got a bike frame i need fixing

cant you buy a cheap arc and buy the right sticks?

mike hose motorcycles kelvin rd wallasey, right opposite st Paul's rd.

altrite mate try arrowebrook engineering on poulton road use to work there they,ll do a good job

You dont want to buy a TIG set just to do one bike frame. A crap second hand one will set you back over £250. You can use MIG with the right wire and gas but the weld is rubbish, you cant use ARC as its way too powerful and will blow holes in the thin gauge metal.
Take it to an engineering company and they will do it for you for cheap, if you speak to them nice, they may even do it for free!
I have had TIG sets before and you want someone who can properly TIG weld and not just someone who can melt some metal over the crack, especially when its going to be taking a structural load, i.e. bike frame.

Tread careful if its an expensive frame, it could well have quite a high percentage of magnesium in the alloy, and it's no fun to end you're life in a huge flash of white light.

Any form of aluminium welding is very specialised, and as Danoh says, an alloy can be even more specialised.

The idea of an amateur or even a steel welder attempting an aluminium job is a farce.

Get aluminium wire for mig. I've never tried it but it's more delicate than steel.

do you have picture

To reiterate DD's comments - Ally welding is about as complex as its gets, for something that you'll be putting a lot of load into, the material needs to be immaculately clean with no impurities or dirt. Chemical cleaning would be recommended.

If its an expensive enough frame to warrant the repair, its probably an exotic enough alloy to not really be a feasible weld.

dont know what or where to go as it was a 2k bike !

Try AMF engineering on the croft bussiness park Brombourough 0151 346 1166. They always used to be able to weld Ally, I think they still do.

Cripes. Full marks for breaking it there though. Good effort! It'll need all that paint stripping off for a start.

Do you not think you'd be better off ripping all the good stuff off and buying a new frame? I can't see you'll ever get a structurally sound repair so close to that pivot.

-> http://www.chainreactioncycles.com/Categories.aspx?CategoryID=625

Heres a suggestion (far from ideal) -

1. Drill each end of the crack out with a 3mm drill to stop it spreading.

2. De-tension the rear shock and remove the pivot.

3. Get yourself a good quality seat post, cut the top off so its merely a tube with no right angle, drop it (or force it) down the tube overlapping the crack, then drill it all the way through above and below the crack to bolt it in place.

Its a nasty fix, but it might save you a frame and a lot of very invasive welding, that will ruin all your paint and probably distort the frame.

Sympathy to you bud. Nasty.

EDIT: By the look of it though, the bosses that mount the pivot and top tube may well interfere with the consistency of the seat post, so a tube may not go all the way down it - worth a look though.

To be honest even if you did weld it i'd say in 12 months it will be back.

dan's suggestion with a seat post down it is a good idea. get an enineering firm to turn a solid piece in a transition fit with M8 female thread in one end so a stud bar can aid fitment to the correct depth.

Drill the frame in 4 points (2 top and 2 bottom) so you can pool weld from frame to boss inside the frame.

Then repair the original split. This will stop the frame twistin from the heat.

Try TSW engineering in Brom, maybe get it done as a forgeiner.

But first - check out the Kona Warranty ....

SOURCE

Note the European Warranty is separate ...

That says "shall be free of defective materials or workmanship", that is a crack due to being used too hard, not defective materials or workmanship. you will be best off trying to repair yourself because it will cost you more in postage than getting it TIG'd locally.

I think you could argue its a flawed design as the load from the seat-post and pivot both meet at that weld, the weld has acted as a stress-raiser and hence the crack has formed from the weld base.

Good luck whatever you try MrPhil's evolved version of my pikey fix sounds like the way to go.

Have you resolved this issue if not please Pm for details of alloy welding