush. Waited a couple of weeks and tried to chip it off with a screwdriver and couldn't. In fact, I couldn't scratch if off using the edge of the screwdriver.
 
SPI has no acids in the plant at all.

Have not for 10 years when we stopped making acid etch primer.
 
Thanks- I did not think it did but wanted to be sure. I am doing some test panels today- one without any acid, and one with DuPont 5717s and 5718s. I followed all instructions accordingly.
 
I think some confusion sets in when people read the SPI epoxy label and see that it says "self-etching." But it's not self-etching in the traditional sense, I think (Barry correct me if I'm wrong) that it says that so people will know that the primer is meant to go on clean metal with no other coatings or treatments beforehand.
 
True, I think we got rid of the self-etch on label 5-7 years ago because of the confusion.
 
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