Brazing pinholes vs. replace sheet metal

The purist in us all shudders to think anyone would do anything other than the proper way. Sometimes you must make concessions to speed and/or expense.

I suppose the area in question would be thin and would simply vaporize if you got it up to melting point, where-as silicon bronze could melt to the parent metal and actually get it back up to thickness. There probably are instances where this would be acceptable. The fears of paint failure are unfounded. Though I haven't tried it, a buddy was explaining this very thing recently. E
He said that even panel repairs can be done strongly if the part is flanged, this method limits warping, speeds the process, maybe saves a car that might otherwise be scrapped.

 

The biggest reason for using brass on steel is the MUCH lower melting temperature. On questionable parts, it might save you from cutting out and replacing a whole panel. Less warpage, too. There are times when brass will work. If you are leading over it, it works fine.
Like I said before, I dont' often use it any more, as my skills, and equipment got better, but when I learned custom work, that's all my old boss used to use. Since the 50's.
In fact my chopped 55 Olds was ALL done in braze, except the sunken/molded lakes pipes. That's when I finally started using the MIG welder I bought a few years earlier to chop the car. My mentor tried it, and then refused to use it. Took some time (my free time) for me to learn the basics of it, and how to set it up, before I was comfortable with using it on a 'real' car.
BTW, except for a crack or 2 where the roof meets the quarter panel, my Olds has held up for over 25 years.

 

This sounds like an application for a spray welder, this is a dual feed welder than sprays a molten metal into pin holes and you work it like metal. The best shop in Omaha, Cars-R-Us has one of these machines. They are big bucks and he gets parts sent to him from all over for repair and return. The welder manufacturer sells only a few in protected areas for the shop to justify the cost. Here is the shops #402-558-6393, ask for Chris or Mindy Hunke. They may know of an operator in your hood if this is a part of the car that can't be removed for repair, a lot of times this is around windows drip rails etc. So here is some info. for what its worth. Good luck on your repair.~Sololobo~

 

years ago i brazed every thing, but now with mig 75/25 gas, i weld with that,brazing is kinda a lost art. but i know a lot of cars ive done and as long as you sand blast the flux out of the rod, ive never had a ploblem with lifting

 

I know opinions can be strong on subject matter like this. The shop working on my car is a good shop in my opinion, otherwise my car wouldn't be there. They have replaced sheet metal where it mattered (a lot of it in fact), and they've been brazing pinholes where the structural strength of the panels wasn't compromised, but had some small holes nevertheless, or where the complexity of the panel fit would be cost prohibitive. Given that I can't do this car myself, I gave them free reign to repair and rebuild as they see fit, as long as:

1) They keep the cost as low as possible, while
2) Ensuring the work that is done on the car is solid.
3) I'm not restoring this car, it's not a show car, but I want a decent, respectable looking driver when it's done.

I don't think 1, 2 or 3 are mutually exclusive (here comes the good, cheap, fast reply).

So far I'm happy with the work they're doing, and they have a LOT of cars in their shop. I know that if I had the money, they'd be the first ones to recommend that I have them fab and replace panels, but I don't. Not to knock my car, but it was a basket case when I bought it.

Given the technically oriented comments so far, I feel comfortable they're doing it right. The car was blasted clean, then sanded and grey etch primered (gray), and as far as I can tell, they're TIG brazing, then immediately epoxy primer coating (black). I haven't seen a hole bigger than a few millimeters in diameter that they've brazed, although in some places there are a lot of small holes.

 

The person who mentioned electrolysis has it right. Braze can work under paint, if you get up all the slag and prepare it properly.

However, if there is any chance of moisture getting at the brass to steel junction (and many paints are allow moisture to pass thru), such as from the back side, then you will get elexctrolysis and the steel is sacrificial to the brass.

This is where statements like 'it will last 5 years' can come from. Eventually, if there is moisture, it will corrode the steel and the first thing you will see is bubbling paint.

 

If you don't want to cut out the pinholes you can use Fiberglass mat on both sides.It will strengthen the panel and if you have all the rust sandblasted off this repair will probably last longer than you will.Enjoy the itching afterward.

 

And I have an amazing homesite on top of Mt Rushmore for sale, cheap! Only 2million to you and the market value is 45 million!!!!!!! run from these hacks as fast as you can........

 

I don't like brazing, if there are many pinholes the panel will probably be warped if you braze with a aceteylene torch because you heat the metal to cherry red.

22 years ago, against the advice of all my friends, I fiberglassed the tailpanel, the part that meets the rear bumper on my '55 Chevy. I sealed the backside with undercoating. Still solid and looking good. I will replace it with new metal when I redo the car in 5 or 10 years!

 

As a GM Fisher Body production line worker during the '60s and '70s, I brazed countless thousands of joints on Oldsmobile 88-98s and F-85s, at a rate of 6-8 points per side on each vehicle, every minuite-and-half, eight to ten hours per shift.
This was the final operation following up the gas and the mig-welding assembly processes performed in "The Gas & Arc Booth" area. Of note to this thread is that some of this brazing would end up being leaded over (in later years "bondo'd" over-under the vinyl tops)
Other points being brazed however, were what were considered "stress points" in the exterior sheet metal, that would be prone to cracks (and often were already cracked or split during the stamping operations) such as the sharp points of the bends at the ends of the rear quarter-panels where the tail light housing attached.
The heat of the brazing operation would "stress-relieve" and "normalize" the area while repairing and stopping any further progress of stress cracking.
Obviously, the brazing work applied to such exterior panels had to be of the highest quality, and recieved particular care in the metal finishing phases.
Brazing was phased out during the '70s, and I had already moved on to the Trim Dept.
But if you own a GM vehicle built before 1970, it is very likely that it has several ext. panels that were brazed in original production.
Of point to this thread, is that any Oldsmobile built before the early '70s will have had brass applied at the ends of the quarter-panels ( I did it! ) and rust or paint failure was and is is notably rare in those areas.
On a personal front, I dabble in old Studebaker's, and being both an experienced welder and brazer, I have employed both processes in rebuilding of rusted out floor pans.

I must add however, that attempting to braze up rust thinned and pin-holed areas is NOT good practice, such weakened areas should be cut out and replaced with fresh steel.
An exception might be made if it were only 2 or 3 pin-holes in an otherwise strong and undamaged area, but then why? when 10 seconds with a mig, or gas and steel rod would make for a far better and easier to finish repair?

 

If they are TIG brazing as you say, then you won't have to worry about flux issues with the paint, and I would say you'll be alright with it. I have a roll of bronze MIG wire ('kin expensive to buy at the time) that they use on some panel joints in new Minis, and I used it as TIG filler to repair tiny pinholes in things like my '34 screen pillar garnish mouldings, which were like a sieve after blasting.

 

What are the thoughts on tig brazing the pinholes in the drip rails of a '46 ford? Shaving or replacing aren't desired, wanting to keep it original without splitting the roof seam. The rot is in the rear downward slope and a few spots near the trunk. Mostly just pinholes with one sliver about 3/8" long. Hole width/diameter is typically in the 1/16 - 3/32" range.

I was hoping to tig braze these. Anyone had success with this or better advice to solve this problem? SPI epoxy will be covering all the metal work.

 

Perhaps you could post pictures, silicone bronze with a tig works wonders on small holes, and plug weld joints.

 

This is the worst of it. Looks like I had a few more "slivers" than I recalled. I've even considered "JBWeld'ing them if that would work as a permanent repair.

 

When I started doing bodywork 50 years ago brazing was all we had. A properly done brazed joint will last forever provided you get all the flux out. This is not easy, and is the downfall of the amateur. All the bubbled brazed joints I have seen were either amateurs who didn't know what they were doing or guys who got in a hurry.

Look at old magazine how to articles from the fifties and sixties. Barris, Hines, Starbird, all the old timers brazed everything.

You must inspect the brazed joint very carefully and make sure there are no pin holes and no flux. If there are you have to go back and braze the pin holes and remove the flux.

Rust pin holes in metal, you can weld them or braze them maybe but you are asking for trouble. The metal is rusting from the back and if it is that thin will soon rust through in other spots. You have to get in behind and cut out all the rusty metal and weld (or braze) in new.

Trim holes and screw holes you can weld or braze as you like.

Today of course everything is MIG or TIG welded. Much easier and cheaper. But in a pinch you can still braze things successfully.

 

I have both MIG and TIG welders so I'd planned to use one of them with my first thought being to TIG braze these. I've done the MIG gob-n-grind method before but never felt good about it and worry I'd be doing serious damage here. If that is a viable solution I'm willing to rethink it. I just found another thread where they were suggesting fillers like ALL-METAL filler or Lab-Metal.

If anyone seeing this has done this type of repair before, I'm all eyes and ears. I very much appreciate your advice.