Fixing broken die-cast ?

Emp_Fab

Much to my annoyance, I managed to break a blade guide holder on the bandsaw last night.  It's only a small thing 3-4cm that holds the blade guide pins and the whole thing bolts to the chassis.  I was trying to get a stuck guide pin out and tapped it with a hammer and the holder snapped around the securing bolt.  I can't get a replacement (I've googled for ages), so my only option is to attempt a repair.  There is no real strain on the thing in operation, though it does hold the lower thrust bearing that resists the pressure of the blade going backwards as you push the wood onto it.

You can't solder diecast zinc and it would be crap even if you could, so that leaves me with bonding (glue !).  I was thinking of making a couple of plates from sheet steel (bean can lids maybe ? - something thicker perhaps ?) to form a sandwich around the broken bolt hole part of it, and using an epoxy of some sort to hold it all together.  The sandwich would extend out onto the holder itself to provide extra strength as far as possible.  

What glue should I use ?  I've got regular two-part epoxy resin (araldite type stuff), but I'm wondering if the metal glue versions out there might be better ?  Anyone used them ?  

randomhandclaps

B&Q do an own brand metal epoxy.  It's cheaper than the bigger named brands and far better IME as it's the only one the dries completely solid.  Have used it dozens of times to fill holes and cracks in damaged diecast and it works really well.

Corvus

Devcon or JB Weld, used these on various castings with good results.

chillidoggy

This might sound a silly question, but how much did you pay for the bandsaw?

Emp_Fab

A tenner.  Is that relevant ?

chillidoggy

Absolutely.

Because if it cost you a lot of money, it's worth fixing. Was there a parts manual with it, you might be able to order spares from somewhere.

Emp_Fab

It's worth fixing regardless.  I hate chucking stuff away that can be restored or repaired.  As a society, we throw away so much stuff, it's insane.  My local council tip actually has a shop that resells perfectly good things that people have just dumped.  Besides, I love the challenge to my ingenuity to take something that's broken and get it working again.  I suppose that's why I ended up doing the job I do, although it's changed somewhat from the break/fix stuff I used to do.

If I could retire, and wasn't able to live my dream retirement of a little house on a greek island etc, then I'd love a little workshop where I could repair bits and bobs that people had just thrown away.

Even now, I'm mulling over in my head where I can get some 2mm-ish thick sheet metal to shape and turn into an epoxy-sandwich to get that bracket working properly :-)

Misterg

As soon as I saw the thread title I thought: "He hasn't broken that bandsaw already, has he?" X_X

Most small bandsaws seem to be one of a few generic designs that get branded depending on who sells them - there are spare lower guide assemblies for Draper, Clarke, Sears, etc. on ebay if you can identify which is the same design yours.

chillidoggy

I do agree we chuck far too much away, and when you see some of the ingenuity of Third World people to get things repaired and going again with fuck all, it's a pleasure. Wales is not Third World, though!

I used to do that, but I got tired of spending more time fixing the tools to do a job than actually doing it. I have now joined the throwaway society, but only after weighing up jobs first. By that, I do a calc on what it will cost to fix, and how much precious time it will take to fix it.

I also consider whether I'm simply sticking a finger in the dyke (no pun), only to have another leak appear five minutes later. I'd cite my last washing machine as an example. I could have fixed it but the thing was eight years old, and there were most likely other parts just waiting in the wings to fail. It just didn't make sense to me for the sake of £200, and my missus would be bending my ear every time it made an odd noise. (Actually, she does that to me anyway.)

As for plastic metal, I found Belzona Super Metal, or Devcon was pretty good. The Belzona held my front door together for many years before I caved in under pressure and bought a new one.

littlegreenman

Emp_Fab said:

If I could retire, and wasn't able to live my dream retirement of a little house on a greek island etc, then I'd love a little workshop where I could repair bits and bobs that people had just thrown away.

TTony

Emp_Fab said:

Even now, I'm mulling over in my head where I can get some 2mm-ish thick sheet metal to shape and turn into an epoxy-sandwich to get that bracket working properly :-)

I've used the Aluminium Warehouse to get stuff for making various guitar jigs.  I think they did steel too, although a local fabricators / engineering shop might be cheaper ...

Emp_Fab

Misterg said:

As soon as I saw the thread title I thought: "He hasn't broken that bandsaw already, has he?" X_X

Most small bandsaws seem to be one of a few generic designs that get branded depending on who sells them - there are spare lower guide assemblies for Draper, Clarke, Sears, etc. on ebay if you can identify which is the same design yours.

Alas, I have re-scanned the Ebay listings and there's nothing.... which is surprising as I've seen my model with a variety of badges on it, as you say.

As for getting hold of steel @TTony, bugger buying it ! - I'll find something around the house that I can chop a bit off ! :-)

Emp_Fab

This is what I'm looking at...

 

Bloody ridiculous design - all that hanging off a couple of mm of cheap alloy.

Nomad

Emp_Fab said:

Alas, I have re-scanned the Ebay listings and there's nothing.... which is surprising as I've seen my model with a variety of badges on it, as you say.

If there's a Clarke version, try the Clarke web site for the user manual. Clarke have pretty good spares backup and they usually have an exploded diagram of all the bits in the manual. If you can find your bit in that, there's a good chance that Clarke can supply it.

chillidoggy

Looking at those photos, you'd be wasting your time trying to fix that, IMHO. Yes, it can be manufactured, but it'll take some machining and welding, and drilling/tapping to achieve a half-decent result.

Better to do as some others above have said, try to find a generic model, Clarke is one, Sealey another, and investigate their parts list for a replacement.

boogieman

Not sure how small the part is, but you'll get a stronger fix if you can drill holes in both sides and tap some steel pins into the join. Then glue with araldite or something similar.

ICBM

Emp_Fab said:

This is what I'm looking at...

 

Bloody ridiculous design - all that hanging off a couple of mm of cheap alloy.

What a terrible design!

Is there enough clearance in front of it to attach a flat piece of steel across the obvious rectangular area (drill and tap it for a couple of small bolts) with a hole for the mounting bolt?

You could use epoxy to attach the broken piece as well, to make it back up to the correct size, but with the steel giving the strength.

Deadman

Interesting Emps, I see your problem now. Can't you get access to some weld/a welder? You could then cut a small piece of metal (bin the old bit), weld it on but then just clean up/reshape what you weld on with a grinder and drill a new hole? Failing that just weld the old piece back on and re-drill the hole.
They seem the only (structurally sound) options to me.
Glue doesn't work. No matter how strong it is.

chillidoggy

If it's a casting, you'll struggle like fuck to weld it.

Emp_Fab

Well, I'm going to give it a shot with metal epoxy to glue a plate onto the flat bit and bolt the plate to the bandsaw instead.  Like I said, it's not under any real strain unless you're mental and push really hard against the blade when cutting (and you shouldn't need to push at all - it's more guiding), so the load on that plate will be minimal - and it will be a torsion force centred around the mounting hole, so the adhesive won't be under any real stress either.

Size-wise, I've taken another shot with a coin for scale.  I've also fitted the blade guides and the thrust bearing (yeah, I know it's buggered, but it doesn't matter). Even with everything on it, it only weighs 44 grams.

Drilling and bolting ? - Hmmmm, whilst it would possibly provide extra mechanical strength, I think any extra holes in the original cast would be unwise - it's fragile enough as it is.  Plus - the bolts would have to be a) tiny and b) countersunk.

Emp_Fab

chillidoggy said:

Looking at those photos, you'd be wasting your time trying to fix that, IMHO. Yes, it can be manufactured, but it'll take some machining and welding, and drilling/tapping to achieve a half-decent result.

Better to do as some others above have said, try to find a generic model, Clarke is one, Sealey another, and investigate their parts list for a replacement.

Oooh !!! - I checked out all of the Clarke models but none of them matched... however - I have found that the Sealey SM1303 is identical in every way to the one I have.  Now I just have to try to find a spares supplier for them.