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Zak's Z

Need quick opinion!

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Heres the story... I got all the paint off the car finally and theres a few spots that were rusted. My neighbor, whos been helping me the whole time confidently says we should braze the rust spots to save some body shop time, fill it in with metal instead of filler,etc.

So I watch him do it, he shows me how to do it and I think all is well. I bring in some photos to work to show a guy who I know restores old 40's Willys to showroom condition. He laughs and says Im screwed cuz the brass will oxidize and bubble within a year and then eventually fall out. He goes on to explain the whole process.

The spots Ive done so far are rear deck lid the rear corners above the deck lid, one spot on a door, a few little spots under the rear doglegs, and one spot on door frame near the firewall.

I had no idea that this was a bad thing because my neighbor has seemed very knowledgeable so far. If Im screwed what do I do short of cutting out the brass to save myself here?

Thanks guys.

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The Wick Humble books talks about brazing in some detail. Do you have a copy of that book?

Using brass as a filler is a pretty common technique, from what I understand, but I've never done it myself. I expect you'll get some more knowledgeable responses shortly.

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My cousin had several areas brazed on his 71 and within 6 months, all the spots that were brazed had bubbled up. To this day we still don't know if this was because the spots weren't cleaned properly or if there was a reaction between the two metals. I too would like to know the reason why this happened.

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The Wick Humble books talks about brazing in some detail. Do you have a copy of that book?

Using brass as a filler is a pretty common technique, from what I understand, but I've never done it myself. I expect you'll get some more knowledgeable responses shortly.

I just happen to have that book here...pg 43. he says he puts brass into the floor when brazing. Hmmm.

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If I'm remembering the gist of what he said in the book, it was that brazing was fine for small holes (like the pinholes that you would find in a floorpan). You obviously wouldn't want to do this for large holes.

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On the deck lid there was a large hole...we cut out a piece of sheetmetal, tacked it in then made a bead all around and ground it flush. The rear outside quarters also had a piece cut out then new sheetmetal tacked in then filled and ground down.

The 'expert' at work says brass will oxidize even under the paint through weather change or exposure to rain over time. He says theres nothing you can do to stop it. Ive searched the internet and found a few references to putting brass into metal and a few who say its not the preferred method but so far nothing says why.

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I found that lead worked well at least so far. It's only been 3 yrs. since we painted the car. ''Back in the day'' LOL when I was in my youth and worked as a driver in a Body shop. All that was used was brass and lead. Around '59 Bondo came out. Many body men wouldn't use it at all for a long time . But in order to be able to compete they were forced to go to Bondo. I used some lead on my Z as filler. Care must be taken because the sheet metal is so thin and the heat will warp the metal if not done correctly. Scanlon brazed the holes that the PO had drilled in the metal and filled with bondo, which allowed the moisture to rust the panel. I found that lead solder with a large soldering iron and NON ACID flux worked fine to fill small areas that couldn't be worked out. With either brass or lead as well as bondo preparation is extremely important. Maybe EScanlon will jump in here on this. Gary

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Zak - Not sure about the oxidation issue - but don't give up. Ask you body shop for their opinion, and go from there. Worst case scenario is that they will have to clean it up, and "re-repair" the spots. From your photo, it shouldn't take the body shop long to set things their way.

GWGarrard

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Thanks Gary. Since I have already used brass...what shape am in? Is it possible to get away with what I've done? Im only looking for some opinions cuz the guy at work here said I'm definetly screwed, and neighbor said it was ok and suggested it in the first place.

Any special considerations for prep on this...would por-15 on the brass be a good idea?

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Hey Zak, I can tell you what I know and what my experiences have been. Brazing is an effective way to fill small pin holes and join very thin metal by flowing the braze over it. The difficulty arises when proper adhesion has not been achieved, leaving gaps or small pinholes. That's the keyword here..ADHESION. This is true also for all subsequent coatings used over the repair area. Any stress cracking, pitting or crevice corrosion will allow water and air penetration to corrode the metal.

You did sandblast the area before brazing so it should have flowed on nicely. I haven't done any brazing for quite some time now but I have done more than my share. If you can, sandblast the brazed areas again before using any surface treatments. This will texture the braze and aid in the adhesion of the epoxy sealer. You want to remove any surface contaminations. There are many products available to treat the metal before sealing. I use one called Metal Prep by Alchem. After wiping this on, you have to wash it off completely with water. I have been using a non-sanding epoxy primer from PPG (DP90). This protective coating is all you will need until you turn it over to the body shop. Water can't penetrate this primer. The way to avoid problems like you are hearing about is to totally encapsulate the repair area on both sides, so nothing is exposed to air/water. If the brazing job adhered good you should have no problems. I never had any problems with braze and the coatings I used at the time were not as good as what is available today. This is how I would do it. Good Luck!

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Good point Ron. I did see a few tiny tiny pinholes left in a few spots after I finished. Ill make sure I get over everything properly before I bring it in. Im on a roll here so I'm getting impatient I think.

Thanks guys.

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Thanks Gary. Since I have already used brass...what shape am in? Is it possible to get away with what I've done? Im only looking for some opinions cuz the guy at work here said I'm definetly screwed' date=' and neighbor said it was ok and suggested it in the first place.

Any special considerations for prep on this...would por-15 on the brass be a good idea?[/quote']

I agree withe geezer . I wouldnt use POR on an area that is to be topcoated with your finish. When cured, it is almost impossable to sand and, if not sanded or first shot with ti coat primer. Nothing else will stick to it. In the hatch area that you showed I did use POR paint but I did spray it with the ticoat .

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I know how that goes. After finally getting to this point you get anxious to paint. This is the point where you can make of brake the job . Do take the time to do it right . If you cut corners in the prep you will be sorry later. I must say here that I don't claim to be an expert painter by any means. I have done it and worked through the entire process more than once and with good results . But others I am sure are far better at this than I. POR, I do know that stuff. Gary

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I researched a bit for this oxidation problem, and couldn't find any references resulting in corrosion due to the braze itself. The only references to corrosion occuring in a brazing process refer to improper cleaning or release of the flux used in brazing but not to the brass or bronze used in brazing.

Which concurs with the times I've found it, when there was poor prep work or poor clean up afterwards. Those times, it wasn't oxidation of the brass, but rather oxidation due to the flux not being cleaned off, or the metal having been oxidized by the heat of the flame used, or the metal being brazed not being cleaned up prior to brazing.

I'm wondering if your "expert" was giving you grief over what you did because you didn't consult with him first, as opposed to doing it with someone else's help who may have experience. His scare tactic may be due to his inhaling lead fumes from using lead on the Willy's body panels....otherwise it's NOT what was done at the factory. The flux used for lead can ALSO have the same problems with corrosion.

Brazing is such a common technique for bonding dissimilar metals and light welding (think of brazing as "hot glue" for metals), that if in fact it were to corrode as readily as your "expert" makes it sound, then it would be common knowledge. Not only that, it IS an accepted production process for several large companies. If it really oxidized that quickly would it be the process they'd choose?

Make sure you clean off the brazed area properly after you finish brazing, even to the extent of grinding the brass surface to smooth it off (probably the best way of removing the flux) and level the surface again. The area you worked on is notorious for rust anyhow so it could rust even if you take all precautions anyhow. If you heated it properly such that the brass FLOWED and actually clung to the metal instead of balling up and rolling off, then you more than likely did burn off the flux. Look for tell tale scorch marks as well as black carbon deposits...those have to go.

Another method would be to use the POR 15 Marine Clean, and Metal Prep process to degrease and etch the metal, and then follow up with the POR, making sure you get it well into all the cavities, nooks and crannies of that panel. But always do some grinding first.

Are there any guarantees? Yes, if you do nothing, it will DEFINITELY continue rusting.

Was there a better way of eliminating rust in this part of the car? Yes, but it would have involved cutting out and re-welding a new part in....and even that wouldn't necessarily guarantee that it wouldn't rust again in the next 6 months. Then again, you could disassemble the car, send it off for dip-stripping and see how much metal you get back and how much work you end up doing.

FWIW

E

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All points well taken guys. E - Thanks for looking into that. I'll keep at it and slow down a bit to make sure its done right. I went at it again last night...it was looking good but there were a few tiny pinholes in the brass so I brazed more and made a bigger mess. Now when I ground it down I had chunks falling off and little actual metal left to get the braze to stick to. Patience was the lesson last night I think.

Zak

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Zak,

How did your brazing repairs hold up? I just got my car back from the sand blaster and there are some brazed repairs. I don't know whether to remove them or just epoxy prime over them.

Charles

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Hey,

I'm STILL not finished my car, but it has been painted and everything looks good. I would say that it was used for filler more than repairs and the rear hatch and corners look good (after prep and paint). It's been a few years since I got it painted and it looks good. If your brazing has been done for repairs rather than filling in some holes I'd have a serious look at it to assess if it would be better to remove it and get a proper weld. Now that you have her down to bare metal you don't want to cut any corners that might come back to bite you later.

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