Removing "glazed" dacron from anodized aluminum

[RIKanaka]

Anyone have any suggestions as to what I can use to remove what I would best describe as "glazed" (as in kiln-fired) dacron and dacron soot from the boom and mast (mainsail caught on fire and melted). I removed the gross chunks of melted with elbow grease and a plastic pain scraper but the soot and thinner layers of debris (almost like streaks of paint) have proven refractory to dish soap, Bon Ami, acetone, Goof-Off (mostly xylene), Interlux 216 (straight xylene). Thanks in advance.


(Older picture prior to cleaning attempts)

[bhartley]

n/m

[Jeff D]

My suggestion is a NMP (N-Methyl Pyrrolidone) based paint stripper. NMP will dissolve almost anything and is reasonably safe. Check the label.

[Troy Scott]

Try MEK, methyl-ethyl-ketone. It's my last resort cleaner for metal when other stuff won't work. If that doesn't work, get some gel-type paint remover and follow the directions. Rinse a LOT. Good luck

[John Vigor]

Bob I'd be tempted to try dry ice so see if it will crack off. I don't know how you'd apply it, though.

Alternatively, how about burning it off with a blow torch? Aluminum has a high melting point. The Dacron should burn off quite easily.

I really don't think there's much hope of recovering a nice blemish-free anodized finish again, so you might want to face the inevitable and simply sand it down and paint it with Interlux's Perfection twin-pack polyurethane. I have brush-painted several aluminum spars with Perfection with wonderful (and long-lasting) results.

Cheers,

John V.

[tartansailor]

See the problem is no matter what you try, ugly stains will remain unless you polish the Aluminum, which I do not think that you want to do.
If I had that problem, I would freeze it in dry ice hoping that the differential in thermal expansion between the plastic and Aluminum would be sufficient to break the now frozen bond, and coax it along with a putty knife, or bronze brush. No guarantees.

Dick

[RIKanaka]

Thank you, all, for the suggestions. Oven cleaner or sanding may be my last resorts as I'd like to try to keep the anodized surface intact if possible and I believe both would remove the anodized layer. I have some Aqua Strip lying around here and a quick reading of the label shows that NMP is one of the ingredients so I'll give that a try 1st. I'll go at next with a heat gun since I have one of those lying around too. I'll try the other methods (dry ice, MEK) if those don't work. I'm less concerned about the cosmetics than I am about the residual that I can't get off easily rubbing onto the replacement mainsail.

[RIKanaka]

Managed to get the chunks and soot off using Aqua-Strip, a chisel as a paint scraper (very carefully), more Bon Ami and lots of elbow grease. There are still some "tiger stripe" stains where the dacron melted and was baked into the aluminum but I can live with that until the fall when I might try some bronze wool.

Splashed in last Monday at Wickford Cove, sailed over Dutch Harbor on Wednesday, motoring halfway, then sailing the rest of the way when the wind picked up. She did OK with the undersized Catalina 25 mainsail (purchased on ebay for $100), which will be relegated to backup duty when I replace it with the new one tomorrow. Sorry about the cellphone-quality video.

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