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 out.
You may have to gr> 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. Randy
"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 difficult.
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 together.
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. Randy