Bronze Brazing Cast Iron

[HT2-4956]

Being as I think we lost a good thread on this subject during the Great WW Server Crash of Ought Eighteen I thought maybe I'd get another one going because I've seen it come up in a few other threads since we're back up.

If any one else has any advice on doing this or pictures of stuff they've used this process on by all means post them.

OK, here we go......

This is an old piece of cast iron I found a couple years back that I've been meaning to do this to for at least the last 2 years. One hinge ear was busted off it and is missing. Thought it might make for a good tutorial about how you would go about fixing something like a broke off cast iron gear tooth . And if any one recognizes (or has a guess) which particular type of old John Deere equipment this goes to I'd sure like to know.



First step was to take a die grinder and make a cleaning cut on the broke surface where you want the bronze to stick to. This needs to be done with either a die grinder or hand file and not a grinding rock or flapper disc.



Being as this was not a complex shape and I was just going to be working in one small area on the edge I didn't do much preheat to the whole part other than run the flame over it to take the 20 F. chill it had on it from coming in from outside. Warmed the whole thing up to around 100 F. before zeroing in on the broke surface and bringing that up to red heat and starting to add the bronze.

If this would have been a gear I was trying to build up a missing tooth on I would have heated the whole gear up to 800 to 900 F. before moving in and bringing a smaller area around where I was going to be working up higher (say around 1200 to 1300 F) before moving in even further directly on to the faying surface and bringing it to red heat so it would be hot enough to wet out and accept the bronze. This happens at around 1700F. for the Harris LFB-15 FC rod I was using.

Got this far until the localized heat built up enough to where it was starting to get a way from me and I had to really start flicking the flame on and off the puddle rapidly to get the build up to stay where I was wanting it. The minute or so it took to stop and take this picture let it cool off just enough to where the puddle went back to behaving a lot better. In fact for the whole rest of this I was adding about this much at a time before stopping (and getting the flame off the part) for a minute or two to let the area cool off some before continuing.

[HT2-4956]

Continuing on....

Just kept building a pad straight up. This picture was taken at one of those points where I was letting things cool back off at bit. I was using the good ear still on it as a visual aid to eyeball against to make sure I was getting the build up where it needed to be. At this point it was still looking like I didn't have quite enough on there yet so I put a few more beads worth on top of what you see in the picture.



After I thought I had enough on in that direction I flipped it around so I could start building out a pad that would be the main body of the ear. Where ever possible you flip the part around so you're working in the flat position. It's not that you can't do it out of position it's more because it takes a lot longer (and requires more finicky heat control by flicking the flame on and off the puddle faster) because you can't put down as thick of layers with out them running off from where you want them to stay.



This is a little further on in building up a rectangular section up off of what you see in the previous picture. Again this picture was taken at one of those points where I thought it best to let things cool back off at bit.



And while it was cooling off some I took the opportunity to eyeball it (against the good ear) from this direction and saw where that other ear had some lean to the left and that I didn't have enough on that side (especially up toward the top corner) yet.



So to make it easier I flipped in around again to this position (the one I started off in) to get some more on that side and corner. This pictures also shows a little better where I'm still needing to get some build up.

[HT2-4956]

Another 5 minutes or so and I had what I thought was enough on in that area.

Attachment 1683678

Getting down close to where I'm starting to think I've got it and am using a straight edge to help make sure.

Attachment 1683679

Saw one place on the inside where it looked a little low (especially in close to the cast where I was going to be wanting to end up with a nice smooth radius) so I flipped it around again and puddled a little more on in that area. What you see in this picture is where I called it as being done.

Attachment 1683680

[HT2-4956]

Didn't have a clock with me to keep an accurate account but I'm guessing from taking the die grinder to it to what you see in that last picture was close to 45 minutes. It took just shy of 3, 36" pieces of 3/32" diameter Harris LFB-15FC filler rod to do it. Was using a 2-W-1 Victor tip mostly turned down as low as I could get it with out it wanting it to "pop".

When I was done I left it lay there on the warm table for around a half hour to cool off while I worked on something else. Then once it was back to room temperature (where I could handle it comfortably with thin gloves on) I used a center punch to peck around on it to get the bulk of the remaining flux to chip off before giving it a once over with a wire wheel on a 4.5" grinder to shine it up.



Attachment 1683682

As far as carving out a new ear from that build up (that hopefully will closely resemble the other one) I figured that would best be a project for another day. At this point though I'm estimating that it will take me at least an hour to whittle it out using some combination of my die grinder, 4.5" grinder and some hand files.

[Will S.]

Thanks. Nice write-up. I'm looking forward to Part II: Grinding and Whittling.

[metalman21]

Good heat control! And that is what it takes to do that. Always better to build up more, it sucks when you finish it, find you need more somewhere and have to go back in.

[rexcormack]

Nice write up.
I call that flicking motion you're referring to "fly fishing".

[HT2-4956]

Good heat control! And that is what it takes to do that. Always better to build up more, it sucks when you finish it, find you need more somewhere and have to go back in.

Yeah, I also tend to err on the side of getting more than actually needed on rather than run the risk of ending up with a low spot you have to go back and put more on. It's not so bad when I'm the one doing the re profiling but I've done a fair amount of this kind of thing where after I've done the build up I'm done with it and the customer takes the part back and does that themselves. I find it a little embaressing to have some one have to bring something back and tell me I "missed a spot".

[farmersamm]

That looks really good.

I was able to get better heat control when I switched to a #2 tip (Harris). Was so pleased with it, that I've ordered some even smaller ones. Just enough to melt the bronze on its face,, and allow you to get a small puddle going........instead of heating the Bejesus out of everything.

[M J D]

Out of curiosity, why didn't you cut a piece of steel and use that for the missing section?

[HT2-4956]

Out of curiosity, why didn't you cut a piece of steel and use that for the missing section?

Well, you know if you're the kind of person that's always looking for the easy way I guess you could have gone that route.

But seriously....

Mostly I did it the way I did just to show how that kind of thing could get done. It was more about doing a Bronze Brazing tutorial than making an economical repair of some kind. But you're right in that there's some point where if your missing piece gets beyond so big it would make more sense to make a replacement piece out of steel and braze it on.

On the other end of that spectrum though... there is a point where even if the customer has the broke off piece it can be of such a small size that it's not worth messing around with to try and put back on but is just quicker and more economical to build up the area and reshape.

[docwelder]

ht; not too shabby on the nugget build up. it should give you no trouble to grind into shape and drill. nice work as usual.

[HT2-4956]

Looks like the forum software screwed with me again on my pictures and they turned to invalid attachments. Let me try getting them in there again where they'll stay....

Another 5 minutes or so and I had what I thought was enough on in that area.



Getting down close to where I'm starting to think I've got it and am using a straight edge to help make sure.



Saw one place on the inside where it looked a little low (especially in close to the cast where I was going to be wanting to end up with a nice smooth radius) so I flipped it around again and puddled a little more on in that area. What you see in this picture is where I called it as being done.

[HT2-4956]

ht; not too shabby on the nugget build up. it should give you no trouble to grind into shape and drill. nice work as usual.

Thanks doc, I'd have to imagine that you've had occasion to do some of this, yes/no?

[HT2-4956]

This is the missing picture from post #4.

[docwelder]

Thanks doc, I'd have to imagine that you've had occasion to do some of this, yes/no?

ht; recently i've built up some bronze lock parts and repaired the crank handle on the machinist's bridgeport.

[HT2-4956]

As an example of what I was saying in post #11 about a piece being so small that it's not worth the hassle of trying to put back on...

If just the end of an ear like this was broke off something (like where I've got the red line) I wouldn't try and put it back on even if the customer had it (which only about half the time they seem to). A little tab or ear end broke off (usually right thru a bolt hole) has been a fairly common type of cast iron repair for me over the years. The hardest part of trying to put a little piece back on is finding a way to accurately locate it and then securely hold it there while you get it hot and make the braze. I just came to the conclusion after trying to do it once (or twice) years ago that it just wasn't worth the aggravation and that I could get a better repair (both in looks and strength) with less dick'n around by throwing the little end piece in the scrap bin and just padding up the area for reshaping and re-drilling.

Attachment 1683703

[M J D]

Well, you know if you're the kind of person that's always looking for the easy way I guess you could have gone that route.

But seriously....

Mostly I did it the way I did just to show how that kind of thing could get done. It was more about doing a Bronze Brazing tutorial than making an economical repair of some kind. But you're right in that there's some point where if your missing piece gets beyond so big it would make more sense to make a replacement piece out of steel and braze it on.

On the other end of that spectrum though... there is a point where even if the customer has the broke off piece it can be of such a small size that it's not worth messing around with to try and put back on but is just quicker and more economical to build up the area and reshape.

The small piece thing is spot on. I guess it comes down the part in question. Have you ever used graphite or carbon plate as a backer for build up? I have used it several times for weld repair on steel or cast, but haven't tried it with braze.

[HT2-4956]

The small piece thing is spot on. I guess it comes down the part in question. Have you ever used graphite or carbon plate as a backer for build up? I have used it several times for weld repair on steel or cast, but haven't tried it with braze.

MJD,

I've never used any graphite or carbon plates for any kind of welding backer (at least not that I can remember). So if you would, please elaborate on that.

The one way I have used graphite in connection with brazing is by making a heavy line with a carpenters pencil to act as a resist to keep the braze from going where I didn't want it. But that was more for just looks on an artsy type thing than any thing else. A forum member from MO named Rodger made a good post about that in a thread we had going on this before the crash. I haven't seen him post since the forums got back up and running but I'm hoping he'll eventually come back around and get involved with this thread.

[M J D]

The graphite plates,which come in different thickness, are easy to cut and shape. They are the same composition as the inside of a coated air arc carbon. By clamping them on the back of a hole you can easily fill it, since the weld doesn't adhere to it. I used them for building up sprockets on a large drag chain. You cut the plates to match the profile you want. Clamping one on each side of the sprocket sets your build up profile. This provides a dam and an indicator for where and how much weld metal is needed. They are a little pricey and hard to find but work outstanding in that application. I believe Arc-air brand sells them.

[shortarc]

Picture of what your lid is off of.

[Yofish]

A lot of work. Was me, I'd make a steel replacement and weld with 309L or 99 nickel. This is a low-duty thingy but I dig the effort.

[HT2-4956]

Picture of what your lid is off of.

Good find. I'd kind of been assuming that at one time JD made some kind of wood stove and that it was a door off of it. I never could track down any pictures of any old stoves that JD might have made though. Now I kind of know why.

Do you (or any one else) know what the piece of equipment in that picture is called? That way I could google up some more pictures.

One thing I noticed though is that while the one in that picture is real similar to the one I have it's not the exact same. The one in the picture has the hinge ears on the bottom edge while the ones on mine come off the top.

[HT2-4956]

A lot of work. Was me, I'd make a steel replacement and weld with 309L or 99 nickel. This is a low-duty thingy but I dig the effort.

Yofish,

That wasn't any kind of official fix for any body that plans on putting it back in service (all though I'm sure it would fine for doing so with). That was just what I thought was a cool old piece of found cast that I thought would make for some good shelf or wall bling. After I get the ear whittled back out I'll probably rattle can it JD Green. Might even get fully carried away and get some yellow and a small paint brush and do the top raised areas of the deer and the lettering. Most likely will end up on the wall as a companion piece to my JD themed feng shui mirror.

[shortarc]

Today, 07:38 AM
HT2-4956. It's a horse drawn sickle bar mower. If there are any Amish farmers in your area you could probably sell when you are finished with the repair, which looks real good by the way.