Technical Using body lead over phosphoric acid treated metal?

I have watched all kinds of videos, and have read all kinds of threads, and have not seen the answer to this question....

Can you "tin" metal that was previously rusty, and has been treated with phosphoric acid. I know that the metal needs to be clean, and all loose rust removed, and all the prep that you can do to make it clean, clean, and clean. I just wondered if anyone has tinned metal prepped with the phosphoric acid successfully.

 

Tinning needs to be done on perfectly clean metal. Just brushing off the loose rust won't do it. I bet you could sand the acid etched area off and get it back down to clean metal, then tin it.

Are you trying to use the acid as a "rust converter"? So you can be lazy and not remove all the rust?

 

My body man does not like lead as he has proved to me that it will cause rust down the track.
Example 1- I have had a 32 Phaeton for 53 years-non-op and there was rust in the bodyline above the rear wheel well. When we stripped the paint off the line was all lead from a previous repair and the remaining steel was rusting inside the lead.
Example 2 - Wife's 33-5 window we purchased about 15 years ago has always had the bondo lifting in one spot behind the cockpit. Stripped it back and the roof to body joint was leaded and had rust along the beadline from the flux. Similar problem on our passenger side B pillar where the pillar meets the roof plus a few other spots around the body where lead had been used.
Both cars have since been repaired with only top quality filler and paint used.

 

The beltline on my project is badly pitted and I was hoping to maybe take care of that with lead. I am fully aware that just brushing the loose rust off isnt going to get the job done, hence the reason I mentioned that the metal needs to be clean. Just looking for the most efficient way to get rid of the rust in the deep pitted areas. I have used phosphoric acid on the frame and it worked well. Where I removed the stainless trim, the metal is thin in some places. I wasnt trying to be "lazy", just efficient, and remove as little metal as necessary. Yeah, I know the metal has to be clean. You haven't managed to answer the question I asked in the title of the thread at all, but thanks for your comments!

 

Thanks for the info Swifty. I have found some areas on my 1950 Chevy Sedan Delivery that had lead from the factory and no signs of rust in those areas. But your experiences offers another perspective for sure!

 

I agree with you 100% as it appears that factory lead is never a problem but non-factory lead is where the problem occurs. Possibly they use a different procedure in the factory, different materials or whatever but it works. My body man is a fan of POR15 and in your situation based on what I have done on the 32 phaeton under his instructions for the beltline he would use the POR15 Metal Ready (phosphoric acid) then coat with a 2 pack epoxy sealer which is water tight giving it a few coats to fill the cavities and sealing at the same time. Sand that back then go ahead with your filler, primer, paint.
Where you have thin metal-say on the inside of your beltline and behind your trim do the Metal Ready then numerous coats of POR15 , 2 is the recommended minimum but I have done 3 and 4 on badly rusted areas. This builds the metal thickness up without having to do any welding with all the additional bodywork.

 

Lead seems like a good idea, it is metal, but I don’t really think it gains you anything in the end. If the pits aren’t large enough to compromise the body structure just use modern products. If they are large, then patches are required.
Sorry ! I didn’t answer your question either!

 

I generally try to do things with the least amount of impact as possible when it comes to issues like this. Deep pits are generally difficult to get clean clear to the bottom with a grinder and not cause a much larger issue. I wouldn't do that myself. Commercial Sandblasting for me is totally Taboo! Sandblasting yourself is a Crap shoot, not to mention the Mess. Trying to lead just to fill pits sounds like way to much work. I think in today's world of epoxy fillers and the fact the car probably wont sit outside much for the rest of it's life I'd take another approach. I would Not Lead just to fill pits. I would sand and body work the aria just as you would any body panel that's not pitted. Then as the pits expose themself go get my hand held blaster with Glass Shot in it and hit the crater till it's clean and move on. Here is a photo of a hand held blaster unit like the one I have.
You press the Rubber cup against the body, pull the trigger for a couple seconds and stop. If your not totally clean hit it again. There is no mess in surrounding aria, just a clean spot. This causes no impact or heat to damage the panel and you don't add Heat applying Lead that could cause you larger issues to repair. Today's Epoxy primers and fillers will cover the pits and outlive all of us if applied properly.

 

P.S. Sorry Monty I didn't actually answer your question either.

 

You really can't get rid of all the rust on heavily pitted metal. You may try muriatic acid to get down into the pits.

I know that lead is traditional but using a rust converter and kitty hair (or gorilla hair?) is probably your best and easiest solution. I do understand the desire to destroy your lungs and bake your brain cells but sometimes driving one is the end desire isn't it.

Note: I have not done it for years but I have enjoyed working with lead and would do it again given the chance.

 

I am curious. The mention of rust under lead work that wasn't factory done sounds like a prepping issue. Improperly cleaned before the work was done. Possibly the metal looked clean but maybe the flux wasn't properly wiped clean after the initial tinning and thus started the chemical reaction that became rust. I don't know these things for sure, just pondering the possibility.

 

I remember thirty-five years ago watching Dad doing lead filling on the fenders of my 40. The most difficult part of the whole job was getting the bare steel tinned correctly. Once the tinning is done, the metal shines with that layer of lead, and heating and squooshing the lead bar onto the surface was easy. If you found you needed to go a bit further, you had to meticulously clean and tin that area as well. Can't just paddle some lead over it and expect it to stick.

For rusty pits, the ONLY way to clean it for me is sandblasting.

As to lead jobs allowing rust underneath, I think they may have tried to put lead over dirty metal. If there was a seam or pinholes, those would allow moisture to creep in and rust under the lead.

 

I think that you both are absolutely correct. lead is cool stuff and if you learn the proper method and are meticulous it produces a beautiful outcome.

That said it is not forgiving. You have to do it right or not at all.

 

If a lead repair has rusted out my first reaction would be to think the previous rust wasn't completely removed before I would think that lead itself caused it to rust again.

 

I agree with Shift Wizard and the less than perfect prep theory in most cases. Other ways for rust to get under Lead is that Lead is non structural so if you have any flex under the lead it will crack and let water in and often under, here comes rust. Next is that when tinning the metal your also burning anything on the back side off it. If you don't seal the back side things will turn brown in a hurry and being out of sight can be a problem down the road. Rust from the back side, deep pits = thin metal and not long before it's a pin hole from behind. I have done a fir amount of Lead work when necessary, I don't like it given today's options but there are still times I just do it because I feel it's the right choice. Another thing to know is that there is Body Lead then Plumbers Lead and Fishing weight Lead, they are not all equal in how they work or stick. Buying body Lead and paying shipping kind of helps me make the choice if it's really necessary to do or not.

 

Body lead or body solder is 70/30 ie 70% lead 30% tin as is Plumbers lead or as we knew it, Wiping metal.
Normal solder used for soldering petrol tanks, radiators etc is 50/50, the tin in the solder is what gives it its ability to flow. You cannot make solder stick to pits no matter what sort of flux you use. The metal must be sanded clean and the area completely tinned. I have 53 years in the plumbing soldering and tinsmithing trade.

 

The flux I use requires neutralizing with water after the lead is applied.
After the lead is applied and paddled I scrub with a brush and rinse the area with hot water to neutralize the flux.
In addition to abrasive cleaning rust can be cleaned from pits with a wire wheel and will become ready for tinning.

 

Here are a few pictures of the worst of the damage. I'm hearing several suggestions of polyester products, fiberglass products ( kitty hair) etc. I have several places I can actually cut lengths of beltline out of extra doors and bodies of cars that are donors and weld them in but that seems to be extreme for no bigger than the holes are. The holes dont appear to be anything that is going to affect the structural integrity of the car. I'm really looking at how this is going to affect the paint once I get to that stage. I dont want the paint to start peeling off due to bad adhesion on irregular surfaces and leftover rust. Maybe I'm overthinking the whole thing?

 

You're going to either have to cut it out and patch or, if the metal isn't too thin on either side of the holes, weld them up.

 

If that were my car or a customers that would be getting cut out and new metal welded in. The pitted areas are nearly the same depth as the holes, so even wire wheeling or light blasting is going to reveal more holes. By the time the metal was clean enough to accept lead there wouldn't be anything left. You could gamble with rust converters and fillers and it may hold up just fine, or you could end up redoing hundreds of hours of body and paint work. There will never be a substitute for quality metalwork. Lead has its place and I like using it, and there are many excellent modern fillers on the market, but good product over garbage still equals garbage.

 

First sandblast (inside and outside). I don't know any way better to remove the rust from he bottom of the pits, unless you are going to acid or electrolysis dip the whole car. Then I'd weld up the very small holes and make patches for the bigger ones. Last I'd use a skim coat of regular filler over the area. Paint will be very important to make sure you don't get bare edges at the holes because of the trim snaps. Don't want the rust to start again after all that work.

 

Repair the metal, you will regret trying to take shortcuts by using filler with or without kitty hair! There is no substitute for doing the job right the first time.

 

I agree with alchemy, although I would epoxy prime prior to filler


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Oh Ick!! That Sucks! That aria don't lend itself to patches and welding very well. The SS trim makes contact on both top and bottom edges of the Trim piece. No real room for build up or change of shape of any kind. Making patches,, yikes, whoever tackles that project better be playing there A Game. That could very easily turn into Waffels into the upper panel.

 

Now you see why I am trying to come up with a solution that is the least invasive. If patching is the way forward, I think the best approach is to cut strips of beltline from the donor cars/doors and splice them in. Even with that, it's going to be a bitch to get the trim to lay down nicely when it's time to put it on.

 

My basic repair rule is to Not do lap seams ever. Were it me on this I might rethink that stand. This could be a time to do a clean metal surface on both sides, form a patch that fits tight on the inside and spot weld them in place. Next take my Tig welder and fuse the edge of each hole to the back patch to seal the edge 100%. Even that will turn into a ton of work.

 

You could opt for zinc spray. However, once you do it you wont be able to do a proper repair without removing all the zinc coated steel first. Don't use it on anything structural and I'd only use it as a last resort. No substitute for doing things properly.

 

If it were mine , I would patch the holes and then fill the rest with some kind of filler. No way I’m replacing all that pitted metal under trim.
Now how to patch? That’s the tough part. Really thin. Panelbond from behind ? Will the inside be visible ?

 

It can't be as complicated as some make it, how about sand blasting wirewheeling to shine it up a bit then hold a copper bar behind the holes and Tig or Mig the hole closed. larger holes, patch em. Ralphie

 

No it wont be seen on the inside. I'm seriously considering cutting some strips of good beltline out of extra doors and parts cars I have. I can get long enough strips to make the repairs. I dont have to replace but maybe a total of a couple of feet on both sides of the car, the longest strip being about 8" to 10" long. The drivers side is much worse for whatever reason.
I'm trying to decide if I should go at the entire beltline with a wire cup on a grinder. The rust needs to be gone.