what welder do you need for steel or AL?

Q

QueenOfSkulls

Hey... I would like to build a bike or 5 but I only have an old stick welder buzz box. its older than me.

I would love to do an AL frame. because their lighter and there is a ton of AL frames to work with.

What does everyone suggest?

Also is brazing an option with AL?

My strong suit is 3d design. And wrenching.
 
Ali is usually the domain of TIG for best results, but MIG & Stick can be done but requires and awful lot of skill and care.
Brazing is an option.
 
To weld both, you really need a TIG welder - I understand you can weld aluminum with MIG, but no direct knowledge of it.
But be aware that the cheap DC only TIGS will only be capable of welding steel - A TIG machine needs to have AC, to weld aluminum.
I've used the aluminum brazing rods, but only for non-stressed repairs - Fixing small pinhole leaks, etc.

The other problem, is that a welded aluminum frame should really be heat treated afterward, something that's not realistic on a hobby level.
I guess that's why most stick with steel - By the time you compensate for welded aluminum weakness, by upping the wall thickness of everything,
you're pretty much at the weight of a thin wall steel frame.
 
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Aluminium needs HF current, to break the oxide layer. Could be MIG (Doug from SV Seeker swears by it) or TIG HF-AC
It's also an aquired taste/skill for a welder, and one that doesn't come cheap. I have welded ali with my home setup, and I don't like it at all.

Working with older ali frames adds a layer of complexity. Removing any spek of paint, dirt, grease or oil is mandatory.

But, yes, brazing aluminium is an option, but then you need the old style, with lugs. Not cheap either.

No, I would suggest using the Brad way. Use steel. But to make life simpler, buy a hotglue gun for steel, a MIG.

The main reason I can work with Titanium and such, is because I invested a boatload of cold hard cash in my personal workshop, where I build way stranger things than bikes. And I'm willing to help others with parts.
 
maddox said:
Aluminium needs HF current, to break the oxide layer. Could be MIG (Doug from SV Seeker swears by it) or TIG HF-AC
It's also an aquired taste/skill for a welder, and one that doesn't come cheap. I have welded ali with my home setup, and I don't like it at all.

Working with older ali frames adds a layer of complexity. Removing any spek of paint, dirt, grease or oil is mandatory.

But, yes, brazing aluminium is an option, but then you need the old style, with lugs. Not cheap either.

No, I would suggest using the Brad way. Use steel. But to make life simpler, buy a hotglue gun for steel, a MIG.

The main reason I can work with Titanium and such, is because I invested a boatload of cold hard cash in my personal workshop, where I build way stranger things than bikes. And I'm willing to help others with parts.
Click to expand...
What strange things do you make besides bikes.???
 
Here is my welder. All 42 bikes on the main page were built using nothing more than this, a hand drill and angle grinder.
I also work outside on old saw horses.

9d10921641854af6a1ba9cdf11c75236.jpg

I also weld on the AC setting using only 3/32 6013 rod.
Since starting AZ, I have never owned or used any other tools.

Of course, this will not be much use for aluminum.
I would also not recommend following my plans using aluminum. You will need some serious frame redesign.


Brad
 
Radical Brad said:
Here is my welder. All 42 bikes on the main page were built using nothing more than this, a hand drill and angle grinder.
I also work outside on old saw horses.

View attachment 15

I also weld on the AC setting using only 3/32 6013 rod.
Since starting AZ, I have never owned or used any other tools.

Of course, this will not be much use for aluminum.
I would also not recommend following my plans using aluminum. You will need some serious frame redesign.


Brad
Click to expand...
Well I got the ability to redesign. and I normally work in 10ths of mm or hundreds some times. I wish I had access to a mill and lathe and proper tube bender. We would kick out some nice bikes.
 
The problem with a recumbent chassis is the metal is used as a beam. There is very little room to triangulate the main beam. Aluminium does not work well when used as a beam. You end up having to use thicker sections because of this thus ruining any weight saving and still ending up with a chassis that won't flex when it hits that pothole.

MIGing aluminium usually involves a spool gun as the soft wire won't feed the length of the torch like steel will. That requires a mig designed to take a spool gun.

TIGing aluminium requires an ac tig which are more expensive that the cheap dc only ones.

Brazing requires lugs (weight) and where would you source them from at the angles and joins that a recumbent chassis needs. You would need to design and make your own. Not impossible by any means but not simple either.

Glues exist that can hold aluminium car chassis together. Again it's lugs though.

I recommend steel for simplicity, long service life, cost and safety. The weight penalty will be minimal if any at all. Aluminium can and has been done for home builders but it's no easy task and if you do go aluminium please detail the build as it'll be of interest to all of us.
 
fatigue is another matter that has to be looked at.

Aluminium and titanium have a "finite" amount of flex , what will fatigue the metal ( real life deadly example, the Comet passenger aircraft, where that fatigue of aluminium was "enlarged" by design) Steel, as long not stressed over a certain limit, doesn't age/fatigue.
 
DodgeC said:
4310 variants too keep weight down?
Click to expand...
You mean 4130 type steel - Chrome Moly .
Yes, that's the classic way to keep weight down - All high-end bike frames used to be made with that kind of tube, and some still are.
But, they were brazed lug construction, mostly, or fillet brazed, until TIG came along.

What's interesting, is that aircraft frames used to be made with that, and OA welded - I have an old book on it, and it goes into great detail.
I learned to gas weld steel a long time ago, and it's not very hard to do, but the skill needed to reliably weld an airplane frame with that VERY thin wall tubing, with all the complex gussets and joints shown in that book? ............ No way I'd even try.
 
Popshot said:
The problem with a recumbent chassis is the metal is used as a beam. There is very little room to triangulate the main beam. Aluminium does not work well when used as a beam. You end up having to use thicker sections because of this thus ruining any weight saving and still ending up with a chassis that won't flex when it hits that pothole.

MIGing aluminium usually involves a spool gun as the soft wire won't feed the length of the torch like steel will. That requires a mig designed to take a spool gun.

TIGing aluminium requires an ac tig which are more expensive that the cheap dc only ones.

Brazing requires lugs (weight) and where would you source them from at the angles and joins that a recumbent chassis needs. You would need to design and make your own. Not impossible by any means but not simple either.

Glues exist that can hold aluminium car chassis together. Again it's lugs though.

I recommend steel for simplicity, long service life, cost and safety. The weight penalty will be minimal if any at all. Aluminium can and has been done for home builders but it's no easy task and if you do go aluminium please detail the build as it'll be of interest to all of us.
Click to expand...
What do you mean by lugs... I dont know all the lingo... and I can out design most peoples pants off. I just need to know wheel and pivot angles. I already have an idea for my crazy out-rigger tadpole. mainly I dont know where i want the height of everything or the seat placement or how I want to do drive train... think out rigger canoe or catamaran. Ideal you would sit with a friend between the main bike and outrigger and would pedal in a reclined state. it would be cool if it was fly by cable... aka cable stirring.

also with an ebike.

I mean I through together a 3d printed insert for my uno tin I just got. 15 mins to get the basics and 4 iterations to prefect.
 
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undertoad said:
You mean 4130 type steel - Chrome Moly .
Yes, that's the classic way to keep weight down - All high-end bike frames used to be made with that kind of tube, and some still are.
But, they were brazed lug construction, mostly, or fillet brazed, until TIG came along.

What's interesting, is that aircraft frames used to be made with that, and OA welded - I have an old book on it, and it goes into great detail.
I learned to gas weld steel a long time ago, and it's not very hard to do, but the skill needed to reliably weld an airplane frame with that VERY thin wall tubing, with all the complex gussets and joints shown in that book? ............ No way I'd even try.
Click to expand...

Thanks, used to do a bit of torch work with chromoly and nickel rods many moons ago. I haven’t TIG anything as thin as bike frame material and was a bit curious as to what material sizes would be vs the square tube here. Never tried tig or mig brazing.
 
A lugged frame giving a large surface area for brazing or glueing. The tubes slide into the lugs.

IMG_20220521_102328-1024x576.jpg


Working out the angles etc should be easy enough for someone familiar with CAD but making them is going to require a lot of skill in tube cutting and welding not to mention the ability to get them the same but mirrored at the two kingpin lugs. Welding would be easier IMO.

Lugs were used before such things as TIG welding were commonplace. The thin tubes used on frames couldn't be welded without distortion and/or blowing holes in the thin walls. The heat from welding also killed the alloys used at the time. Later frames could be welded thanks to TIG and better alloys that could be welded without the heat killing the structure of the metal. A recumbent frame can't use such thin walled tube as the frame is not in compression or tension but is a beam.
 
Very little knowledge and experience compared to above experts but all I can say is i was dissuaded from attempting aluminium by people who know their stuff ( ac Tig experience or pulsed mig needed, heat post treatment, more distorsion, surface oxyde to break, more prone to cracks )… steel tube welding is already hard enough to learn. I admire those who manage thin wall tubing with stick welders, I learnt on a dc Tig and thought it was well worth it.
 
Trickytrike said:
Very little knowledge and experience compared to above experts but all I can say is i was dissuaded from attempting aluminium by people who know their stuff ( ac Tig experience or pulsed mig needed, heat post treatment, more distorsion, surface oxyde to break, more prone to cracks )… steel tube welding is already hard enough to learn. I admire those who manage thin wall tubing with stick welders, I learnt on a dc Tig and thought it was well worth it.
Click to expand...
Do you still think tig is well worth it
 
When I was thinking about building a warrior, I went down the same road regarding aluminum. I ultimately decided against it when I realized that 'real' bikes and trikes made by the professional have wildly varying warranties. Aluminum frames (generally) carry a warranty of five years, while the steel frames were 'life time' warranties. I didn't really know why five years, but I didn't want to find out.

Looking back I'm glad I went with steel as my first build is about 3.5 years old and has over 1,000 miles on it, time moves fast and while I know 5 years isn't a expiration date, it's nice knowing the steel is able to last longer. You also mentioned brazing, not sure what parts you were thinking about, I have seen/heard that done with things like cable guides or posts for V brakes, I did both with mig on the builds I've done. No reason steel or tig would stop you using them.

"the days are long, but the years are short"
 
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