I am "rejuvenating" the lower cowl on my '66 Cherokee Six 300. This has involved stripping the remains of the previous paint with chemical stripper and soda blasting. I have some minor fiberglass repair work to complete, then painting and installing heat shielding in the areas near the exhaust headers and muffler. Does anyone have a good recommendation for a type of paint to use on the interior of this fiberglass cowl that will hold up well to the high heat and flexing?
Try engine enamel. One possible source is Summit Racing.
I'd clean it up very well, then brush a coat or two of epoxy into it to fill/seal any voids. Then I'd mask it and run it over to a local body shop. At the body shop, I'd ask if they could spray it with white catalyzed urethane or polyurethane (the white to be a shade of their choosing and convenience) when they have a little paint left over at the end of a job. Often they will do that kind of work for very low cost since you've done all of the prep work. I've gotten that kind of work done for free (plus a tip for the guy holding the paint gun).
On the heat issue, no paint or fiberglass will hold up to a 1200 degree exhaust sitting an inch or less away. So if that condition exists under your cowl, Aircraft Spruce and Van's (among others) sell products designed for insulating areas with severe heat impingement. When I built my RV, I had those issues and insulated a couple of small areas with "Kool Mat" from Aircraft Spruce, which has held up well for 13 years. Several of these products are self adhesive. Others require glue. No big deal either way.
I'd recommend Ranthane polyurethane with a flex additive. Enamels, even catalyzed are not nearly as good as polyurethane in this application.
Thanks for the tips. I like the Ranthane idea, but I'm wondering about the flexible additive as I thought that their paint was made with flexible additives as one of the main selling points.
A cowling doesn't flex much. You shouldn't need a flex additive.Quote:
Originally Posted by BlueFly
I've been using Ranthane for decades. In the past, before the high-solids formulations, they didn't offer (as I recall) a flex additive. My Stearman and other pojects are covered in this, and flexing is absolutely not an issue on fabric or aluminum components.
A few years ago, since introducing the high-solids Ranthane, the company began offering a flex additive and I believe they (Randolph) recommend using it on fabric applications. I suggested using the flex additive guessing that the cowling undergoes some flexing, at least more than a fixed portion of the fuselage. If that's not the case, skip it. Ranthane is pretty darn bulleproff in my experience, and very high quality.
I've used the flex additive a couple of times, and it certainly doesn't hurt the finish in any way.
Obviously a call or email to the Randolph folks would help the decision.
I've had a great experience with Lizzard Skin on cars. A friend put it on the inside of the firewall of a Yak and he thinks it made a difference too. No connection; just a satisfied customer. http://www.lizardskin.com/