Tetrahydrofuran (THF) High Purity Solvent - 500mL (16 Fl Oz)

This is the solvent that is used in the Electrical PVC Cement from the hardware store. I had some nicks/dings in a harlequin (vinyl) dance mat and could not find a PVC cement that matched the color. I ground up some scraps of the same mat and dissolved it in this THF. The result is PVC filler that perfectly matches the mat color! This stuff is high purity and quite volatile. Be careful when working with it. Nitrile gloves, VOC respirator, and well ventilated area are a must.

I Ordered a small bottle of THF for the sake of supplies, It was almost a year later Cleaning out the cabinet I discovered I still had it, never opened. I decided to preform a grignard with it. All I did was drop seives in, waited 4 days, and ran the reaction. Didn't even need an iodine crystal. Just a hot water bath to kick it off. I made the decision to strip off the THf under vacuum even though it was old. Had no problems so I'd like to think it's stabilized, regardless it worked fine. That was with a 120ml, I ordered another 500ml. Poured off a bit into the empty 120, seived them both, ran another grignard and it preformed equally well. So if you need this for a reagent and not for 3d printing. Save the dollar and order this, don't bother with the more expensive brhands.

Will dissolve/bond TPU in the similar fashion as acetone to ABS. Be careful not to over-apply and be in a well ventilated area.

I don't have a means to test the purity, but it seems to be what it says it is. According to the SDS on the vendor's website, this is a pure reagent they're getting from Sigma Aldrich and reselling, so it is likely not stabilized. I ordered some BHT and added 30mg of it to my 4 oz bottle so I won't have to worry about it detonating if I put it on a shelf and forget about it for 10 years. For those unaware, THF belongs to a hazard class called "peroxide-forming compounds." In long-term storage, it reacts with air to form an organic peroxide which is a shock-sensitive explosive. If you don't intend to use all of it in fairly short order, you should add an oxidation inhibitor such as butylated hydroxytoluene (BHT) to mitigate this hazard.

Is what it says it is got here on time for the project

And read the MSDS. THF is a very useful solvent, but can be dangerous if not handled correctly.

I was brought here by a forum post saying it's good at smoothing out PLA prints. I got it and the label said it can catch on fire or cause cancer, and I'm honestly a little scared to open it.

It's definitely THF. Use it to polish PLA plastic! Clean things with it if acetone just doesn't have enough of a kick to it and you're not quite patently insane enough to use MEK on everything! Do actual chemistry things with it! Just be sure to use it in a ventilated area well away from all heat sources (this is the unadulterated, unstabilized version, people, and explosive peroxides can ruin (or end) your day cat-quick), don't let it touch your skin, don't breathe it in, and in general just use it sparingly. If you're going to try and use it as a PLA polish, you'll probably want some sort of /passively/ heated vapor bath solution (like leaving it out in the sun) since a hot-plate based vapor bath is a patently Bad Idea (TM). If you use the paper-towel-wicked-can trick, you'll probably either want to use a fair amount (which is expensive) or leave it out in the sun for several hours. If you use it as a hand polish, you'll appreciate a respirator in short order. Whatever you do, wear some nice nitrile gloves, wear your rubberized butcher's apron, safety goggles, and a face shield might not be a bad idea either. A full on isolation suit may be a bit much--it's just THF--but you still don't want it on you in any way, shape, fashion, or form.