The Bucket Foundry

[F5 Dave]

I'm just hoping they don't make 3 phase plans out of step with other power plans or I'll have to repower & that isn't worth the investment in my ooold lathe or my limited time. A nice new (say 30yr old) lathe would be nice but unless that super lucky lotto ticket comes in . . . (super lucky 'cause I don't buy them, it would have to find me).

[Michael Moore]

Ken, would you be better off just 3D printing sand core boxes and a 3D mould, straight off the drawing?

I looked into that a few months ago here in the USA for a 2T air-cooled cylinder. I emailed a cylinder model to the printing company for evaluation.

The printed sand mold was looking like US$7-800. That was just the printing, it would be up to the customer to model gating/risers etc. And then that would have to be shipped to the customer or a foundry with no assurance that it survives the shipping. And then there's no assurance that the mold casts properly. If the customer didn't get the gating right, or the foundry had some problem, then "whoops, sorry about that, would you like to send us another $800 to print a revised mold after you make your best guess on what will work?"

It sounds like a very cool technology but at that price my friend and I were looking for more assurance of a good part in our hands than ""You've got to ask yourself one question: 'Do I feel lucky?' Well, do ya, punk?"

Instead, we put that money into buying foundry supplies to try and DIY.

There was also the issue of finding a foundry that was interested in dealing with a hobbyist one-off project. I talked to a local foundry and "you want thin fins?" seemed to be an issue they weren't interested in dealing with.

cheers,
Michael

[F5 Dave]

. . .""You've got to ask yourself one question: 'Do I feel lucky?' Well, do ya, punk?". . .

Is that one or two questions? Switching from first to second person narrative makes me not so sure.



But cool story to learn from.

[ken seeber]

In fact, if centre lathes had just come on to the market now, they would be banned straight away with no chance of ever making it. ?

Wil, often thought the same thing myself, just shows what hypocrites we (not all) are because we are still using these dangerous things, despite that they are really useful. Oz is getting overrun with do-gooders and corrupt self interested unions etc, all working together to stifle the country. We’re rooted for the future I believe.
Car mfg industry almost totally gone, 2016 totally gone, supply industry going as well, losing all those skills. Send our bauxite to china for near zero and now our foundries are paying more for raw alum than we are getting totally finished parts from china. Oh, let’s be a high tech nation they say, that’s a good idea, dunno what in though and forgetting one thing, “necessity is the mother of invention” and, if we have no necessity cos we’re not doing anything, then what are we going to R&D. Dream on guys. No, let’s just focus on things like the service industry, much nicer and cleaner than mfg, despite the fact that it makes the country nothing. Let’s just get further into debt, spoiled by a now declining mining boom, fed politicians that have no balls and vision other than tread softly, softly and appease the media so they can hang around for a couple of 4 year terms making no waves, so after than they can sit back on some juicy super package. Let’s just be a dumbed down country. Jeez, look where you got me Wil.
Grumph. Lost foam casting. All good stuff. Mercury uses(d ?) it on some of their 3 & 4 cyl outboards. So instead of a separate head and gasket and separate exh water cover, gasket, stainless exh cover, gasket assy and all the machining, just combined it into a single casting. Neat. No leaks. Basically it was a series of styrene mouldings or “biscuits” layered up & glued, dipped, surrounded by sand and metal splashed in, vapourising the styrene. Like the wax burning out, one does get the odd drop of noxious fumes (understatement), so best done at night or on weekends. The downside is that the moulds for the biscuits are done in metal moulds, thereby representing a high capital investment and changes would be expensive. You’re right though, you can see various 4 stroke heads (VW) where you can actually see a reproduction of the expanded styrene beads in the surface.

[Ocean1]

True Dave, but try and get ACC etc. to agree with that! you'd have to have every safety device in the book attached to it plus an extra levy for lathes in the home.
In fact, if centre lathes had just come on to the market now, they would be banned straight away with no chance of ever making it.
Furnaces and foundrywork? - forget it!
How about roll cages for bikes? - no?

The first safety professional I ever came across was from the old marine dept. He was visiting our govt workshop to promote safety. Every single tradesman that he attempted to engage in discussions about safety told him to fuck off and mind his own godamned business, to a man. The shop foreman was showing him out when he spotted an 18" pedestal grinder which had the tool-rest set at about 3/4" from the wheel. He noted that the wheel was beautifully dressed but then launched into a tirade about how dangerous that rest was, sticking his finger into the gap to demonstrate. It was still running. He lost the first two joints. The foreman was a lovely old bloke, got him a nice clean rag soaked in cold water and told him to fuck off.

Y'know what gets me? Is the absolute absence of any costing for any of these safety initiatives. In fact a lot of corporate and govt safety policy explicitly exclude any form of financial analysis.

I reckon the trend making businesses legally culpable of and financially responsible for any and all blame associated with any workplace injury is utter bullshit, another example of the time honoured bureaucratic practice of blaming those who can afford to pay. The old blokes had it right way back then, their safety is none of anyone else's godamned business.

[WilDun]

you can see various 4 stroke heads (VW) where you can actually see a reproduction of the expanded styrene beads in the surface.

There must be some cheap product (liquid) which will dissolve expanded styrene patterns (other than petrol, turps etc.) without destroying a mould, or failing that, some alternative material for patterns which would easily dissolve in water. - anybody for candy floss?.
I know that polystyrene is evil stuff when on fire but yet they say it isn't really toxic (mostly Co2) - still suffocates people though. Probably not good for the planet.
Water!!........I dunno, what am I saying!
Oh and don't get me going on safety inspectors - I could tell a few tales there, but I'd better not start!

[Flettner]

Yes lucky all the cool stuff has been invented already, toasters, chainsaws, motorbikes, lathes, ( in fact whole workshops ) because if these items were released onto the market today we would all be in mortal danger!
Imagine riding a motorbike through a tree lined forest at brake neck speed! We all need cotton wool suits, yes Fuck Off indeed.

[Flettner]

I looked into that a few months ago here in the USA for a 2T air-cooled cylinder. I emailed a cylinder model to the printing company for evaluation.

The printed sand mold was looking like US$7-800. That was just the printing, it would be up to the customer to model gating/risers etc. And then that would have to be shipped to the customer or a foundry with no assurance that it survives the shipping. And then there's no assurance that the mold casts properly. If the customer didn't get the gating right, or the foundry had some problem, then "whoops, sorry about that, would you like to send us another $800 to print a revised mold after you make your best guess on what will work?"

It sounds like a very cool technology but at that price my friend and I were looking for more assurance of a good part in our hands than ""You've got to ask yourself one question: 'Do I feel lucky?' Well, do ya, punk?"

Instead, we put that money into buying foundry supplies to try and DIY.

There was also the issue of finding a foundry that was interested in dealing with a hobbyist one-off project. I talked to a local foundry and "you want thin fins?" seemed to be an issue they weren't interested in dealing with.

cheers,
Michael

So, you are going to use good old pattern making technique?

[WilDun]

Imagine riding a motorbike through a tree lined forest at brake neck speed! We all need cotton wool suits, yes Fuck Off indeed.

Joey Dunlop's last road race was through a tree lined forest road in Latvia - we'll never know what he might have thought of the track!

[Michael Moore]

So, you are going to use good old pattern making technique?

That's the plan. We've spent a fair bit of time looking at your photos/videos/posts to glean tips from them. We've got Petrobond and sodium silicate for core making, SiCrb crucibles and A356 ingots on hand, but haven't built flasks, tongs or patterns yet. My pal Jeff has made a nice propane-powered furnace, and I bought a 5.2kW electric kiln to try using.

The sand printing looked very attractive as I'm reasonably handy at making 3D models (as long as they aren't too complicated). I had thought it was only a matter of sending the CAD file and that the printing company would then add the feed system as part of the printing price, but that proved to not be the case. The price is still high enough to make do-overs prohibitive.

If there was 100% probability of a good part each time the print would be fairly easy to justify for complicated parts like 2T cylinders or 4T cylinder heads. But $800 "I hope this works" is a bit too spendy for this hobbyist. Industrial parts where they've got trained pattern makers/foundry people on hand to design things for the sand print would be a different deal.

cheers,
Michael

[Grumph]

The thought of making tongs made me chuckle. I live in a rural area of Canterbury, NZ, and one of the local projects to celebrate the millenium was a set of gates for the local Domain. They were made by the semi retired owner of the local engineering company from what was lying around plus items donated.
They are a magnificent collection of blacksmiths tools, spanners...and tongs.... all welded together.
One day someone is going to realise how collectable much of it is and they'll go missing.

[Yow Ling]

There must be some cheap product (liquid) which will dissolve expanded styrene patterns (other than petrol, turps etc.) without destroying a mould, or failing that, some alternative material for patterns which would easily dissolve in water. - anybody for candy floss?.
I know that polystyrene is evil stuff when on fire but yet they say it isn't really toxic (mostly Co2) - still suffocates people though. Probably not good for the planet.
Water!!........I dunno, what am I saying!
Oh and don't get me going on safety inspectors - I could tell a few tales there, but I'd better not start!

Molten Aluminium will do the trick, seeing as it is a permitted activity for farmers to burn plastic bale wrap in Waikato , a little bit of polystyrene isn't going to hurt anyone

[Flettner]

Yes, those bloody farmers and their bail wrap!

Michael Moore, I've never cast an air cooled cylinder yet, I'm keen to see how you will do it. I have started to make an F9 Kawasaki cylinder but thought why bother, I can't ride the thing with the power it has now. I was just going to use the old cylinder cut in half for the outside pattern but the draw angle is slight and the casting rough. It would take a lot of polishing to remidy that. Also the cylinder studs would go right through where I wanted to put eye ports anyway.
I have some ideas though.

[WilDun]

Yes, those bloody farmers and their bail wrap!

I was just going to use the old cylinder cut in half for the outside pattern but the draw angle is slight and the casting rough. It would take a lot of polishing.

I was very familiar with (and part of) the farming scene, ie till about 48 years ago and the bale wrap stuff wasn't an issue then, but I see that it has now become a big issue.
Is there no recycling program in place for it? surley it is useful for something - what sort of plastic do they use anyway - polyethelene?
It's unbelievable that they allow the stuff to be incinerated, but I guess that farmers are the "little darlings" of this country at the moment as we are dependent on them for exports.

Yow Ling, - Only Waikato? - New Zealand wide surely? I would have thought so anyway.
Yes, we're not allowed to burn coal anymore (and it's not selling well offshore either) so we will need a replacement pollutant, why not polystyrene!

Flettner
So how would lthe lost 'expanded' polystyrene process work (quite easy to fabricate and burn out) for aircooled cylinder patterns in plaster/sand moulds?

Or am I dreaming?

[ken seeber]

We made an aircooled cylinder a couple of years ago. It was part of a proposal to the, then Australian Karting Association, for us to manufacturer an aftermarket cylinder for a karting engine that was unique to Oz, the Yamaha KT100J. Whilst a cheap and reliable engine, it had a problem in lack of performance parity, meaning there were good ones and shitters. The variation in transfer ports was, I think, the main issue. See http://www.strikeproducts.com.au/features.asp and look up cylinder proposal.
What we did was what Neil suggested, was to wire cut an existing cylinder in half and mount these onto/into specially made aluminium moulding boxes. We added riser and coreprint bosses to the cylinder pattern as well.
Spent a lot of time cleaning up the roughness of the original casting, mainly the fins, with body filler, putty, tons of sanding etc. It was always a prick to get a decent mould despite using some Foseco stuff called Slipcoat. The main secret to success was to draw the moulding box from the sand (in this case, Fenotec, a cold box sand resin) before the sand had finally hardened so it was still a little soft and pliable. It definitely was a way to do prototypes only.
Neil has described previously fins with breaks in them, I think that this would help a lot.
However the best way would be to make production tooling would be with metal, done in fin by fin layers, with proper smooth finish and consistent draft a and squareness.
However, if we had to do it again, now we have the 3d printer (even if it is just an FDM style), I would use that, at least for small quantities. They’re cheap as chups these days.http://www.kiwibiker.co.nz/forums/im...milies/yes.gif
The pics show one moulding box and the other a rooted mould, but it gives some idea. The shepherd’s crook is the downsprue that we formed by carving into each face of the moulds.