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!

[Peterroy]

Thanks Scott. Agree. It does look like calcium deposits. I would think however, they would have shown up a long time ago when the paint was fresh. It's been 20 years, and now they start showing up. Agree, whatever it is, it's going to take some kind of fine rubbing compound. I'll pass your info along to my brother and we'll both be on the lookout for some "Supercoat". Thanks for the tip.

Peter

[Scott]

Perhaps something changed in the water supply?

Is there a pulp mill or other industrial activity nearby? Rain and morning dew often contain polutants from the air... sand, Sulphur dioxide (aka acid rain), soot containing various combustion by-products. The finish can be "etched."

Well water often contains higher levels of calcium and other minerals.

I don't use water on my aircraft, just detailer (and supercoat to remove stains) and lots of microfiber.
S

[Peterroy]

Scott,

My brother said:

"I don’t understand the water spots. The airplane has never been wet, never been in a rain shower the last 13-14 years and probably before that as well."

(I didn't see that coming!)

He's right though. That plane has never seen rain since he owned it. I suggested he talk to Randolf.

I also told him about a product that I use on the gel coat on my motorhome. It gets rid of water spots. Maguir's 47. When I first used it, I couldn’t believe how effective it was. I always had to use a light rubbing compound to get water spots out. This stuff worked very well. I suggested he try it out on an inconspicuous area. After a few weeks, if nothing bad has happened, give it a go.

Thanks for the follow up.

[Peterroy]

Follow-up......

My brother contacted Consolidated Aircraft Coverings about the blotches. Here's what they said:

"The final stage of the 3M line of “Perfect It” Polishing regimen is called “Glaze”.

Use that with a rag to start.

After this, have some Mothers 100% Carnauba Wax and use a microfiber rag with that after you use the Glaze.
It will seal the micro-scratches and usually make the material shine.

If the oxidation or the aging effect goes deeper than the Glaze will remove, it might be wise for us to speak again.

Warmly,

Greg

951-684-4280"

I asked my brother to let me know how it works out. I'll pass his findings along to the tribe.