Fiberglass vs. All-Metal

[PachecoJ]

Under what circumstances would you use a metal filler, such as All-Metal, over fiberglass filler?

I just finished welding a new sail panel on my car. I had to do some repairs on the panel before I put it on so there are some weld seems. I dressed them as best I could, but they will need some filler. But more importantly there is a slight crown that I'd like to get rid of. The crown is slight enough and would be a big enough pain to work out that I'd rather level it with filler. Basically I don't have enough access to the back of the panel at this point to work it out by hand.

Should I use something like All-Metal here or just go with a fiberglass filler? In general is there any reason why I'd want one over the other?

Jason

[Roch_Greg]

I can't see the need of using both in the same instance.

To your point though, I've had rather good success with USC All-Metal (when used as a filler) I use a glaze over it. It's not the easiest thing to sand, but then neither is fiberglass.

I use it in instances like yours, to dress my welds.

Greg

[Steve g]

I can't see the need of using both in the same instance.
Greg

I think he meant metal over fibreglass as in instead of.

I believe it's primarily a personal preference. The idea is to use a filler thast is impervious to water in case there are any pin holes open to the back side. Both will satisfy that criteria. I prefer fibreglass.
Steve g

[Chris L]

I use Metal 2 Metal by evercoat.I think it sands easier and isn't as gummy as all metal.Maybe it was just one can,i don't know but i like M2 M better.

[Len]

We usually use a fiberglass paste but we also use All Metal with approximately the same result. We use either one of these to create a moisture barrier then we finish the leveling using standard bondo-type fillers.