Brazing Broken Cast Iron: Repairing a Stanley 55 Plane 

That was a satisfactory job on the brazing but I can't help myself. I'm not looking to criticize but I wanted to share some of my experience in the hopes that we all learn how to improve our skills. I learned to braze from a master back in the late 90's and he was really good at explaining the science of metal bonding (ionic bonds) and how different materials react to different temperatures and how to apply the torch flame to achieve optimal temps. He taught me that the "secret" to good brazing is to recognize how the materials involved behave and react when your materials and flame temps are in the "green zone". . I noticed that you had your torch set too cold and you were applying the flame from too far away during the brazing work. . The torch flame has two parts, the "feather" and the "needle" (as I learned to call them), the feather being the transparent blue long and wide part of the flame and the much hotter short blue-white opaque "needle" in the center. The needle is the real working part of the flame for the actual brazing part of the work. . A lot of guys call it a "neutral flame" when the needle is about a quarter inch long and you get more of a "whoosh" sound from the torch and they call it a "carbonizing flame" when a little bit more acetylene is added in to make that needle flare out to about a half inch long and you get more of a "hiss" sound. I would have used the torch as it was set in this video if I were brazing something like copper tubing joints or plumbing joints. For the work in the video, I would go much hotter. . The feather of a neutral flame is fine for the preheat work but when you do the actual brazing (the part where you actually melt the rod in to the gap), you want to be using the heat projecting directly from the tip of the needle for that. That much hotter part of the flame will more quickly melt the rod and allow it to flow like water in to the gap. If the flow of the metal from the rod looks and feels more like maple syrup or pudding than watery, that's a good indicator that you're too cold or too far away. Most of the time it is best to push the tip of the rod in rather than lay the side of the rod down. . You don't want the metal parts being bonded to do the melting of the rod, you want the flame to melt the rod. Ensuring that you apply the rod/heat in that manner, you avoid most of the "clumped and humped" metal around the joint and it's much more efficient, makes a stronger bond, and it really cuts down on the clean up part of the job. When the material on both sides of the gap is sufficiently hot, and you are putting the needle to the rod, that rod metal will naturally flow in and cling to the sides of the gap through capillary action and when your material temps are hot enough, very little flux is necessary. In fact, over fluxing the joint can weaken it if you aren't careful. . When you set your flame for this type of brazing work, in the future, I'd listen for a little more "hiss" and little less "whoosh". I would have set the needle to be "carbonizing" at about a half inch long, with a sharp point, for the work you were doing and apply the flame to the rod/joint so that the needle tip is about an inch from the rod/joint (much closer than you were applying the flame in the video) with very short, quick, tight sweeps of the flame. That will get the temps up to where you need them for a "watery" flow and a very strong ionic bond that creates a very clean and efficient joint. It even uses less rod, less flux, and less time. . As I said, I'm not looking to talk down to anyone, I just hope to make everyone better at the task. Hope this info helps someone. Take it or leave it as you see fit. Best of luck to all.

Can't tell you how good it was to hear that intro music again! Glad you're back, Keith!

Haven't brazed in 27 years, but I'm still a fan of it. I learned to repair a diesel fuel tank the first time I brazed, did it right the first time.... made me grin from ear to ear :-)

Keith, your vids are single handedly walking me through the entire process of restoring my 1890 Edwin Harrington engine lathe. Every time i discover a new problem i come check the channel for a video on how to address it. THANK YOU!

hey Keith, I just did my first brazing repair on cast iron and thanks to your video it turned out great. luckily I remembered watching this video and when the job came up I was able to pull it up on my phone and work along a great teacher. thanks

Excellent job!! This is just the way our instructor taught us back in the 60's. And also, the way an old railroad blacksmith, back in the 70's, built up the teeth on an old obsolete hand brake gear . Building up bronze takes a delicate skill of balancing the heat. If you have too much heat on one side, the bronze will sag and run off the other side. You have to have the right temp as you fill in the gap, or it will just run out. If more heat had of been used, as some suggest, it wouldn't have worked. This video shows the correct way to braze.

We got some knowledgeable commenters here. This was cool. Learning a lot from both sides. Why didn't i use you tube when I was younger? 40 years ago.

Excellent. I love brazing. Many thanks, Keith.

Hello Keith your the man that would tackle anything no matter what comes through the door or the mail ,,,,,,you proved yourself you can do it looking forward on your next project

Nicely done, sir. The perfect application for a braze repair.

Well demonstrated and explained. Thank you.

when parts comes apart at crack level, an easy way to repair is to clean the fracture fascia without disturbing it, spread a coat of flux on the fascia of the fracture, squeeze parts together and braze with EasyFlo 45, this leaves a small line at the fracture and the brazes part needs almost no touch-up to bring back in service. I use this technique on mechanical parts with a good success for decades

Enjoyed...great discussion/instruction....I did my first CI repair the other day using Tig, very small part and I will say it was very easy to control the application of the filler metal/heat

Did my first project after watching your work .applied what I learned, project came out perfect . You are the best!! Tks.

Hey Keith, Nice repair and great tutorial on welding cast iron! Thanks for sharing! Ray

I love the setup on that second piece. Good engineering.

Thank you so much for sharing your knowledge I learn something new every time I watch your work

the bird sound effects are awesome - what a great place to work!

Nice video giving that old plane a new lease on life! Glad to see you back Keith, I can't wait for the freezing weather to be over here so i can get back to pouring concrete on my shop.

oh man watching this just made me have a serious braze craving. ive done tons of cast brazing on antique stoves during restoration its one of my favorite parts.

Im a retired welder over 35 years, and you are right you can't just use hard wire in a mig or 7018 that's a no , you wanna use brazing rods , nickel rods , SS cast iron rods etc. There's quite a few , the reason cast iron is so hard to deal with is the stretching and bending is only at a 2 to 4 percent when applying heat to it , unlike mild steel has a 50 or better stretching, bending warping point , not to mention cast is dirty anyway .....but warm the cast up pretty good before welding the crack , just let it flow slowly , lot of people try to get in a hurry with cast and it just want happen , patience is key when welding cast ....clean the area and bevel the area clamp it down good cause it will warp ....

I really appreciate all these videos. I have learned so much

I use to do a lot of exhaust manifold repair / cracked / broken , missing parts . I knew about the specialized process of preheating - welding with nickel - and slow cooling in oven [ the main thing I found was that preheating & slow cooling was to keep the cast iron from heat-stress-cracking , heating too fast and especially cooling off too fast . What I found that worked very well , using mig welding with standard steel wire and adjusting the power to keep from heating up the base / part - putting most of the heat in the wire [ which means welding very fast ] as soon as the welding done [ on big jobs - long time with welder , do the welding in short steps ] then through insulating blanket over work - too cool slow ' Fast cooling with lots of heat in piece would get very fine & many heat stress cracks . Many of these manifolds came back months or years late when other areas did the same and the 1st repair was still good . Sometimes just trying to do what we are told we can not do is rewarding ;)

Nice job Keith! I have done lots of cast repairs with very good success. You are correct! Getting good at brazing is a lot like getting to Carnegie Hall, practice practice practice!

Howdy! Thanks for the video. Like you, I learned to braze in a high school metal shop class. My teacher was a stickler for technique and brazing was his specialty. When I see brazing videos on the Internet (like this one) I think to myself 'Mr. Grizwald would have failed them on technique and appearance!' We had to heat the joint so the brazing rod could melt and flow into the joint without the torch on it. And 1/8" over coverage is all we were allowed. I haven't tried brazing since then (1984) because I use to think of it as a hassle. But after seeing you and many other 'pros' on the Internet demonstrating your 'awful' brazing techniques it gives me hope that a mere mortal such as myself may be able to pull off a successful braze job in a pinch. Thanks for the inspiration and education.

Good work Keith, And thanks guys for all of the great comments. I realy like using the heat indicating crayons as I am crap at guessing heat colors

Agree with everything you said. Just wanted to add I have done some TIG on small items using Aluminum Bronze rod with good results. TIG - AC due to the Aluminum and clean, very clean!

Another great video Keith! Thanks for sharing!

I really have learned a lot from you. Thank you taking time to explain the job you are doing. Thank you very much. Edward Smith.

Great tutorial Keith - many thanks!

Great video. That was a very nice repair. I thought expansion might give you a problem on that first part and sure enough it did. back in the 70's I had a vise that broke near the base. I welded it up and it is still with me. I thought at the time it was cast iron but it is probably cast steel. Thanks for the video.

its good to see you and mr fenner reviving the art of brazing i used to braze a lot on cars till the changed the laws here in the uk

There's a special jig i use... it's called threaded block and some hold down bolts. You guys are great. I'm not really a ball buster. At least that's what my friends would say, if I had any.

I like to use the 10% Nickel rod (SifBronze No.2) as it has a wide plastic temperature range and you can build it up quite easily. I used to do quite a lot of tube frame work using that rod and a gasfluxer.

beautiful video of the process. explained masterfully. i really enjoyed that! thank you

I find brazing works a lot better for me as well. I have used ni- 99 some times it works. other times well you all know the sound that no one wants to here. So i favor brazing over welding. Maybe a tig might work or a mig , I stand with Keith on brazing cast iron. Just saying. Nice job Keith, Also thanks for showing.

Very nice clean job Keith !

This guy is in love with the sound of his voice. Detrimental to the overall effect.

He's back! Glad to see a new video!

You are very skilled ! Nice work sir.

Keith, Nice job of brazing. Like you, I prefer to add the flux to the rod. The prefluxed rods are sort of fragile. It doesn't take much of a bump to knock off the flux. I did a lot of gas welding and brazing back in the early '60s when I was a lad. I couldn't arc weld to save my soul! The nice thing about gas welding is you can reflow your errors and no one's the wiser! Thanks for the great video. With spring coming on, I would imagine you will be down at the museum more and complete the Vance planer-matcher. I look forward to that and other restoration projects! Have a good one! Dave

Very cool and informative video. Thank you

ok. i thought for sure the end was going to fall off as the heat built up while trying to braze the bottom. great job. wow everyone's a critic, he was successful what more do you want !! great job.

Thanks for doing this vid. Very useful for us noobs not experienced in this type metal joinery.

Thanks for repairing the pieces for me Keith! Once I get them back and cleaned up, and the rest of the plane clean, I'll be sure to send you some pictures.

Great video again Keith.

Loved your videos. Thank you

Very nice lighting on the video. Well done!

Big Ralph, I appreciated your additional notes. I tried a similar project and took both yours and Keith's advice from his video. Thanks to you both. Francisco, exactly what point are you trying to make other than to make yourself look stupid? BR is just adding (in a very gentlemanly way) some insight. We can all learn from each other, and I for one very much appreciate that this opportunity and these guys take the time that they do to explain and demonstrate their craft. Rather than being critical perhaps add constructively to the conversation. Should you choose otherwise, or rather, be unable to do so, then I would respectfully ask that you go elsewhere with the negative comments, this area is for the "grown ups". Regards gentlemen.

Nice work Keith . Enjoyed !

I tried to take a drink every time you said "Uhhhh." I died.

Thanks Keith!!

Keith I'm glad to see your back at it. Keep up the good work, PS Braydon says Hello Mr Keith

Just what I needed! Very informative right before I start brazing back a broken bearing seat. 🤞 my MAPP gas setup will be hot enough to do the job. I don’t currently own oxy unfortunately. Greg

I'm not an expert, but I did my share of brazing. I used to braze in patch panels before I got a Mig setup. Did my share of stick welding cast iron too with mixed results. I found brazing to be the most successful way to repair cast iron especially if the results don't have to be aesthetically original looking. I used both bare rod and flux coated and find the flux coated easier to work with. Matter of preference, you need to do it a while before you figure out what you like better. I can gas weld, stick weld, mig and tig weld, but find as technology advances you go with it. Never gas weld anymore, a little stick, mostly Mig and Tig.

amazing skills...

Very informative and very professional. Thanks!

Thank you for sharing the knowledge sir! It would have been nice to see the finish product, a side by side comparison, before and after would have been really nice, heck, I wouldn’t mind watching you grind those suckers down. I learn faster by watching, that’s all. Thank you again!

I have a cast iron table saw bracket that I was going to try and weld but I think now I try and braze it instead? How you didn't drop an "F" bomb when the part slipped out of the clamp shows that you are not only a more skilled craftsman than be but have a much better temperament...Damn I dropped the "F" just watching the vajayo! Nice job!!!!!

Thanks for this keith - helped me out of a tight spot on a repair I was doing yesterday :)

keith you awesome. your using what you have it works keep up the good work

Hi Keith great job on this one i only have one criticism and a solution , when you've heated the object with the torch you feed the rod in with your left hand . if at that point you change hands you will have much better control of your heat/rod feed rate and will improve your brazing ability 20-30% i had the same problem because i favour my right hand and it was pointed out to me by a master of welding and brazing ...... keep up the good work . Alf .....

Great informative video Keith...i just subscribed. Thank you, Jon

Great video man I learned a lot.

Kieth - Great intro to brazing. I would like to add two things which may help. 1) The brazing joint has something like a 90,000 lb bond so breakage is unlikely if treated with respect. 2) Covering the parts both during and after, particularly cast pieces, with a welding blanket will slow the cooling process and prevent joint failure and new cracks from forming.

enjoying all your videos ! nyc job man . Zimbabwe

nice work, thanks for the video.

Nice job

To cool a brazed part slowly, try burying it in silica sand or powdered limestone. I do agree with some that it appeared to me that you used to much heat.( A neutral flame yields higher strength) A good tip is that the filler metal follows the heat.

That looks really tricky! good job on the repair though!

Loved your vid plus the stuff ups! That’s me to a T. I hope to hell thatBigralph is still around,,cos his knowledge is invaluable, John from Oz

If he sends you any pictures of the finished product will you be sharing them with us? You cant just leave us hanging Keith!

Thanks for the video. As opposed to some here I have only a small amount of skill at brazing. Your method has the appeal of reduced likely hood of damaging the CI. Like many things getting the work clean and getting a good "wetting" action are probably the 2 most important. The big V helps on getting the surfaces clean. There are brazing rods that have better "flow" so you can work with smaller clearances. I can see the value of using a soft flame on CI.

How would it work if you didn't grind anything off, but just coated both surfaces of the break with brazing material, then pressed the break together while heating the joint? Wouldn't that be a cleaner joint, just as strong?

Very nice video... BUT had like to see the job finished, ready for deliver back to the costumer as ONE finish grinded part, ready to reinstall.

love the bird sounds

nicely done ,,,tomorrow i will give it ago ,,,

Very good vid, I prefer the torch over Tig, Old school.

Pretty calm guy. You wouldn't be able to see in my shop if that happened to me, air would be crackling blue.

Nice brazing repair Keith! Very informative too. Would you have any interest in a Miller Syncrowave 250? I know where one is and can probably be bought at a very fair price. Would make a good addition to the Museum. Let me know and I'll get some more info. Adam

U R HEATING A LOT !

I had a feeling that the part would expand and buckle! But, in the end, you were successful! My friend repairs racing engine blocks. He has a special oven that heats the block until it is glowing (and the electric meter spinning)! Then he uses some eutectic rod and a TIG to glue it together. Cast iron is tricky!

Looks good boss. Brazing is becoming a lost art.

Try a fine fire brick that is somewhat square and flat for retaining under heat, maybe diamond wheel cut some vee cuts for round work. Great job I think..takes me back to my machine building days ..some with commercial aviation ...tolerances so tight you could scale the prints!

Geezus I jumped when you touched that hot piece.

hi, very good

Certanium 889 stick rod. I always preheat cast. I have used it with TIG by knocking the flux off. I've seen it listed on eBay It would be worth your time to try it. It is also very easy to machine.

Good job young man and I agree with you if you need a temp stick you should not be brazing !

I've stick welded cast before, but it's more hassle getting it right. And it was just a fire grate so didn't matter too much.

Hey Keith. Another great video. I am always sure to learn something from your videos. Thanks for the effort. Can I ask what the name of the flux you use is? I looked through the comments and didn't see it mentioned anywhere. Thanks

Hi Keith, With all the kind of brazing materials that exist, you can join just about anything to what ever, beyond that, there is always Crazy Glue... lol Pierre

If memory serves me correct, if you had access to TIG, you could TIG braze the pieces using ERCuSi-A Silicon Bronze rod. It would require preheating to 600° and controlled cooling but might offer less contraction stress than welding. Just a thought.

Keith, I need to do some focused heat brazing of aluminum tube to tube about the size of what you're working with. Will a micro propane torch be enough to release the aluminum braze already on the piece without heating a huge area, move the tube to a different position and rebraze.

Great set-up! Wouldn’t Sta-Silv or Safety-Silv have worked in this case? There would have been less removal of the parent metal necessary and less filler rod used as well. There would have been a stronger repair as well!

like that homemade apron

skip to 10:05 for action

I like you. You sound like FOLKS. ;-) Thanks for the video and the work you put into it. And mostly the experience and knowledge you impart. Of the big four (or five ... or six) machinist youtubers, you are by a sight the best TEACHER. I do, however, recommend thatlazymachist to curious onlookers. He's not fun to listen to and speaks some kind of moon language type canadian, but he's an adept metallurgist and can also teach. This goes for you too, Keith!

Never having done this before, I am curious how you can apply such heat to do the underside and not melt the work you did on the topside?

I try to heat the difficult parts first and the easy parts tend to take care of themselves. I guess you cannot get the steel block too hot without brazing your work to it as well, ROFL. I haven’t tried this on a firebrick or a nest of firebrick (to limit radiation and convection losses), but I have seen videos. Hmmm, a tunnel of firebrick with a space to braze comfortably might work. I like fluxing the rod too. Nice job!

Thanks for yet another nice video. Ive watched some videos of jewlery makers and they put flux first on the surfaces to be braced and then puts a litte piece of brace rod that gets sucked into the crack when heated. Is that not a viable method on cast iron or why do one do it they way you do in this video?