Painting over Imron

[Jim Collins]

I have what I thought was a simple question. Can I use automotive paint over Imron and will it stick?

I want to do touch-up work on my plane which was painted with Imron about 15 years ago but there are almost no suppliers of Imron near me. If I have automotive paint mixed to the right colors, will it stick? I have looked on the web and asked automotive painters but could not find any good answers.

Thanks in advance

Jim Collins
C170B N2488D

[ghostflyer]

Imron paint that’s 15 years old will be very hard and the surface contaminated and will require rubbing back and thorough cleaning to form a adhering surface but be wary of damaging the rivet heads . But saying that what type of auto paint are you using ? There is single pak and dual pak paint and different types of this type , plus acrylic types and plus the older celluloid type of paint. Personally I would paint strip it and start from the raw skin. You want it to stick for another 15 years ? Plus a lot of paints are not compatible but only react after a length of time . I found this out the hard way ,part of my rudder and vertical fin had been previously painted by a original owner and the paint while in excellent condition [as new] had been rubbed back to give a rough finish and a new twin pak was applied . The silver color that was applied matched the silver that I was originally spraying my aircraft . I didn’t respray the rudder or vertical fin. 2 years later it’s started to bubble and crumble . My fix is to strip it totally and start again.

[GAHorn]

Imron is DuPont’s brand-name for polyurethane process paint. I had a fairing and a patch on the flap of my 206 re-painted by a local automotive shop who used something else (also polyurethane) and it did fine for the next 5 years I owned the airplane. Imron is still available for sale and shouldn’t be a mystery to obtain and use.

[Jim Collins]

Thanks for the feedback,

Dupont sold the Imron product line to Axalta and the number of places that still sell it and can do color matching are much less than in the past. All the local paint supply houses near me no longer handle this product line. As I live in the Chicago area, I have a number of auto paint supply places within a 1/2 hour drive and the exact product lines they sell, I do not really know. The closest place that still sells Imron is about a 2 1/2 hour drive and about 2-3 times the cost.

So as I see it, I have two choices.
1) Bite the bullet and drive a long way and pay a lot of money for something I know will work.
2) Try the best auto paint the local stores sell (Polyurethane if possible) and do a test in a small un-noticed area of the plane to insure it is sticking (after surface prep, of course). However, this will not insure against long term effects.

Thanks

Jim Collins
C170B N2488D

[ghostflyer]

You want the paint to stick and trying to get 15 year old imron to adhere to some of the modern paints is a big ask . Even some poly urethane paints are different these days . Stone chips can be spotted painted but getting paint to stick with a smooth finish is nearly impossible . I watched a Boeing 747 being painted and the preparation that was carried out out before painting was incredible . The technology that was involved is mind blowing. I spent 5 days there trying to learn modern preservation techniques of aircraft and walked away totally mystified . I realise we are only dealing with a 170 but we are trying to preserve a classic .
Do not use the newer water base paints as they only stick due to gravity

[johneeb]

Y...……………..Do not use the newer water base paints as they only stick due to gravity

So always keep positive Gs while looping and rolling?