A welding question.

[PeterSibley]

A welding question .

I'm building a crane for the back of my truck, it is going to have a manual slew using a worm and wheel from an old reduction box . I'm turning the inside of the wheel out at the moment to fit the mild steel round pipe that makes up the post. I'm going to have to attach the cast iron wheel to the mild steel post somehow. There isn't really enough material left for a steel band and a bolted connection.

I can get it brazed on at considerable expense but is there a more normal and modern method around now ?

[Canoeyawl]

Nickel wire or rod

[PeterSibley]

So ...any shop with a MIG ?

[stromborg]

Cast iron is hard to get a good weld on. The highly localized heating/melting and solidifying along the welded joint leaves the area weak and crack prone. It can be done, as I recall the iron gets pre-heated before any welding occurs, but it's been a long time and I was taught welding in theater school where the emphasis was heavy on practicality and low on theory.

I'm sure there are more experienced metal workers here, but I'd be leery of a highly stressed cast iron/mild steel joint.

Steve

[PeterSibley]

Steve, I've received some good advice down in the Bilge too. Thanks.

[Tom Freeman]

One of the guys at Jensen was about to get a cast iron cylinder head welded in Port Townsend I think. He is in Alaska this week, but let me know if you want me to get some more info when he gets back week after next.

[Nicholas Scheuer]

We used to weld steel to cast iron on several of our products using rods from UTECTIROD. This was back in the 1970's; don't know whether they're still in biz.

[Runner]

I have done it when I was in to building rock clawling buggies. The parts will have to be pre-heated before you weld. Then after welding you want to post heat the part for as long as you can, preferablly over night. You can wrap it in insutation or burry it in hot sand. I used my large shop wood stove at a controlled temperature. I would have to look it up but I think you are shooting for 700-800deg farenheit. The weld should also be peened as it cools to help relieve stress. The rods I have are Uniweld UNI99. I bought them at United Welding here in Portland but someone like Air Gas should have them as well.

[Chip Chester]

Might be easier to bore out a mild steel flange and weld that to the pipe, and then drill and bolt the cast iron to it. Even though it's not a supporting element of the load, you don't want your maneuvering mechanism to let you down due to a bad weld. Chip

[paulf]

cast iron is tridky unless you know what alloy.
The three best ways are:
1. Braze with a oxy ace flame, good flux, brass rod and preheat cycle with temp stick indicators.
2. Attach with bolts to mild steel attachment, then weld that with 7018.
3. Nickel rod with before mentiond preheat.
I guess you could locate a steel gear and side step the problem. Iron can be very brittle and crack easily if shocked.