Fixing a Uno-vac stainless steel thermos

I’m new to the site, just re-read Every Tool’s a Hammer and thought that an army of makers might be able to help me with my problem.

This morning I dropped my stainless steel thermos in the parking lot and it landed right on its bottom edge. It is still intact and functional, of course, but now there is a dent on the bottom edge that causes it to wobble.

Before I take a hammer to it I was wondering if any of you might have some suggestions or advice. I don’t expect to fully restore it, just want to level it out a bit so it doesn’t wobble as much and whatever I do I don’t want to breach the vacuum. Any thoughts or should I just pound away?

Edit: here is my crude drawing of the ding

You may try some heat from a heat gun and see if it pops out. I would not suggest a torch.

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Unfortunately, I don’t have a heat gun on hand. Do you think a hair dryer might get it hot enough, or maybe a lighter?

epoxy to fill the void and level the bottom. automotive body filler even.


It is worth a try.

I think see what you are saying, but I don’t think it will work in this particular case. The problem is that while the corner is dented in, the bottom is bulging out by the dent. I tried to take a picture but I is kinda difficult to capture.

I will bear that in mind if I need to fill in the corner to make it look nicer. Thanks!

Added a drawing of the problem to the original post since it is difficult to photograph.


that’s good news, creased dents are tough to work with so being able to work it back in, as opposed to pulling out, is the best scenario. I would hammer it.

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Don’t know how big of a dent you’re working with, but I hammered one back in on the bottom my girlfriend’s stainless water bottle. No problems. It takes a pretty hard crease or a couple bends back and forth to break steel.

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Yeah, stainless steel will eventually work harden (it is austinitic) but I would be surprised if two cycles cause any microfractures that would breach the vacuum seal. And honestly, if it does, there’s a good chance that it’s already breached. Hammering it carefully would be my choice as well.

Most stainless steel needs to be heated to 1900°F and then water-quenched to anneal it, so there’s not much point taking a torch to it to try to undo any work hardening. :relaxed: