The Acetylene Tube Borium is a finer grit and better at adsorbing impact but the Borod has better straight abrasion resistance. They both come in electric rod form too. Depending on the size of the parts and the angles involved, you might be able to clamp some mild steel against the off-face to both keep that edge from picking up any deposit and to help control melting of the corner. To control oxidation on the back sides, you can coat with a mixture of standard wet brazing flux and lampblack before starting. Don't use flux under a backing bar though, 'cause it will held the capillary action draw the melt inside. Maybe lampblack and Waterglass there? I should try that some time.
I've hardfaced shredder/chipper flails, and needed to keep really square corners on relatively small parts. With plain alloys, a TIG torch can be used to shape the deposits to a good corner, but with Tungsten Carbide, TIG will dissolve the carbide.

BTW, we'll need both 'Before' and 'After' shots of the parts; don't forget!

 

I've done quite a bit of hard/wearfacing over the years. I chose the product based on what the part was required to do. Did I need more abrasive resistance, or Impact? Sometimes both. There are so many products to choose from. I am partial to McKay and Stoody. They've both done well for me.

For small parts, I used to "powder spray" them with a special torch used with O/A. This was called "hot spray". Had different powders in varying degrees of Rockwell or Brinnell hardness. Even had Tungsten Carbide powders.

I had a job come in one time. Had to reface the knives on a LaBonte Shear. This shear is attached to an excavator and used for demo work. Cuts through a large I beam like it's butter. Required a special rod. I ordered 40 lbs at $20 a lb (15 years ago). Took forever to apply the stuff on 3 big blades, but it worked good.

There were times when the customer would agree, that I would apply different material to different parts, and record what went where. After a period of time, we'd do a comparison on what was doing the best job.

Good Luck with your job.

 

If you go with borium make sure to get the small grit, one thing don't try to shape annything you have put borium on with a hammer and anvil unless you don't like the surface you have on their faces as it will wreck both the anvil face and or hammer face(which ever one the borium is against).

 

flatbustedbroke,

Thanks for the advice. I'm passing on the borium because my LWS says it's $49/lb with a 10 lb minimum. Yikes. Too rich for my blood as I'll never use 10 lbs on this job. The customer would never go for it either.

So instead I'll be figuring out how to make the McKay Hardalloy 140 do the job. 10lbs of it was $77. Still pricey, but much more affordable.

Will post photos of the bean planter pieces soon, along with a couple questions that occurred to me when I picked up the parts. Stay tuned...

 

So, Here are some photos of the parts I have to hardface. There's 10 or 11 more just like these in the whole set. The areas boxed in black are the places that need hardfacing applied; basicly anything that's cutting through the ground as the equipment is used.

The third photo shows the two components assembled. The fourth shows the cross-section of what I'm calling a 'blade'.

The flat housing is pretty straightforward. Just have to make sure I don't warp them with too much heat.

The blade is where I'm looking for assistance from y'all. That blade has to keep a sharp edge. It also shouldn't have a different shape or profile once the hardfacing is applied. I'm thinking that I need to actually grind down the sides just a bit, and allow the hardfacing beads to restore the blade to it's original shape.

The other thing is, how do I handle the actual edge of the blade? This is why I was looking at the tube acetylene borium. It's sweated on with an OA torch, just like solder. I could see flowing it right over the edge. But the arc from the Hardalloy 140 is just going to melt that edge away and leave a blunted edge behind. Do I try intentionally blunting the edge, then build it up with 140, and finish by grinding back to a sharp edge? I hope I don't grind off all the hardfacing in the process? This is not my first choice.

Any other suggestions?

 

Since that wire is very high alloy used by MIG, it should be reheatable by TIG so you can move the deposited material around and form a sharper edge, as mentioned in post 2. You have TIG, right?
The Bible has a small section on hardfacing which mentions where not to face so the edge continues to remain sharp as it wears slowly.

 

hardalloy 140 is a stick electrode. It is very high in chromium. I do have a TIG machine, so I'll run a couple beads on some angle iron, and see if I can move the deposit over the cutting edge.

I'll have to look in the bible again. I checked Lincoln's hardfacing guide, but didn't catch the reference you mentioned.

Thanks for the suggestion.

 

Sorry for not re-reading and catching the MIG vs stick.
The TIG should work for that too, after deposition as stick. If the flux is just for cover and not alloying, you might get away with applying the corner w/ TIG (after removing flux from the rod) and the rest as standard stick, but often some alloy material is in the flux so results aren't as good that way.

 

Just a quick update. Seed boots too thin for 1/8" McKay Hardalloy 140. Even if it doesn't burn through, the deposit is too thick and it warps more than I'll accept during cooling. Might be do-able if they made Hardalloy 140 in a 3/32 rod, and if I had a big industrial furnace I could use for pre-heat and slow cooling.

So, instead, I managed to scrounge some misc TIG hardfacing rod from a friend who didn't have any use for it. Customer knows it's mystery material, but is happy with the end result. It's definitely hard stuff, difficult to grind and the grinding wheel throws no sparks on this stuff.

The blade-like attachements are cast, high carbon steel or grey cast iron. Horrible cracking problems, so I'm returning them to the customer without hardfacing.

I'll post some photos of the TIG hardfacing work this weekend, when I have them done.

 

Wall Colmonoy used to sell a "Sweat-on Paste" which came in 1# cans, was applied by OA, carbon-arc or TIG, and had a hardness of 68-72 Rc. It was applied in thin (~0.020") layers, so 1# would go pretty far.

I don't see it in the "alloy selector" on their site, but they have lots of other powders which are applied in various ways including those above. That list is here:

http://www.colmonoy.com/Products/support/TECH_Data/Colmonoy Alloy Selector Chart--Tech-1J.pdf

I'd bet that one of these could easily be applied to the cast iron parts, if needed.

 

The cast 'teeth' things -should- be steel.

Cast iron would crack/snap in a heartbeat if it hit something and really wouldn't wear all that well either.

Massive preheat and slow-cool didn't help on the 'teeth'? Like preheat them up to 800F or so, weld, then a little more heat and slow cool?

Don't you have a gas BBQ/grill? Preheat the red parts in that.

Or get a bonfire going. :laugh:

McKay Tube-Alloy 240-O FCAW wire is listed as equivalent to the McKay 140 stick. Catalog says it comes in 0.045 wire, but that's still going to be at least 120 amps or so which is the same for the 1/8 inch 140 stick. But maybe you could move along a bit faster with the smaller diameter compared to the 1/8 inch stick.

 

Oldiron2,

Thanks, I'll check out colmonoy's website and see what they have to offer. The big hurdle is price. If their products are prices comparable to other hardfacing materials, they're too expensive for this job. Looks like Colmonoy produces Nickel based hardfacing compounds. That's pricey stuff; look at nickel rod for repairing cast iron.

I looked at some Cobalt based hardfacing, because it was available as a TIG rod. It was $80-$90 a pound, 10 lb minimum. This is a 1 lb job. Even the Mckay hardalloy 140, at $7 a lb and 10 lb minimum order, was expensive.

The rod I've turned to is something I picked up from a friend for cheap; maybe free once we get around to discussing the price. He inherited it from a previous job, and it's been sitting in his shop for years. I think there's just enough of it for this job...

Moonrise, yeah, I have a barbeque, but I'm not really set up to deal with massive pre=heat and post heat requirements. Let's just say this job isn't earning me enough money to invest that kind of effort. From what I know, these cast parts are intended to be thrown away, so I'm fighting an up hill battle when it comes to cost. My customer wasn't upset when I told him the knives were not practical to hardface. They're the less expensive of the two components.

I'm intentionally avoiding MIG/Fluxcore products because I don't want to buy 10,20, or 40 lbs of wire to do this job. Like I said, the job is a '1 lb of filler metal' job. As it is, I need to find a job where I can use the hardalloy 140 now; as I own it, if the customer doesn't want it to use himself on some other project.

 

Sorry oldiron2,

I missed the fact that the colmonoy product you recommended came in small quantities. I sent their customer service dept an email asking for more info. Will keep you posted.

 

From what I know, these cast parts are intended to be thrown away, so I'm fighting an up hill battle when it comes to cost. My customer wasn't upset when I told him the knives were not practical to hardface. They're the less expensive of the two components.

Yeh sometimes you have to take a hard look at the cost of a tooth or cutter and ask just how much money do you want to spend extending the life of it. Most are made easily replaceable for a reason.

 

Job Done. Customer Happy. More work in the weeks to come. I'll post pictures as soon as I figure out how to ransom them from my new cell phone camera....

 

So, I finally got the photos downloaded from my new camera. Here are a couple shots of the finished work.

TIG welding the hardfacing on to each part was not as easy as I expected. The worn edges that were thin have a tendency to vaporize as you're pushing the hardfacing puddle around. The hardfacing rod also tends to spit and the molten droplets are hard on the tungsten and tend to coat the mouth of the TIG torch cup.

In speaking with someone at Colmonoy, I found out this spitting behaviour is a side effect of the manufacturing process used on some of these bare hardfacing rods. Supposedly applying these with gas welding is easier, but I chose to use TIG because I was running short on acetylene and oxygen....

 

Looks like a job well done :drinkup: