From reading it seems using silicon bronze Tig wire allows a softer weld which will dolly nicely due to its soft nature. Is it just the Tig welding which allows this or can you purchase silicon bronze wire for a mig to use on steel and will it still dolly ok after welding? Am I talking rubbish? Is standard mig wire silicon bronze? Can someone enlighten me?
It's for brazing not welding so not a filler wire in the welding sense as you do not melt the parent metal. You can use it with Oxy-Acetylene and flux too. I like it with Tig as it's less messy than OA, I have not tried peening it though I can see it would be quite workable. Not tried it on Mig either.
I use it quite a lot with my mig....either when I'm fixing metal that I don't know to other metal that I don't know....or when I need to keep the heat down. The other day I repaired pin holes in a steel water pipe....regular steel wire would have blown thro. Haven't tried beating it yet. I use it with argoshield which isn't totally correct but seems to work for the stuff I do.
Silicon bronze is mostly copper with a bit of silicon, to help it flow? Either way pure copper wire does appear to work but will be softer to feed. It requires a lot of amps! Copper takes a lot of heat to melt and my 130xt was maxed out (and tripping the 16a mcb) to get a decent bead. It needed the wire feed high which was putting too much down and a lot of heat. I think I need 0.6mm wire for it to be useful with my mig, which doesnt appear to exist in sillicon bronze. This is the cheapest I could find 1kg www.ebay.co.uk/itm/Welding-Wire-MIG-0-8mm-CuSi3-C9-Brazing-Soldering-1kg-D100-Silicon-Bronze/363115469126
I use it on my Kemppi which is synergetic and has a setting for CuSi. I have a small roll....it's handy to have because jap cars have a lot of braze joints on roofs and rear quarters. It's also easier to use where you can't get something totally clean...for example repairing the return fold on a door skin.
968 silicon bronze wire used to be only available in 1m lengths for TIG. It is now more common on reels for use in a MIG. Both processes require pure Argon. (Modern vehicles have boron in the steel, A18 wire causes embrittlement. So 968 is used)
Good advice there guys cheers. So I understand that synergic welders are fine with it how about something like my PortaMig 185 with DCEP negative earth only? It doesn’t have the ability to change polarity as you would for say flux core so can it still be used with a roll of SB wire? My reason for trying this over the regular wire is the fitment of my BMW mini pano roof in the classic mini and the ability to sort out any distortion.
It runs at the same polarity as regular mig wire. Lack of synergic just means you will have to dial in the settings yourself but once you know what size wire you are getting and what thickness panels you are welding one of us with a synergic machine could just dial that in and see what the settings are
That’s great. My only reservation is that the parent metal won’t be getting fused as it would with regular wire. Should this be a concern on a roof panel or would it be ok? I want to keep the heat down and want to be able to beat out any distortion without worrying about cracking welds once complete. I don’t want a roof full of plastic filler once complete.
For a roof panel I can't see the advantage in it? Why not just weld it as normal, lots of tacks working from side to side to avoid the distortion? The wire is expensive enough that I only use it if the job needs it. It will still need just as much post-work as normal mig. Well, you will get less distortion but if it's just a one off job you could just slow down and avoid the distortion in the first place. If you are paying somebody by the hour to weld then it might make sense but not on a diy job I dont think.
If you look at my mini in the project section you’ll see I did exactly this when repairing the lower rear quarter and just joined up the spot welds. At £29 for a kilo reel I’m not bothered by the cost but I appreciate the advice.
I didn't realise it was available in 1kg, for £30 I would use it! Last real I bought was nearly £200!
I dont think it will do what you want without the proper mig brazing machine or thinner wire. With a normal mig it will put almost as much heat and distortion in as welding. Please ignore my suggestion of copper wire, fine for playing about but wouldnt use it on car stuff. What you need is a tig , have you seen the Sherman thread? Ive ordered this to play with, just to see if my mig can be useful - otherwise I doubt I will use it once the tig turns up! www.ebay.co.uk/itm/Bare-unplated-uncoated-SOFT-COPPER-WIRE-0-6mm-22-GAUGE-500grams-99-95-PURITY/121648438907
Cheers @Kram , I already have a Parweld Tig and pedal, I’m just not confident enough in my abilities with it to carry out the install using Tig.
