What kind of metal is the rong fu rf 31 head casting???

[zdiaz925]

I found a couple cracks during a inspection,while changing the motor capacitor. I am new to metal working and am wondering what kind of material the head casting is? Im guessing cast iron however im not sure. to be precise it's an Acra rf-31. I'm sure most of the round column machines(Acra,Rong Fu, Enco Etc.) head castings are the same material if not very similar. I ground out channels around the cracks and tried to use Blue Demon triple play brazing rod(made for aluminium and zinc based metals) for the repair. I'm now realizing that may have been a mistake. Did I mention I was a noob,lol. It feels and looks like its stuck to head casting where I started to braze but Im not seeing any fusion along the edges. Im almost positive at this point that was not the proper brazing rod. Ill attach pics and see what you guys think. im thinking of grinding the blue demon braze out and getting a rod specific for cast iron. That is if its cast iron. Please guys if it isnt obvious yet I need help. thanks

 

[zdiaz925]

yep I was right about one thing def the wrong rod and after some much needed research its seems welding cast iron is something that shouldn't be attempted by the hobbyist. im gonna call some local welding shops tomorrow but I payed $600 for the machine
plus a lot of extras and tooling and im thinking at this point it may be worth trying a through bolt through the head to hold the crack tight and some JB weld??? guessing a shop is going to be many hundreds of dollars plus now i've probably caused uneed damage by grinding out the channels.

 

[mikey]

It is definitely cast iron.

 

[Buffalo21]

It is definitely cast iron.

with a hint of Moo Shu Pork..........

 

[Lo-Fi]

You want silicon bronze rods to braze that up. Easy enough if you've got some kind of oxy-fuel torch available.

 

[zdiaz925]

It is definitely cast iron.

thanks

 

[zdiaz925]

You want silicon bronze rods to braze that up. Easy enough if you've got some kind of oxy-fuel torch available.

thanks the video was great. rods ordered

 

[zdiaz925]

thanks everybody for giving the quick responses. I ordered silicone bronze brazing rods. However since I have $1500 dollars that I payed up front for materials on a time sensitive project for someone I decided to try my luck with the good ol JB weld. Worse case scenario it doesn't hold and I have to grind it out. At least I already have the rods on order. Best case the stars align and the JB weld holds strong fixing my issue. Even If the JB weld holds long enough to finish this project it will have been worth it. Ill keep everyone posted

 

[WCraig]

I'm no brazing expert but my understanding is that the whole casting needs to be preheated before applying the braze. Then the whole thing needs to be wrapped in insulation and allowed to cool slowly so as to not end up with hard (brittle) spots in the cast iron. Eg:

Craig

 

[machPete99]

The jbweld is just going to be a decoration here. Aluminum bronze is one potential solution, could also braze it. In either case need to heat the whole casting up (maybe around 400-450F) and let it cool slowly.