Tig welding with Silicon Bronze rod

[spv]

I am currently doing a resto on a car from the 70's. I have a few small holes and surface blemishes that I am cleaning up and need to fill. I am thinking of using some Silicon Bronze to do the job. I think the risk of blowing a hole using standard mild steel filler is too great. The lower heat for Silicon Bronze might be the go. I will be hand filing and sanding afterwards to get a perfect finish. One goal of this resto is to avoid using all non-metal filler, including plastic/metal filler mixes. I also want to avoid Lead Solder if possible.

Any experience Tig welding Silicon Bronze for this purpose?

 

[hotrodmetalgarage]

I would use mild steel, and metal finish it. Just avoid putting too much heat into the piece.

You could use lead. Make sure you tin it right. It does take a lot more time, that is why Bondo replaced it. quick & easy. It doesn't mean bondo is nescessarily bad, but it depends on the car/application.

I wouldn't use silicon bronze for this. I have tig welded with it for some other applications, but it wouldn't be my first choice for what you have in mind.

 

[Wastedwagesracing]

We have run miles of both tig and mig on galvanized. It works well. I used it so I could to jack up the inches of weld per minute that our robots could lay down. Basically the part would be all mig welded then we would wrap the corners with a tig. It was used on a military application and they did the testing and had no issues with the process.

 

[NASTYZEN]

Use a heat sink behind your work if your afraid of blowing holes in it. Preferably copper so your welding won't stick to the heat sink.

 

[rdawson]

I have used a lot of the Silicon Bronze and it works well. It should be OK for what you want to do but I wouldn't think you would have any problem using mild steel. That would be my first choice and using a heat sink would help.

 

[spv]

I have used mild steel on the panel. I am concerned about holes as noted and in other repair areas warpage (I neglected to mention this). I have looked into the copper backing previously, but could not locate any vendors that sell this. All I could find was thin sheet, but nothing resembling a heat-sink. Additionally, the panel already has a small amount of bronze on it from a previous repair.

Is there any distinct reason why one should not use bronze in this manner? I see the "No" responses but nothing really stating why it is a "No". The area of concern is not structural, I do not want to put much heat into it, it seems like the logical choice?

 

[rdawson]

There's no distinct reason I would advise against it. It has been sometime since I've used any but I do seem to remenber it would become fairly hard on certain base metals. I'm an old retired aircraft welder so may have forgotten half of what I knew. If you wanted to make a copper heat sink flatten a peice of copper tubing. It wouldn't be very big but might work for what you have in mind.

 

[OccupantRJ]

I used the rod to weld up holes in my 40 Ford pickup. It worked quite well for me, using a simple portable tig setup on a Craftsman AC/DC welder. It has somewhat of a putty state during welding, which I felt worked well for filling holes. Cut a large copper plumbing fitting into pieces and flatten for a heat sink backer, if you feel you need one. I didn't even do that.

 

[SWT Racing]

I would use mild steel, and metal finish it. Just avoid putting too much heat into the piece.

I would agree. I don't think helibrazing would be ideal for filling holes, but I've never tried it. Even though you are using lower heat, you may have to dwell at the area longer to wet out the Silicon Bronze, which may cause problems. Also, if you need to actually weld later, you will have to grind out all the Silicon Bronze.

What holes and/or "blemishes" are you trying to fill? Where are they located? Are these body moulding holes, accessory holes (such as on a firewall) or rust pin holes? Any pics?

 

[mike13u]

I have looked into the copper backing previously, but could not locate any vendors that sell this. All I could find was thin sheet, but nothing resembling a heat-sink.

Thats all your looking for with the backing, copper sheet. Just hit eBay

 

[welder4956]

I have used silicon bronze on a fender repair and thought it worked very well and was much easier to control from blowing through than steel filler. It does not take much current to establish a puddle, maybe 30-40 amps and it flows well on the steel. Here's some photos of a fuel filler opening I patched with it.

 

[UncleDirty]

Back in 1981 I wanted to fill the trim holes on my lowered VW, my high school metal shop teacher told me to TIG braze them using silicon bronze rod. I did and it worked great.
I have TIG brazed alot of holes since then, has always worked well for me.

 

[Beaumont67]

This is a great information thread / with options shared:

Re Quote...
I am currently doing a resto on a car from the 70's.

Love to see a PHOTO, of the car in restoration !!

 

[Frank The Plumber]

If you are going to roll the work the silicon bronze will most likely crack. Use the mild steel and the heat sink backer as these guys recommend. If you are having troubles you just need more practice at lower output.