Thread: Dawn Disaster

Here is the broken casting
Broken Drill_3893.jpg


Other than using it as a pattern and having it recast, are there any CHEAP repair solutions. I read that welding cast iron is a science in it's self, the whole casting needs to be heated up to the welding temperature before welding and then let cool as a whole. Otherwise the weld makes the repaired area brittle. So that sounds expensive also.. Remember expensive is relative, and to me most things are out of my budget.

I was thinking maybe I have to wait for another incomplete drill becomes available at a swapmeet at a reasonable price.

Maybe put a post in the welding/metalwork section.
There are some tricky blokes over there, someone may be able to offer some advice or even help you out.

Originally Posted by Barterbuilt

Maybe put a post in the welding/metalwork section.
There are some tricky blokes over there, someone may be able to offer some advice or even help you out.

Thanks I have put a post about repairing a casting and a link back here.

Hi DSEL74

bronze it up if you have oxy
there is some good info here
Blazing Brazing PART 1 - YouTube
I found Keith Fenners videos to be most excellent
also i know where there is one of these drill for sale i can find out how much and get some pics for you if you like its in pretty good nic from memory

cheers
Harty

dsel74
Looking at your pics, that casting looks like it was already cracked most of the way through before you started to pull it apart. As far as a repair, as others have stated yo have a couple of options. You could get it welded (either oxy or arc) but it would have to be preheated. You could also braze it but again would need to be preheated.
What do you intend to do with this drill opnce its refurbished? If its only for decorative purposes then you might get away with using an epoxy adhesive to hold it together. A couple of pins in the middle to give it a bit of extra strength.
Something to consider anyway.

regards
bollie7

If it makes you feel any better it looks to me like about 80% of that crack was there before you got to it.

Stuart

I don't have any welding equipment or experience so would have to outsource hence expensive. Good to know what is the right way for it to be done though.

I do or did intend to use the drill. Mainly for guided tapping of holes, maybe for drilling but I have never used one to know how difficult it is to use as a drill vs electric.

Originally Posted by DSEL74

I do or did intend to use the drill. Mainly for guided tapping of holes, maybe for drilling but I have never used one to know how difficult it is to use as a drill vs electric.

One is always left in the poo when the Dawn breaks.

Thinking on it. If it is welded it will always show as a repair. What if I knurled the end of the shaft and epoxied the shaft and the two halves of the casting all together would that have sufficient strength?

Originally Posted by DSEL74

I don't have any welding equipment or experience so would have to outsource hence expensive. Good to know what is the right way for it to be done though.

This doc from BOC explains a few things, type of cast, preparation, filler type and procedure.

http://www.bocworldofwelding.com.au/...ast%20Iron.pdf

Originally Posted by DSEL74

Thinking on it. If it is welded it will always show as a repair. What if I knurled the end of the shaft and epoxied the shaft and the two halves of the casting all together would that have sufficient strength?

Probably not

you could grind back the weld and finish with a bit of body filler to hide the repair and make both sides match and no one will know

cheers
Harty

Would it be possible to file a channel along the line of the crack and weld to the inside so the weld is hidden????? Of course it would have to be filed smooth for the shaft so the amount of weld would be limited to the size of the channel filed out. The part is about 2" long where sheared off. The shaft is probably about 30-35mm Dia.

While "welding" is often used as a generic term for joining 2 metals together, it actually has a specify meaning to a welder. I'm not trying to tell you how to suck eggs, but if it were me I'd be instead leaning towards having it brazed instead of welded. If you ask the welder to deeply groove the joint, as you want to grint it back, you should be able to achieve a relatively seamless surface. I'd suggest leaving the welder to do that so they can match the parts. If you then give it a coat of flat black paint it should hide the bronzing and will be a reasonable job aesthetically. Pre-heat/cool down is no big deal by the way, and any welder should know about it. Maybe just confirm with them as to how they'll achieve it.

Pete

Dsel74,

Did this happen yesterday at about 5pm? I was in Sydney at the time, and I heard some loud screaming and yelling off in the distance coming from the south.

I have not personally welded any cast, but if Matty is around I know he has, and he may be able to give some advice. I am not a great welder, but I can do a reasonable job with an arc welder, which is what most back yard guys are used to and all that you need for welding cast.

If the budget will not stretch to taking it to a professional welder, and you know someone who is handy with a stick welder, and you have access to a barbecue (assuming the part will fit under the hood) then you can get welding rods designed to weld cast (unfortunately again they are not cheap, but they are available in small quantities).

For the benefit of others (and not trying to rub salt into the wound, as others have already pointed out that part was probably already 80% cracked), I have found from experience 2 crucial rules to follow when possible, when trying to remove something from a seized up shaft. Firstly I use a wire wheel on a grinder (the brass bristle type as it will not scratch the steel) to take the rust off the shaft, I find by doing this, once you break the initial hold it will slide freely. This makes it easy to tell if something is not right. Secondly always go further onto the shaft before cleaning the end of the shaft with the wire wheel and inspecting for burs. From my experience I would say 80% of the time, at some stage, some idiot has taken to the end of the shaft with a hammer and mushroomed the end (I see it so often that when I am getting the tools together I always grab a file). I quickly learned these two rules in the beginning, after spending hours taking a part off a mushroomed shaft (in fact it took days, because I had to keep walking away, I would get so frustrated).

Good luck, and keep the pictures coming. I haven't tried molasses yet (I have some ready to try this week), usually I use electrolysis which works well, but I thought I would give this process a go, from what I have read, the mix is 9 to 1, is that the strength you used? Any suggestions from your experience with the molasses?

cheers,

camo

EDIT: Pete sounds like he has some experience re "welding" and he is also a quicker typer than me (as his post was not up when I started with my response)