Sand casting unobtainium parts at home.

More studies from the home hack sand caster. This time there are no prizes for guessing the object but feel free anyway.

The pattern made from 6 mm MDF and some dowel took 23 minutes in total including several coats of matt paint. Try that with your poncy 3D printers.

The casting came up quite nice with green sand. For this one I used green sand because I thought resin bonded sand with it's higher yield strength might pull the solidifying metal apart as it cooled because of the thin sections (6 mm). Remember aluminium shrinks 7% from a liquid state to solid to ambient temperature. Green sand on the other hand just crumbles quite easily and would offer little resistance to the solidifying aluminium, anyway it worked.

There is however a blemish on my casting record because it took 3 goes before I got it right, I had to add an extra 4 gates and a bigger sprue as can be seen. But for now it's off for final linishing and polishing, stay tuned.

IMG_5156.JPG
IMG_5168.JPG
IMG_5170.JPG
IMG_5174.JPG
IMG_5177.JPG
IMG_5175.JPG
 
More studies from the home hack sand caster. This time there are no prizes for guessing the object but feel free anyway.

The pattern made from 6 mm MDF and some dowel took 23 minutes in total including several coats of matt paint. Try that with your poncy 3D printers.

The casting came up quite nice with green sand. For this one I used green sand because I thought resin bonded sand with it's higher yield strength might pull the solidifying metal apart as it cooled because of the thin sections (6 mm). Remember aluminium shrinks 7% from a liquid state to solid to ambient temperature. Green sand on the other hand just crumbles quite easily and would offer little resistance to the solidifying aluminium, anyway it worked.

There is however a blemish on my casting record because it took 3 goes before I got it right, I had to add an extra 4 gates and a bigger sprue as can be seen. But for now it's off for final linishing and polishing, stay tuned.

View attachment 210445View attachment 210446View attachment 210447View attachment 210448View attachment 210450View attachment 210449
A window frame for a convertible top?
 
More studies from the home hack sand caster. This time there are no prizes for guessing the object but feel free anyway.

The pattern made from 6 mm MDF and some dowel took 23 minutes in total including several coats of matt paint. Try that with your poncy 3D printers.

The casting came up quite nice with green sand. For this one I used green sand because I thought resin bonded sand with it's higher yield strength might pull the solidifying metal apart as it cooled because of the thin sections (6 mm). Remember aluminium shrinks 7% from a liquid state to solid to ambient temperature. Green sand on the other hand just crumbles quite easily and would offer little resistance to the solidifying aluminium, anyway it worked.

There is however a blemish on my casting record because it took 3 goes before I got it right, I had to add an extra 4 gates and a bigger sprue as can be seen. But for now it's off for final linishing and polishing, stay tuned.

View attachment 210445View attachment 210446View attachment 210447View attachment 210448View attachment 210450View attachment 210449
Well done. Nice to see the progress in gating.
 
In the «Renault straight eight» thread casting an engine block were discussed. So I came to think of this facebook thread of Paul Koski recreating an 1913 Renault engine.
https://www.facebook.com/groups/975721692468728/permalink/3424176667623206/
Good photography.

Iv'e been watching the Youtube videos of the old pattern maker for a few years and was wondering if he ever got it made, and what do you know, he did.

Thanks for the link Reidar. Facebook is not my favourite place but now I have another reason to go there. (y)

1664180150668.png
 
Filled with naive optimism and a cavalier disregard for the rules that apply to common men I decided that today was the day I would melt cast iron, and I did but only just. I fired Lucifer up and gave him the beans, I gave him as much gas/air mixture as he could burn up and waited for 1.5 hours for a result. I maxed out my digital pistol thermometer within 10 minutes (1048 deg C) I then dropped in a chunk of Ferro silicone and it burned up pretty quick (1250 deg C) By 1 hour the iron started to slump and I could see the magnesium starting to sparkle, then the iron looked like it was bubbling, I was almost there when my gas bottle which was water cooled started to freeze up which meant game over for today, but I managed to get the crucible out of the furnace and harvested a dribble of molten iron. Had I managed to go for a further 15 minutes I would have completed the melt.

The pics don't show it but as I peered down into the anus of Lucifer I could see the refractory lining glowing well and truly whitish in colour, the crucible was light yellow and therefor not quite hot enough. I reckon I needed another 50 deg or so and I would have nailed it, but at least I survived to melt stuff another day.

The solutions to my shortcoming are to use a larger gas bottle and/or keep it in tepid water or, my preferred option, introduce some clean diesel injected into the manifold after the gas has things warmed up a bit.

IMG_5262.JPG



IMG_5259.JPG
 
I have no idea what you're talking about, but I'm mightily impressed.
 
Meet Lucifer..


Instead of the centrifugal blower would a small Roots style blower driven at speed be of more benefit due to its significantly higher air output temperatures?
I don't much about this stuff either, just a thought.🤷‍♂️
 
GP the blower is perfect for this sized furnace and if I turn the air and gas up too high the un-burnt gas just creates a flame out the top of the furnace as can be seen above. The un-burnt gas is just wasted energy because all the combustion should take place inside the furnace and indeed, since the above video was made I have refined my settings so as not to create said flames.

The problem today was the same problem as last time I melted cast iron i.e. the gas bottle froze and therefor slowed down the gas available at the torch end (See pics of the ice) and just as I was at the vinegar stroke the pressure dropped and I had to abort. Just as an air conditioner gets cold by moving gas around so do my gas bottles because I run a 30 kPa regulator. A Bunnings 4-5 kPa regulator just won't cut the mustard.

I'll make some adjustments next time I melt cast iron so I'm not wasting my time. :cool: See pic of today's trophy:rolleyes:

IMG_5266.JPG
IMG_5268.JPG
IMG_5269.JPG
 
GP the blower is perfect for this sized furnace and if I turn the air and gas up too high the un-burnt gas just creates a flame out the top of the furnace as can be seen above. The un-burnt gas is just wasted energy because all the combustion should take place inside the furnace and indeed, since the above video was made I have refined my settings so as not to create said flames.

The problem today was the same problem as last time I melted cast iron i.e. the gas bottle froze and therefor slowed down the gas available at the torch end (See pics of the ice) and just as I was at the vinegar stroke the pressure dropped and I had to abort. Just as an air conditioner gets cold by moving gas around so do my gas bottles because I run a 30 kPa regulator. A Bunnings 4-5 kPa regulator just won't cut the mustard.

I'll make some adjustments next time I melt cast iron so I'm not wasting my time. :cool: See pic of today's trophy:rolleyes:

View attachment 210934View attachment 210935View attachment 210936
Oh OK, I was thinking more along the lines of heating the air rather than increasing the volume per se. Not sure if introducing hotter air will increase the flame temp?
Obviously the same volume of air at a higher temp will contain a little less O2.
A small shot of nitrous oxide would liven it up a bit though.🤔
As I said I know nothing about forges.
 
Graham in a car setup the lpg is extracted as a liquid from the tank so no freezing up there and then reduced to working pressure in a water heated regulator. You might be able to do that to help. You can get liquid out of 9KG normal bottles by turning upside down.
You can get LPG conversion parts for nothing at the scrap or wreckers these days. I had some I think they are all gone to scrap now.
Jaahn
1664866956597.png
 
I’m comfortable publicly acknowledging that @56 Fregate’s is bigger than mine.

E84BD94D-2D7A-475C-94FB-A952F2E34237.jpeg
 
I think mine's been used more than yours as well. It started out as a pristine graphite crucible and has been used at least 50 times. They suffer from acid attack which erodes the clay. At one point the crucible was in danger of falling apart so I made up a glaze of wood-ash and terracotta and re-fired it, bugger me it worked and I still use it. During Covid I tried to buy another but the world market had dried up and I could only get the small ones, so I made some more out of fireclay and graphite, they aren't as strong as the real thing but good enough.

IMG_5272.JPG


IMG_2359.JPG
 
Yours has certainly been used more than mine. I personally have not used these at all.

20AE2223-73E4-4620-8725-C2F1494E71C3.jpeg


They were in a box with my “new” favourite SPARK-L striker.

D477064E-9B88-4192-8375-69571EC5F659.jpeg


From the workshop of a jeweller’s deceased estate I packed as much as I could into the back of Dad’s 308 before the family called in a scrap merchant and a skip. No idea what I missed. 😱
 
I know the OP is not a fan of 3D printing but I love the fact that you can use the same CAD drawings as a base for both prototypes and then for casting patterns and core boxes.

I’m currently working on an Opel OHV inlet manifold. An enthusiast modified an inlet from a late 1200 version by raising the roof to gain volume and changed the carburettor flange for one for a Weber 36DCD. I got challenged to try to recreate it to make some castings. I was supplied with an original inlet and the measurements from the modified one.

5A31FB38-7D0D-4EA7-9980-9F297B43A45B.jpeg
B27D6122-E165-4398-91F2-ABB4C306EEFD.jpeg
993819A6-AB13-4B30-86C0-9C2FC462C4D5.jpeg


I printed this half model prototype yesterday and I think it is more or less done. The original inlet have some strange parting lines witch I guess might require that is called an «odd piece». I’m not yet sure if I will stick to theese parting lines or choose a curved one.
I also think I might turn to silicate bound or resin bound sand for this one…
Pattern,odd piece and core box is yet to printed.
 
Last edited:
Top