Race chassis

[WilDun]

Thanks Michael,
A lot of very interesting stuff on there! it was available in most of the motorcycle mags and books then but there's hardly any real technical stuff in the mags etc these days, (all glitz and glamour instead), but we can now get it easily and quickly on the net instead.

However, I'm not really into the politics of companies trying to grab the upper hand etc. - these problems were sorted years ago and I haven't heard of Waddon since then.
Really just looking for a basic recipe for a 'middle of the road' experimental bike to dabble with (but not to ride) till I can't do that anymore (I would also like to fly planes, but my wife said "over my dead body"!).

Must say that if so much info was was as easily accessed back in my younger days, I would probably never have got married - wouldn't have had time to even consider that (I still could have grabbed the odd tender moment on the run though!).

However, I did do just that (marry that is) with no regrets, but ....... if only I had married into money, I could have fed my bike habit!

[Grumph]

Michael's pretty much covered it Will. There's a point where tube thickness gets too big to comfortably bronze weld. Personally, knowing what's on the NZ market in mild steel seamed tube, I'd use 1.8mm wall, around 2.25 - 2.5 inch OD. Rather than the old SWG thicknesses it's sold in metric sizes - 16SWG is 1.6mm so 1.8mm is just a tad heavier. From 2.0mm wall I get major joins TIG welded.
Most of the steel suppliers will sell you a 5M stick - and cut it so you can get it home.

For the seamed mild tube, i use a biggish soft fillet of manganese bronze rod. Soft tube, soft bronze.
For a better quality tube - less liable to crack - I've used nickel bronze. I don't like using it on the soft ERW stuff as the joints finish up stiffer than the tube...


As an aside, I'm going to have to stand further back when my mate TIG's stuff for me now - I'm told the new pacemaker doesn't like it....

[WilDun]

Michael's pretty much covered it Will. For the seamed mild tube, i use a biggish soft fillet of manganese bronze rod. Soft tube, soft bronze.
For a better quality tube - less liable to crack - I've used nickel bronze....... I'm going to have to stand further back when my mate TIG's stuff for me now - I'm told the new pacemaker doesn't like it....

Think you might be right about the pacemaker!

A pacemaker is about the only thing I don't have, and I'm determined to have a go at TIG!
So do you guys think it's not really necessary to go to seamless tube? - Probably not really important for me as I'm only dabbling and not aiming to embark on a career of bike building or racing - but who knows, if I could by a miracle get one on the track, maybe some young guy could test it for me.

[Grumph]

Think you might be right about the pacemaker!

A pacemaker is about the only thing I don't have, and I'm determined to have a go at TIG!
So do you guys think it's not really necessary to go to seamless tube? - Probably not really important for me as I'm only dabbling and not aiming to embark on a career of bike building or racing - but who knows, if I could by a miracle get one on the track, maybe some young guy could test it for me.

Hey, I'm now idling comfortably at 60 BPM and don't want to upset that...
Yes, i'm saying that for your purposes, seamed mild steel will be quite adequate. One big plus is that it's pretty ductile as received.
The optional DOM tube which is nominally the same steel and is available to order, is often not ductile at all...at least here in NZ anyway.
I know one old school frame builder here - with plenty of UK experience - who uses it. BUT he always does a bend test on sample pieces before using a particular stick. His rejection rate is high he tells me...Too costly for me.

If you can gas weld they tell me you should be able to TIG - I can't as my eyes don't adapt fast enough. So I'm happy with gas...

[WilDun]

Hey, I'm now idling comfortably at 60 BPM and don't want to upset that...
Yes, i'm saying that for your purposes, seamed mild steel will be quite adequate.
If you can gas weld they tell me you should be able to TIG - I can't as my eyes don't adapt fast enough. So I'm happy with gas...

Yeah, you wouldn't want to upset that rythm!

I used to be a dab hand at bronze welding on tubular steel, but funny enough I never did much actual gas welding. I have (once or twice) had a go at TIG and I daresay that like everything else, practice will make perfect - no doubt I could master it, but with the price of Argon that could be expensive if I'm a slow learner, so I'll dive in at the deep end and do the least important parts first!

Brazing (bronze welding) I always enjoyed, but that was using vapoflux (which worked a treat) and was in the acetelene line, this was at a factory where I used to work, - they also had great bending gear which I loved to use! - I guess I was a bit of a thief really .

Nowadays even though I have the welding torches etc. I just can't afford the gas! I have heard though that it is possible to use (much cheaper) LPG as a substitite for acetelene, ie for brazing??.

It's all just a thought as yet, but I'd like to make it a reality as soon as I've mastered my foundry work of course! - then I can finally kick the 'bucket' in peace! (excuse the pun!).

[Ocean1]

Nowadays even though I have the welding torches etc. I just can't afford the gas! I have heard though that it is possible to use (much cheaper) LPG as a substitite for acetelene, ie for brazing??.

You can use Propane/OXY for brazing, which is a fair bit cheaper, but not Propane by itself.

For very light stuff you can use straight MAPP gas, but probably not for 16swg tube and certainly not with any of the above bronze rods.

PS: you'll need to damn near double the tip size.

[Grumph]

Brazing (bronze welding) I always enjoyed, but that was using vapoflux (which worked a treat) and was in the acetelene line, this was at a factory where I used to work, - they also had great bending gear which I loved to use! - I guess I was a bit of a thief really .

Nowadays even though I have the welding torches etc. I just can't afford the gas! I have heard though that it is possible to use (much cheaper) LPG as a substitite for acetelene, ie for brazing??.

I got offered an inline fluxer some years back - but after finding out what a flux refill cost at the time, I declined it. With good cleaning practices on the workpiece, you can do without it.

Gas in NZ is a perpetual problem. BOC have had almost a monopoly for decades but if you look around there are now alternatives. Down here, at least two mobs have started up then been bought out by BOC...We've still got a couple going though who are cheaper than BOC. One here in ChCh is doing Acetylene cylinders - leased - which actually come with a gauge...Another - Southern Gases - is bringing cylinders in from Aussie. They're local to me so they're who I use. Ask around in the trade local to you Will, often these places don't advertise.

[WilDun]

Gas in NZ is a perpetual problem. BOC have had almost a monopoly for decades but if you look around there are now alternatives........... often these places don't advertise.

There are quite a few small outfits up here (Auckland) too - recently when I was in hospital, there was a young guy in the other bed who said that he worked for a crowd who refilled cylinders, sorta got the impression that they would fill just about any cylinder cheap, but I guess there is a very fine line between cheap refillers and cowboys and it is a dangerous business with the non-inert gases - even with the inert gases sometimes!
I would like to bronze weld again, but having a little TIG machine now - the only real reason for building a frame was to get familiar with using that and I think I should probably persevere and learn to use it properly in the meantime.

[Grumph]

Did you realise you can bronze weld using a TIG plant ? Seen it done but don't know the gas requirement.
Google is your friend...

[WilDun]

Did you realise you can bronze weld using a TIG plant ? Seen it done but don't know the gas requirement.
Google is your friend...

Yes, I had considered that - I once saw it done on YouTube but I was not impressed by the spread of the bronze, the bead looked a bit too concentrated (as in a weld) but I'm sure it could be better done with a bigger ceramic and spread out a bit by having the tip a bit further back into the ceramic - I dunno of course, but just an idea, somebody must be familiar with the process.

[dark art]

Yes, I had considered that - I once saw it done on YouTube but I was not impressed by the spread of the bronze, the bead looked a bit too concentrated (as in a weld) but I'm sure it could be better done with a bigger ceramic and spread out a bit by having the tip a bit further back into the ceramic - I dunno of course, but just an idea, somebody must be familiar with the process.

I have TIG brazed and have some rods around. Sil-bronze is the stuff I used. I am not a good welder but it seems it work best on mild steel if fusion/brazed at the same time. It is possible to braze cast iron and some inox stuff as well.
The beads seem wider than TIG fusion but not like gas brazing, gas requirements are pretty much the same like fusion welding, since I weld a lot of thin stuff, use low amps and my argon is set around 3.5 l/min.

[WilDun]

I have TIG brazed and have some rods around. Sil-bronze is the stuff I used ......... it seems it work best on mild steel if fusion/brazed at the same time.

I certainly could not be called a good welder either!
Not quite sure what you mean by "fusion/brazing" does that mean "tinning" - ie when a thin layer of braze is applied before applying the fillet?
I always found that fusion temperatures (as in fusion welding on mild steel) burned the metal and the bronze would not take unless the part was properly cleaned up to remove the oxide etc, but then I may be totally on to the wrong wavelength here!

[dark art]

Not quite sure what you mean by "fusion/brazing" does that mean "tinning"

I should have been more clear, after re-reading my post, it seems very confusing

The TIG rods I have seem that can be used both to weld (fusion) and to braze (tinning). If not too much temperature is used (or the bronze start to burn), fusion weld with sil-bronze rods seem to produce a acceptable weld.
The best way I can weld mild steel with them seem to be both fusion and brazing at the same time. Create a small puddle and let the bronze flow at the sides of the puddle. This maybe because of lack of technique and skill but the hammer tests (not much scientific huh) hold pretty good.

Later today will post the spec of the rods and maybe some pictures.

[Grumph]

If you've got the spec of your rods you're doing better than us here in NZ....The major welding suppliers here only supply what they call "manganese bronze rod" and "nickel bronze rod" over the counter. Yes some rods with known spec are available to special order but if you don't know what's available they won't tell you...
I went in to one of my local suppliers with a photo copy of the rod spec page from "The Racing Motorcycle" and it was greeted with astonishment. Where did you get this ? Can we have a copy ? Ha bloody Ha.
From my own enquiries, the manganese bronze rod is roughly the old basic sifbronze and the nickel rod is pretty low nickel content.

[WilDun]

If you've got the spec of your rods you're doing better than us here in NZ....From my own enquiries, the manganese bronze rod is roughly the old basic sifbronze and the nickel rod is pretty low nickel content.

So I guess that with common or garden mild steel I should use good old common or garden sif bronze rods (I think that the "SIF" originally referred to Suffolk Iron Foundries who produced them - amongst a lot of other stuff).
I'm sure that is the bronze I used for the frame I built all those years ago but I'll never know because the factory doesn't exist any more and I never really knew anyway, but I used their premises, their gear, their time, their materials (borrowed and stolen respectively ) and everything worked fine! - no bloody wonder the factory doesn't exist anymore!
In fairness to myself though, must say I did buy the seamless tubing from somewhere else! (HS White maybe??).

I think I'll just use TIG welded tube, but also have an (experimental) stab at bronze welding with TIG as well and see which turns out best, - ie with my "suck it and see" attitude and the seemingly questionable bronze we have here!

That attitude actually worked out well with my foundry furnace burner!