Just put bondo on the fiberglass last night. Went to sand it off tonight, it came off in flakes. It did not cure in places. I could scrape it off very easily in places with a putty knife. Sanded through the fiberglass in a couple of places while I was trying to get it off.
I said many bad words.
Try again tomorrow. This time I'll just use the white epoxy I shoulda used in the first place....
Smart move, Brit.
I've heard and seen some bad things that have happened to my friends that have used bondo. Maybe not even right away, but the next season, bummer. Sounds like you lucked out to me, think of it as a positive lesson. :wink:
Brit, sounds like the bondo was bad, as far as the curing. However, you might want to note that while epoxy will stick to bondo, bondo will not stick to epoxy..... so if you fair with bondo you have to do that step before glassing for the best results. Keep on keeping on, no harm no foul! :wink:
What Angie said... I went through the same thing with my kayak. I new better but it was late at night, spurt of energy, bondo was all I had...it never did set up right.
Bondo on a boat you intend to keep for a while is not a good idea. Use an epoxy fairing compound or make your own.
What a pleasure to see all these folks off the Bondo bandwagon. I'm the one that usually is trying to convince people not to use the stuff. Even "good" automotive repair shops don't use the stuff any more (Macco maybe still does) because it doesn't stay stuck and doesn't like moisture or vibration.
Your Bondo may have been on a "blushed" area, but typically polyester based products (Bondo) don't stick very well to epoxy, though the reverse is true. You may have had a poor hardener to resin ratio, temperature conflicts, contaminates, etc.
Ditto what everyone else is recommending. Use some micro balloons in epoxy. It sands nicely, fairs out sweet and sticks good.
i happen to think bondo is ok under the glass but not so much over it....if it is under the glass it has no where to go. - but i would agree that on top epoxy and filler is probably the best bet.
a.
Somehow along the way it hadn't occurred to me that Bondo couldn't be applied over epoxy. Thanks, one and all for another lesson learned on this forum!
Bill[/u][/b]
You would be better off if you mixed up a "peanut butter consistency" combination of epoxy plus equal parts of wood flour and microballoons to use instead. It spreads on quickly with just a drywall trowel or plastic spreader and sands beautifully as a fairing compound.
I would recommend using a long board to fair it out until you are satisfied with its appearance. Then prime and paint with wet sanding between coats using an ROS and 120 grit paper until the final coat.
Let the long board do the work for you and you will end up with a nicely faired in surface by filling the low spots and just knocking down the high spots until it is all faired out. It goes quickly with a long board and 80 grit paper. The problem with a ROS at this stage is that it isn't large enough to even out the overall surface. But once it is all faired out the ROS makes quick work of wet/dry sanding between primer and coats of paint.
Angie Wrote
Quote:However, you might want to note that while epoxy will stick to bondo, bondo will not stick to epoxy.....
Paul Riccelli
Quote:Ditto what everyone else is recommending. Use some micro balloons in epoxy. It sands nicely, fairs out sweet and sticks good.
I'm not saying that I agree with the use of bondo versus thickened epoxy. I kind of wish that I had the patience to use thickened epoxy . .
But I didn't. And I stuck just fine. Before I used it, I asked Larry at RAKA if it would stick. He said "Yes, It is compatable, But
why would you want to?? Turns out thicked eposy is almost the same cost when you add all the fillers.
That being said, there are a bunch of things that can go wrong including blush. (nothing is gonna stick well to your epoxy blush)
Also need to remember that any bond will be physical, not chemical, so you got to rough up the surface.
Anyway, there is bondo Over and Under my epoxy. Everyting has stuck together fine. The thing I'm more worried about is the bondo soaking up water. . . I'm sure all bets would be off if that happenes.
J. Stephen Mustico