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Dupont Variprime - Does it need to be sealed or primed??
Hi Everyone,
I've been a user of Variprime 615s/616s for a while now, and a friend of mine is looking into priming his own RV-10. Then he discovered something disturbing. If you read the DuPont Technical Datasheet on page 3 it says: "Note: Variprime? 615S?/625S? should be primed or sealed within 16 hours for best performance." http://www.performancecoatings.dupon...19303_615S.pdf So we're effectively priming a primer. Or Sealing the primer with a 2 part epoxy. That begs the question, has anyone else looked into this issue with Variprime? Thanks, Phil |
Vaiprime is an etch primer that adheres very well to metal if properly prepared however you might also need an intermediate primer to help a particular top coat adhere to the Variprime. The Variprime is most receptive chemically to the intermediate primer and top coat for the first 16 hours after application. It becomes harder to top coat as it ages and after a period of time will need serious cleaning and sanding to get effective adhesion. Having said all that it works very well on it's own as a protective barrier on interior surfaces and in my experience is almost bullet proof in it's ability to resist scuffing and scratching - much better than Marhyde rattle can etch primer for example.
Jim Sharkey RV6 - Wiring etc |
If you don't seal the vari-prime it will soak up everything that touches it. Hand prints show the oil smudges and won't clean off. It is fine when used as intended but I use Sherwin Williams P-60 and don't seal it because it dries hard enough to not pick up dirt and oils. That's just my opinion for what little it's worth.
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I have noticed that it cures to the touch within 5-10 min. But it can still be scratched off easily. If I leave it for 24 hours, it's hard as nails. |
IMHO Variprime is a very low quality primer. Does nothing for corrosion protection and some solvents will wipe it right off.
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You need cold weather in Texas!
I have seen no evidence that the corrosion protection of Variprime is less than claimed.
I have used laquer thinner to remove most Variprime. Wipes it right off. However, I learned something by chance the other day when I decided to clean up a primed part and take it to get anodized. I had one heck of a time getting the primer off. It took lots (20 min) of elbow grease and pressure with a scotchbrite pad and lots of thinner to get the stuff off the 2 small parts. I realized that the difference in these parts were that I had set them on my alladen kerosene heater grill to "bake" them dry because it was a little chilly the day I painted them. I plan to bake all further parts that will be easy to do (Hmmm.. the wife works second shift and there is a big window in the kitchen... hmmmm :rolleyes:) |
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You sound like a pro painter. Variprime is old tech but does seem to be as hard as nails when fully cured and it takes MEK to soften it. Also it does pick up oily marks from hands and over lubricated rivet guns. Suprised that you don't think it provides corrosion protection though. What would you recommend? Jim Sharkey |
Primers Self Etching! to use or not to use
Phil man I put some more info out on my site containing priming with Self Etching primers.
http://www.txrv10.com/pages/primermain.html I think what it comes down to is use a self etching primer if you want to save the alumiPrep and alodine steps, but I would prime over your self etching primer as stated on the Dupont Tech Sheet, with a 2 part Mil-Spec primer. Dave www.txrv10.com |
The spars that came with an older kit I purchased were primed with VariPrime and no additional primer/sealer. I was considering removing the VariPrime and using something else. My reasoning for this is that I've read that VariPrime doesn't create a vapor barrier because it is porous. If this is the case, would I need to remove the VariPrime to inspect for corrosion? Since self etching primers contain acids that etch the metal, could I just remove it and eliminate the etching step when using another primer? Or would I be better off just inspecting a small area, putting VariPrime back over that area, and then putting another primer over it all?
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Just my 2 cents of advise. |
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