Problem with rosette welds

[Michael Horowitz]

I'm practicing with an Ox/Ac rig; Using mild steel (.035).
Got a little cocky and decided to try a patch on tubing. With a
rosette weld as well as along the edges.

Well, I chased that hole all over the patch! burning it and filling
and burning and filling! The patch obviously getting hotter than the
base metal. Tried different angles, nothing successful. Any
suggestions are appreciated.

Had the same problem along the first edge. Then I wised up and clamped
a 'chill bar' on the patch. Worked like a charm; however, I can't see
an experienced welder stopping for each side and reclamping the 'bar.

I'm using 2psi of both gases, and a blowpipe tip with an opening
appropriate for metals .037 thick.

Suggestions? - Mike

[Morgans]

"Michael Horowitz" > wrote in message
...
> I'm practicing with an Ox/Ac rig; Using mild steel (.035).
> Got a little cocky and decided to try a patch on tubing. With a
> rosette weld as well as along the edges.
>
> Well, I chased that hole all over the patch! burning it and filling
> and burning and filling! The patch obviously getting hotter than the
> base metal. Tried different angles, nothing successful. Any
> suggestions are appreciated.
>
> Had the same problem along the first edge. Then I wised up and clamped
> a 'chill bar' on the patch. Worked like a charm; however, I can't see
> an experienced welder stopping for each side and reclamping the 'bar.
>
> I'm using 2psi of both gases, and a blowpipe tip with an opening
> appropriate for metals .037 thick.
>

Less heat, possibly less Oxy. Does your flame have a feathered cone? Might
need to hold the flame a bit further away, and come off the area with the
torch when it starts getting too hot.
--
Jim in NC

[mhorowit]

"feathered cone?" No, I'm using a neutral flame, the two inner cones
coincide and there is only the faintest hissing noise. More Ox and I'd
have an oxidizing flame. - Mike

[[email protected]]

On 11 Oct 2005 04:35:15 -0700, "mhorowit" > wrote:

>"feathered cone?" No, I'm using a neutral flame, the two inner cones
>coincide and there is only the faintest hissing noise. More Ox and I'd
>have an oxidizing flame. - Mike

Mike, the way I've been welding and the way it's taught in the EAA
video is that you need to have a slight feathered edge to the inner
cone. The reason for this is, you cannot tell whether you have a
carborizing flame or oxidizing flame if the cone is neutral without
that feathered edge. It is a visual indicator of how the flame is
set.

My experience after welding the complete tube fuselage for the
Christavia Mk4, and other projects, is that the torch can and will
change setting now and then, or at least mine did. If you have set
the cone with a slight feathered edge, you can tell when the torch
changes it's setting and re-adjust immediately.

Also, the description you made sounds an awful lot like you had too
much heat. Any time you are burning holes in your work, you need to
either reduce the flame, move the flame further away or move quicker.
You might even have to reduce the size of your torch tip. Oh yes,
there's one more way to reduce burning through, use the filler rod as
a quencher. Adding the rod reduces the temperature of the puddle. If
you are using a very narrow rod, you might be able to move up one size
rod and keep the flame the same size. But this means dabbing the rod
in the puddle constantly, or you'll burn through again.

Corky Scott