Frame Building questions

[tgaydos]

I am looking to get into building custom frames for myself, I'm wondering what type of welding would be best for this.

I know there's more than one way to skin a cat and build bike frames, so for someone with no previous knowledge of welding which is one of the easiest to learn that will provide good results?

-Travis

 

[Tony01]

I have no welding experience. I asked the very same question and many hours of research brought me this:

Short answer-
I've found that the cheapest useful method for bike frames will be MIG welding with flux-core wire or with gas shielding. I think even the cheapest MIG flux core welders will allow a gas hookup for when you rent Ar and CO2, so you could start on the cheap with flux-core.


Long answer-
Research gave me a very wide variety of opinions with a common denominator: "take a welding course and then you'll know for 90% what equipment you need". This answer was very frustrating.

Of course me being a cheapskate, I won't be taking a course. So I did even more research.

Worst to best is AC arc, DC arc, MIG flux core, MIG gas, TIG.
The price difference? basically add a 0 to the price for each step up between arc, mig, and tig. i.e. $30, 300, 3000+. I almost jumped the gun on a $50 AC welder, until I started doing more research and found that it is difficult not to burn through thin metal with AC stick.

In fact, all this research and needing to buy the welder, then spend a few days or weeks learning how to use it, has just caused me to look for a project that doesn't require so much welding.. something I could take to the local welder for $20 (like stretching a motorcycle swingarm.. etc). Suddenly building my own frame doesn't seem so attractive an option!

 

[curtisfox]

Tig would be the best as ya can weld anything with it, Aluminum,Stainless,even braze with it, Basically the same as oxy acetylene, but with a faster heat. Is the best for body work. And if your young enough you can recover the coast by doing small jobs for other friends....Just my opinion..................Curt

 

[Venice Motor Bikes]

The frame is arguably the most important part of the bike!
If your frame breaks at the wrong moment?, death can occur!

Just because you managed to weld two pieces of metal together doesn't mean the weld will hold.

Please do a lot of homework & take some welding classes BEFORE trying to build your own frames.

 

[racie35]

I think you'ld see kits or pieces available for people to melt together if it were easy to do.
There's the clue.

 

[tgaydos]

i'm trying to get together with a local certified welder to learn some of the basics, i'd of course do rigorous stress testing before ever putting a motor on it. and it sure as **** wouldn't be on my first custom frame.
that being said i would like to take the local certification course through my community college, i've heard it's one of the best in state. it's either that or i try to learn from my uncle who owns his own manufacturing company in the woodburn oregon area.

i've thought about it and done my research just the same and am still on the fence as to how i will approach it. i'll probably end up taking the course at the community college, but that won't be until after summer.

 

[2door]

Take the welding classes then practice, practice, practice. Building a frame for a motorized bike isn't something for the amateur to take on.

Even if you were a qualified professional welder you need to consider the legal side of building and selling bike frames. Protect yourself from 'personal injury' lawsuits. That might prove harder and more expensive that the actual building of the frames.

Tom

 

[racie35]

Set up properly as a business....you may be able to sue yourself if you do it wrong and get hurt. I think

 

[Gbrebes]

I agree with everyone else that TIG welding is the best choice, but the equipment can be expensive. I would also like to offer acetylene/oxygen torch and brazing as a valid means of fabrication. It can be a more economical way to go.

I modified my bike frame using brazing and it has worked out well. Every joint I welded had an internal sleeve inside the main tubing to strengthen the joint. I did end up developing a crack in the front loop near the bottom bracket. I rebuilt this area with two gussets attached to the bottom bracket and welded to either side of the tube.

I also agree that the frame is the most important component, strength wise, and that extra attention must be given to stress points, like head tube, rear chain stays, dropouts, and bottom bracket.

Good luck,

Gilbert

 

[tgaydos]

i'm not looking to sell them only to build one or two for myself.

 

[Tinsmith]

Have a real welder do the frame work for ya. Cheaper in the long run.

Dan

 

[Agreen]

I can attest to the fact that welding thin metal like bike frames is not easy if you've never welded before. However, with some experience, you can do it right with a regular $100 welder from harbor freight. I've seen some welds come from good welders on the HF flux core unit that put some mig welds to shame. It's all in the preparation of the metal and your skill/patience level.

I would not start with a motor bike frame first. You could weld up a regular pedal bike and give that a go if you wanted to try it. For the cost of a welder, a pipe bender, and all the materials... I'd seriously just buy a frame. I can weld fairly well (with my own quality Lincoln welder), but I'm not about to spend more money on a pipe bender to make a frame.

Just my opinion

 

[KevininPa]

I did not read all of the posts so this was probably said already........wait for it............TIG! I do not have a motorized bike yet as I am here doing research on building one. But I am a former welder (Navy and civilian for a few years, even had a lot of certs). Tig( if done properly and with patience) is your purist and strongest weld. Also perfect for steel and aluminum frames due to thinner metals. And actually quite easy and relaxing once you get the knack. Quite a bit like oxy-acetylene welding. Just a little more high tech. Have fun and good luck!

And now my information search continues!

 

[Tony01]

Having more experience now I can say tig is the only way to go. Apparently tig welds "cooler" than other types and therefore is better for frames because it less affects the microstructure of the metal tubing it joins. I think the best way is to buy any welder just for tacking, then take it to the pro to do all the tig welding. In fact it's what I'm soon going to be working on right now, building a jig and tacking a new rear suspension setup then take it to the pro to tig it.

 

[exokinetic]

I agree with everyone else that TIG welding is the best choice, but the equipment can be expensive. I would also like to offer acetylene/oxygen torch and brazing as a valid means of fabrication. It can be a more economical way to go.

I modified my bike frame using brazing and it has worked out well. Every joint I welded had an internal sleeve inside the main tubing to strengthen the joint. I did end up developing a crack in the front loop near the bottom bracket. I rebuilt this area with two gussets attached to the bottom bracket and welded to either side of the tube.

I also agree that the frame is the most important component, strength wise, and that extra attention must be given to stress points, like head tube, rear chain stays, dropouts, and bottom bracket.

Good luck,

Gilbert

I have to agree with Gilbert here, I have been teaching myself to weld for the past two years, staring on small projects, and working into more complex ones.

I started with a cheap MIG and a cheap TIG, and I learned after many poor welds that I should start with the basics if I am teaching myself

I started oxy-acetylene welding, and have been making progress in my welding proficiency much faster.

If using steel, brazing, using lugs, is preferable to TIG for the same reason TIG is preferable vs other types: much lower heat needed to bond the joint. This means even less thermal distortion, and a stronger joint.

If it has to be aluminum, TIG is the best way to WELD it, hands down. But that doesn't mean you can't use the lug technique and glue the aluminum into the lugs, many OEM bicycles are constructed like this, with a bond many times stronger than its welded counterpart.

There are also many resources -http://www.paragonmachineworks.com/mobile/ comes to mind- that you can go to for pre-made frame sections, and the various lugs to join them together.


I also agree wholeheartedly with the members advising caution in building you own frame.

This does not mean you are not capable of building a mechanically sound motorized bicycle frame. Just make sure you do all the research, and TRULY understand the forces that the bicycle frame has to withstand under the strain of driving at speed.

I wish you the best of luck!

 

[mogollonmonster]

Ok Tgaydos, I'll chime in.

My grandaddy worked in the car depot of BNSF for twenty years, welding boxcars for the Atkinson Topeka and Santa Fe Railway, back before the big merger. I've been welding for as long as I've been painting which is just about since I could walk. I'm not certified, although I have no doubt in my skill. I would still, and in fact plan on, contacting a professional welder. If for no other reason than, you'll have someone to blame besides yourself.

Its your life, do what you want, literally. I say take a class or three, get certified, buy a welder (I like Miller, my Thunderbolt AC/DC was recently stolen and it was a fine machine) practice and learn. Better yourself,strive for more, knowledge is power, friend. Nothing wrong with learning something new, or old for that matter.

 

[tgaydos]

i completely agree with the desire to learn, i've kinda put frame building on a back burner for now.

 

[mogollonmonster]

Just so long as you keep the fire lit bud, I'm curious to see what you come up with. Different people with different ideas lead to innovation and progress for everyone. In fact I have an idea for you to chew over, while your waiting...

The problem with rear suspension is chain tension. On a rigid build, not much of an issue. Spring tensioners and these motors don't get along. Golf carts, some go karts, and a number of other things, mount the engine to the rear suspension, eliminating the chain tension issue. I'm sure you can see where I'm going with this. It would be interesting to have to independent builders tackle the concept, then merge ideas for a final product... Could make worthy competition for the skyhawk...

 

[tgaydos]

i was going to look at dirtbikes and figure out how they do it and see if it's something i might be able to take away, for suspension.

i think a way to do something like that would be to put the pivot point in front of the engine such as using the base plate mount for a four stroke as part of the frame and have the front swing separate or just sticking with front suspension.

 

[1hp]

MIG is a great simple way to start , but after few project youll want a tig and learn brazing , welding is addictive ..

bought a baseline 250$ mig flux core kit , and after a month of youtubing and training , i was pretty good at it , i already 'Attempted to build a tube bender' 'Fixed the car trailer' 'built 2 custom bikes frame/fork including a cargo' 'a bike trailer' 'a springer fork' all in this single first year ... but i did study and practice allot to make sure i was getting it right