question about Bondo hardening time

DMartin9N-2N · Apr 1, 2021

Good evening: I want to use Bondo on a household project, where I will put the Bondo on as sort of a puddle about 1/8 inch deep, with duck tape forming a dam around the edge of the item. Since it will be about 50 degrees F. tomorrow, my question is: Can I do the messy work outdoors, and then when I have formed my *puddles* (and when I am ready), bring the project item in the house where it is warm and will the Bondo harden ok?

Dennis M. in W. Tenn.

MJMJ · Apr 2, 2021

Sure, it cures from a chemical reaction so the only difference is that it may cure slightly faster inside since its warmer. Though the difference probably wont be enough to notice. The most obvious way to increase or decrease cure time is changing the amount of hardener.

showcrop · Apr 2, 2021

I don't know what the "messy" work may be, but you can depend on the filler to harden in the time that it says on the label provided you get it up into the recommended temperature range, and provided that you get the mix ratio correct. In my experience the mix is much more important than temperature. The 1/8 inch thickness is not excessive so once you bring it inside it will heat up to ambient temp pretty quickly. Again, the mix ratio is what is really important. I had to scrape some off one time, when I didn't pay close enough attention to the amount of hardener that I was using. The temperature was the same as always.

Stephen Newell · Apr 2, 2021

The messy part is the sanding. You could just put a piece of newspaper underneath where you are working. Anyway there is no reason you couldn't do the work outdoors and then bring it in. Just remember just because it is dry enough to sand doesn't mean it's hardened.
You can sand bondo level, paint over it and in a month or so the spot will show an indentation where it shrunk. To be safe in cool weather let it dry a couple days before sanding.

DMartin9N-2N · Apr 2, 2021

Reply to my own post: The Bondo was actually used on the feet of a small folding ladder or step stool. I applied the Bondo outdoors, it was a sunny 50 degrees F. today. after an hour or more, the Bondo seemed fairly hard, so I tried sanding it to final shape with a disc sander, it worked fine. The application and then sanding was what I was calling messy, I did not want to do those processes in the house. I think in a few days in the warm house, the Bondo will finish curing to its full strength. Thanks for the suggestions, they made me feel better about going ahead.

Dennis M. in W. Tenn.

question about Bondo hardening time

DMartin9N-2N

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MJMJ

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showcrop

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Stephen Newell

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DMartin9N-2N

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