Thread: Cast repair

Hi Stu,
Balance is the ratio between the positive and negative parts of the AC wave. From memory I think I ran about -55 which is 55% of the wave negative (penetration) and 45% positive (cleaning). I was using a 2.4mm ceriated electrode, #12 gas lens and 1.6mm filler.
I’m certainly no expert and this may not be the best setup, it just worked for me at the time. Mix things up and let us know how you go.
The hardest part I found was getting the silicone bronze filler which few places seem to stock and it’s two or three times the price of manganese bronze.
Cheers,
Greg.

ATM I am limited to welding outdoors, to cold wet and windy today to have a good go at it so I just had a short test with some mild steel. It sure wets out well on MS after things warm up a little. Was down around 15A.

Will report back once the weather clears and I can set myself up with the oxy/acet and a torch to perheat.

I am somewhat surprised at the several recommendations for silicon bronze in this scenario. When I did the 2Yr Advanced Oxy Acetylene Welding course at a NSW Technical College (now TAFE), the recommended bronze for CI repair was Manganese Bronze. That was 60 years ago; what has changed? As I remember, Sil Bronze has an inferior bond strength compared to Manganese Bronze, and is mainly used for joining copper alloys to steel. Although not recently, I have successfully repaired a number of cast iron fractures using Manganese Bronze.

I would be interested to know the reasons why no one has suggested Manganese Bronze for this repair?

Chas.

Originally Posted by Chas

I would be interested to know the reasons why no one has suggested Manganese Bronze for this repair?

My guess would be that I mentioned that I had Sil/Bronze and perhaps further it doesn't need to be particularly strong(well unless I tip the linisher over again )

Had a go with pre heat to about 300C today.
Much better. Still inconsistent, no pics of the not so good ones, but showing signs of improvement
Unlike the MS, once and area "doesnt wet" it seems unlikely to wet. Maybe its contamination from the edges?

Anyway wont get another chance until Monday at best.

G’day Chas,
Manganese filler would be perfect for this repair if using oxy but it’s high zinc content makes it un useable for the TIG brazing process. Silicone bronze contains very little zinc making it suitable for TIG brazing which was the process mentioned in the original post.
Cheers,
Greg.

Originally Posted by kwijibo99

G’day Chas,
Manganese filler would be perfect for this repair if using oxy but it’s high zinc content makes it un useable for the TIG brazing process. Silicone bronze contains very little zinc making it suitable for TIG brazing which was the process mentioned in the original post.
Cheers,
Greg.

Hello Greg,
Thanks for updating my knowledge, my welding experience is limited to OA and Stick. Tig is not something I have ever used.

Chas.

Update is no update.
Weather isn't cooperating so I am going to finish off the wheels and mounting the VSD, g-clamp it back together and push it out of the way so I can get back to cleaning the shed up. I'll return once when I can either weld inside or the weather improves.