I have seen the same thing with mortar and grout, or was it my imagination?
"EXT" etonks@sunstormADD-DOT-COM wrote in message
anews.com...
I found another way to speed it up -- pressure! In addition to the amount
of
hardener, and the ambient temperature, put it under pressure.

I wanted to fill some holes in concrete and anchor some eye bolts into the
holes. So I mixed up some Bondo with a little hardener to extend its
working
life, then packed it into a large 3/4" diameter syringe with a large tube
on
the end to get it down into the hole drilled in the concrete. All went
fine
untill I pressed onto the plunger to get the Bondo to inject into the
hole.
The moment that I applied pressure to the plunger the Bondo instantly set
up
into a solid lump. I got nothing out the tube. I was able to push a nail
up
the outlet tube and remove the Bondo in one solid piece.


"Kyle Boatright" wrote in message
...

"Robert11" wrote in message
...
Hello:

Have been playing for the first time with with BONDO to fill in some
siding cracks.

Boy, the stuff sure sets-up quickly; a matter of a few minutes.

Is there any way to lengthen the set-up time, without degrading any of
its other properties ?

Thanks,
Bob

The set-up time of bondo is controlled by two things - first, the amount
of
hardner you use, and second, temperature. You can use VERY little
hardner
in bondo and the product will still set-up fine. The hardner really isn't
a
hardner at all. It is a catalyist which speeds the curing process. Less
catalyst = slower curing, not "won't cure". In fact, if you let bondo sit
on
the shelf long enough, it'll cure without the hardner, and will have the
same properties as bondo mixed with hardner.

So, to answer your question, use far less than the recommended amount of
hardner and you'll slow the reaction. Also, the cure slows down if you
mix
smaller batches, because the larger the batch is, the more it heats up.
As
it heats up, it cures faster and creates a continuous cycle of getting
hotter and curing faster. It is an exothermic reaction, and can get out
of
control to the point of catching fire. Spreading flaming bondo is best
left
for the pro's ;-).