Properly prepared and applied any filler should not craze, crack or
Surface preparation is critical. Sand the area thoroughly with 80
grit, It must be bare metal with no rust. Wash with a degreaser like
Prep-Sol, then blow dry.
Select the right filler for the job. For areas more than 1/4" thick,
which should be rare if you've done the metal work properly, use a
fiberglass filled product. For areas 1/4" or less, regular polyester
fillers are fine. For areas less than 1/8" thick there is a putty
(the exact name escapes me) which flows like glass and leaves a
beautiful blended edge. The putty can be applied over primer if you
find some low spots or scatches after priming. All of these are
available from any auto body supply shop.
The key here is to work the filler firmly into the area being filled.
This is critcal for adhesion and to avoid air bubbles which will prove
fatal to the repair over time. Use the plastic speaders supplied with
the product. When using the putty, I find a soft rubber spreader more
If you are working large flat areas, use a long flat sanding block.
It helps to start working the high parts off while the product is in
the final stages of curing, but before it fully hardens. Check with a
fingernail. If you can pick at it, but not get a glob of stuff on
your finger, it's ready.
Use progressively finer grades of paper and be sure to feather the
edges. When checking your work, run your hand flat over the spots,
not your fingertips. You'll find it easier to detect low spots.
Once you feel you are close to where you want to be, spray a very
light coat of primer over the area and sand again. The high and low
spots will become obvious, as will problems with edges.
Final sanding before priming should be with 400 grit paper to give the
paint something to stick to.
Anyone inclined to spend the effort can do this, and it's pretty cheap
Hope this helps!
______________________________ Reply Separator _________________________________
Subject: Fillers - was "rust buckets"
Author: <email@example.com > at ccout
Date: 1/8/98 8:47 AM
I've been watching the thread about fillers and would be very interested
in people's experience/opinions.
I have all new metal where the rusted out portions would be. However, the
work is imperfect in that there are depressions and ripples etc. Are
there any acceptable fillers for this? I've seen a lot of Bon-dough
falling off of old cars (or measling or crazing or cracking).
The snap-down rim on my car is strong but pitted and could use something
like Nory mentioned.
As I don my asbestos underwear (waiting for the "do it right" comments) I
would like to espouse the virtues of just halting the deterioration.
Sometimes that is all us "financially challenged" folks can do for the
Thanks for the help!
'69 Sprite MKIV HAN9U78817G