Help with Uneven Bondo surfaces

[styzzo]

Hey guys im working on my Jorge armor and im running into a slight problem with adding bondo and sanding it down. I keep getting these uneven textures. I try and sand them out but it doesn't seem to be working. I want a nice smooth surface. anyone have any suggestions?

 

[Ral Partha]

Holes in bondo are unavoidable so use spot putty. Use a spatula or putty spreader to "smear" a thin layer over the holes or depressions and then sand them down like regular bondo.


EDIT: when you apply the spot putty, your armor piece will look like this:

The red areas are the places where I applied the spot putty.

 

[SLane972]

Right on with the spot putty, but I wouldn't recomend it for the big spots if you want it to dry completley. best bet at that pint is to skim a coat of bondo ver the top of what you cot there, lat it on going one way then smooth it out going the other and keep the coat thin and smooth. snad it down with 80 grit then step down to 180, repeat until the big spots are gone then finish oof with the spot putty. For what you have there you may get it in the first skim coat with luck. That's the fun of Bondo, a lot of time you wind up sanding almost as much off as you put on.

 

[JediStumpy]

You are using to much bondo at once it looks like. I did the same thing. You need to only make very small batches. The idea is not to put down a thick layer but to only put done 1/4 of an inch or thinner the the 1st layer, and other layers would be only 1/8th or thinner. The first layer can always by the thickest. After sanding you find your big hole. Don't just add another layer. Literally scrape in a smaller batch of bondo into the pits. Don't even worry about thickening the main layer.

Another tip is to put the bondo on, smooth until you get it in to place (press down hard and scrape it in) and stop before to starts to harden. If you are trying to move around bondo in its "clay state" you will keep get more air pockets. Only spread and scrape bondo in the "liquid stage"

Other than than don't use spot putty for holes. Spot putty should only be used on "pen"' holes, meaning hole that are the size a pen head. You should never have a to fill 1/4 inch wide holes with spot putty.

There is my 2 cents. The more you play with bondo the more you will learn its secrets.

 

[Nintendude]

I agree with Slane you don't want to use spot putty over large holes in the bondo because while it cures it can make cracks from the curing process with the spot putty, something else I have heard from other sources is using wood glue since it's a easy liquid material that dries hard and it's sandable as well.

 

[styzzo]

wow thanks guys this has all been very helpful

 

[Brandon McClain]

Another issue you are probably having is that you are working air bubbles into the bondo. Don't stir, fold. And don't over work the bondo, once it starts to kick and doesn't spread really evenly and easily, don't work it any more. This is why many small batches are better than big batches. Also, spread thin layers. It will also largely eliminate this problem too.