TIG welder for a small bicycle company

[roadsidecycles]

Hey guys,
first time poster, long time lurker.

From what i've been able to learn, is that MIG welding is not suited for very thin aluminium tubes and does not allow the amount of control like TIG welding does.

The question i have now, is which machine to buy?

I've been looking at some machines and some of them are very expensive(1000 pounds and up). As you might have picked up, im relatively poor at this very moment.

I'm looking for a AC/DC inverter, with HF, so I can weld both Aluminium and Steel(steel will be very rare).

The price range should be around 500 pounds or so. It can be cheaper if its used, but I dont want the absolute cheapest machine.

Any suggestions?

Thanks a million in advance

 

[Wozzaaah]

Are you looking for a new or used machine?
If new then your £500 will only just about get you a generic Chinese machine which may or may not be reliable, it really is like that with those machines.
Add another £200 and you could get a 160 amp R Tech one with a foot pedal, they are built in China but are sold by a reputable UK company who pride themselves on their aftersales support and who also carry spares and do in-house repairs should the need arise.
A few members have them and some have been fortunate to get 'shop soiled' machines from them at discount prices so it's worth a phone call.

 

[FranV8]

I've got an RTech AC 161 - 160 amp machine - pretty pleased with it so far (had it a couple of months) - done some ally with it, it'll have no trouble on bike thickness stuff and is pretty much 'fully featured' (pulse welding modes, AC adjustable frequency etc.)

Only thing that annoys me is that they've dropped about £200 off the price I paid for it...

..also, if you're into heavy use, it's duty cycle isn't the highest (I've never had trouble yet, but then I'm pretty slow...)

 

[roadsidecycles]

The r-tech welder seems pretty good.

I'm looking for a new machine, dont really want used ones.

The goal is to produce around 1 frame every day, sometimes 1 per 2 days. 1 frame has about 60-100cm of welding seams. Most of the welds are between tubes with a thickness of 1.5/2mm.

If my chainstay tubes are 2mm thick and the dropout(where the axles are mounted) is 6mm thick, it should be able to provide adequate penetration, yes?

 

[Engineer]

Have you got all the heat treatment side of things sorted out? That always seems to me a lot more hassle than the actual welding. Without heat treatment an aluminium frame is almost certainly going to fail, as the welding process tends to mean the HAZ is very soft.

 

[roadsidecycles]

Heat treatment/tempering will be done by a friends company, they have the smart people there+ the kilns/ovens. In the future, when business picks up, thats when i'll see if i can buy myself a personal oven .

But as far as i remember, welding removes about 1/3 of the aluminiums strenght, around the weld?(talking about 6063-t6 alloy)

 

[Engineer]

If your friends company is experienced in heat treating lightweight tubular aluminium frames, then thats a stroke of luck, as this its very very difficult to find anyone prepared to get involved with this work due to the consequences of any sort of failures.

However it might be worth you investigating the cost of public liability insurance before going any further with this project, as unless you are building frames purely for your own personal use, this is something you are going to need, and it can be pretty costly.............

 

[roadsidecycles]

I am not 100% sure, if they specialize in heat treating bicycle frames, but they have done several performance stages from aluminium, which they had to heat-treat.

So far we've done 4 experimental frames, with 2mm wall thickness and they have been running all season long since 2008. As far as i know, they were not heat treated at all, and they are very stuff(good tubes).

Since we've put alot of effort into designing the bikes, from a "staying-in-one-piece" point of view, i'm confident that with proper welding there should not be any issues with the frames.

But just to prove(to ourselves mostly) how stiff and strong the frames are, they will be tested at the local Tech University. If all goes according to plan, next year we will release them into the general public .

 

[Shox Dr]

Have you got all the heat treatment side of things sorted out? That always seems to me a lot more hassle than the actual welding. Without heat treatment an aluminium frame is almost certainly going to fail, as the welding process tends to mean the HAZ is very soft.

7005 series doesn't require heat treatment

 

[roadsidecycles]

True, but i'm using 6063-t6 alloy.

Anyways, back to the welder selection, any other contestants?

 

[Shox Dr]

For the money you have, R-tech is the only choice

 

[Engineer]

Sorry thought you were in the UK............probably no need to worry about public liability insurance, which is pretty useful!

If you have access to 3 phase power an old transformer TIG set is big and heavy, but far more reliable than a cheap Chinese inverter, and here is the UK can be found for about the same price as the inverter.

You may be able to avoid heat treatment if you add carefully designed gussets in areas likely to crack, but the main problem with aluminium is that it tends to be affected by fatigue cracking, and the likelihood of this seems to increase over time.

I think that Cannondale are now out of business, but there used to be quite a lot of interesting info concerning alloy frames on their site. You could of course consider air hardening materials such as 7020, but the 7000 series materials are very costly and some cannot be welded at all.

Might be worth looking at gusset plates to spread the load, and using a low temp brazing rod, which if the joints are designed around this, should reduce the chances of cracking somewhat?

If you were in the UK and had 3phase this looks a real bargain on Ebay:
250828095075

 

[hotrodder]

I'm guessing here but the 4 prototypes... presumably the welding was subbed out as you're looking for a machine? Do you have an experienced weldor (person) on board yet? With regards to the welding plant... at your budget everything will based around generic cheapnese kit and it can be a right minefield in that there's many similar looking machines around (albeit in different colours with different names). Rtech and Tec-Arc are two that come to mind in the UK with a reputation for good customer service and of those brands, as Shox Dr said, only the baby Rtech is anywhere close to your budget

Engineer, Cannondale are still about albeit quite different to how things used be. Easton have a bit of free info about fabrication using their tubesets... http://www.eastoncycling.com/bike/wp-content/uploads/2010/04/fab_instructions-7005_6061.pdf, cold setting and heat treatments for their tubesets discussed on pg3. There's a seperate one for scandium tubesets.

 

[citizen kane]

Can we see some frame pics, interested to see what your making.

Frames sold in the EU will of course need to pass the CEN standard.

One frame a day, thats quite intensive use, way more than the typical DIY user. I think I would be looking to buy the best quality machine I could, what would be the cost to your business if the machine was out of action for a week?

The price point for an alloy hard tail in the UK starts at £250 or less, cant even begin to imagine how anyone can make a living out of that.

 

[roadsidecycles]

Hotrodder - you are correct sir, the welding was done(and still is for the prototypes) by a company that specializes in welding alloys.

The idea is that, since i am trying to move away from my day job, towards working more on my bicycle company, i would also like to start learning more skills pertaining to the manufacture of parts. I've already ordered the parts for a CNC mill, to make more precise parts,since the bigger companies here really dont want to take orders with a quantity of 10 or slightly more. but about that later.

I will check out the link tomorrow, need to get ready for the office droning rituals.

Mr Kane,

I can probably manage closeups of the frames sometime during the week. Currently you can have a look here, at what we've been working on: www.roadside.ee

As for the standard, that can be aquired with the help of the Tech University and their boffins.

As for the one frame a day, that might have been an over estimation on my part. If all works out well, we'd like to make around 30-35 framesets for the next season and then use the machine to make prototypes.

I would like to point out that in Estonian, we dont really distinguish between bicycle and tricycle. But our pricepoint will be slightly higher than 250 pounds (and we have a few customers already eager and waiting)

 

[citizen kane]

I see, not your typical bicycle. Looks very interesting.

 

[gavuk]

Never catch on in UK.........it needs windscreen wipers .....nice trike,something different...

 

[tflnemesis]

Think i would only get one cheek of my ass on that skinny seat, maybe its time to get a bike....

 

[scott0031]

7005 series doesn't require heat treatment

It's 7020

 

[roadsidecycles]

hey guys, thanks for all the responses

Engineer - we did 1 frame without gussets and 1 frame with gussets. because the frames are we designed(i participated, but my friend the techie was the one doing the main job) are so strong, we once took it out for a spin and went to get beer, after 30 minutes, it was me in the front, my mate in the back(we're both around 100kg) and some 4 cases of beer. did not notice any flexing at all.

so far, none of the frame welds have cracked, although on the second generation frames we noticed that on one of the frames we put it under the "mig welding please" category. needless to say that the welds were not exactly pretty, but the frame has been in one piece now for 2 seasons and the only thing that has flexed during that time is the rear end axle support tubes(since i put the wrong ones on there).

We have the heat treating option as well, but i doubt that we will really need it. The frames have demonstrated exceptional strength and durability, so unless i start welding, we wont need to heat treat it,natural aging will do just fine