Tig welding alloy wheels

[Richard.]

How does hot wire feed work?

There is a slight amount of current applied to the wire before it gets to the weld pool to get it hot.
It's again an automated cladding process. The extra heat in the wire allows you to get more deposition down before pool chilling. I suppose It also aids with burning off any last contaminants before they get to the pool.

 

[Maker]

There is a slight amount of current applied to the wire before it gets to the weld pool to get it hot.
It's again an automated cladding process. The extra heat in the wire allows you to get more deposition down before pool chilling. I suppose It also aids with burning off any last contaminants before they get to the pool.

So there's not enough current in the wire to make a puddle?

 

[Richard.]

So there's not enough current in the wire to make a puddle?

No. The arc creates the pool, and the filler is fed into the pool just in the same way as cw tig. Difference is in hot wire tig the filler is pre heated with a very small amount of current. Not enough to melt it.

 

[Maker]

Is the wire power CC or CV?

 

[Richard.]

Is the wire power CC or CV?

Now your testing me!
As we know a tig power source is constant current but mig is constant voltage. It's a pure guess but as the current is applied to the filler in pretty much the same way as current is applied to a stick electrode I'm gonna guess cc. I could be wrong but as a cc powersource is used for the arc I'll assume the power generated to heat the wire comes from the same powersource but much lighter current. Fronius and polysuede are big names in HWT cladding perhaps you'll get info from their web pages.

 

[Richard.]

Looking at this it's a seperate power source used for wire heating so I don't know whether it's cc or cv
The deposit rate increase is massive simply by been able to apply lots more fill and avoid quenching the pool.

 

[Rrunnach]

This talk of hot wire TIG reminds me of various fab/weld work I use to do for the then, SubSea Offshore. Now SubSea7. Did various manu for SSO OTTO welding system, including hyberbaric chamber to facilitate OTTO. Those were the days when UK engineering companies were leading the field with their expertise!!

Old article, I wonder how this cutting edge engineering has been improved?

http://www.offshore-mag.com/article...less-steel-hyperbaric-challenge-for-otto.html

 

[roger64racing]

All I did was to ask on Google what the best filler rod was for welding aluminium wheels and it pointed me here. After a long thread there are a couple of answers but mostly basically saying "Dont do it". Well I have been welding cracked aluminium wheel rims for ages now with good success (Mercs and Beemers), I think there is too much science applied to everyday welding.

 

[PhillipM]

Everyone 'gets away with it' until the day they don't.

 

[slim_boy_fat]

@roger64racing Welcome to the forum

Genuine question/observation. Have the rims you've welded/repaired been for your own on-track vehicles, your own road cars or third-party 'customers'? If the latter, there's the matter of liability to consider if just one should fail, setting aside the more important safety of yourself and other road users. Can we assume you have this aspect of your work covered?

 

[anto44]

I asked a guy who works with a large car manufacturer training people in welding on cars about the subject of welding alloy wheels and his basic reply was it's fine until something goes wrong and it ends up in court. No alloy wheel manufacturer (of wheels for road cars at least) recommends welding their wheels, they all specifically say not to weld them. You will be asked to explain what qualifications you have and what r&d you have carried out that proved it was safe to go against that.

I do actually weld alloy wheels for off road vehicles regularly but refuse to do it on road cars. I use 4047 filler to do it. The problem is that after welding it needs to be heat treated and thats not practical to do correctly without very expensive equipment.

 

[stuvy]

I was a powder coater and wheel straightener for an alloy wheel repair company a good few years back.

The chap that owned it was a cowboy but had a system of repairing the crack different to other companies that we all had to sign a non disclosure agreement with him. He refused to do motorcycle wheels as some of the welds were guaranteed to fail do to there location on the rim. Iv also seen wheels come up stairs with upto 7 cracks being previously repaired.... it must have cost more per repair than to buy a new one

Either way you look at it welding alloys won’t be 100% successful as iv said we had wheels come back and that was from the chap that welded them day in daybout for 15 years

 

[MattH]

Realistically though people, what’s the worst case scenario here?

All the alloys I’ve seen welded up (fabricator neighbor did them) were to stop a leak and in no way structural.
If the weld failed then the wheel just has the leak it had before.

Let’s be honest, these things aren’t doing 20KRPM so we’re not talking about them explosively flying apart.

I’m going to guess that if a rim is cracked most of the way across the rim or has damaged spokes then most welders who are doing repairs are going to say it’s done.

 

[PhillipM]

How can it be in no way structural? The entire thing is structural.

I've seen enough broken and cracked alloys in my time (in our sport, you'll see a dozen per weekend at the rough events), to see how fast a wheel will shatter from a crack or spit the tyre off even with a small amount of the bead damaged.

 

[MattH]

As is a sill on a car but plenty drive around with rust holes in them with no catastrophic affects.

They are then welded up and deemed safe.

 

[Shox Dr]

Realistically though people, what’s the worst case scenario here?

All the alloys I’ve seen welded up (fabricator neighbor did them) were to stop a leak and in no way structural.
If the weld failed then the wheel just has the leak it had before.

Let’s be honest, these things aren’t doing 20KRPM so we’re not talking about them explosively flying apart.

I’m going to guess that if a rim is cracked most of the way across the rim or has damaged spokes then most welders who are doing repairs are going to say it’s done.

Problem is you have no idea to the extent of the damage, a Polish guy on ut, repairs a rim thats almost flat, the rim has split 1/3 of the way round infact it’s detached. Pulled heated, BFH’d, and welded up. you cant see the repair once he’s finished.

Dont know about you but I would want to rely on it holding together under heavy braking.

 

[MattH]

Problem is you have no idea to the extent of the damage, a Polish guy on ut, repairs a rim thats almost flat, the rim has split 1/3 of the way round infact it’s detached. Pulled heated, BFH’d, and welded up. you cant see the repair once he’s finished.

Dont know about you but I would want to rely on it holding together under heavy braking.

Agreed, but I don't know anyone that would undertake welding 1/3 the way around a rim.

Most people who I have seen looking for a wheel welded have a tiny crack that is letting air out.

 

[Shox Dr]

Agreed, but I don't know anyone that would undertake welding 1/3 the way around a rim.

Most people who I have seen looking for a wheel welded have a tiny crack that is letting air out.

Does that matter, clearly someone thinks it’s acceptable.
Do you know the history of your wheels?

 

[Richard.]

tiny crack

This is the thing mate. Your right 9/10 if the crack reappears it will let down the tyre but cracks are unpredictable things. They can propergate quickly especially if you apply heat to them. What starts out as a tiny crack can quite quickly be right across the rim in no time. If that crack goes quite deep but looks 10mm on the surface by welding it your not fully arresting it and with the heat your giving it ammunition to run. There is too many unknowns with it and it cannot be compared to a rotten sil.

 

[stuvy]

Some of the cracks are upto 120mm in length, it doesn’t just split in one direction they can go across the wheel or run with it. They would repair edges as in rims and the wheel excluding the spoke unless it was to pop a bit of weld from kerb damage

One thing is the weight it would add was a hell of a lot