I sure couldn't do it. . I cut a 2x3 section out and put a patch inside and
tacked it. Then put a patch in the opening and tried welding this patch
perimter to the roller steel.No matter how many beads I did there was always
a pin hole left somewhere that leaked
Yes it can but it is not as easy as you might think. The reason you are
repairing is that it rusted through. Rust thinned sections are tough to
weld since they are randomly thing, you tend to blow holes.
Best is to start over with a slightly larger hole, making sure that you
have reasonable metal thickness all the way around. Tack it in place,
weld with the lowest power that lets you get a solid bead and good flow
You may have to grind it down and lay in a solid new bead to defeat the
porosity that you are getting right now.
Ken Hils> I sure couldn't do it. . I cut a 2x3 section out and put a patch inside and
Put about 5 psi air pressure in the roller and then use a soapy solution to
locate your leaks. Release the pressure and repair the pinholes.
To repair the hole do not just tack on top. Take your grinder and grind
a shallow groove about an inch long then run a proper bead filling the
groove made by your grinding disc. On some wire feeds you can adjust pre
flow and post flow of our shielding gas. I doubt you have that nice option
so give the gun a quick pull before starting to release extra gas then hold
your gun over the puddle when you stop to keep the air away and prevent
porosity. Even if you had a pinhole at the end of your repair bead it
should be at the shallow end of your grinding trough so it would not reach
into your roller interior.
"Ken Hilson" wrote: (clip)No matter how many beads I did there was always
a pin hole left somewhere that leaked
This may be a cop-out in terms of welding skill, but, if you have a torch,
how about silver-soldering the pin holes?
Throw the old rusted-out roller away, replace it with a cut-down propane
cylinder. Weld spiders onto the ends to support the axle (probably the
old end bearings, cut off). Fill with water (with antifreeze and some
fernox) or concrete.
Might be rusted through in that spot. That makes a repair a lot more
When I worked in-plant maintenance at a ring rolling mill, we often had
to build new "water jackets" for the soaking furnaces. We used the air
and soapy water to good effect. These were water-cooled 4X6X1/4-inch
wall rectangular tubing in a squared off "U" shape. They were mounted
along the sides and across the top behind the furnaces' vertical rising
doors to keep the insulation on the doors and inside walls from sticking
Two things helped solve our leakage problems:
(1) To long after my getting in trouble for wasting time, it finally
occurred to the plant bosses that beveling the joints before welding
resulted in fewer leaks. That and installing steam release valves also
resulted in no more uncontrolled releases of steam when a jacket lost
water circulation for some reason but was still full of water. I knew my
severe limitations as a welder at the time required that I give the
welds every chance to seal the joints.
(I'm not all that much better now, but at least I've taken training in
three methods from a good teacher. It helped a lot.) :)
(2) It's a helluvalot easier to fix leaks while the piece is on the
floor before mounting the jackets to the furnaces and getting the
furnaces up to 2300 degrees f, thus having to do vertical welds in a
real hot place to try to repair them. So we'd air them up and do the
soapy water thing.
After reading your description several times Ken I am wondering if you used
a proper interior patch. The proper way would make your patch at least 2.5
by 3.5 inches so that it is bigger than the hole. Hammer the patch to fit
the curve of the roller skin. Tack weld a welding rod to the cneter of the
patch and insert the oversize patch through the hole and pull it tight to
the inside of the skin. You should have at least an overlap on the inside
of 1/4 all around. Next make your flush patch 1.75 by 2.75 inches. Set
that flush patch in the opening so that you have an eighth inch gap all
around. Now you are ready to weld.