I am learning this stuff as I go.  Was wondering if you guys could give a quick leason based on your own experience what are the best applications to use bondo, fiberglass jelly, bondo short strand, bondo long strand etc. 

I am about to start filling in the gap from my quarter panel stretch.  Up to this point I have only used bondo filler or fiberglass jelly on my build.  I think for such a large area I should use short or long strand and use something alot smoother for the final layer.

I quick class from the forum Yodas on what to use ans when would be very helpful.

Comments welcome.

michael

Thanks murcilambo,

So is the short and long fiber stuff basically jelly with fibers mixed in the compond?  Or is it a thick liquid like fiberglass resin?

michael

First of all, congrats on stretching the F40....stock fiero is WAY to short . Doesn't even come close to doing justice to such a beautifull car.

I would suggest grinding back the gelcoat at least 2 inches on either side of the patch and building up as many layers of  mat and resin as it takes to bring it up to the original level. Putty and long strand fillers contain too much resin and therefore offer very little strength. Carefull to work out bubles so they don't come back to haunt you later. Then, a skim coat of quality bondo and high build primer.

first you will need to grind the sides of the repair area feathered out about 4 inches on both inside and out.  add fiberglass matt or cloth until you have  about 1/8 inch at LEAST. each piece wider than the next to build out along the feathered edge.  once that is cured sand smooth.  use short hair filler next to fill the low spots.  sand smooth.  next use regular body filler to skim coat it. it this point your repair area will be rather wide and smooth

bondo is a brand name like bandaid.  the drying time for either fiberglass or filler will depend on outside temps and hardener ratio.  you can make either cure fast or slow depending on how much hardener you use.  faster hardened fiberglass tends to be more brittle than slow cured.

Alum foil tape.  Works good, some think it's kind of pricey.  I have used it but have also used blue painters tape and even packing tape in a pinch.

Yep,  grind the area around the repair 3-4 inches with a coarse 35-grit, your panel is probably fully cured by now & the patch will be bonded mechanically rather than molecularly, so you need a good rough surface.  The inside will likely have a coat of waxy finish resin so be sure to grind it all off or else your patch won't stick.  when you laminate be sure you are using non-waxed lay-up resin.