What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Dupont Variprime - Does it need to be sealed or primed??

Phil

Phil

Well Known Member
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.dupont.com/dpc/en/us/html/prodinfo/chromasystem/H-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.
 
Last edited:
jsharkey said:
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
Click to expand...

That's what I was thinking too. I've been using it internally as a barrier, but I have no plans on using it on the external surfaces. I plan on leaving all the external stuff to the pros.

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.
 
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:)
 
KTM520guy said:
IMHO Variprime is a very low quality primer. Does nothing for corrosion protection and some solvents will wipe it right off.
Click to expand...


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
 
Last edited:
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?
 
rzbill said:
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:)
Click to expand...

I would NOT bake my aluminum parts, especially 2024 T3 Alloy. It will permanently alter its original heat treatment condition, making it softer hence reduce its strenght depending on the temperature and duration.
Just my 2 cents of advise.
 
Nedimbek said:
I would NOT bake my aluminum parts, especially 2024 T3 Alloy. It will permanently alter its original heat treatment condition, making it softer hence reduce its strenght depending on the temperature and duration.
Just my 2 cents of advise.
Click to expand...

As with many things, it is not what one does but rather how it is done. I did continue to bake parts that would fit in a toaster oven I had in the shop. 200F was plenty to get the adhesion improvement I was looking for. That is WELL below any issues with aluminum.. If one reads the Variprime docs, it is above the paint service temp but I experienced no downside during baking or 6 years of service.

To your point, I am not a fan of powder coating aluminum for the reason you stated. The baking temps are too high for my comfort level.
 
rzbill said:
As with many things, it is not what one does but rather how it is done. I did continue to bake parts that would fit in a toaster oven I had in the shop. 200F was plenty to get the adhesion improvement I was looking for. That is WELL below any issues with aluminum.. If one reads the Variprime docs, it is above the paint service temp but I experienced no downside during baking or 6 years of service.

To your point, I am not a fan of powder coating aluminum for the reason you stated. The baking temps are too high for my comfort level.
Click to expand...

A few minutes at 200F in a toaster oven is nothing significant. I was thinking more like 1 hour in a 450F baking oven :eek:. As long as you are aware of what you're doing that is fine. My point is to bring some awareness to other readers who might not know. Cheers.
 
You must log in or register to reply here.
Back
Top