Body filler questions

[rcx132]

Never used body filler before. Some questions:

1. Does it apply straight to bare metal or on top of primer?
2. What happens with metal that is flexing? E.g. the tin top roof on my Vitara is pretty flimsy, worried if I apply filler it will crack.
3. I remember people saying that body filler is porous and causes rust problems. If I filler now then it will sit in my garage for two months before it gets painted and could absorb water. My garage seems dry though, I've had one of the wheel arches stripped to bare metal for two months and not a spot of rust on it yet.
4. Just a P3 mask is enough to sand it? It smells pretty harmful.

Thanks for the help as always!

 

[gaz_moose]

1, bare metal is best but well keyed pain is ok.
2,providing your filler isn't 3" thick it should bend with the panel
3,sounds like it will be ok in your garage.
4, I never wear a mask when sanding filler so cant comment. don't get it in your eye, it burns.

 

[rcx132]

2,providing your filler isn't 3" thick it should bend with the panel

Few mm only. I've been pulling out dents by screwing in a wod screw and then pulling, then welding up the hole. I'm sure there's better ways but I don't know them. Once dent is pulled then I will only need a bit of filler.

 

[steveo3002]

its pretty flexible i wouldnt worry too much

as for it absorbing water/damp yes it will , id suggest you epoxy it asap rather than leave it sitting about , or some gloss aerosol paint and wipe it off when ready to continue

 

[anjum]

2 pack (lechler) epoxy primer first, fill sand and, essential if you go through to the metal again, epoxy primer on top.

 

[angellonewolf]

Few mm only. I've been pulling out dents by screwing in a wod screw and then pulling

to save a bit of work cant you hammer out the dents a dolly on the outside tap lightly so the dent goes near flat and then fill ?

this will only work on smaller dents but the bigger dolly the bigger you can do dont stick an anvil on your roof might make you more work to do