Seeing that I was doing the same kind of rust fix, I'd been posting a bit on wengejor's thread (https://forum.ih8mud.com/60-series-wagons/305208-rust-issues.html). But my wife and boss gave me Thursday off and the weather cooperated, so I finished my project--and now that it's done, I figured I should post a few pics of my own.
Over all, the project got easier as it went along. Fiberglass and Bondo aren't particularly hard to work with, and the learning curve is pretty shallow, so I've got to believe that the next time will be a lot easier. The results aren't perfect, and I'm sure that MIG welding in metal panels would have been better, but I think that I've done a decent job slowing down the rust and winterizing my rig. But you be the judge. Unfortunately, I forgot to take "before" pictures, but trust me that the rust had gone all the way through the outer skin of the fender, and was cut/ground out before I began glassing.
After the second layer of fiberglass mat:
Great stuff on the interior, in hopes of reducing vibration and noise, after two layers of fiberglass mat and two of fiberglass cloth on the exterior, and one layer of cloth on the interior (PS got the same treatment):
After final layer of fiberglass and three layers of Bondo, each one ground to shape:
After final sanding, primer, and rattlecan:
With a little more effort, I could probably have done the compound curves a bit better, but that would have taken more days off from work and the
and kids, so it wasn't really viable--especially considering how bad the rest of the rig's paint job is. Hopefully, this will hold up for the next few years until I can spend the time and $$ for a nice paint job and more fully assed attempt at fixing the rust. But I'm really glad to have this done before the snow starts falling. 
Over all, the project got easier as it went along. Fiberglass and Bondo aren't particularly hard to work with, and the learning curve is pretty shallow, so I've got to believe that the next time will be a lot easier. The results aren't perfect, and I'm sure that MIG welding in metal panels would have been better, but I think that I've done a decent job slowing down the rust and winterizing my rig. But you be the judge. Unfortunately, I forgot to take "before" pictures, but trust me that the rust had gone all the way through the outer skin of the fender, and was cut/ground out before I began glassing.
After the second layer of fiberglass mat:
Great stuff on the interior, in hopes of reducing vibration and noise, after two layers of fiberglass mat and two of fiberglass cloth on the exterior, and one layer of cloth on the interior (PS got the same treatment):
After final layer of fiberglass and three layers of Bondo, each one ground to shape:
After final sanding, primer, and rattlecan:
With a little more effort, I could probably have done the compound curves a bit better, but that would have taken more days off from work and the
and kids, so it wasn't really viable--especially considering how bad the rest of the rig's paint job is. Hopefully, this will hold up for the next few years until I can spend the time and $$ for a nice paint job and more fully assed attempt at fixing the rust. But I'm really glad to have this done before the snow starts falling. 
way of doing it. I probably wouldn't have done it if I'd heard about it causing rust, but since it's mostly in contact with Rust Bullet or fiberglass on the inside, and since this is a hack fix anyhow, I figured I'd give it a go. Besides, this rig's frame is so rusty that it might not last as long as the fender patches. But that's another project.
