Melted plastic on glass.

General Questions
#1

Friend of mine moved into a new house with a gas fire place. Somewhere in the moving in phase her son decided to check out the fire place. It still had the original plastic protective film on the glass panel. The result is a 2footx3ft piece of tempered glass with a messy baked on plastic mess.

I’ve been volunteered to fix this. First order of business was disconnecting the gas so the fire place will never be used again.(She hates gas fireplaces, just something that came with the house)

Now I have the plastic mess to deal with. Fear of scraping the glass with a razor blade has her hesitant to just let me go with that method. If it were mine that’s all I’d do.

Any recommendations for chemically assisting me in the cleaning process? I thought maybe acetone?

#2

What’s a replacement glass sheet cost? Check at your local hardware/home-improvement store in the fireplace section. If it’s cheap that will almost assuredly be the best way to go.

My first thought was a heat gun and a scraper but some googling turned up these methods (all seem to come from melting plastic onto glasstop cooking ranges):

http://www.ehow.com/how_4510585_remove-melted-plastic-from-metal.html (ammonia and a scrubby)

http://cleaning.lifetips.com/tip/96669/kitchen-cleaning/kitchen-cleaning-tips/melted-plastic-removal-from-glass-electric-cooktop.html (acetate and heat - that’s a touchy combination! Do in a well ventilated area, wear proper breathing protection and have a fire extinguisher handy)

Some people recommended this stuff (used for cleaning clothes irons): http://www.sewingmachinesplus.com/dritz-575.php

Whatever you do, take the glass panel into the garage or outside because it’s going to be potentially stinky/messy/flammable.

#3

I recently used a clothes steamer to remove the tinting on my auto windows.
It worked charmingly.
You probably are dealing with a different kind of plastic, but such gentle heat might be more effective for you than blasting away with a heat gun.
possibly useful: http://www.wikihow.com/Remove-Window-Tint

I’d go with solvents like acetone only as a last resort.
If it actually does dissolve the plastic, the chances are good that your cleanup will leave an ugly smeary film behind on the glass.

#4

I think your first instinct is a decent one; try acetone. I’m not sure what the plastic cover is, but acetone chews up a lot of plastics.

Use lots of acetone plus some heavy scrubbing.

Acetone is cheap enough, you won’t hurt anything by trying it. Just make sure to guard against fires (acetone burns like you wouldn’t believe).

#5

missed the edit

Scraping with a razor is probably the best overall option. My R&D lab uses a lot of glass molds with thermoset plastics.

We usually scrape. Most hardware stores sell scrapers with wide razors (I dunno, maybe 4 inches wide). These do a good job for cleaning our molds.

#6

My first thought was hydrochloric acid, but acetone would probably work, too, and is probably a lot cheaper. I think that chemical methods are indeed the way to go, since plenty of things eat away plastic, but almost nothing eats glass.

#7

Fear for what? Cleaning glass of recalcitrant substances with a razor blade scraper is a common and longstanding practice. What is she afraid of?

ETA: And it’s a hell of a lot less messy and stinky than using any chemical.

#8

Let me get this straight - she asked you to do this as a favor (no payment involved?) and then has the nerve to tell you how to go about doing it? I think that’s the point where I say, “Fine. You don’t like how I plan to do it then you can just do it yourself.” But maybe I’m just a jerk that way. Anyway, my standard rule is that if I’m doing the work for free, I do it however suits me. You want it done your way, you either do it yourself or pay someone.

#9

Chemicals can be dangerous to use. Go for the razorblade scraping…it is the easiest.

#10

Don’t even think about acetone. At best you will end up with an apalling sticky mess and use a phenominal amount. Plus you will probably be high for a week. It will be useful to clean off residual adhesive, but not fun for the film proper.

As others have said - scraper is a very good bet. You won’t scratch the glass. It is possible you might leave a mark on the glass which will be metal off the scraper. Here hydrochloric acid can be useful. Acid won’t touch the plastic. It will probably come in a plastic bottle.

Another possibility is paint stripper. Evil stuff, it will usually rip into plastic film. But requires care in handling - it will rip into anything you let it touch.

You didn’t say how messed up the plastic film is. It is just bubbled? Curled up a bit? Brown? If it is still mostly intact and not too brittle I suspect heat and trying to peel it off will be the best bet. The adhesive will probably be sufficiently denatured that it will leave a residue, but acetone will fetch that off.

#11

Another vote for the razor method. Every professional window washer uses them, they cause no damaged if used properly. A scrub pad is much more likely to scratch than a razor.

Proper use involves making sure there is no grit; a grain of sand dragged by the razor will scratch the glass. Use a fresh razor, a damaged edge can scratch. Keep the razor at an oblique angle to the surface and always use a motion perpendicular to the blade edge; a slicing motion can scratch as well. Keep the surface lubricated with a solution of warm water with a few drops of dish soap in it.

#12

There is a mildly abrasive product for cleaning glass stovetops - I have some at home but I can’t remember what it’s called.

A few years back my son’s friend leaned back against the warm fireplace glass while wearing a sports sweatshirt with numbers on the back, leaving a melted plastic mess. A razor scraper and the cleaner took care of it with little effort and no scratches or residue.

A Mr. Clean “eraser” might do the trick too.

#13

I’d be careful with the heat gun. Even if it’s tempered, heating just one area substantially different temperature than the rest could result in cracks. The sheet is designed to be heated pretty evenly.

Razor should be best. Scrubbing with anything too hard risks leaving lots of scratches - either marring the finish or making it more susceptible to shattering. Then maybe wipe with a cloth with acetone or something (no need to soak in it) to soften the remaining bits to razor them off. Done right, razoring should not scratch the glass.

Still, the simplest answer is to buy a replacement. By the time you spend a day or two, buy acetone, rubber gloves, and razors - it’s pobably easier and not much more expensive to just take the glass out and replace it.

#14

Many folks already have acetone around the house-- That’s what nail polish remover is.

#15

If you’ve got a friend with a sandblasting setup, you might be able to soda blast it. The soda won’t damage the glass and should just peel the plastic right off.

#16

Was your tinting film melted? :confused: Sounds like a different situation (I’ve done the same thing, just peeled it off then used acetone to clean off the adhesive).

Here’s another vote for a razor blade. It will not scratch the glass if you use a minimum of common sense.

To those who have tried, does re-melting really work? My impression from trying this with a toaster that had an intimate encounter with a plastic bread bag is that the initial melting process somehow cooks the plastic and changes it to glue from the planet Sticktite.

#17

The OP’s situation sounds very much like the bread-bag-on-toaster-oven-window thing that everyone experiences. Heck, it happened to me last week. And the solution? A razor blade.

#18

It may not actually be tempered glass. If it is tempered you should see a small label etching in one corner that says so, called a ‘bug’

It might be neoceram which is a transparent ceramic used in wood stove doors and other high heat applications. It has a little of an amber tint to it. That stuff is expensive, about $75 sq/ft. So if it doesn’t say tempered in a corner, don’t break it!

#19

Would it work if you could put the glass in a freezer? I think think the wax might super contract and allow you to just pick it off. Just a guess, though.

#20

Nah, it might be a similar situation here because the film was attached to the glass somehow before it was melted.
The low heat of a steamer could be useful in dealing with that, and with softening plastic that’s gotten brittle because it’s been toasted.
As described in the link, you still need a razorblade, but steam might allow you to avoid the mess of mass dissolution of the plastic in solvent.