Put in a patch for the rust holes. As for the screw holes, you should be able to just weld them up and grind flush. Just be careful not to take your time and not heat the metal up too much when welding or grinding or it will warp.

 

I always cut out the rust and Mig in new stuff. I can get the seams pretty nice, but a layer of lead over my work area after I've put in new pieces would probably work best. Putting putty in an area that could have standing water just doesn't seem like it would last.

 

There shouldn't be a problem with body filler over the welds, if it is covered with proper primer and paint. Body filler is gonna be easier than lead for most people. Lead can work well if you know what your doing, but if you don't your gonna make a mess and its harder to remove that filler. There's also a chance of warping the metal with to much heat from the lead.

White97, would seam sealer itself be enough in your rain gutters. Most of the guys I know use it there.

 

Does lead cause any galvonic action to the steel? I am considering trying to learn that lost art of leading. Me and bondo/resin ect don't see eye to eye no matter how I clean,prep and ect. After few years that crap pops up on me!
The old guy down the road died before he could answer that question. Bummer he could't show me the tricks of the trade too....

 

It is still two dis similar metals ,,but the lead ,is very strong .

Start out with 0 rust ,,it should be fine...

 

I don't know if it's the total answer, but on welded seams, etc. I usually use a very light coat of "metal to metal" (an Evercoat product) over the welds before applying any other fillers or primers.... I do a lot of sheet metal work and custom work on the old stuff, seems to work quite well for me...

Learning to do the leading because it's a lost art is probably a worthwhile undertaking, but from someone who had to use it because that's all that was available back then, I'll never go back to it...especially now that the lead isn't even lead anymore....No idea what the reaction to the sheetmetal is on this new stuff, I guess if you believe all the ads is "just as good as"..... Think I'll stick with the new products and methods, so far it has worked great for me on any number of projects......

 

X2.....you're right on!

 

I will replace the rusted metal but I want to use the lead as a seam filler after spot welding. I have read up more, and found if both parts are properly tinned the lead should flow right in and will become a seam sealer and filler. Just like soldering pipe work. The galvonic reaction should not occure as does make a single layer of lead oxide much like galvnized metal's tin does. Afterwards I would seal the total area just like if you used bondo ect... Just want to stop that newer seam sealer crap from breaking down in time alowing water in and do it's dirty work.

Now if I had a super sized tub to put the cab in and electrolize it like my Dad does with his tractor parts. That would get rid of rust, loose paint, even rused up bolts/nuts come free after that treatment.

 

I use Metal to Metal also even for small holes. Just grind dimple them in and fill it. On the other side just make sure its rustfree and protected from water.I spray the inside with fluid film or similar cavity wax..MTM is waterproof bondo isn't.

 

you can use metal to fill in or tinning butter and led or bondo that is fibber impregnated, it all works. I personally would use metal patches for any thing larger than a dime, smaller though, like screw holes I like the fibber class just dimple the hole fill, then sand and re-coat with a light bondo to be sure you are level with the metal.
The old timers hated bondo because of shrinkage and spider webbing, led will not shrink or check, and its cool to know how it use to be.