Cleaning melted plastic from MC275 chrome surface


It's a nightmare on MC275th Street - A brand new demo MC275 was plugged in at a show without the I.I.C. (Idiot's in Charge) having removed the styrofoam tube cover. That's right. They bypassed all warnings on the amp itself and without a thought, cranked the amp on only to smell burning and then see smoke pouring out beneath the tube cover. What we have now is the chrome tube surface scarred with a thin layer of melted black plastic residue. The tubes got waxed with black, but fortunately we were able to crack that off. Is there anything we can do to rehabilitate the chrome without taking off any lettering? Please. This whole thing has made me sick. Kind of reminds me of Mr. Bean defacing poor old Whistler's Mother... but this is worse... Any ideas?
moonshot
Give MacIntosh a call. I Have a feeling it's happened before. Nobody reads User Manuals.
Goo Gone

This stuff works pretty good on most stuff, it'll take a while but certainly worth a shot.

Best of Luck

Peter
NO GOO GONE!!! It will definitely take off the lettering, and probably won't dissolve MELTED foam anyway.
What you need to do is heat up the melted foam and begin wiping/working it off in stages. The best way to heat up the melted foam is with steam (which won't hurt the lettering or the tube sockets (but try to cover the tube sockets with something like plastic bottle caps of the same diameter, if they didn't get any melted foam on them).

I recommend one of those home hand-held steamers (in the $40 price range) using the spread nozzle first and if that doesn't do it, then the "spot" nozzle. The advantage of steam is that you can't heat anything to over 212 deg. F. which should be more than enough to release the melted foam..
I agree with Peter. Goo Gone has come through for me many times where other products failed. Be gentle, and let it sit there for a while. If it is working, do it repeatedly.
Good Luck.
One of Goo Gone's primary purposes is paint(spills/over spray) removal. The OP mentioned wanting to retain the chassis' lettering. I'm guessing that lettering would be silk-screened(paint/ink). Also; Goo Gone is a pretty mild solvent. Plastics generally take something more aggressive, to dissolve. Personally; I'd soften the styrofoam with a hairdryer and try to peel it off first.
I was going to recommend the same thing that Rodman did, but instead of a hairdryer, (which may not get hot enough) use a heat shrink gun. My heat shrink gun gets very hot, but be careful to not overcook the plastic.
I'd suspect that the silk screened lettering is a baked on epoxy which is pretty hard to dissolve, then again the styrofoam is now baked on too. I'd still give the Goo Gone a try, its a natural citrus based product, quite oily in viscosity, might just be able to get in-between the chrome and the styrofoam and loosen it. I'd be very hesitant to apply more heat to the process, if the MC 275 was mine.

Best of luck and let us know how you make out.

Peter
Acetone is very aggressive on styrofoam and will melt it. How it will work on burnt styrofoam is anyone's guess. Be careful, though. It is very aggressive on other surfaces also. Acetone is the active ingredient in nail polish remover.
I hope you get that Mac cleaned.I use Goo Gone and it is a good cleaner. Jesus , how did these guys do that? I am upset hearing about it.
Best of luck

George
Nsgarch

Steam? you have to be kidding. Moisture would be the very LAST thing I would apply to any electronic component.

Anyhow, best of luck with your project, let us know how it turn out.

Peter
Moonshot, I will approach this from a different angle. There is a product called "Road Rub" that is used when boot soles melt onto chrome motorcycle pipes. Part of my nylon chin strap got on my hot pipes and left a melted black spot. I was able to get it off without damage to the chrome using Road Rub. Its a dry type of product in a stick that is really effective. Anything with an abrasive content will damage the chrome. I would suggest going to your local Harley dealer and picking up a stick. It's the only thing I use when stuff gets on my hot chrome pipes.

http://roadrub.com/

all the best!