# Repairing cast iron casting.



## Herbiev (Jun 6, 2013)

Hi all. In a careless moment I dropped my Quorn t&c grinder breaking one of the castings. Just wondering about the best method of repair. Tig with stainless rod, brazing or silver soldering. The casting supports the work head. Tia Herbie.


----------



## ruzzie (Jun 6, 2013)

Hi
I have had success brazing a casting back together, I have never tried to silver solder but I have seen rods for stick welding cast iron.

A bit of imfo from BOC
http://www.bocworldofwelding.com.au/media/pdf/WELDING CONSUMABLES-Cast Iron.pdf

Cheers 
Paul


----------



## hi speed scrap (Jun 6, 2013)

Hi Herbie,
I repair a lot of CI castings, incl exhaust manifolds etc.
for that I would do as follows,

V out area you are welding
heat casting and let cool (burn out oil etc)
regrind vee area slightly so shiny clean
Jig casting up to hold in position
Preheat the the casting (evenly all over)
Weld with AC arc and high nickel rods (ie cast craft 100 or equiv)
Weld a section and peen thoroughly with point of chipping hammer.
Wire brush clean.
weld ,peen and brush small sections until complete, as quickly as 
possible.
cool slowly.
There are other ways to do it, but in this case thats what I would use

Dave


----------



## Swifty (Jun 6, 2013)

I'm with "high speed scrap" on the method. Definitely need to burn out the oil in the casting, and have also used cast iron welding rods, I think that I have some cast iron filler rods somewhere as well, for use with an oxy/acetylene set.

Paul.


----------



## gus (Jun 6, 2013)

I am with "high speed scrap's '' method which was used in the Singapore British Army 40 Base Engine Workshop where I was attached for 2 months during trade school days some 52 years ago. 
A make shift oven was built with fire bricks n topped up with heat resistant asbestos and steel plate to preheat an army truck engine exhaust manifold with large oxy-acet burners. Took three hours to preheat before using very long stick rods to weld. Was quite a sight and experience for a 18 year old trade school kid.


----------



## moya034 (Jun 6, 2013)

hi speed scrap posted the correct method for welding cast iron. 

That being said, I would urge you to consider brazing instead. It's typically just as strong and will be easier to pull off correctly if you aren't experienced with welding cast iron. Preheating and cooling slowly is still advisable for brazing, but is less critical as compared to welding.

The reason for the even preheat and slow cooling is to keep the brittle cast iron from cracking due to the internal stresses created from heat related expansion and contraction. Keeping a normalized temperature reduces the chance for catastrophes, but does not eliminate it.

If you do decide to weld the cast iron, I would do some practice on some scrap to get your technique down.


----------



## kf2qd (Jun 6, 2013)

Cast iron welding is not all that difficult if you have experience with oxy-fuel welding of steel. The big difference is that you need to keep the casting hot the whole time you are welding. Depending on the size of the part for the size of the heater.Plenty of flux and flow the cast iron rod in and make it bigger than the original cast area so you can grind it back to shape when it cools overnight. A box of powdered lime with about 9X the volume of the part you are repairing is good for a slow cool process.


----------



## chipenter (Jun 7, 2013)

I have silver soldered cast iron the break must be shiny it won't stick to the grey , a cup wire brush in an angle grinder does the job , and has the advantage of locating the break in the right place and leave a smaller fillet .


----------



## Herbiev (Jun 7, 2013)

Many thanks to all for the replies. I guess the key is to get some practice in on some scrap before tackling the real thing. Will keep you posted.


----------



## Maryak (Jun 8, 2013)

Hi Herbie,

Would you like me to pop in and give you a hand, I also have some castcraft rods. Just say the word and I'll come up, ( as long as the cofee's hot 

Best Regards
Bob


----------



## Herbiev (Jun 9, 2013)

That's a deal Bob. Many thanks.


----------



## Septic (Jun 9, 2013)

I've welded thousands of cast machine tool parts using MMA electrodes specially formulated for malleable cast iron and while it does require a little more care than mild steel, the result is extremely strong and the strength of the surrounding material suffers very little compared to some techniques... A 120 ton press-brake I welded in 1974 after it cracked a main section is still shaking the ground in East London to this day as far as I am aware...


----------



## John Rus (Jun 9, 2013)

I have successfuly soldered cast iron with Muggy Weld, I used the paste and put the parts together without V grooving. Heated the parts with a propane torch and the solder just flowed in. If you have thicker parts you may have to heat the parts in the oven so the heat doesn't get wicked away before you can solder them.

Just another method too consider,
John.


----------



## Septic (Jun 9, 2013)

I As John Rus suggests, "muggyweld" and many other low temperature, alloy/cast, solder compounds are surprisingly good for repairing broken castings in non-critical applications.

There are also some excellent engineering glues and fillers which are very good and can also be machined if required.


----------



## moya034 (Jun 9, 2013)

In all reality, to recommend the best method of repair we would need some pics of the part and failure, with some basic measurements.


----------



## Herbiev (Jun 10, 2013)

http://www.homemodelenginemachinist.com/photo/quorn-casting-737.html 
Hi Moya. This is the casting. It mounts on the vertical shaft of the Quorn and is part of the work head assembly


----------



## Herbiev (Jun 14, 2013)

Just want to say many thanks to Bob for stopping by this morning and doing a fantastic repair job on my casting. The great thing with forums such as ours is that you get ideas from around the globe and meet like minded people in your own neighborhood. Thanks also to all who replied. 
Herbie the happy moderator.


----------



## Maryak (Jun 14, 2013)

Your very welcome Herb and the coffee was great too. 

Best Regards
Bob


----------



## /// (Jun 14, 2013)

Onya Bob!

While all the advice was great, nothing beats having someone experienced do it properly for you and in a fraction of the time.
And you have learned something new, hopefully


----------



## goldstar31 (Jun 14, 2013)

I'm going to fly in the face of the opposition. The reason is because I have a Quorn and I have seen 'other Quorns' which were made by local modellers. there is NO reason whatsoever why a Quorn part cannot be fabricated from mild steel sections. Frankly, if that had happened to mine, I would have glued and then put two steel pins in it. The load on a Quorn is so demanding that Chaddock thought that a cut of a quarter of a thous was a whopping cut!

I once did an awfully tricky mend on a AGA type fireplace where the replacement grates and indeed the whole gubbins was not only obsolete but dated back to the Dodo. I built it up by shoving white hot arc mild steel welding  rods into the remains and building up on the new mild steel.

Oh and a bit of adding insult to injury( perhaps), I went off for a motor to drive a Quorn or whatever. The 1/6th HP 2880 variety recommended. It came home fastened to a Stent- the 'short wheel base' variety and I was in a rush. dumped it into the back of the little car-- and found that it was --fabricated from mild steel sections. I suppose that I got my hundred quid's worth.

I'll get me coat

Norm


----------



## Herbiev (Jun 14, 2013)

I did consider many options but considered the welding option to be stronger than glue and pins considering the thickness of the iron.  The bonus being as Simon mentioned, that I learned something and spent a couple of hours with a fellow member.


----------



## goldstar31 (Jun 14, 2013)

Respectfully, I did the 'arithmetic' on the Quorn way back in the Dark Ages after mine actually overturned.

In 'arse to the marste' naval stuff, it is all to do with meta centric height with a load of metal 'way up' and a motor - aloft. Same as on a Myford lathe- and one has to live with it.

I was looking at the competition- the forgotten Tinker and thought that I could make one out of purloined plastic trays from a certain hamburger outlet. Not quite so daft as the new A something  Blunderbus is being made out of carbon fibre- and the tires on the last Dornier Do17 Flying Pencil were still inflated after 70+ years- in the North Sea.

Great idea - this natter thing. Must have one with me ole Goldstar engine basher 'cos the Do17 is going to Cosford where his pair of Gypsy Queen71  engined DH Devons are.

Fun innitt?

Norm

------------------------------------------------------------------------------

Breaking News( pun intended) We had a bit of 'top hamper' with the million quid 'Gloriana'  in the Thames. Happens to the best of people!


----------



## bazmak (Jun 15, 2013)

Hi Herbiev of Hallet Cove.Reading this thread brought back memories
Having been a time served sheetmetalworker/welder i learned at that time 
that were 2 main methods of successfully welding cast iron.Electric with cast iron electrode
and Bronze welding (brazing) But could Never be Guarenteed under heavy loads
50 yrs ago people were always wandering into the welding shop with a broken bench vice
and a request to have it welded.The formans answer was always the same.Cant be done throw it in the scrap bin
It would never be any good except for holding wood.One day an apprentice came with the usual request
and the foreman was out so i told him i would see to it,threw it under my bench and forgot about it
saying it couldent be done.A few weeks later i stripped it all down.It was almost new and a nice 3' model
I clamped the parts together and tack welded,drilled tapped and c/bored and fitted 2 M8 cap screws.
Took it apart V grount all around almost full depth and bolted back together.I then preheated and laid a no of weld runs
to ill out all the joint and left in the oven to cool down overnight.I then spent a number of days cleaning ,grinding refurb and painting
It was like new.I had many comment and envious glances from my workmates.I put the new vice in my haversack in my locker
ready for the 1st dark night (overtime no foreman) When i was readt to take it home to my little workshop
THERE IT WAS GONE. I never did find out which of my mates took it but i still believe its still out there working away
Still they did let me finish it first. All the best BARRY


----------



## jwcnc1911 (Jun 16, 2013)

This is curiosity based entirely on my own experiences... sorry I have no welding advice... I'd probably use Belzona! 

Sounds like concerns for the quality of the casting to me.  How far did you drop it?  Was it really structurally weak in that area?  Did it have excess porosity?  I know I deal with much heavier castings but I can't see cast iron breaking just from dropping.

I would like to see pictures.  I'm curious!


----------



## Herbiev (Jun 16, 2013)

Hi Barry. He could have at least left a " thank you" note. 
JW. #6 has a picture of the casting. This is part of the work head assembly with the motor mounted on it. The whole t&c grinder landed upside down on a concrete floor from about four feet.


----------



## hi speed scrap (Jun 16, 2013)

Hi Herbie,

Good to see you had success with your repair, now all
you have to do is fix it to your bench,  

JW, with you on the Belzona, I use it regularly, but in Herbie's 
case probably a lot cheaper to weld it.

Dave


----------



## jwcnc1911 (Jun 16, 2013)

I don't know how I missed that picture...

That's smaller than I imagined, I guess you could always make a replacement out of bar stock if you wanted to but then that beats the point of buying the castings.


----------



## goldstar31 (Jun 16, 2013)

jwcnc1911 said:


> I don't know how I missed that picture...
> 
> That's smaller than I imagined, I guess you could always make a replacement out of bar stock if you wanted to but then that beats the point of buying the castings.


 
Actually the whole lot can be made out of bar stock. The drawings and construction notes for Mr Willis's Bonelle are on the net.

A worthy contender- and cheaper now.


----------



## rjd048 (Jun 26, 2013)

Here is one for you to ponder on too, had a tractor piece which was cast and had broken, tried the heat and weld process and it kept cracking the more I tried to repair it. At this point I was about to give up on it and buy a new piece. A friend of mine stopped by and saw what I was working on and said , got a mig welder with gas , said yes. He ground "V's" in the crackes and proceded to mig eld it and no cracks after it cooled in ambient air temp. Will admit that the areas he welded were so hard couldn't drill holes in it as it destroyed drill bits. Had to use  grinder to get build up weld out of fitting area. Still holding up and that has been 2 yrs ago. He says he repairs engine blocks the same way as he owns a automotive engine shop and has repaired many race blocks that hea d rods hanging out of the side of the block.


----------

