How to Remove These Blotches

[Peterroy]

My brother has a museum quality J3 Cub that has developed some blotches he can't remove. He asked the Cub forum if anyone had any ideas, but only got three responses that didn't help. He asked me to re-post his message to the Taylorcraft tribe. any ideas?

"I noticed a couple of months ago that the upper outside surfaces of my J3 moveable surfaces/fuselage/wing (?) have numerous small blotches in the paint-wax system. The J3 was resurfaced with Ceconite 102 , finished with Randolph Butyrate, and finished per Ceconite Manual 101 in 1993 and has looked pristine until now. I have been using ComposiClean Super Spray Wax, probably twice a year to keep it shinny (may have overdone that). Has anyone had this issue and what can I do? Thanks, Joe"

Again, any ideas? The blotches are a lot easier to see if you blow up the images.

Thanks.

Peter

[Scott]

Looks like water marks aka calcium deposits. Possibly sealed in by the polish.

two choices I think. 1. Mechanical removal ie an actual polishing wax (containing very fine compound) as opposed to a spray polish.
2. Chemical removal of both the spray wax and the calcium. A mild calcium remover like CLR might work.

In every case you'll want to do lots of testing. Dope is not a particularily tough finish so a good deal of caution will keep you from making things worse.

I have used alkaline cleaner on butyrate dope. It will remove the stains, but also the gloss.

I have a cleaner/polish called "Supercoat." Doesn't seem to exsist anymore. I'm certain it would remove those marks without hurting the finish. I've had my quart since the 1980s! If you can find some, or perhaps the same stuff under a new name, let me know!