4130 can't be OA welded?

On Jan 2, 1:28 pm, "Morgans" wrote:

I'm not sure where this all fits in, but most lightweight bicycle frames
have a reinforcing "lug" around the tubes at the joints. Are you talking
bicycles or motorcycles?
--
--------------------------------------------------------------------------

Hadn't really thought of it... but you CAN use O/A on a bicycle
frame. The swaged fittings you mention are available as a kit, by the
way. They are normally secured via brazing. This allows you to use
very thin-walled tubing, resulting in excellent strength-to-weight for
the finished frame. Motorsickles typically require heavier walled
tubing and are almost always welded directly, typically with MIG. But
if you take a close look at low-cost import bicycles you can see they
tend to use heavier-walled tubing & MIG. (Just lift one. Big
difference between a 'Red Dawn' and a custom-built bike (bicycle).)

-R.S.Hoover

wrote

Hadn't really thought of it... but you CAN use O/A on a bicycle
frame. The swaged fittings you mention are available as a kit, by the
way. They are normally secured via brazing. This allows you to use
very thin-walled tubing, resulting in excellent strength-to-weight for
the finished frame. Motorsickles typically require heavier walled
tubing and are almost always welded directly, typically with MIG. But
if you take a close look at low-cost import bicycles you can see they
tend to use heavier-walled tubing & MIG. (Just lift one. Big
difference between a 'Red Dawn' and a custom-built bike (bicycle).)
Yep, and they get lighter all the time.

I remember back in about 1973, I bought a Peugeot, UO-8, I think was the
model.

At the time, it was around 27 pounds, and considered to be pretty light.

Now, that's a tank, compared to the new models.
--
Jim in NC

Blueskies wrote:
I meant while the part was in service. If an engine mount was brazed, and there was an engine fire, would the braze
joint fail (come apart) where a welded one would hold?



Dunno, Mongo.

I guess it would depend on how hot for how long.

But remember that it takes an acetylene flame to braze in the first
place.

If if gets that hot in the engine room, whether the mount welds hold or
not is probably going to be a secondary issue...

Richard

Its just gotta last long enough for me to get it on the ground ;-)




Getting it on the ground is no problem, gravity will help you with that
task, now doing it in a survivable manner, that is the trick.

George

"George" wrote in message . net...
Blueskies wrote:
I meant while the part was in service. If an engine mount was brazed, and there was an engine fire, would the braze
joint fail (come apart) where a welded one would hold?



Dunno, Mongo.

I guess it would depend on how hot for how long.

But remember that it takes an acetylene flame to braze in the first
place.

If if gets that hot in the engine room, whether the mount welds hold or
not is probably going to be a secondary issue...

Richard

Its just gotta last long enough for me to get it on the ground ;-)




Getting it on the ground is no problem, gravity will help you with that task, now doing it in a survivable manner,
that is the trick.

George

Reminds me of the guy with the souped up O-200 formula racer. The engine was putting out great power at something like
3200 rpm, till it threw a prop blade at something like 2000' agl... Shook real bad and tore the engine off the mount,
but the safety cable kept it from coming loose from the airframe, so he was able to get it back on the ground "in a
survivable manner". If it had broken completely loose the CG would have been way off and that would have been the end of
it...

Same thing with a fire in flight. I would at least want the engine to hang on for a while to give me a fighting
chance...

On Wed, 2 Jan 2008 17:01:59 -0500, "Blueskies"
wrote:


"clare at snyder.on.ca" wrote in message ...

It is not your standard brazing. It is "fillet brazing", using a much
stronger "spelter" than your standard braze. The process uses a gas
flux (a "Hookah" bubbling the acetelene (I think - might be the O2)
through the liquid flux ). The flux in the flame is EXTREMELY
reactive, so the flame "scrubs" the joint, leaving little if any flux
behind. These brazed joints ARE stronger than the 4130 or 4140 base
metal.

The process was developed for and used extensively by small race car
chassis fabricators in England and the continent. Lotus is a good case
in point.


What is the melting point for the brazing material?
Designation Description UNS A5.8 AWS Spec Tensile Strength
Lifquidus/Solidus
C-04® Nickel Bronze 680 RBCuZn-B 65,000 psi 162O° F / 1590° F
882° C / 866° C
GF-78 Low fuming Bronze 681 RBCuZn-C 63,000 psi 1630° F / 1590° F
888° C / 866° C
GF-72 Nickel Silver 773 RBCuZn-D 80,000 psi 1715° F / 1690° F
935° C / 921° C





--
Posted via a free Usenet account from http://www.teranews.com

"Blueskies" wrote

Same thing with a fire in flight. I would at least want the engine to hang
on for a while to give me a fighting chance...

I would bet big that the firewall would be burned or melted off from the
aircraft, (thereby letting the engine loose) long before a braise got hot
enough to let loose.
--
Jim in NC

"Blueskies" wrote in message
...

"clare at snyder.on.ca" wrote in message
...

It is not your standard brazing. It is "fillet brazing", using a much
stronger "spelter" than your standard braze. The process uses a gas
flux (a "Hookah" bubbling the acetelene (I think - might be the O2)
through the liquid flux ). The flux in the flame is EXTREMELY
reactive, so the flame "scrubs" the joint, leaving little if any flux
behind. These brazed joints ARE stronger than the 4130 or 4140 base
metal.

The process was developed for and used extensively by small race car
chassis fabricators in England and the continent. Lotus is a good case
in point.


What is the melting point for the brazing material?


Depends of coarse on specific alloys, but in rough numbers you can figure on
about 1700 for brass filler rod as compared to 2600 for the steel. So you
have a valid point. The next question is what kind of temps will a oil or
fuel fire generate, if being accellerated by 70 to 100 mph intake air?

"Blueskies" wrote in message
et...
|
| "George" wrote in message
. net...
| Blueskies wrote:
| I meant while the part was in service. If an engine mount was
brazed, and there was an engine fire, would the braze
| joint fail (come apart) where a welded one would hold?
|
|
|
| Dunno, Mongo.
|
| I guess it would depend on how hot for how long.
|
| But remember that it takes an acetylene flame to braze in the
first
| place.
|
| If if gets that hot in the engine room, whether the mount welds
hold or
| not is probably going to be a secondary issue...
|
| Richard
|
| Its just gotta last long enough for me to get it on the ground
;-)
|
|
|
|
| Getting it on the ground is no problem, gravity will help you with
that task, now doing it in a survivable manner,
| that is the trick.
|
| George
|
| Reminds me of the guy with the souped up O-200 formula racer. The
engine was putting out great power at something like
| 3200 rpm, till it threw a prop blade at something like 2000' agl...
Shook real bad and tore the engine off the mount,
| but the safety cable kept it from coming loose from the airframe, so
he was able to get it back on the ground "in a
| survivable manner". If it had broken completely loose the CG would
have been way off and that would have been the end of
| it...
|
| Same thing with a fire in flight. I would at least want the engine to
hang on for a while to give me a fighting
| chance...

An ex Air Force pilot landed with his engine separated from his airplane
over Illinois a good many years back. I think the airplane was a Globe
Swift that had a Continental 65 in it with a wood prop. The whole
incident from throwing a prop blade, physically loosing the engine and
making a safe landing took place in less than a minute. When the
airplane whipped up into a stall, his jet training kicked in, and he
knife edged it. Let the nose fall through and with full down elevator
and plenty of airspeed he was able to do a near vertical dive to a fresh
plowed field. At the last second he rounded out and plowed the field
again with the firewall. The article said the investigators figured the
plowed field kept the airplane from whipping back up into a stall after
initial contact.

--
Anyolmouse

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I currently have an aircraft welding business that does repairs,
modifications, and fabrication of 4130 steel, 321 stainless, and all
weldable aluminum alloys. To answer the OP's question, yes, you can
weld 4130 with an OA torch. As to the rest of the discussion, yes,
it's alot like politics and religion...lots of opinions, all dearly
held. So, here is mine, based on many years of daily application.
All fixed wing OEM's that I know about MIG weld airframes. It's
faster and cheaper. Also none do any pre or post weld heat treatment,
as far as I know, and neither do I. Same goes for major kitplane
OEM's. I have been doing more MIG welding as time goes by, for the
same reasons. After-market airframes are mostly TIG welded, I think
because they are more esthetically pleasing to a potential buyer and
because MIG welding thin-wall tubing to aircraft standards is much
more challenging and therefore hard to find and keep competent
weldors. TIG is the same as OA in that you have a heat source in one
hand and a filler in the other. With TIG you have much better heat
control and now with the availability of TIG welders is very popular.
I would recommend TIG or OA for the homebuilder using ER70S-2 or ER80S-
D2 filler. I would not recommend MIG for the homebuilder, even tho you
can get a MIG welder for very little money. They are a different
process and much more skill and experience with thin-wall tubing is
required to do consistent airworthy welds. And triple that experience
to get as nice looking welds as TIG.
Good luck and ... practice, practice, practice in combination with
competent instruction.

aviweld: In keeping with the religious aspect of this discussion I will
give you a big Amen. BTW where do you practice? We publish a magazine
dedicated to experimental helicopters and occasionally cite some resources
such as an aircraft welding business.
Stu Fields www.experimentalhelo.com
wrote in message
...
I currently have an aircraft welding business that does repairs,
modifications, and fabrication of 4130 steel, 321 stainless, and all
weldable aluminum alloys. To answer the OP's question, yes, you can
weld 4130 with an OA torch. As to the rest of the discussion, yes,
it's alot like politics and religion...lots of opinions, all dearly
held. So, here is mine, based on many years of daily application.
All fixed wing OEM's that I know about MIG weld airframes. It's
faster and cheaper. Also none do any pre or post weld heat treatment,
as far as I know, and neither do I. Same goes for major kitplane
OEM's. I have been doing more MIG welding as time goes by, for the
same reasons. After-market airframes are mostly TIG welded, I think
because they are more esthetically pleasing to a potential buyer and
because MIG welding thin-wall tubing to aircraft standards is much
more challenging and therefore hard to find and keep competent
weldors. TIG is the same as OA in that you have a heat source in one
hand and a filler in the other. With TIG you have much better heat
control and now with the availability of TIG welders is very popular.
I would recommend TIG or OA for the homebuilder using ER70S-2 or ER80S-
D2 filler. I would not recommend MIG for the homebuilder, even tho you
can get a MIG welder for very little money. They are a different
process and much more skill and experience with thin-wall tubing is
required to do consistent airworthy welds. And triple that experience
to get as nice looking welds as TIG.
Good luck and ... practice, practice, practice in combination with
competent instruction.