Welding question: joining an inner sleeve

Post by Michael Horowitz
Please see the sketch at http://members.cox.net/mhorowit/cluster/
Using Oxyacetylene, how do I get the base molten without burning the
two pieces that form the 1/8" gap? Are "chill bars" the only choice?
MikeH

If while playing with different heat settings you can't get the base
metal hot enough while not burning away the edges, you'll have to clamp
heat sinks to the upper parts.

However, you don't have to get the base completely molten to start a
weld. You get it just under molten, drop a molten bead on it, then heat
the bead itself until it fuses and blends with the underlying metal on
each surface, then start adding more rod to get the resulting puddle
nice and full with a nice fused feather edge all around, then start
moving. Putting down molten rod just before the base metal is molten
is the best way to weld exposed edges without burn back. You'll have to
carefully observe the edge of the puddle that is on the base material to
be sure it is blending and fusing.

The rod tip itself is key to controlling the amount of heat going into
the puddle. If an edge gets too hot and starts to burn away, don't back
right off, just back off a tiny bit while at the same time putting the
rod tip between the torch and the overheated edge and drop some rod
metal there. That gives a bit of breathing room while you adjust and go
back in. Mastering the technique of backing off just enough but not too
much makes a big difference because now you can stay in control while
doing a really tricky joint that is not tolerant of excess heat, and
when you get burn through's, you can pause to fill the hole and then
keep going without missing a beat.

John

unknown

2007-09-20 01:47:28 UTC

On Wed, 19 Sep 2007 20:25:46 -0400, "J.Kahn"

If while playing with different heat settings you can't get the base
metal hot enough while not burning away the edges, you'll have to clamp
heat sinks to the upper parts.
However, you don't have to get the base completely molten to start a
weld. You get it just under molten, drop a molten bead on it, then heat
the bead itself until it fuses and blends with the underlying metal on
each surface, then start adding more rod to get the resulting puddle
nice and full with a nice fused feather edge all around, then start
moving. Putting down molten rod just before the base metal is molten
is the best way to weld exposed edges without burn back. You'll have to
carefully observe the edge of the puddle that is on the base material to
be sure it is blending and fusing.
The rod tip itself is key to controlling the amount of heat going into
the puddle. If an edge gets too hot and starts to burn away, don't back
right off, just back off a tiny bit while at the same time putting the
rod tip between the torch and the overheated edge and drop some rod
metal there. That gives a bit of breathing room while you adjust and go
back in. Mastering the technique of backing off just enough but not too
much makes a big difference because now you can stay in control while
doing a really tricky joint that is not tolerant of excess heat, and
when you get burn through's, you can pause to fill the hole and then
keep going without missing a beat.
John

This is tubing, right? Drill a couple of holes and rosette weld, or
plug weld the sleave in place. It is now doing it's job Now weld the
ends of the tubes together. If the weld penetrates into the
re-enforcement sleave, good. If it doesn't the sleave is still in
there providing extra strength to the joint (done properly, the joint
is almost strong enough with just 4 plug welds per end)

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

Fortunat1

2007-09-20 04:46:45 UTC

Post by unknown
This is tubing, right? Drill a couple of holes and rosette weld, or
plug weld the sleave in place. It is now doing it's job Now weld the
ends of the tubes together. If the weld penetrates into the
re-enforcement sleave, good. If it doesn't the sleave is still in
there providing extra strength to the joint (done properly, the joint
is almost strong enough with just 4 plug welds per end)

This makes sense to me, however, looking in my books, it's stated pretty
clearly that the inner tube should be welded to the outers.
there's a copy of that text here:

http://www2.tech.purdue.edu/at/courses/at308/Technical_Links/Ac43-13-1B/CH4
_5.pdf

Now, it would seem to me that penetration of the inner tube would add very
little strength at all, particularly if it was a good snug fit. Am I
reading this wrong?

Michael Horowitz

2007-09-20 09:45:15 UTC

This makes sense to me, however, looking in my books, it's stated pretty
clearly that the inner tube should be welded to the outers.
http://www2.tech.purdue.edu/at/courses/at308/Technical_Links/Ac43-13-1B/CH4
_5.pdf
Now, it would seem to me that penetration of the inner tube would add very
little strength at all, particularly if it was a good snug fit. Am I
reading this wrong?

You're quoting a very general section. If you could cite the specific
sub-paragraph it might help - Mike

Fortunat1

2007-09-20 18:32:15 UTC

Post by unknown
This is tubing, right? Drill a couple of holes and rosette weld, or
plug weld the sleave in place. It is now doing it's job Now weld the
ends of the tubes together. If the weld penetrates into the
re-enforcement sleave, good. If it doesn't the sleave is still in
there providing extra strength to the joint (done properly, the
joint is almost strong enough with just 4 plug welds per end)

Post by Fortunat1
/CH4 _5.pdf
Now, it would seem to me that penetration of the inner tube would add
very little strength at all, particularly if it was a good snug fit.
Am I reading this wrong?

You're quoting a very general section. If you could cite the specific
sub-paragraph it might help - Mike

Sorry. Scroll down to 4-84.
There's a whole section on the type of repairs you're talking about.
4-84 specifically mentions including the innner tube into the weld. It
seems to me that the weld area would be at least as strong without
welding across the inner tube like that. If you weld a doubler on the
end of a strap, for instance, you don't lap weld across the widthe of
the strap where the thickness steps down, you only edge weld around the
outside perimeter. That would indicate to me that welding across a piece
of tubing, unneccesarily, only puts stress risers around the weld. If
it's a snug fit, you've got to have at least the same strength there you
had with the original tube.

Morgans

2007-09-20 21:00:17 UTC

Post by Fortunat1
Sorry. Scroll down to 4-84.
There's a whole section on the type of repairs you're talking about.
4-84 specifically mentions including the innner tube into the weld. It
seems to me that the weld area would be at least as strong without
welding across the inner tube like that. If you weld a doubler on the
end of a strap, for instance, you don't lap weld across the widthe of
the strap where the thickness steps down, you only edge weld around the
outside perimeter. That would indicate to me that welding across a piece
of tubing, unneccesarily, only puts stress risers around the weld. If
it's a snug fit, you've got to have at least the same strength there you
had with the original tube.

The repairs detailed in the "acceptable repairs" publication are time tested
and true. There have been tube and fabric planes being repaired in this
manner, for a very long time.

I would tend to believe that if it is outlined in a certain way, then there
is a good reason for it. As far as stress risers, gas welding done
correctly will not create them.

--
Jim in NC

J.Kahn

2007-09-21 01:45:24 UTC

I believe that you have to effectively have a full lap joint weld
between each outer tube and inner tube, AND the joint must be a
truncated cut and not just straight across in order to have sufficient
weld cross section since it's essential that the weld zone be much
stronger than the virgin metal up the tube.

The rosette welds done further up don't contribute that much strength
and are mostly (I believe) to prevent the inner tube from having an
unsupported length that allows "wiggling" of the inner tube in the outer
tube under stress. possibly leading to cracks in the main weld.

John

Fortunat1

2007-09-21 05:49:03 UTC

Post by unknown
This is tubing, right? Drill a couple of holes and rosette weld, or
plug weld the sleave in place. It is now doing it's job Now weld the
ends of the tubes together. If the weld penetrates into the
re-enforcement sleave, good. If it doesn't the sleave is still in
there providing extra strength to the joint (done properly, the
joint is almost strong enough with just 4 plug welds per end)

Post by Fortunat1
B/CH4 _5.pdf
Now, it would seem to me that penetration of the inner tube would add
very little strength at all, particularly if it was a good snug fit.
Am I reading this wrong?

I believe that you have to effectively have a full lap joint weld
between each outer tube and inner tube, AND the joint must be a
truncated cut and not just straight across in order to have sufficient
weld cross section since it's essential that the weld zone be much
stronger than the virgin metal up the tube.
The rosette welds done further up don't contribute that much strength
and are mostly (I believe) to prevent the inner tube from having an
unsupported length that allows "wiggling" of the inner tube in the
outer tube under stress. possibly leading to cracks in the main weld.

OK, I can buy all of that, but I don't know exactly what you mean by
truncated. Are you talking about the profile of the edges of the outer
tube, or do you mean the outer tube must be cut diaganally?

cavelamb himself

2007-09-21 08:37:18 UTC

Post by J.Kahn
I believe that you have to effectively have a full lap joint weld
between each outer tube and inner tube, AND the joint must be a
truncated cut and not just straight across in order to have sufficient
weld cross section since it's essential that the weld zone be much
stronger than the virgin metal up the tube.
The rosette welds done further up don't contribute that much strength
and are mostly (I believe) to prevent the inner tube from having an
unsupported length that allows "wiggling" of the inner tube in the
outer tube under stress. possibly leading to cracks in the main weld.

OK, I can buy all of that, but I don't know exactly what you mean by
truncated. Are you talking about the profile of the edges of the outer
tube, or do you mean the outer tube must be cut diaganally?

Look at it from a "stress riser" point of view.

A weld (I see what the problem is here - how to describe in words what
you are thinking in yer head)

Ok

If a welded tube is butted together with square cut ends (90 degree cut)
the weld will cause a sudden localized change in cross section - a
stress riser - something we try hard to avoid.

But lopping the tubes at 45 to 60 degrees spreads the "bump" in the
cross section of the weld across a longer distance.

Think of the weld bead as a "hard" spot. Angling the weld avoids having
a hard spot in a tiny localized area.

What John said about the rose on the inner tube is about what I recall.
Stabilize the inner tube and (again) avoid having the hard spot all
concentrated at the end of the inner sleeve (at the cluster).

FWIW?

Richard

J.Kahn

2007-09-22 03:50:18 UTC

Post by unknown
This is tubing, right? Drill a couple of holes and rosette weld, or
plug weld the sleave in place. It is now doing it's job Now weld the
ends of the tubes together. If the weld penetrates into the
re-enforcement sleave, good. If it doesn't the sleave is still in
there providing extra strength to the joint (done properly, the
joint is almost strong enough with just 4 plug welds per end)

Post by Fortunat1
B/CH4 _5.pdf
Now, it would seem to me that penetration of the inner tube would add
very little strength at all, particularly if it was a good snug fit.
Am I reading this wrong?

I believe that you have to effectively have a full lap joint weld
between each outer tube and inner tube, AND the joint must be a
truncated cut and not just straight across in order to have sufficient
weld cross section since it's essential that the weld zone be much
stronger than the virgin metal up the tube.
The rosette welds done further up don't contribute that much strength
and are mostly (I believe) to prevent the inner tube from having an
unsupported length that allows "wiggling" of the inner tube in the
outer tube under stress. possibly leading to cracks in the main weld.

OK, I can buy all of that, but I don't know exactly what you mean by
truncated. Are you talking about the profile of the edges of the outer
tube, or do you mean the outer tube must be cut diaganally?

The joints between the splice sections can be either a diagonal cut
(truncated) or fishmouth cut but never straight. In either case the cut
angle is 30 deg to the long axis of the tube.

John

Fortunat1

2007-09-22 10:38:15 UTC

Post by unknown
This is tubing, right? Drill a couple of holes and rosette weld, or
plug weld the sleave in place. It is now doing it's job Now weld the
ends of the tubes together. If the weld penetrates into the
re-enforcement sleave, good. If it doesn't the sleave is still in
there providing extra strength to the joint (done properly, the
joint is almost strong enough with just 4 plug welds per end)

This makes sense to me, however, looking in my books, it's stated
pretty clearly that the inner tube should be welded to the outers.
http://www2.tech.purdue.edu/at/courses/at308/Technical_Links/Ac43-

13-

Post by Fortunat1
1

Post by Fortunat1
B/CH4 _5.pdf
Now, it would seem to me that penetration of the inner tube would add
very little strength at all, particularly if it was a good snug fit.
Am I reading this wrong?

I believe that you have to effectively have a full lap joint weld
between each outer tube and inner tube, AND the joint must be a
truncated cut and not just straight across in order to have

sufficient

Post by J.Kahn
weld cross section since it's essential that the weld zone be much
stronger than the virgin metal up the tube.
The rosette welds done further up don't contribute that much

strength

Post by J.Kahn
and are mostly (I believe) to prevent the inner tube from having an
unsupported length that allows "wiggling" of the inner tube in the
outer tube under stress. possibly leading to cracks in the main weld.

OK, I can buy all of that, but I don't know exactly what you mean by
truncated. Are you talking about the profile of the edges of the outer
tube, or do you mean the outer tube must be cut diaganally?

The joints between the splice sections can be either a diagonal cut
(truncated) or fishmouth cut but never straight. In either case the cut
angle is 30 deg to the long axis of the tube.

Yep, I understand that OK. Just the way the word truncated was used I
thought it might have meant that the edge of the outer tube had to be
beveled or something, but surely this is not neccesary with .035 or .049
tubing anyway. I think I'm happy with the mechanics of it all.

F1

Michael Horowitz

2007-09-21 15:02:40 UTC

On Thu, 20 Sep 2007 21:45:24 -0400, "J.Kahn"

John - please see http://members.cox.net/mhorowit/cluster/lapjoint/
I took your suggestion and treated each side of the "outer sleeve" and
the "inner sleeve" as the components of a lap joint; hence two beads.
That's what you were talking about instead of my trying to integrate
the outer and inner sleeves in one weld, correct? - Mike

PS - I don't think taking a shortcut by simply cutting a partial
slice in a larger diameter tube would make a difference in the
exercise;

J.Kahn

2007-09-22 03:48:05 UTC

Post by Michael Horowitz
On Thu, 20 Sep 2007 21:45:24 -0400, "J.Kahn"

John - please see http://members.cox.net/mhorowit/cluster/lapjoint/
I took your suggestion and treated each side of the "outer sleeve" and
the "inner sleeve" as the components of a lap joint; hence two beads.
That's what you were talking about instead of my trying to integrate
the outer and inner sleeves in one weld, correct? - Mike
PS - I don't think taking a shortcut by simply cutting a partial
slice in a larger diameter tube would make a difference in the
exercise;

Sorry Michael, I went back over AC43.13 and realized I made a mistake.
Para 74 covers this type of weld repair where there is an inner splice
tube and it says to leave a 1/8" gap between the outer tubes of the
splice and then it simply says "Weld the inner sleeve to the tube stubs
through the 1/8" gap, forming a weld bead over the gap."

So you just do one bead, but make sure you get penetration down to the
lower layer. It really is just an elongated rosette weld.

The angle cut for the splice should be 30 deg for both a straight angle
cut (truncated) or fishmouth. Do not make splice joints straight across.

If you don't have AC43.13 handy I can scan the page that shows the
splice repair method.

To avoid that burnback notch at the open end of your slot if you have to
come to it at the end of the bead run instead of the start, stop the
bead about 1/4 inch from the end of the slot, so that you finish the
bead with the last 1/4" at the open end of the slot unwelded. Let the
piece cool off, then go back at it and quickly finish the unwelded
section. The burnback happens when trying to finish the weld to the end
while the whole piece is really hot after doing a long bead.

John

Fortunat1

2007-09-22 10:43:11 UTC

Post by Michael Horowitz
On Thu, 20 Sep 2007 21:45:24 -0400, "J.Kahn"

sufficient

Post by J.Kahn
weld cross section since it's essential that the weld zone be much
stronger than the virgin metal up the tube.
John

John - please see http://members.cox.net/mhorowit/cluster/lapjoint/
I took your suggestion and treated each side of the "outer sleeve" and
the "inner sleeve" as the components of a lap joint; hence two beads.
That's what you were talking about instead of my trying to integrate
the outer and inner sleeves in one weld, correct? - Mike
PS - I don't think taking a shortcut by simply cutting a partial
slice in a larger diameter tube would make a difference in the
exercise;

Sorry Michael, I went back over AC43.13 and realized I made a mistake.
Para 74 covers this type of weld repair where there is an inner splice
tube and it says to leave a 1/8" gap between the outer tubes of the
splice and then it simply says "Weld the inner sleeve to the tube stubs
through the 1/8" gap, forming a weld bead over the gap."
So you just do one bead, but make sure you get penetration down to the
lower layer. It really is just an elongated rosette weld.
The angle cut for the splice should be 30 deg for both a straight angle
cut (truncated) or fishmouth. Do not make splice joints straight across.
If you don't have AC43.13 handy I can scan the page that shows the
splice repair method.
To avoid that burnback notch at the open end of your slot if you have to
come to it at the end of the bead run instead of the start, stop the
bead about 1/4 inch from the end of the slot, so that you finish the
bead with the last 1/4" at the open end of the slot unwelded. Let the
piece cool off, then go back at it and quickly finish the unwelded
section. The burnback happens when trying to finish the weld to the end
while the whole piece is really hot after doing a long bead.

Hope you don't mind me butting in here, but the photo that Michael put
up of that splice with the slit cut into the outer tube. Is anyone
suggesting that this is a good type of splice for some applications? I
can't see any inherent advantages in this as opposed to the diagonal
type. Or is this just an experiment in welding through a small gap in
the tubing?

Morgans

2007-09-22 11:29:44 UTC

Post by Fortunat1
Hope you don't mind me butting in here, but the photo that Michael put
up of that splice with the slit cut into the outer tube. Is anyone
suggesting that this is a good type of splice for some applications? I
can't see any inherent advantages in this as opposed to the diagonal
type. Or is this just an experiment in welding through a small gap in
the tubing?

If you do not make the slit and weld the inner to the outer, you are only
making the splice strong in STRAIGHT COMPRESSION, or STRAIGHT TENSION. You
have done nothing to marry the ENTIRE length of the two tubes together, so
they are strong in bending.

By only welding along the edge of the truncated or fishmouthed tube, you are
concentrating all of the bending to where the ends of where one tube meets
the other.

The slit is to spread all bending (and compression or tension) loads all
along the length of BOTH tubes.

Follow the picture he posted. That is the only recognized, strong and safe
way to make that type of splice. Any other treatment of the joint is not as
strong as it could be, and should be.

Again I say, AC43 is a time tested, an recognized way to do things,
especially in things such as splicing tubes. That technology has not been
changed in nearly 100 years. The methods contained in it are the right way
to do things, and were developed over many years of trial and error and
through experiment and testing.

Take the extra time to do what is suggested.

--
Jim in NC

Fortunat1

2007-09-22 12:38:20 UTC

Post by Fortunat1
n welding

through a small gap in the tubing?

If you do not make the slit and weld the inner to the outer, you are
only making the splice strong in STRAIGHT COMPRESSION, or STRAIGHT
TENSION. You have done nothing to marry the ENTIRE length of the two
tubes together, so they are strong in bending.
By only welding along the edge of the truncated or fishmouthed tube,
you are concentrating all of the bending to where the ends of where
one tube meets the other.
The slit is to spread all bending (and compression or tension) loads
all along the length of BOTH tubes.
Follow the picture he posted. That is the only recognized, strong and
safe way to make that type of splice. Any other treatment of the
joint is not as strong as it could be, and should be.
Again I say, AC43 is a time tested, an recognized way to do things,
especially in things such as splicing tubes. That technology has not
been changed in nearly 100 years. The methods contained in it are the
right way to do things, and were developed over many years of trial
and error and through experiment and testing.
Take the extra time to do what is suggested.

Well, I can't find that type of repair anywhere in AC43. I also can't
see how it would contribute at all to the strength of a repair done
using the inner sleeve method. Even on the outer sleeve method, it only
states that a gap be left when the outer tube is split longitudinally.
when the outer tube is a snug fit, there doesn't even need to be rosette
welds... (I'm looking at and aound 4-38 here)

D***@yahoo.com

2007-09-22 15:57:16 UTC

Post by Fortunat1
n welding

through a small gap in the tubing?

If you do not make the slit and weld the inner to the outer, you are
only making the splice strong in STRAIGHT COMPRESSION, or STRAIGHT
TENSION. You have done nothing to marry the ENTIRE length of the two
tubes together, so they are strong in bending.
By only welding along the edge of the truncated or fishmouthed tube,
you are concentrating all of the bending to where the ends of where
one tube meets the other.
The slit is to spread all bending (and compression or tension) loads
all along the length of BOTH tubes.
Follow the picture he posted. That is the only recognized, strong and
safe way to make that type of splice. Any other treatment of the
joint is not as strong as it could be, and should be.
Again I say, AC43 is a time tested, an recognized way to do things,
especially in things such as splicing tubes. That technology has not
been changed in nearly 100 years. The methods contained in it are the
right way to do things, and were developed over many years of trial
and error and through experiment and testing.
Take the extra time to do what is suggested.

You might have a really old version of AC43.13. You need
43.13-1B to reference it in section 4. The old 1A version has it in
Chapter 2, paragraph 74, Figure 2.7. The FAA website has it but I
haven't been able to get at it the last two days. They must be fixing
it. I hope.

Dan

Michael Horowitz

2007-09-23 07:05:43 UTC

Post by Morgans
Follow the picture he posted. That is the only recognized, strong and
safe way to make that type of splice. Any other treatment of the
joint is not as strong as it could be, and should be.

Dan

Dan - you seem to be agreeing that treating each side of the gap as a
lap joint is the way to go as opposed to attempting to bridge both
sides while including the inner sleeve. Correct? - Mike

Michael Horowitz

2007-09-23 06:57:38 UTC

Post by Fortunat1
"
Hope you don't mind me butting in here, but the photo that Michael put
up of that splice with the slit cut into the outer tube. Is anyone
suggesting that this is a good type of splice for some applications? I
can't see any inherent advantages in this as opposed to the diagonal
type. Or is this just an experiment in welding through a small gap in
the tubing?

OP here - what I was trying to do as easily as possible was to
duplicate the single part of the weld that would give me problems:
getting the inner metal molten without cooking the outer metal
sleeve. I simply cut an 1/8" slot in a piece of tubng, slipped the
inner tube in place and welded the two beads. Yes, I know why a real
weld would be along a 30^ angle, but that wasn't the point of the
exercise, which was to see how to run that bead, whether on the TE of
a split outer tube, or the gap proscribed for a splice by inner
sleeve. - Mike

Fortunat1

2007-09-23 11:13:26 UTC

OP here - what I was trying to do as easily as possible was to
getting the inner metal molten without cooking the outer metal
sleeve. I simply cut an 1/8" slot in a piece of tubng, slipped the
inner tube in place and welded the two beads. Yes, I know why a real
weld would be along a 30^ angle, but that wasn't the point of the
exercise, which was to see how to run that bead, whether on the TE of
a split outer tube, or the gap proscribed for a splice by inner
sleeve. - Mike

OK, thanks. I reckoned as much but had to ask!

I tried a few of those myself with the 30 deg cut and they were tough
enough. But I did get a few inches of good weld which does prove they are
possible! For me I found thye clicked along best when I kept the torch in
nice and close and concentrated on getting the inner sleeve melting, just
like the rosette, which are also working fine for me now.

Michael Horowitz

2007-09-23 11:38:07 UTC

OK, thanks. I reckoned as much but had to ask!
I tried a few of those myself with the 30 deg cut and they were tough
enough. But I did get a few inches of good weld which does prove they are
possible! For me I found thye clicked along best when I kept the torch in
nice and close and concentrated on getting the inner sleeve melting, just
like the rosette, which are also working fine for me now.

Someone in another group recommended I read this article -
http://airbum.com/articles/ArticleZenWelding.html
I gotta read it again for comprehension. Good read over coffee.

I normally wear glasses but take them off when I'm working with
goggles. I _think_ I'm seeing things OK, but for $12 I'm going to
visit the drugstore and see what they got. I would like to get my
face closer to the work - Mike

J.Kahn

2007-09-23 18:04:44 UTC

OK, thanks. I reckoned as much but had to ask!
I tried a few of those myself with the 30 deg cut and they were tough
enough. But I did get a few inches of good weld which does prove they are
possible! For me I found thye clicked along best when I kept the torch in
nice and close and concentrated on getting the inner sleeve melting, just
like the rosette, which are also working fine for me now.

Someone in another group recommended I read this article -
http://airbum.com/articles/ArticleZenWelding.html
I gotta read it again for comprehension. Good read over coffee.
I normally wear glasses but take them off when I'm working with
goggles. I _think_ I'm seeing things OK, but for $12 I'm going to
visit the drugstore and see what they got. I would like to get my
face closer to the work - Mike

I use reading glasses of about 1.5 diopter for reading and close work,
but for welding I got some 3 diopter reading glasses from the drug
store. They worked great. Makes a huge difference when you can see
the puddle in detail.

John

Fortunat1

2007-09-23 23:39:16 UTC

Post by Fortunat1
"
Hope you don't mind me butting in here, but the photo that Michael
put up of that splice with the slit cut into the outer tube. Is
anyone suggesting that this is a good type of splice for some
applications? I can't see any inherent advantages in this as opposed
to the diagonal type. Or is this just an experiment in welding
through a small gap in the tubing?

OP here - what I was trying to do as easily as possible was to
getting the inner metal molten without cooking the outer metal
sleeve. I simply cut an 1/8" slot in a piece of tubng, slipped the
inner tube in place and welded the two beads. Yes, I know why a real
weld would be along a 30^ angle, but that wasn't the point of the
exercise, which was to see how to run that bead, whether on the TE
of a split outer tube, or the gap proscribed for a splice by inner
sleeve. - Mike

OK, thanks. I reckoned as much but had to ask!
I tried a few of those myself with the 30 deg cut and they were tough
enough. But I did get a few inches of good weld which does prove they
are possible! For me I found thye clicked along best when I kept the
torch in nice and close and concentrated on getting the inner sleeve
melting, just like the rosette, which are also working fine for me
now.

Someone in another group recommended I read this article -
http://airbum.com/articles/ArticleZenWelding.html
I gotta read it again for comprehension. Good read over coffee.
I normally wear glasses but take them off when I'm working with
goggles. I _think_ I'm seeing things OK, but for $12 I'm going to
visit the drugstore and see what they got. I would like to get my
face closer to the work - Mike

What I did was go down to my opticioan and get them to make some lenses
for my goggles (they have clear lenses under some flip down tinted ones)
I can't recommend these highly enough.
Thanks for the link. I'll check it out straight away.

Michael Horowitz

2007-09-23 06:58:06 UTC

On Fri, 21 Sep 2007 23:48:05 -0400, "J.Kahn"

Post by J.Kahn
So you just do one bead, but make sure you get penetration down to the
lower layer. It really is just an elongated rosette weld.
John

Well,we're back to attempting to get the lower level molten while not
burning away the upper layer. In the case of the rosette weld, I was
told to make a small hole in the upper layer, aim thru the hole, wait
until the lower layer begins to flow, then add filler, ignoring how
far back the upper layer burns back. I'll go practice. Mike

Fortunat1

2007-09-23 11:16:50 UTC

Post by Michael Horowitz
On Fri, 21 Sep 2007 23:48:05 -0400, "J.Kahn"

Post by J.Kahn
So you just do one bead, but make sure you get penetration down to the
lower layer. It really is just an elongated rosette weld.
John

Yeah, I've been learning those as well. I found that the rod is a great
help here. when the metal underneath starts to go I start adding rod to the
edge of the hole going around the edge and voila! some of them even look
like rosettes.

Michael Horowitz

2007-09-23 11:33:02 UTC

Post by Michael Horowitz
On Fri, 21 Sep 2007 23:48:05 -0400, "J.Kahn"

Post by J.Kahn
So you just do one bead, but make sure you get penetration down to the
lower layer. It really is just an elongated rosette weld.
John

I haven't ask or been told whether or not it's considered good
welding, but like trim to someone doing woodwork, filler covers up
blow-thrus -Mike

Post by Fortunat1
Yeah, I've been learning those as well. I found that the rod is a great
help here. when the metal underneath starts to go I start adding rod to the
edge of the hole going around the edge and voila! some of them even look
like rosettes.

Michael Horowitz

2007-09-23 12:08:39 UTC

Have you worked with heat sinks? Try this: get a heavy steel washer
with a 3/8" hole. Drill an 1/8" hole in a piece of sheet and lay it
over another sheet - you're forming a flat version of the same thing
you do in preparation of a rosette weld. Now center the washer on the
1/8" hole. The heavy washer will wick away a lot of heat and reduce
the amount the upper sheet burns back. The equivalent for tubing would
be 'chill bars', which I'm thing of trying, but also thinking that's
going over-board - MIke

Fortunat1

2007-09-23 23:43:57 UTC

Post by Fortunat1
Yeah, I've been learning those as well. I found that the rod is a
great help here. when the metal underneath starts to go I start adding
rod to the edge of the hole going around the edge and voila! some of
them even look like rosettes.

Haen't really tried them yet. None of the info I have mentions them so I
hadn't really thought of it. What I have doen is not cut off ends of tubes
and what not until I've welded them up in order not to blow edges away,
which kind of amounts to the same thing, but I'm going to try it..

Michael Horowitz

2007-09-24 11:13:47 UTC

Post by Fortunat1
Haen't really tried them yet. None of the info I have mentions them so I
hadn't really thought of it. What I have doen is not cut off ends of tubes
and what not until I've welded them up in order not to blow edges away,
which kind of amounts to the same thing, but I'm going to try it..

For the ends of tubes I've heard that inserting a large diameter bolt
into the tube end will act as a heatsing and wick away heat; however,
not burning off the end of the tube or the end of any weld is an art
that is used over and over, so it's probably something to work on. I'm
at the point when coming to an edge that I say to myself "Ok, you know
what happens here, pull the torch away" Sometimes I even get it right!
But then again, filler rod covers a multitude of sins - Mike

J.Kahn

2007-09-24 14:31:33 UTC

When you get close the edge that's going to burn away stop and let the
piece cool off then go back and finish it quickly.

John

Morgans

2007-09-24 15:40:08 UTC

Post by Michael Horowitz
For the ends of tubes I've heard that inserting a large diameter bolt
into the tube end will act as a heatsing and wick away heat; however,
not burning off the end of the tube or the end of any weld is an art
that is used over and over, so it's probably something to work on.

[[[[[[ BINGO ! ! ! ! ! WE HAVE A WINNER ! ! ! ]]]]]]]] <GGG>

Really, in all seriousness, that is the wisest thing anyone has said in this
whole thread.

Gas welding thin tube is an art, and the art should be practiced until
perfected, for perfection's sake.

So, if you are burning away things you do not want to burn away, keep
working on it until you get it right.

Another tip, is to use the rod to carry away heat. In cases where you are
having to be careful not to burn something away, the heat should be cool
enough that the rod is not in the puddle all of the time (while you are
waiting for the small (being patient) flame to heat up an area), so while it
is not[in the puddle], pull it away far enough that it will cool. Then,
when an edge is in danger, stick the rod against it to help cool it. Even
when the rod is almost constantly in the puddle, it can still be used to
control heat in different parts of the puddle. A lot of heat energy is
sucked up in making the steel go from a solid to a liquid. Use that fact,
to cool where it is getting too hot.

Post by Michael Horowitz
I'm
at the point when coming to an edge that I say to myself "Ok, you know
what happens here, pull the torch away" Sometimes I even get it right!

Learning patience. Good! You can't rush this thing, that is for sure.

Post by Michael Horowitz
But then again, filler rod covers a multitude of sins.

Bad attitude! ;-) Be a perfectionist, as much as possible. The fine line
is knowing when a little more rod to cover is a mistake is an OK thing to
do. I am hard on myself, because if I am my worst critic, my work will look
good to anyone else.

--
Jim in NC

Maxwell

2007-09-20 04:53:01 UTC

Will your situation allow you to increase the gap? Perhaps heating a little
slower and increasing the gap would work for you.

Michael Horowitz

2007-09-23 07:00:13 UTC