Welding Rods for Dissimilar Metals – Maintenance Welding Rods
Maintenance rods are for those jobs when you dont know exactly what you are welding.
You know its some kind of steel but you dont know exactly what kind.
In other words, you know its not aluminum, its not titanium, its not magnesium, and its not copper.
Its steel. but what kind?
It could be cast steel, stainless steel, tool steel, high speed steel, manganese steel, abrasion resistant AR400 steel, 303 free machining steel, nickel steel, P91 chrome steel, etc.
There are all kinds of steels that are used to make machinery. And its hard to determine the exact metal things are made of sometimes.
I have a friend who has maintenance contracts for several small factories.
He often welds wear in conveyors, cracks in brackets, removes broken studs, and just basically welds anything that is broken and needs fixing.
He swears by Certanium 707 stick welder rods.
Now I am not saying its OK to use Certanium 707 or other maintenance arc welder rods indiscriminately for anything and everything.
When the job calls for it, you need to determine the exact metal that is going to be welded and even get engineering support when the application calls for it.
But if a stainless steel angle iron bracket gets backed into by a forklift and now the conveyor system is broke, you need to have an all purpose steel welding rod that will get the job done.
You can worry about details later when the machine can be shut down for an outage.
When a machine breaks down and is costing a factory 500 dollars or more per minute, you need a maintenance welding rod that will get the job done, wont crack, can be drilled and tapped if needed, and will make a sound weld that will hold up to future abuse.
Certanium 707 is such a welding rod.
It is similar to 312 stainless but my analysis showed a much higher Chromium content.
The tests I had run indicated a chromium content of around 40%.
312 stainless arc welding rods have about 30% chromium and 9% nickel and the rest is mostly iron.
But Maintenance welding electrode manufacturers are not bound by AWS specifications and if they discover that an extra 10% chromium helps the rod weld better, crack less, and makes a stronger weld, then by gosh they will add it.
In fact , they are free to add frog legs, sawdust, and pig testicles if they want to.
Other welding electrodes similar to Certanium 707 are:
Eutectic 680, American filler metals Patriarc, All State 275, MG 600, Inweld 955, UTP 65, Welco Super missileweld, and Rockmont Brutus A.
The cool thing about maintenance rods is that they work.
They are not bound by AWS or UNS tolerances for chemical composition so if they discover that a little more of this or that works better for welding thru rust or coatings, then they can add it and not get spanked for not complying with a AWS specs.
Besides, Maintenance Welding rod makers are very tight lipped on the exact composition of their maintenance welding rods anyway.
When they find a recipe that works and that welders like, they keep it a big secret.
Speaking of secrets.
some maintenance welding rods are not much different than 312 or 309 stainless welding electrodes. In fact, since they wont say whats in them, what is to keep a company from buying some 312 stainless rods and labeling them with some exotic name like Neptune Astro and charging 10 times as much?
I have heard from some welders that some suppliers charge as much as 100 dollars a pound for Certanium 707.
309 and 312 are way cheaper. like around 20 bucks a pound..sometimes less.
How to Price Welding jobs
Lets talk for a minute on how to price tig welding jobs.
While I was shooting this video, I had to finish a welding job for a machine shop and so I thought it would be interesting to talk about how to price welding jobs.
I have done quite a bit of work for machine shops and here is how I quote jobs.
Since the machine shop fronts the money for materials, I don’t have much risk, but I still don’t like bidding a job too low and working for peanuts.
Here is my highly scientific formula for pricing tig welding jobs.
1 dollar per inch and 1 dollar per tack weld.