Page 1 of 1

Quick question 'bout BONDO

PostPosted: Wed Sep 20, 2006 12:55 pm
by oklahomajewel
I'm getting ready to use All Purpose Bondo on the screw holes, etc on my plywood walls (exterior)

I mixed a little scoop of it last night and noticed it started getting kinda hard , just like the can says "3-5 minutes" till set up time.

If I add about half as much of the hardener, will that give me a little more lee way and still set up just as good? I'm not in too much of a hurry to sand and paint, etc. but need the extra time to fill holes.

thanks.

yes, the Jewel box is coming along. I'm taking pics but the home computer's dead so I'll catch up with those later.

PostPosted: Wed Sep 20, 2006 12:59 pm
by SteveH
Don't skimp too much with the activator....I've had it not set up at all. Then it's a nasty mess to clean up and start over again. You're better off mixing a smaller portion that you can work in the time it takes to start hardening.

PostPosted: Wed Sep 20, 2006 1:19 pm
by angib
You can reduce the catalyst/hardener a long way before it won't go off at all - but you might have to leave it overnight to set. My experience is that it's hard to get it so it won't go off by using too little catalyst. I'd rate the two biggest causes of Bondo not going off as: the presence of water on the job or on the Bondo, and Bondo that's got 'old' - one year old stuff is just grumpy and is best thrown away*.

Unlike epoxy, you can vary the catalyst ratio enormously on Bondo - I just squeeze out what looks right - no measurement required.

I'm with Steve about getting used to mixing smaller batches - you can then put two layers on larger jobs where the first layer gets the shape about right and the second layer gets it perfect.

Andrew

*Oops, I'm not recomending you ever throw raw Bondo away - it's an environmental no-no. Instead mix it up as a 'hot mix' (2 or 3 times the usual catalyst) so it will definitely go off - but put it somewhere safe outside just in case it gets hot enough to catch fire while it sets.

PostPosted: Wed Sep 20, 2006 3:38 pm
by oklahomajewel
Thanks guys for the info.
See ? You're the best !

I did only mix up the little scoop full. and then squeezed out the 1.5" hardener like the directions say. I 'm thinking I could use just a little less of the hardener, like just a 1" line of it. I'll work much faster next time too .

If I have some already hardening up in the scoop, and set it aside for a while to finish hardening then throw it away , is that dangerous?
Just the smell of it made me know not to toss any right away into the paper trash bag.

I'll be careful

PostPosted: Wed Sep 20, 2006 3:48 pm
by rasp
bondo is a polyester resin, it does have a shelf life of around 6 months, after that time it may not go off with less activator

PostPosted: Wed Sep 20, 2006 4:04 pm
by Podunkfla
For just filling small screw holes, dents and such... Bondo may not be the best thing to use anyway. Auto Glazing Putty is made for filling minor flaws. It comes in a tube like toothpaste, does not need to be catalized and sands easy to a very smooth finish.

More info here (auto body related article, but it works for other applications too) http://www.doityourself.com/stry/smallrustspotscar

You can get it at most any auto parts store or here: http://www.autobarn.net/usc32035.html

PostPosted: Wed Sep 20, 2006 5:04 pm
by angib
oklahomajewel wrote:If I have some already hardening up in the scoop, and set it aside for a while to finish hardening then throw it away , is that dangerous?

Nope. Bondo getting so hot when it sets that it catches fire is really only a theoretical risk - I've never seen anyone get close to it - unlike with polyester resin which is quite easy to get smoking, if not actually on fire.

Nevertheless, it is sensible to allow unused Bondo to set before throwing it in the trash. If you time it right, you'll feel it get at least as warm as your skin - which is hardly a fire risk!

Andrew

PostPosted: Thu Sep 21, 2006 10:12 pm
by Hardin Valley Magic
Jewel, I'm with brick on this one. I used the glazing putty in the tubes. No mixing required. Use two or three layers slightly sand between coats and clean it well!!
No fuss, less waste!!!
Good luck.
I'm looking forward to the pic. up date. 8)

PostPosted: Thu Sep 21, 2006 10:29 pm
by apratt
I do not care for glazing putty. Because after you think you have it dry and then sand it, then paint it, the glazing will continue to dry and strink then it stick out like a sore thumb under your shinning paint. :thumbdown: I go with catalize glazing putty.

PostPosted: Thu Sep 21, 2006 10:47 pm
by Podunkfla
When I'm in a hurry... :twisted: I just use this stuff:

http://jbweld.net/products/jbstik.php