I have a 1950 F-1. I am getting close to starting to prepare it for a paint job. I need to fil in a few spots that have tiny holes or cracks in the body because I want the paint job to be smooth and shiny. Any ideas on what I should use to fill the holes? Also, the running boards have developed some rust over the years and I want to clean them up. What do I use to sand these running boards because they have a shape which does not allow an ordinary sander to fit in the grooves?
Joker50

 

First, don't try to fill any holes or cracks with filler, it will not hold long and will soon ruin your nice shiny smooth paint job. If the holes are due to rust, you will need to cut out the rust thinned area back to solid metal typically at least about 6" around a pinhole or series of pinholes. As you start cutting away the rusted metal it will be pretty easy to tell when you have finally arrived at full thickness metal. Don't be shy about it, it's better to cut away some solid metal than to leave any rusted areas. Rust is like cancer, it starts from the inside by the time it appears on the outside it is a serious problem. If it is not all removed, it will start regrowing underneath any filler or paint you apply and will soon reappear. Weld in new metal patches to replace the damaged metal and refinish.
The best way to deal with surface rust and any rust for that manner is by media blasting with a soft media such as walnut shell or the newest and best, soda blasting.
deeper rust should be spot treated to a blasting with a slag media such as black beauty. Have the blaster use as low a pressure as possible that will do the job and DON'T use sand! Sand is hard enough to heat and warp metal and embed itself into the surface turning the metal into sandpaper, it is also a serious health hazard. Be sure to blast clean the back side as well.

 

I appreciate the advice for concerning the rust removal and the small holes in the body. I surely want the paint job to be as close to perfect as possible.
Joker50

 

Paint is one of the most expensive and fragile parts of a build, and is only as good as what is underneath it.

 

If you don't have the access to any blasting equipment for the running boards,then you might just try using a cupped wire scale remover fitted to your grinder. It will remove all scale and rust to bare metal. I am assuming you are refering to the grooved tread on the running boards. This will get down in those areas. Plus it is something else you can do your self,instead of having to hire it done. More money to spend on your new paint job, or something else. It will make short work out of surface rust,and find holes if any so you can fix them too. Then I would use something to prep the surface top side and bottom. If you use some type of bed liner, on the bottom, I think it would be to your benefit.Then paint the tops.Just my .02

 

Axracer and the above have nailed this pretty good. Since you said that you wanted this to be as near perfect as possible.
If not grind/sand/por15 and duraglass the holes and hope for the best. I have done some in this manner and have had lasting and nice paint jobs....especially if you do not have the tools for the cut and weld and blast methods.
..............Bill

 

Now, I love Bondo. My gallery will tell you how much.

But I know it's trash on the long term, especially if you just roll it over some rust and pray for the best.

There is some filler that a friend of mine has used on his old Yota work truck that claims to be as hard as steel, and you shape it with acetone, and not sanding.

The man practically has acetone for blood, so he jumped and bought this stuff and used it as an excuse to do some body work on his Yota. There was a hole in the side of the bed from testing a drill a bit (don't ask me..) and he put some of this stuff in there, let it harden, and shaped it smooth. He then proceeded to beat on it with a hammer. Bondo would have turned to dust and cracked and fallen out, but it held.

No clue on the long term durability, but it seems to do a job of holding up to it's claim.

Now if only I remembered the name...too much acetone..

 

I try to avoid wire wheels if at all possible after my brother had a wire thrown off a wheel puncture the lens of his eye. I have been using some new style wheels for rust and paint removal. I purchased them at my local Ace hardware store. They look similar to a wire wheel but have material that visually looks kinda like yarn that had been dipped in brightly colored stiff plastic. The "yarn" has abrasive embeded in it and comes in 3 grit ranges, course medium and fine, as well as in cup and wheel shapes on 1/4" mandrels. The "yarn" conforms to different shapes very easily yet doesn't wear down quickly, get mashed out of shape or produce much dust or residue. They cost about 7.00 each, but I have yet to put much appreciable wear on mine so the per use cost is low. Highly recommended!

 

Was he wearing safety glasses?

Another good alternative are the solid sponge matrix sanding discs. They are similar to what you described, but you can't use the face of them such as in a wire wheel. You could actually use the face, but the hub of the thing might chew up the sheetmetal you are sanding.

 

No he wasn't... He was helping our other brother removing rust and ran home nearby to retreive another wheel and left his safety glasses at his house. Rather than going back for them he decided to work without them, a VERY serious mistake!
Are you refering to the "clean and strip" wheels that look like plastic steel wool? I also use those for paint and old bondo removal. They don't overheat the panel or remove any significant metal, just the paint.

 

I will be tackling body work and paint in a year or so. It is all good info.
John
NNY

 

http://www.cadvision.com/blanchas/54...es/38strip.jpg

That's it right there.

I love these things, don't even hardly scratch the metal. Almost polishes em to a mirror finish with high RPM drills. They are fantastic.

 

Yes, I use those but they do wear quickly and are difficult to work into corners. The plastic string cup wheels will reach into tight places like cleaning the rust off a casting without beating themselves to death. Try one, you'll like them. I find the orange colored ones the best overall grit IMHO.

 

As alternative to bondo, you may consider using a product call All Metal. Its applied and mixed just like a filler, but is much harder material. There is no replacement for cutting out the rot, but this stuff works much better than standard filler. Its also much harder to sand down; a job best suited for a grinding wheel. Its tough stuff.

I'm in the process of cleaning up my running boards now too. After having them blasted, I found they were pitted pretty bad in spots. Sanding these panels is really tough with all of the body lines in the metal. I may try a spray-on filler for these panels. It still requires a lot of sanding between coats, but I think this may work better than applying by hand. The spray on stuff is pretty thick and requires a larger tip for my HVLP gun -- gotta get that first.