Posted by Jim Chance on August 22, 1999 at 07:24:24:
In Reply to: Re: How do fix a rust hole posted by Mike on August 19, 1999 at 10:11:52:
I am about the world's worst bodyman, but a friend did teach me a foolproof / no-skill way to patch a hole. It works well on small parts where you can turn them so the hole is horizontal. After a little practice you can use it on vertical pieces as well.
Basically, you use a big piece of copper to absorb the excess heat and keep you puddle from flowing off. I use it to fill holes of about 1" x 1/2" with no filler plate - Running board brackets being a prime example. You can use it for much larger holes with a fill in panel.
1. Cut out the bad spot using a die grinder with cutoff wheel. For small stuff you may be able to use a dremel tool.
2. Make a pattern by tracing onto cardboard through the hole, then cut the pattern out.
3. Find a piece of steel of similar thickness - best source is an old car part. If your hole is in a curved part, you must get a curved piece or curve the one you want.
4. Cut out the piece of metal using the pattern as a guide. You can rough cut it over size w/ a torch, but trim it with a grinder. It should be snug fit in the hole.
5. Make sure the patch and surrounding metal is shiny clean - sand blast is best, grinder is good to.
6. Put the patch in place and put a piece of copper behind the spot you want to weld. The copper should be about 1/8th inch thick or more. Hold it all together with clamps. The tighter the copper is against the steel the better.
7. Use a mig with a small wire deposit some metal in the hole. It's best to weld just an inch or so and then let everything cool to minimize warping, but on things like running board brackets just weld away. The pool should lay on the copper until it turns solid.
8. Wire brush the area between passes.
9. To keep from leaving a holeon your closing pass don't let go of the trigger. Instead pull the tip awayuntil it quites arcing then release the trigger.
10. Grind it smooth, finish with bondo.