Basic priming question - dry time to rivet

[FlyGuy65]

How long do folks wait from prime to rivet? Dry to touch, hours, days? Using 7220 in shake can. I understand temp and humidity play a role, but what are some general guidelines? Just sprayed stiffeners and rudder skin - anxious to start riveting!

Thanks!

[rocketman1988]

I found that you can handle a primed piece in a relatively short time, however, it takes much longer to get a durable finish. Freshly primed parts are easily scratched...

[mturnerb]

I got in the habit of reading ahead and prepping parts including deburr, dimple, scuff, prime (usually in that order) well ahead of time whenever possible. This way the priming is more durable. Be careful to follow steps closely if a part has to be fitted before dimpling - generally OK to dimple after priming (occasionally a little touch up).

[tims88]

You might spray a piece of scrap (prepped the same way you did everything else) and then periodically try scratching it to see how durable the primer is. I've used Stewart Systems EkoPoxy and now I'm using PPG Omni epoxy primer and have found that both are fairly easy to scratch off until they've had about 48 hours to cure.

[wirejock]

I've assembled lots of parts primed with P60G2 after the shop and paint equipment was cleaned. Maybe 30 minutes to an hour. Not a scratch. Depends on the session. If it was a long one, I usually assembled the next day because I was tired.
That said, Jet Flex Solvent Based paint takes a good 24 hours before it's cured enough to work without scratching.

[GeoffP]

Originally Posted by FlyGuy65

How long do folks wait from prime to rivet? Dry to touch, hours, days? Using 7220 in shake can. I understand temp and humidity play a role, but what are some general guidelines? Just sprayed stiffeners and rudder skin - anxious to start riveting!

Thanks!

I've just done some of the parts you mentioned in the last few months, so it's fairly fresh in my mind. At the very least, I primed in the morning on a warm day (it's summer here), and assembled in the afternoon. Most often I had parts ready from a session a week or two prior, but when I've finished off the last few pieces I was also very keen to get them riveted. I just tended to be careful, and touched up anything that was damaged in the process.

Like others mentioned, I also noticed the primer was pretty hard and well cured after about a week, which works if you prep and paint one weekend, leave things during the week, then assemble the following weekend.

[MS1095]

After watching this video I tried hitting the part with a heat gun. Sure enough it cured to a point where it won't scratch and you can rivet right away. I am using SEM primer. YMMV.


https://video.eaa.org/detail/video/1...=true&q=primer

[Mark Burns]

Hey John,
Do yourself a favor and try some Duplicolor Self Etching Primer!
You can get it at O'reilly's auto part stores.

It's green like aircraft primer is supposed to be
Old school like me.
The part number is DAP 1690

And it's the toughest spray can primer I found and I think I tried nearly all of them. The NAPA 7220 is OK but not nearly as tough as this Duplicolor.
And the 7220 is gray. Who wants gray aircraft parts?

I used lots of Dupont Vari-prime with the spray gun for the big jobs but as the build progressed the Duplicolor self etching was my go to primer for a lot of jobs.

To answer your question "time from prime to rivet"? Wait a hour or two if you can. If you can't wait just handle the parts carefully!

Skip to 1:34 on the video below
https://duplicolor.com/video/type/ho...i-color-primer

Have fun!
Mark