Cast iron repair to jointer

[Michael Shoffner]

So I recently acquired an older model Grizzly G1018 jointer. It's well worn. I spent the weekend cleaning off the rust and now the tables look great.
My problem now is that a piece of ast iron has chipped off the back corner of the fence mount bracket. This supposedly happened during delivery, though I suspect this damage happened prior... or at least was started prior to my ownership.
Disclaimer: I only have $100 bucks invested in this project so if it goes badly, then there is no huge loss. Nevertheless I think I can get this machine serviceable still provided this chip does not get any worse.
I've been told that welding cast iron is a tricky endeavor. So I was thinking of tryi to JB weld this corner back together. I have no experience in metal work. Thoughts or advice here?
IMG_0296.jpg IMG_0294.jpg IMG_0293.jpg IMG_0292.jpg IMG_0295.jpg

[Vinito Caleb]

I can't tell exactly where that chunk has cracked off. Is it the casting at the back where the fence workins' are?
If that's the case, I don't think there's a lot of force happening there and JB weld might be fine. At first I had my metalworking blinders on and assumed you'd be looking at having it brazed, which is much trickier at best. But if you heap up some JB weld it might just be OK. Maybe post a pick from a bit further back to show which part of the machine you're needing to fix there.

Tips: 1) you can use masking tape to make dams so you can pool up the epoxy, working in stages so gravity is on your side rather than working against you. Dams below the crack will keep the stuff from seeping through and dripping out too.
2) you can heat the epoxy with a heat gun or blow dryer to make it more viscous (thinner) to flow into tight things if you need it too.
3) you can add fibers, like loose fiberglass cut short (maybe 1/4" to 3/8") to mix into the epoxy to make it stronger. Kind of like micro cheap rebar. Maybe not really necessary though.
4) You can clamp things together a bit, drill & tap a hole, and insert long set screws to align things closer to what it was before it got tweaked. Then epoxy it all, leaving the screws where they are. Even better if you epoxy the set screws thickly before installing them so they become a solid permanent part of the repair.

Work in stages, completing a chunk at a time until satisfied.

Build it up leaving important areas flat and it may work out just fine. Do a little sanding and apply a coat of paint and you're gold... until it breaks again

But if it's an important part that requires maximum strength, your best repair may involve brazing and all the other afterwork that will undoubtedly go with it.

[lowell holmes]

A bit far fetched, but cast iron is brazed. Is that an option?

[Rick Johnston]

If non structural - I'd use a epoxy paste called PC products - pc-7 . It comes in a greater volume than JB weld. Home Depot has it. Or check other resources for larger cans of it. You will need to build a good size backing to reinforce it.

[Cary Falk]

I have had zero luck with JB weld for anything metal. I would braze it.

[Chris Fournier]

This is crazy but crazy glue really works well on cast iron. I used it on a machinist's vise almost 20 years ago. That being said I would braze that piece of yours because I can. It is likely not that critical structurally given that it has been this way forever.

[Doug Garson]

I have had zero luck with JB weld for anything metal. I would braze it.

Interesting, I've only used it a half dozen times but my experience has been the exact opposite. Every JB Weld repair I've made has been a success. Not highly stressed parts but the repaired parts have been rock solid.

[lowell holmes]

I am with Chris on this one. Brazing is my choice. I'm not sure the strength would be equal to new, but it would be substantial.
I would talk to someone in the business for advice.

[fRED mCnEILL]

The problem with welding cast iron is that it has to be pre heated and then slowly cooled over a long period of time. Apparently the heating changes the molecular structure which is then prone to cracking after.
I recently had to repair a cast iron part on my tractor(highly stressed) and came across some new brazing AND welding rods(http://www.breckocorp.com) that does NOT require pre-heating or extended cooling. In fact the brazing rod has a higher tensile strength that the metal.
So I brazed it and it is holding fine-even though a welder friend said it wouldn't work.

The rods are expensive (i.e. $10 each) but they sell them individually so you can buy just a few.
Worked like a hot-damn.
I would braze it.

[Pete Staehling]

I'd braze it. Easier, more reliable, possibly weaker, but probably plenty strong for what you have there.

If you would go the welding route... An expert welder friend I knew told me that for welding cast iron there were two approaches, either:
1. Preheat and cool slowly
2. Weld it in a way that heated the piece as minimally as possible

The second one is iffy, but he seemed to manage to do repairs that way that I could not have handled. If I tried it the work would crack. He claimed that it was mostly the uneven expansion and contraction of the metal in heating and cooling that was the issue and that he could manage it best by method one, but could usually get by with method two when he had to. I did see him manage successful repairs by both methods.

[Michael Shoffner]

Thanks everyone. Good tips here.
Here is a picture of the break location.
IMG_0300.jpg
Its on the back corner of the lower fence mount. I don't think this area will see a lot of stress. It appears not to be affecting the fence movement.
-The corner is a bit deformed now. The chipped piece fits back in place, but not exactly. As shown in the picture in my first thread, there is a 1/8" gap on the side where the 2 pieces do not meet. Can I span that gap with metal epoxy?
-regard metal epoxy ( JB Weld or similar) will I make the repair stronger if I heap on a bunch in stages on the under side? Or is less more when working with this stuff?
- Brazing - I have no idea how to do that. Where would I go to get that done?
- the entire lower fence bracket that is chipped needs to be adjusted a bit higher for the fence to properly slide over the table. It bolts to the table in 2 places. So it would be easier to make this repair if I removed this bracket from the table. Is that a bad idea? Do you think unbolting it will change the stesses on it and make it move more?
Thanks to all for you help.

[Bradley Gray]

I'm sure brazing would be better but try the epoxy.

If that doesn't work you could heat the epoxy and remove it and have the piece brazed by someone who knows how.

I would probably just stash the broken piece in the base of the jointer and use it as is.

[Charles Lent]

There is a high nickle content rod for welding cast iron, but if it was mine I would braze it. Brazing would be the best and reliably strong way to repair it. If you use any kind of glue or epoxy on it, it will not be very strong. Also, it's very difficult to weld or braze if it has been glued, because it will be very difficult to completely remove these in order to get a good braze or weld. Have someone with considerable brazing experience repair it.

Charley

[Rick Johnston]

The repair with epoxy will be much stronger with it feathered and thickened along the crack line. I'd go 1/2" thick - easier to get that volume with the pc product - unless jb comes in something other than tubes. You will want good access and prep the surfaces.

[Chris Hachet]

I am with Chris on this one. Brazing is my choice. I'm not sure the strength would be equal to new, but it would be substantial.
I would talk to someone in the business for advice.

Brazing or ordering a new part from the Griz.