The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: pato08 on 27.02. 2012 04:54
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Hi All
I did a search on "cast iron welding" and could not find any topics. I am in Canberra Aust. and need a fin welded on my head (BSA A10) any recomendations
Thanks Pato
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some good infomation here.. > http://www.a7a10.net/forum/index.php/topic,5079.0.html
I'm still waiting for iansoady's GUMMY leg to come good.. *whistle*
Brian also gave me some good info re MIG stitch welding it..
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Recently repaired cast iron barrels using the M.I.G process (mild steel wire) argomix gas , "Brian" set Me right ..came out a treat .
Put some heat into the item in the oven , stitch carefully after cleaning and prepping edges with a grinder ..dont forget to angle the broken fin down a fraction to allow for distortion bringing flat then allow to cool down in the oven , trim with grinder later .
Hope this helps ?
Steve ...
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some good infomation here.. > http://www.a7a10.net/forum/index.php/topic,5079.0.html
I'm still waiting for iansoady's GUMMY leg to come good.. *whistle*
Brian also gave me some good info re MIG stitch welding it..
It's gammy not gummy......
Operation successful but still limping around so it'll probably be a few weeks yet. You did say you weren't in a hurry........
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Hi PatO,
You can also use silver solder to reattach broken fins !!
It works very well, heres a photo of a vintage Blackburne head I repaired *smile*
HTH
John O R
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some good infomation here.. > http://www.a7a10.net/forum/index.php/topic,5079.0.html
I'm still waiting for iansoady's GUMMY leg to come good.. *whistle*
Brian also gave me some good info re MIG stitch welding it..
It's gammy not gummy......
Operation successful but still limping around so it'll probably be a few weeks yet. You did say you weren't in a hurry........
You say GAmmy I say GUMMY... (http://i245.photobucket.com/albums/gg63/WozzA_photo/rolling-1.gif) as long as it's getting better (http://i245.photobucket.com/albums/gg63/WozzA_photo/thumbs_up.gif)
I'm not in a hurry... It will be awhile till I'm having a (http://i245.photobucket.com/albums/gg63/WozzA_photo/bikeday_smilie.gif)
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Thanks for the replies, I have a mig but not on gas, I am a fair welder, but this is not a job I realy want to tackle *work* *work*. I am willing to pay (deliver) for the job.
Pato.
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G'day Pato,
try the Dunster boys (twins Peter & Paul) over there, I think their in Mitchel. Old classic racers.
Cheers
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Cast iron can be welded with a high nickel content rod, brazed or silver soldered. Mig or arc may distort things a bit due to the higher localized heat involved. If the pieces are silver soldered they must be very clean as any dirt or grease will not allow the silver to flow into the broken pieces. Also silver is not very strong. I have repaired broken fins by brazing for years. The only thing is you need to have the cast iron HOT. 300 degrees F or 150 C will be adequate. Brazing rods are now flux coated so you don't have to poke your leg with a hot rod putting more flux on the rod. Good luck! Ron B
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I used a high nickel stick weld rod off ebay with a home DIY welder. You should preheat the barrel in a domestic oven on max. Perform the weld then put it back in the oven and turn it down 50 degrees at a time to reduce the thermal shock. I have dune a few hundread miles since the rebuild and all is still well. Pic below - not perfect weld but looks perfect when back together.
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Here is a pic of a fin I recently repaired with a mig.
I had always either used nickel rods in a stick welder or brazing to repair cast. A few months ago I thought I would try the mig just to see what happened and I found it is the easiest and the best way to repair cast.
I used the standard mild steel wire, my gas is Argoshield which is the standard mig gas supplied here in AUS for general purpose mig welding. I did find I needed to increase the amperage slightly.
I tack weld each end and in the middle and then weld about 1/4" at a time allowing a few minutes between each weld for it to cool. I dont preheat or do anything else.
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After taking note of "Brian"s advice I repaired a heavily damaged barrel in the same way , did pre-heat / post heat in the oven though .
Believe that to be important with cast iron .