Welding Tips and Tricks

I have a couple of 1960's vintage BMW motorcycles that I am restoring.
Both bikes need some frame repairs and some of the repairs require welding.

I have from a reliable source that the material used to build the frames was "St R 2 G" and the welding process used in the factory was Arcatom welding with CO2.

Have looked up the Arcatom welding process and figure TIG should be able to do the job. But would like advice on which filler rods to use (as I can't find any reference on the web to St R 2 G" steel composition) and also when would it be advisable to go to a Argon helium mix shielding gas rather than the pure argon which I usually use?

Thanks in advance
Mal

Mal,

I don't think you'll go wrong with plain ol' E70s-2. It's the filler of choice for most steels including 4130 chromoly (this is a break point--- some will argue for E80d-2 on 4130, but there are highly successful welds out there, including on airplanes, with the E70).

Don't take my words as gospel until one or two of our serious cycleheads comment as well.

Steve

P.S. "Mal"? Short for something? A fan of the character Malcom Reynolds on Firefly? Or just saying "bad" in Latin? Just curious. The way people choose usernames and sign their posts interests me.

I'm with Steve.

Whether carbon steel or moly, I use ER70S2 on frames.



Kym

Would 309l work too? Jody has said it is a very high strength weld for steel or is it under matched for chromoly?

exnailpounder wrote:Would 309l work too? Jody has said it is a very high strength weld for steel or is it under matched for chromoly?

I'd be iffy on this. A vintage '60s frame is unlikely to be a high alloy where I might consider this.

Just a personal point of view...

Steve S

exnailpounder wrote:Would 309l work too? Jody has said it is a very high strength weld for steel or is it under matched for chromoly?

309L would be for welding regular mild carbon steel to stainless grades wouldn't it? Never read about using it to weld mild-to-mild. For chromoly, I've read using austenitic SS filler (ie: 304,308,312, etc) is a big no-no. Austenitic SS with insufficient base metal dilution can lead to a very hard and crack-sensitive weld deposit(!). (Source: Gerry Uttrachi, Advanced Automotive welding, 2012 Cartech). I agree with those saying that it's hard to go wrong with regular, ol' ER70-S2. So long as the joint is cleaned and prepped properly, and a correct bead profile is created, as with any other joint, I'd say the chances of making a successful weld are high.

Oscar wrote:

exnailpounder wrote:Would 309l work too? Jody has said it is a very high strength weld for steel or is it under matched for chromoly?

309L would be for welding regular mild carbon steel to stainless grades wouldn't it? Never read about using it to weld mild-to-mild. For chromoly, I've read using austenitic SS filler (ie: 304,308,312, etc) is a big no-no. Austenitic SS with insufficient base metal dilution can lead to a very hard and crack-sensitive weld deposit(!). (Source: Gerry Uttrachi, Advanced Automotive welding, 2012 Cartech). I agree with those saying that it's hard to go wrong with regular, ol' ER70-S2. So long as the joint is cleaned and prepped properly, and a correct bead profile is created, as with any other joint, I'd say the chances of making a successful weld are high.

I can't find the link right now for you Oscar but Jody did a video about welding mild with 309l and/or supermissleweld. I have seen so many of his vids I can't remember which one it's on. If I find it, I'll post it. I was just more curious than anything after my debacle with welding up that cromo tool that kept coming back broken.

I do a fair bit of work on vintage bikes and always use 70-S2, straight argon, and a 3/32 tungsten. The tubing is pretty darn thin, so watch your heat and use a 1/16 wire if the area is narrow enough. Using a pedal, I probably end up applying about 25-40 amps maximum.

exnailpounder wrote:

Oscar wrote:

exnailpounder wrote:Would 309l work too? Jody has said it is a very high strength weld for steel or is it under matched for chromoly?

309L would be for welding regular mild carbon steel to stainless grades wouldn't it? Never read about using it to weld mild-to-mild. For chromoly, I've read using austenitic SS filler (ie: 304,308,312, etc) is a big no-no. Austenitic SS with insufficient base metal dilution can lead to a very hard and crack-sensitive weld deposit(!). (Source: Gerry Uttrachi, Advanced Automotive welding, 2012 Cartech). I agree with those saying that it's hard to go wrong with regular, ol' ER70-S2. So long as the joint is cleaned and prepped properly, and a correct bead profile is created, as with any other joint, I'd say the chances of making a successful weld are high.

I can't find the link right now for you Oscar but Jody did a video about welding mild with 309l and/or supermissleweld. I have seen so many of his vids I can't remember which one it's on. If I find it, I'll post it. I was just more curious than anything after my debacle with welding up that cromo tool that kept coming back broken.

Welding carbon steel with 309 is a common test procedure for stick and TIG. I "think" the boiler animals use 309 for roots in water wall repairs for the corrosion resistance, but in practice it's only the root, not all the way out.

For motorcycle frames, I'd have to see some serious study before I'd support it. Not saying it can't be done, but to my knowledge, Oscar (and his source) is correct.

Steve S

malmac wrote:I have from a reliable source that the material used to build the frames was "St R 2 G"

Likely that's DIN 1624:1987 St 2 G, aka 'Werkstoff 1.0330', aka ASTM 1008/CS. Also known as 'mild steel'

I'd say TIG with ER70-S2 will be fine

Bye, Arno.

arno
would you happen to know which steel was used
in the 1960-70'S BSA frames?
craig

Thank you for all the replies. I will try some ER70 S2 and repair the centre stand first to see how it goes.

My user name for interest is malmac - really simple, my full name is Malcolm McIlwraith - so for short malmac - also when we did professional photography it was malmac photography.

Thanks again for your help everyone. Here is a pic of the bike I am getting ready to restore - doesn't look to bad at first glance but I am repairing a pretty dodgy previous rebuild coupled with engine / gearbox wear and tear.

Mal

Nice old bike, Mal - looking forward to seeing progress pics.


Kym

Looks good are all the parts there? It looks complete!
On another note did someone mention Bsa!

The bike is all there - however there is also a second bike in pieces - so I will be restoring both sort of at the same time - without being too pedantic.

The first task is to sort out the steering head bearings on the second bike - then alignment of the frame and then re welding some earlier crap repairs and also bush/ or repair several worn pivot points (centre stand and such).

Lots of small steps.


Mal

Mal -

Are earlier repairs in steel or bronze? I find a lot of repairs done on old motorcycle frames with OE process and bronze filler.

I always tell the owners to look after their suspension and not overload their bikes. Have seen lots of frame damage simply caused by riders getting around on sacked out suspension that passes bumps and vibes straight on to the frame.


Kym

motox wrote:would you happen to know which steel was used in the 1960-70'S BSA frames?

Oh dear.. British bikes... Likely they chose to use whatever some guy found in the back of a shed somewhere

Kidding aside.. I doubt it's going to be anything special for run of the mill bikes that were not some special one-off race build. Plain mild steel is the most likely. Tiny differences here and there in the carbon content of the steel, but probably nothing to get too worried or excited about.

I'm no 'bike buff', so I wouldn't know the specifics. Possibly there are special snowflakes out there frame-wise in some production series (eg. homologation runs for race classes) that used some different materials, but then you'd need someone who has detailed background info on the production series and processes used.

Bye, Arno.

British bikes?

Steam pipe, scaffold poles...whatever was lying around.



Kym

British bikes?

Steam pipe, scaffold poles...whatever was lying around.

thanks guys ill call a plumber
craig

MosquitoMoto wrote:Mal -

Are earlier repairs in steel or bronze? I find a lot of repairs done on old motorcycle frames with OE process and bronze filler.

I always tell the owners to look after their suspension and not overload their bikes. Have seen lots of frame damage simply caused by riders getting around on sacked out suspension that passes bumps and vibes straight on to the frame.


Kym

Kym


No luckily the repairs are not brazed , they are just really badly welded and in some cases the parts have been welded in the incorrect location to fit non standard parts rather than forking out and buying the correct part (seat mounts for example).

So I will have to grind off the incorrect bits, machine up replacement tabs and weld them in the correct position.

Mal

Mal -


I see. I reckon it will be well worth the effort, it looks like a lovely old bike.



Kym

You could probably weld it with a coat hangar and it would be ok. It's probably not a chromoly frame. Coat hangars are tough.

https://youtu.be/POPxWaBGMqY

Coat hangers have done great things for humanity

I use them for non important stuff all the time. I get 10-12 every week on my uniforms from work. They charge me 2$ to wash them and I get all that filler for FREE!

For those who have read and recall "Zen and the Art of Motorcycle Maintenance" I find myself reflecting on the part where the author wanted to fix his mates BMW with a small piece of shim cut from a beer can and the owner of the BMW was horrified. Now I am faced with repairing my bike with a "coat hanger" - must admit it is an option - but not one of those coated ones I assume (pun intended).



Mal