Electrode for sand rail chassis?

[BoyntonStu]

Your life depends upon the weld.

You are welding a DOM 1-1/2" Diameter 0.095" wall roll bar and chassis.

Would you bronze braze or weld for dynamic loading and for crash
worthyness?

What electrode would you choose for toughness and ductility?

BTW If you connnect all the tubes and pressurize the entire chassis, a
pressure gauge will instantly show evidence of a crack.

BoyntonStu

[JohnM]

Post by BoyntonStu
Your life depends upon the weld.
You are welding a DOM 1-1/2" Diameter 0.095" wall roll bar and chassis.
Would you bronze braze or weld for dynamic loading and for crash
worthyness?
What electrode would you choose for toughness and ductility?
BTW If you connnect all the tubes and pressurize the entire chassis, a
pressure gauge will instantly show evidence of a crack.
BoyntonStu

7018.

John

[SteveB]

Post by BoyntonStu
Your life depends upon the weld.
You are welding a DOM 1-1/2" Diameter 0.095" wall roll bar and chassis.
Would you bronze braze or weld for dynamic loading and for crash
worthyness?
What electrode would you choose for toughness and ductility?
BTW If you connnect all the tubes and pressurize the entire chassis, a
pressure gauge will instantly show evidence of a crack.
BoyntonStu

7018.
John

7018 on .095" ?

My preference would be TIG.

Steve

[Artemia Salina]

Post by BoyntonStu
Your life depends upon the weld.
You are welding a DOM 1-1/2" Diameter 0.095" wall roll bar and chassis.
Would you bronze braze or weld for dynamic loading and for crash
worthyness?

I'm no expert on braze strength but personally I would not get into
a vehicle that was brazed together, especially if done by an amateur
(such as myself). It is said that a properly welded joint is stronger
than the parent steel. I would not even consider brazing as an option.

Post by BoyntonStu
What electrode would you choose for toughness and ductility?
BTW If you connnect all the tubes and pressurize the entire chassis, a
pressure gauge will instantly show evidence of a crack.

Two things come to mind here. First, all joints would need a passage
for air pressure. This would in many cases require drilling holes in
the structure's members. Why take a chance on weakening these members
with holes when there are other methods of inspecting weld integrity?
Second, even if air pressure could flow through all parts of the chassis,
how would a drop in air pressure indicate *where* the leak was?
You would have to go over every joint with soapy water or something
like that.

If I were to attempt to weld a tubular chassis together, I would first
be sure of my welding skills and my knowledge of the pitfalls of tube
welding (for example, when completing a weld around the circumference
of a tube, the beginning of the weld has cooled and the steel at that
point is thicker than the tube walls, so you'll need to backstep over
the beginning of the weld to be sure that the two endpoints of the weld
flow together completely and that penetration is complete in that area).
Then I would get set up making test welds on scraps from the same batch
of steel tube and destructively test them. Once I was sure that my
welding equipment was properly set up for that steel I would move on
to welding the chassis tubes.

[BoyntonStu]

FYI Many race cars are brazed. All Fuli bicycles are brazed and most
high end racing bikes are as well.

6013 = 60,000 PSI

http://www.brazing.com/PDF/Copper%20Data%20Sheets/C680%20(Low%20Fuming%20Bronze%20Nickel).pdf

65,000 psi and 25% elongation. Not too shabby.

There are brazing alloys that are over 100,000 PSI.

IMHO, an amateur can 'see' a good braze easier than he could 'see' a
good weld. If it flows, it holds.

The flexible nature of a braze is a very nice attribute.

I have a recumbent trike that I built that has one main tube brazed to
the head tube. No problema.


BoyntonStu

[SteveB]

Post by BoyntonStu
FYI Many race cars are brazed. All Fuli bicycles are brazed and most
high end racing bikes are as well.
6013 = 60,000 PSI

Well, then, just do it and go racing!

Steve

[Artemia Salina]

Post by BoyntonStu
FYI Many race cars are brazed. All Fuli bicycles are brazed and most
high end racing bikes are as well.

Bicycles I knew were brazed. Car frames? That's news to me. Seems
to me that a car chassis would be subjected to much much more
stress than a bicycle frame.

Post by BoyntonStu
6013 = 60,000 PSI
http://www.brazing.com/PDF/Copper%20Data%20Sheets/C680%20(Low%20Fuming%20Bronze%20Nickel).pdf
65,000 psi and 25% elongation. Not too shabby.
There are brazing alloys that are over 100,000 PSI.

Do those numbers represent the bond strength of the joint, or is that
the strength of the braze material itself?

[BoyntonStu]

I can't speak for "modern" tube frame race cars, but standard practice
for road racing cars with tube frames in the 1960's and 1970's (such as

formula fords, sports racers, etc.) was thin wall mild steel tubing,
in the range of 3/4"-1 1/4" diameter by .047 - .062" wall, joined by
a process called "nickel-bronze welding". The latter is a high nickel
content brazing rod, applied with an oxyacetyline torch, with minimum
heat so a bead is created, rather than a full flow typical of
ordinary brazing. I believe that it is stronger than simple brazing.
The common alternative of the era was TIG-welded high alloy "chrome-
moly" steel, I think typically 4130. This latter construction called
for normalizing the entire frame after assembly, which wasn't feasible
in most small race shops. British suppliers, and US suppliers of cars
sold to markets typically dominated by British suppliers (i.e. the
purpose-built road-racing car market) tneded to use the nickel-bronze
welding. I believe that sprint cars and the like were more likely to
use alloy frames. I don't know why TIG (or MIG) welded mild steel
frames were not more common.
At least in the nickel-bronze on mild steel construction, there were no

lugs of any kind. The tubing (typically round, but sometimes square
or rectangular) was carefully fitted to to minimize any gap at the
joint prior to the brazing. One of the benefits of the nickel-bronze
approach may have been that the bead provided a larger surface area,
and acted a bit like a small lug.

And :

At least half of the British motorcycles ever made had their frames
brazed together - Norton, Triumph, BSA, and Royal Enfield all did it -
back fifty years ago the US Crosley car company built engine blocks by
brazing together pieces - brazing is also used to hold together some
modern tube-frame racing cars.

And:

have to second this - brazing, if done properly, can actually EXCEED
the
strength of standard welds. There have been reports where brazed
joints have
been pull-tested in the 80K PSI range, and most standard arc joints are
in the
70K PSI range.


BoyntonStu

[Artemia Salina]

There have been reports where brazed joints have been pull-tested
in the 80K PSI range, and most standard arc joints are in the
70K PSI range.

Wow! That's amazing! I never would've thought that brazed joints could
be stronger than welded ones!

Still don't know if I'd trust it though! :-)

Thanks for the response.

[BoyntonStu]

Artemia,

That is why a forum is so educational. I would gladly trade my many
held misconceptions for accurate information. The process is called
'Science'.

I have ridden many miles on a single brazed joint. At first, I was
very hesitant to trust it, because like you, I did not have any first
hand experience.

The nice thing about brazing is that you can always come back to a
joint to add a little more here and there and it all flows nicely
together.

Another advantage is that all you need is a pair of sunglasses not a
welding helmet. (I don't even use them)

I have been learning to stick weld and I find it to be very
pleasureable when it makes a nice bead. It feels good to see steel
melt and puddle.

I thank Bob Fraser for his most valuable input. It is nice to know
that what I plan to use at 70 MPH actually worked at 250 MPH!

This is my project:

A 2F1R hybrid 2 seater. (That means 2 wheels up front and 1 wheel in
the rear)

Not quite a Trihawk.
Aero.
A 2 seater with about 10 cu ft of cargo space.
Not a short micro car. (Dymaxion influence)
500-600 pounds of batteries up front.
65/35 weight ratio
No power steering.
Disk brakes.
The swing arm pivot axis located jackshaft to mount the drive
sprockets.
Regen and disk braking in rear.
Weight under 1,500lb (hoping for 1,200)
Roll cage protection using DOM 1-1/2" Dia .095 tubing. (6013 or
brazed)
Is this sized/process tubing overkill?
Roll cage/frame designed to allow batteries and engine to go underneath
in a head on collission.
Fabric or other lightweight body panels.
Rechargeable A/C unit (make ice at night, make ice when at work when
recharging batteries)
Engine/tranny is from a 1981 Kawasaki 550 GPZ. Engine on right side
with chain to jackshaft going forward.
10-20 HP ADC motor on left side.
The goal is 45 mph for 30 miles commute/shopping in town.
70 mph top speed.
50+ mpg on engine.

BoyntonStu

[JTMcC]

most standard arc joints are

Post by BoyntonStu
in the
70K PSI range.
BoyntonStu

No they're not. 6013 has a required MINIMUM tensile strength of 60,000 psi
but in actual as welded condition it will run up to around 78,000 psi. Same
thing with 7018 (or any other rod), required minimum tensile strength of
70,000 psi while in as welded condition the true numbers will run from
around 85,000 psi to around 93,000 psi. If that's not enough it's a simple
matter to go down to the local welding supply and buy 11018 and thatwill put
you into the 120,000 to 128,000 psi range using a commonly available, easily
run consumable. Just regular old run of the mill stick rod.

JTMcC.

[RDF]

Artemia,
Brazing is a FAA approved standard for aircraft. It's also fine on
spindles and cages on drag cars. (NHRA/IHRA) certified classes AA/FC TA/FC
TA/D ect.and below. A brazed weld can indeed be superior and we use our
blowdown tubes from the valve covers to vent into the frame as a "catch-can"
under vacuum. Bourgett motorcycles also use the inside of the frame in lieu
of an oil tank to open up space and provide a bigger heatsink surface. The
engine oil is circulated and cooled and fed back into the engine using the
frame itself as the tank and cooler. Pretty slick. And Spitzer, TRZ, and
most other good drag frames of the older days were sticked with 6013 and on
the certification sticker and paperwork for annual inspections. My 235" 2004
Spitzer TA/D is all TIG and MIG now. But if your gonna run stick. Check with
any sanctioning body before you get started if you are in a competitive
event. You might be surprised to find a fly in the ointment. I have gas
brazed onto many frames in drag racing. I did so under the guise of the fact
if the FAA approves it, it's gonna have merited science behind it. Sealing
a frame can be a real bad idea. corrosion can be a factor and at the lowest
point I always have a small hole for air with a small pipe-plug to drain off
blow by that crept past the blowdown tubes. As far as anything like the rear
carrier or link mounts I put a lot of heat and filler down. I have cracked a
few frames and this season, bent one into a horse-shoe after a knarly crash.
A lot of the areas that were welded had shown no signs of fracture with
Magnaflux (A post-mortem on the effects of 195mph to zero in a few hundred
feet sideways in my last Alcohol dragster before I got the new car I can't
drive from results of the crash) I can photograph some of the welds and
send them to you. I have been putting well over 2500hp to mine and there is
attrition and rework still, regardless if it was welded by god himself.


Have fun going fast, and let me know if you need a powerplant, parts, or
tranny's I'm between shops and working out of a friends auto shop and he is
pissed my trailers and two of his service bays have my cars in them as well
as my clients work! I have spare engines all over I'll never move. I'm going
to break them up for parts. KB Hemi's, Donovan 640CID's and a hodge-podge of
blowers, good blocks,heads, cranks, rods, slugs, sleeves,
injectors,magneto's, Lenco's, PG's, Insane cams I had cut myself, etc. I
also have a bunch of Wilwood and Strange brake components and spindles if
you need em for a frame-up build I'd rather a guy here or racer get them
than an idiot on E-bay!

All the best,
Rob Fraser

Fraser Competition Engines
Chicago, IL.
Long Beach, CA, ( Soon!)

Post by Artemia Salina

Post by BoyntonStu
FYI Many race cars are brazed. All Fuli bicycles are brazed and most
high end racing bikes are as well.

Bicycles I knew were brazed. Car frames? That's news to me. Seems
to me that a car chassis would be subjected to much much more
stress than a bicycle frame.

Post by BoyntonStu
6013 = 60,000 PSI
http://www.brazing.com/PDF/Copper%20Data%20Sheets/C680%20(Low%20Fuming%20Bronze%20Nickel).pdf
65,000 psi and 25% elongation. Not too shabby.
There are brazing alloys that are over 100,000 PSI.

Do those numbers represent the bond strength of the joint, or is that
the strength of the braze material itself?

[RDF]

Oops. I meant this to be addressed to Stu. Sorry about that... But the parts
are still to anyone interested!

Rob

Fraser Competition Engines
Chicago, IL.
Long Beach, CA, ( Soon!)

Post by RDF
Artemia,
Brazing is a FAA approved standard for aircraft. It's also fine on
spindles and cages on drag cars. (NHRA/IHRA) certified classes AA/FC TA/FC
TA/D ect.and below. A brazed weld can indeed be superior and we use our
blowdown tubes from the valve covers to vent into the frame as a
"catch-can" under vacuum. Bourgett motorcycles also use the inside of the
frame in lieu of an oil tank to open up space and provide a bigger
heatsink surface. The engine oil is circulated and cooled and fed back
into the engine using the frame itself as the tank and cooler. Pretty
slick. And Spitzer, TRZ, and most other good drag frames of the older
days were sticked with 6013 and on the certification sticker and paperwork
for annual inspections. My 235" 2004 Spitzer TA/D is all TIG and MIG now.
But if your gonna run stick. Check with any sanctioning body before you
get started if you are in a competitive event. You might be surprised to
find a fly in the ointment. I have gas brazed onto many frames in drag
racing. I did so under the guise of the fact if the FAA approves it, it's
gonna have merited science behind it. Sealing a frame can be a real bad
idea. corrosion can be a factor and at the lowest point I always have a
small hole for air with a small pipe-plug to drain off blow by that crept
past the blowdown tubes. As far as anything like the rear carrier or link
mounts I put a lot of heat and filler down. I have cracked a few frames
and this season, bent one into a horse-shoe after a knarly crash. A lot of
the areas that were welded had shown no signs of fracture with Magnaflux
(A post-mortem on the effects of 195mph to zero in a few hundred feet
sideways in my last Alcohol dragster before I got the new car I can't
drive from results of the crash) I can photograph some of the welds and
send them to you. I have been putting well over 2500hp to mine and there
is attrition and rework still, regardless if it was welded by god himself.
Have fun going fast, and let me know if you need a powerplant, parts,
or tranny's I'm between shops and working out of a friends auto shop and
he is pissed my trailers and two of his service bays have my cars in them
as well as my clients work! I have spare engines all over I'll never move.
I'm going to break them up for parts. KB Hemi's, Donovan 640CID's and a
hodge-podge of blowers, good blocks,heads, cranks, rods, slugs, sleeves,
injectors,magneto's, Lenco's, PG's, Insane cams I had cut myself, etc. I
also have a bunch of Wilwood and Strange brake components and spindles if
you need em for a frame-up build I'd rather a guy here or racer get them
than an idiot on E-bay!
All the best,
Rob Fraser
Fraser Competition Engines
Chicago, IL.
Long Beach, CA, ( Soon!)

Post by Artemia Salina

Post by BoyntonStu
FYI Many race cars are brazed. All Fuli bicycles are brazed and most
high end racing bikes are as well.

Bicycles I knew were brazed. Car frames? That's news to me. Seems
to me that a car chassis would be subjected to much much more
stress than a bicycle frame.

Post by BoyntonStu
6013 = 60,000 PSI
http://www.brazing.com/PDF/Copper%20Data%20Sheets/C680%20(Low%20Fuming%20Bronze%20Nickel).pdf
65,000 psi and 25% elongation. Not too shabby.
There are brazing alloys that are over 100,000 PSI.

Do those numbers represent the bond strength of the joint, or is that
the strength of the braze material itself?

[Andy Dingley]

Post by Artemia Salina
Car frames? That's news to me.

Not commonly these days, but go back to the '60s and look up
"Superleggera" (spuerlight) construction of aluminium panels over brazed
tube spaceframes. It's good enough for Aston Martin and the famous
Maserati "birdcage".

[Brian]

Not to be pedantic, but super leggera is a method of car body construction -
not car frame construction, indeed using very light tube structure covered
by aluminium panels. Space frame chassis construction is something
different. But indeed uses nickle or silver bronze welding of mild steel
thin wall tubing extensively, and is still in use in current spaceframe race
cars like Formula Fords. The joints are indeed stronger than the tube
material in this construction method, as evidenced by my buddies Formula
Ford crash this weekend where a few tubes got torn out - next to the joint,
at the point of highest stress concentration but not in the joint.

This is not to say that Tig welding wouldn't be as good or better than
nickle bronze welding - space frame cars made in the US normally were Tig
welded, such as the Swift cars. But there are advantages and disadvantages
to each method, understand them and know that either is a good choice if
done well.

Brian

Post by Andy Dingley

Post by Artemia Salina
Car frames? That's news to me.

Not commonly these days, but go back to the '60s and look up
"Superleggera" (spuerlight) construction of aluminium panels over brazed
tube spaceframes. It's good enough for Aston Martin and the famous
Maserati "birdcage".

[Andy Dingley]

Post by Brian
Not to be pedantic, but super leggera is a method of car body construction -
not car frame construction, indeed using very light tube structure covered
by aluminium panels.

So what's the difference ? I don't know about Maseratis, but Astons are
a tube spaceframe clad with aluminium. The aluminium panels aren't
load-bearing (i.e. it's still a spaceframe structurally, not a
monocoque). Is superleggera a stressed panel method, and is it
inaccurate to describe Astons as using it ?

(It's also a real sod for galvanic corrosion where the panels touch the
tubes)

[Brian]

The difference is basically one is a body and the other is a frame. Super
Leggera is a way of constructing a light support structure for a body - the
whole works is then mounted on a frame - often a ladder type with two big
tubes front to rear with brackets to attach motors, suspension etc. A space
frame is is a bunch of little tubes that make the actual frame of the car,
usually a very light (fiberglass or aluminium) self supporting body is
clipped to it.

Brian

Post by Andy Dingley

Post by Brian
Not to be pedantic, but super leggera is a method of car body
construction -
not car frame construction, indeed using very light tube structure covered
by aluminium panels.

So what's the difference ? I don't know about Maseratis, but Astons are
a tube spaceframe clad with aluminium. The aluminium panels aren't
load-bearing (i.e. it's still a spaceframe structurally, not a
monocoque). Is superleggera a stressed panel method, and is it
inaccurate to describe Astons as using it ?
(It's also a real sod for galvanic corrosion where the panels touch the
tubes)

[Ernie Leimkuhler]

Post by BoyntonStu
Your life depends upon the weld.
You are welding a DOM 1-1/2" Diameter 0.095" wall roll bar and chassis.
Would you bronze braze or weld for dynamic loading and for crash
worthyness?
What electrode would you choose for toughness and ductility?
BTW If you connnect all the tubes and pressurize the entire chassis, a
pressure gauge will instantly show evidence of a crack.
BoyntonStu

For maximum ductility on thin wall tube, 6013.

[Vernon]

Stu,

I'm not sure if you're posing this as a hypothetical or real life
scenario.

If the latter, your question will likely be answered by the rules of
the racing regulatory entity.

Mind you I'm ranting purely as an amateur welder, althouth a fairly
well read one.

But there seems to be a large measure of harmony between the generally
accepted practices of the race car and aircraft industries.

I think I'm on solid ground to assert that, among the homebuilt
aircraft and racecar building crowds, both gas welding and TIG are the
standards to which the other processes are merely compared.

Not that I'm qualified to do either, but my natural choice would be to
gas weld 'em with an aircraft type torch.

Vernon

Post by BoyntonStu
Your life depends upon the weld.
You are welding a DOM 1-1/2" Diameter 0.095" wall roll bar and chassis.
Would you bronze braze or weld for dynamic loading and for crash
worthyness?
What electrode would you choose for toughness and ductility?
BTW If you connnect all the tubes and pressurize the entire chassis, a
pressure gauge will instantly show evidence of a crack.
BoyntonStu

[Jeff Sellers]

Please pardon the intrusion, but I gotta ask....

When you guys speak of airplane and race car frames that are brazed, are
they lugged joints ?? like on a bicycle frame ???

Please tell me it is not just a fishmouth like I would do for welding ????

Thanks

Jeff

[Brian]

Sorry, Jeff, the joints in question are close fitting fish-mouth joints -
also butt joints where two tubes join. The vast majority of Formula One
cars produced in Britain up to the beginning of the Monocoque era were made
with butt jointed and fishmouthed mild steel tubes nickle bronze welded.
The particular alloy used was a little unique in that it produced a fairly
wide, thick fillet, perhaps 1/4" to 3/8" wide and up to 1/8" deep on a
typical joint, and that had the effect of creating a low stress, ductile
joint that was stronger than the parent material. In catastrophic failure
these joints almost always held while the tubes themselves tore. A typical
tube was 1" OD 18 Ga. mild steel. The chassis as well as the suspension
members were fabricated this way/ Fusion Welding with Tig or gas was very
rare.

Brian

Brian

Post by Jeff Sellers
Please pardon the intrusion, but I gotta ask....
When you guys speak of airplane and race car frames that are brazed, are
they lugged joints ?? like on a bicycle frame ???
Please tell me it is not just a fishmouth like I would do for welding ????
Thanks
Jeff

[Jeff Sellers]

<Snipped>

Post by Brian
with butt jointed and fishmouthed mild steel tubes nickle bronze welded.
The particular alloy used was a little unique in that it produced a fairly
wide, thick fillet, perhaps 1/4" to 3/8" wide and up to 1/8" deep on a
typical joint, and that had the effect of creating a low stress, ductile
joint that was stronger than the parent material.

Nickle Bronze Welded sounds a bit different than a typical torch brazed
joint. Is it in fact done with a torch in a similar way ??? Or what ???

thanks for the insight....ya gotta love this stuff !!

Jeff (Color me Curious) Sellers

[Brian]

Basically the only difference between brazing and nickle-bronze welding is
the alloy. You do need to use more heat to get NB to flow, and it does make
those nice fillet joints easier to form. It typically has a lot more
strength, up to about 120Kpsi depending on the rod. You would use it with
flux, or preferably with a gas fluxer. I haven't tried Tig-ing it

Brian

Post by Jeff Sellers
<Snipped>

Post by Brian
with butt jointed and fishmouthed mild steel tubes nickle bronze welded.
The particular alloy used was a little unique in that it produced a fairly
wide, thick fillet, perhaps 1/4" to 3/8" wide and up to 1/8" deep on a
typical joint, and that had the effect of creating a low stress, ductile
joint that was stronger than the parent material.

Nickle Bronze Welded sounds a bit different than a typical torch brazed
joint. Is it in fact done with a torch in a similar way ??? Or what ???
thanks for the insight....ya gotta love this stuff !!
Jeff (Color me Curious) Sellers

[Jeff Sellers]

Thanks Brian !!!

Info is now filed under "Thing I Have to Know but Will Probably Never Use"
Category. Lotsa stuff there !! ;)

Jeff

Post by Brian
Basically the only difference between brazing and nickle-bronze welding is
the alloy. You do need to use more heat to get NB to flow, and it does
make those nice fillet joints easier to form. It typically has a lot more
strength, up to about 120Kpsi depending on the rod. You would use it with
flux, or preferably with a gas fluxer. I haven't tried Tig-ing it
Brian

Post by Jeff Sellers
<Snipped>

Post by Brian
with butt jointed and fishmouthed mild steel tubes nickle bronze welded.
The particular alloy used was a little unique in that it produced a
fairly wide, thick fillet, perhaps 1/4" to 3/8" wide and up to 1/8" deep
on a typical joint, and that had the effect of creating a low stress,
ductile joint that was stronger than the parent material.

Nickle Bronze Welded sounds a bit different than a typical torch brazed
joint. Is it in fact done with a torch in a similar way ??? Or what ???
thanks for the insight....ya gotta love this stuff !!
Jeff (Color me Curious) Sellers