Originally Posted by Beemerider
I just bought some but I've never used it before. I have some very small imperfections to fill in the process of a repair/rebuild. I also have some of the ultralite filler used for patching nail holes and such in walls. Will the latter work as well? Seems like it would be much easier to work with. No mixing with anything--just apply, let it dry and sand smooth.
Depends what you are trying to fix.
Light filler is great on wood and styrofoam. goes on quick and dries fast. But my experience is it does not work well with plastics or very flexy foams as it cracks. It has no real structural value. The beauty is that it is light and sands easily to a nice surface for paint or other finishes.
Epoxy with microballoons is much heavier but it is more structural, will flex with the surface and does have structural value. It can span small gaps and you can even mold it into shapes. Mix in some shreaded fiberglass and you add more strength.
Epoxy/microballoons is easy to sand and holds a surface well. And if you are working with wood that is cracked and has some small gaps it will fill them and add some structural strength which the filler won't.
As for the speed of the epoxy, well that depends on how long you need it to stay as a working mix. Most of the time I am going for a quick patch of a small area, so I will use 6 minute epoxy. But if I was working with a large or complex area I would use a longer set epoxy.