I'm not sure what kind of glue this is. It's an amber color and it's very rigid, like hard plastic.
I've tried Goo Gone, which didn't do anything.
I was able to chip away at it with a putty knife, but it's slow work and I'm afraid of damaging the tile/bathtub.
Any suggestions ?
It looks like an Epoxy adhesive. Chipping away is okay if your careful. But, try a single sided razor blade. A lot of the time you get right under it & almost peel it off. You can also lightly hammer these types of razor blades. Holding it with gloves or with pliers.
You'll also want the razor blade to actually scrape or peel any residue away after the bulk is off. I'm not sure if nail polish remover, turpentine, minerals spirits or acetone would do much in the bulk removal, but any of those would be great for the final clean up.
since its rigid and brittle, its most likely an epoxy. the only solvent i know of that will dissolve it will be methylene chloride. hard to get, carcinogenic, but good solvent for this. just make sure you wear silicone gloves (get a bunch as it can dissolve certain silicones too) and a full face respirator with a VOC cartridge or two in it. you can get it at your local plastics supply house or fabricator, or at a boat supply store (its used sometimes for acrylic and fiberglass work)
heres the rub - if its an acrylic tub, it will dissolve the acrylic too, so go slow and in a controlled manner. you might be better to mechanically abrade away what you can first. even if you chip or scratch the acrylic, it won't be an issue. if you haze the surface with some errant solvent, you can just polish it up later with buffing compounds.
if its a porcelainized steel tub, the mc will not do it any harm. just dissolve away. don't mechanically abrade anything because if you chip the porcelain, now you have a permanent rust starting location.
I ended up using a heat gun to soften the glue, and then I was able to easily scrape it away with a putty knife.
After scraping, there was some small remnants of glue. I used a low grid sandpaper to get rid of those. I worked slowly with sandpaper to only rub on the glue. It did leave some scratches on the tile, but you could only notice them close up.
