Any welders around?

whyamihere

Having found Ceeway, and seeing that I can get a full set of tubes etc for just over £100 (though I would probably get my own spec tubes), it got me to thinking of building myself a custom winter/commuter bike... Having looked at the website for my local college, I can get a welding course for £265 for an 18 week course, 3 hours a week, which seems fairly reasonable as it's a useful skill to have anyway. They offer Mig, Tig and ARC welding, but which should I go for?

From what I've found so far, Mig will give me neater welds, but ARC is easier for beginners. Is this accurate?

jimmcdonnell

Done a lot of welding through DT teaching, strictly amateur but with proper training; all I'll say is oxyacetylene is by far the easiest.

Since that's not an option though I'd recommend MIG or (even better) TIG. Arc seems to be short for Arcane - it's like voodoo. At least with MIG or TIG once you have the current and rate of feed of the wire sorted it's like using a pen it's that straightforward. Look online for courses at your local college.

However - I'd think learning to weld is the least of your problems compared to actually assembling the parts of the frame accurately? Bike builders use complex jigs and large optically flat tables to make sure the angles are correct to within narrow tolerance, don't they? You could end up with a custom bike that looks like it's been made by Picasso in his most cubist period...

Good luck, keep a photo/video diary and pass on your experiences, I for one would be interested in showing it to students...

(Edit - I really ought to read all the words in a post, as you clearly said you've already scoped out your lcal college. :oops: )

rockmount

I'm not a welder, but work with the welding process (aerospace), TIG (tungsten inert gas) is the preferred method. Not quite as easy and straight forward as the previous post suggests, I can't see you having a mechanised TIG setup, manual setups are costly enough, and expensive to buy and run (properly). Our welders go through a comprehensive approval re-approval process. It would be incredibly easy to mess up your frame, too much current, and you'll burn through it, too little and your weld will lack penetration, and be weak .... the pitfalls are many. As the previous poster said, the jigging would be a nightmare too, we use pretty substantial jigs for joining a couple of bends in a simple duct for instance ...

Sorry to be so negative, but it really is quite a task. I think a more realistic project would be adhesive joints, but I'm not sure if such kits etc are readily available,

whyamihere

The jig isn't a great concern to be honest. I've been working with wood for a very long time, so creating a jig to hold the tubes in place should be well within my ability. The rear triangle jig would be more of a challenge, but I'll be able to come up with something to hold it all in place.
A friend has suggested contacting a local metal working shop and performing a general workshop underdog role in exchange for lessons, which I feel is worth looking at...

Jim - I shall keep a photo diary, I'll hopefully be doing it during my summer off from uni...

ademort

As a constructer i use welding as part of my job. I,ve also done MIG, TIG and arc welding. IMHO the easiest to learn is electric arc welding, just stick your electrode in the holder and your,e off.,however i would definitely not recommend it to a beginner for welding bike frames. To weld to that standard you need to be very good, if there are any welders on this forum i am sure they will agree that welding a bike frame is a real specialist job. I,v e spoken to fully Loyds coded welders about this in the past and the majority would not fancy welding a bike frame. If you would still like to go on with this project, i would suggest putting plenty of weld on the lugs and grinding them down so they look neat, any painting or spraying of the frame should then look ok.
As far as MIG welding is concerned the two most important elements to remember are the Voltage and Speed of the wire. All machines have 2 dials so that you can regulate both . Depending on what type of material you are welding you will also need to have the correct wire type. Imho this would be the best to learn for a beginner. Biggest mistake people make when using this process is getting gas in the weld. If you do a course then all of this will be explained. Tig welding is imho the best way to weld a frame, finish is smooth and really tidy, and needs much less preparation for painting, spraying than the other two methods.
Whatever you decide to do please keep us informed and good luck Ademort

synchronicity

Arc welding is basically the crappest method of them all (and I studied them in my Materials degree). At least when I had a go, the welds looked like shite. I wouldn't want to weld a bike using arc welding. Most steel frames use lugs and are brazed. Either that or TIG or even MIG. I could be wrong, but I'm not aware of any that are arc welded... :?

Monty Dog

Bike frames are typically brazed with lugs or TIG welded. Tubes are pretty thin and it's very easy to blow a hole in a tube wall. Tube prep is critical if welding i.e. getting the mitres right and often require a high level of precision machining or hand filing. Jigs also need to be pretty stiff because of weld 'pull' i.e. a cooling weld can distort the frame.

Gavin Gilbert

http://www.daveyatescycles.co.uk/

A 24 month wait 'lo

And if you want proper iron I've still got a few sets of 531DB knocking around the shed.

don key

I would have reservations about wood, it is easy to mess up and fixing mistakes takes new tube, I did welding, gas, tig and arc twenty six years ago and I don't miss it. When you get good it can be really satisfying , esp. the gas.

John.T

You could try fillet brazing. Quite a few frames were made that way some years back.

whyamihere

John.T wrote:

You could try fillet brazing. Quite a few frames were made that way some years back.

That was actually the original plan (means I can use some lovely lugs for a classic look). The problem is that nowhere around here offers tuition in brazing, and I'd prefer to be shown how to do it by a professional before trying it myself.

Martin Van Nostrand

Depends on what you are welding, but some metals only really work with TIG.

This seems like eventually a lot of money and effort, and would likely be cheaper and better to be done by a professional.

Many bike builders rely on fillet brazing because it can be self-taught. Even cheap frames are robotically brazed these days.

Seems to me, if you want to learn a skill with potential career applications, learn carbon fiber composite construction, molding and layup.

John.T

No lugs needed for fillet brazing. Normal brazing using lugs is fairly easy and is rather like a hotter version of soldering copper pipe. Care needed not to over heat the steel or the temper is lost.

whyamihere

Sorry, I was unclear. Original plan was for normal brazing, partly because I do love lugged frames. My old school has brazing torches, and Ceeway will do cheap scrap tubes and lugs for practising, so I may try to get some practise in there and see if I can do without the course. I have brazed before in the past, but it was a few years ago, so I may as well see if I can still do it...

BigStu2

Found this site
http://www.diydoctor.org.uk/projects/brazingjoints.htm
Might help explain a bit about whats involved in brazing, possibly the cheapest and best option. I assume you buying ceeways columbus tubing and not aluminium.
Buy a heap of frame lugs and scrap pipe and just practise getting the flow around the joint, controling the flame and dipping the rod to keep the molten pool moving along.
You'll find it easy to braze two pieces of metal as on the link but the trick is controlling your arms to go around a pipe at an equal distance to maintain the heat and rod application so the finished joint looks neat and is mechanicaly sound.
Even though it feels like a big project just remember that when the frame is in the jig and your applying the heat the joint will be finished in minutes not hours so get relaxed and you'll soon be laying down some smooth filleted welds 8)