The Casting Thread

Got nothing to add car wise at the moment, but I'm working here locally in Madagascar to change some local cooking pots into pressure cookers. Local foundry conditions are definitely not OSHA approved. 

http://youtu.be/fSb-QtEZm5Y?t=70 

Going to use a 3D printer to make some new patterns and hopefully manage to get them machined "enough" to seal up with strips of bike inner tubes or rubber strips off tires, which are ubiquitous here. Certainly not in line with my previous casting work with industrial transmissions, but it gives me something to do and work on here at the edge of the world.

Home made pressure cookers?  That is incredibly ambitious.  What are you planning for a pressure release valve?

Mr_Asa said:

Home made pressure cookers?  That is incredibly ambitious.  What are you planning for a pressure release valve?

It's VERY third world here, so the valves and everything have to be dead simple and made locally. Going to be 2 weights, first one will be fitted to a conical (hand reamed) hole to lift off at cooking pressure of 1.2 bar (17.4 psi) which is more than enough given that 85% of the population lives above 800 meters ASL. Safety valve will be a larger weight in a similar but larger hole sized to open at 1.4 bar (which is normal pressure cooker operating pressure). Basically 2 old school jiggler style blow-offs with the secondary being much larger than the primary. 

"Lid Lock" will be two cast bits to catch a small stick or bamboo and lock the lid tight on the scrap innertube/car tire strip seal. Got to keep things simple here where 90% of people earn less than $2 USD a day. 

Standard cooking pot is ~45,000 Malagasy Ariary ($11.82 USD) and is unaffordable for most people.  Hoping to be able to make the pressure version for about 55k to 65k Ariary, and then use local NGO's and donors to help reduce the sales price to locals. I've got a few locals using pressure cookers, and like everyone here they cook on charcoal indoors. Their charcoal use drops by over half if they use the pressure cooker regularly, and most cooking is dried beans, stews, lower quality cuts of "meat" such as hooves, snouts, ears, and heads. 

I've got an NGO sponsoring stuff, and a tie-in with the local Polytechnic University (should COVID ever clear up here). Hope to have a few prototypes in a couple months with the students for their semester project.

My casting buddy pulled his groin last week so I am stepping in for him and helping a PhD student do some bronze casting.  More pics as we go.

Warming ingots so they don't shock the molten metal and freeze it, and adding metal

Damn.  That always wipes me out.  I was pouring, so no pics yet.  Someone is supposed to send me some later and a YouTube link.  Meanwhile, one of the molds cracked for an as yet unknown reason, so one failure and one success.

JFW75 said:

Mr_Asa said:

Home made pressure cookers?  That is incredibly ambitious.  What are you planning for a pressure release valve?

It's VERY third world here, so the valves and everything have to be dead simple and made locally. Going to be 2 weights, first one will be fitted to a conical (hand reamed) hole to lift off at cooking pressure of 1.2 bar (17.4 psi) which is more than enough given that 85% of the population lives above 800 meters ASL. Safety valve will be a larger weight in a similar but larger hole sized to open at 1.4 bar (which is normal pressure cooker operating pressure). Basically 2 old school jiggler style blow-offs with the secondary being much larger than the primary. 

"Lid Lock" will be two cast bits to catch a small stick or bamboo and lock the lid tight on the scrap innertube/car tire strip seal. Got to keep things simple here where 90% of people earn less than $2 USD a day. 

Standard cooking pot is ~45,000 Malagasy Ariary ($11.82 USD) and is unaffordable for most people.  Hoping to be able to make the pressure version for about 55k to 65k Ariary, and then use local NGO's and donors to help reduce the sales price to locals. I've got a few locals using pressure cookers, and like everyone here they cook on charcoal indoors. Their charcoal use drops by over half if they use the pressure cooker regularly, and most cooking is dried beans, stews, lower quality cuts of "meat" such as hooves, snouts, ears, and heads. 

I've got an NGO sponsoring stuff, and a tie-in with the local Polytechnic University (should COVID ever clear up here). Hope to have a few prototypes in a couple months with the students for their semester project.

Is there a legitimate NGO or entity to which we can donate specifically to help you out with this project?  Those folks sound like they need $20 more than I do...  

I've been interested in this stuff for quite awhile and have a degree in Materials Science and work in the automotive field.

A few thoughts.  Don't start on mission critical parts like suspension uprights or brake components where failure can equal death. Start on stuff that if it fails just means the fun ends. My thoughts on a starting place would be intake manifolds for some more obscure engines to adapt different carbs or EFI conversion. Efi conversion using ITB from readily available parts would be fun and fairly lucrative for some platforms. Motorcycle ITBs being adapted is a real starting point.   The other factor is that the majority of machining would be simpler than say, making a head. Most of it would be ensuring flat surfaces and possibly adding injector bungs rather than all the stuff associated with valves and sealing. 

If you want to get to mission critical parts, you would likely want to have a gooood lock on inclusions and defects and still have parts x-rayed or radiographic or ultrasonically tested (all non-destructive methods).  The other thing is making mission critical parts to sell as a side gig has a LOT of liability. Just something to think about. 

That said, if you play with iron casting, turbo manifolds for more obscure applications is another possibility. 

stroker said:

Is there a legitimate NGO or entity to which we can donate specifically to help you out with this project?  Those folks sound like they need $20 more than I do...  

Let me get the wheels moving here in Antananarivo first. We are going back into lockdown due to the SA variant exploding here and zero vaccinations for the locals. The NGO I've been working with, slowly and at a distance, is BeLocal (https://www.facebook.com/belocalgroup/). Probably going to rollout with a combination of GIZ, USAID, Peace Corp, and a few others here in Madagascar. 

To be honest for now I've got plenty of funding and working to tie it into a makerspace program the US Embassy is going to open soon. This isn't a huge project to get ot a prototype and testing it. When it moves beyond that I'll gladly point you to a local NGO here who is going to be getting them out to the market here.

has a pressure cooker like this been done before ?

Sounds like a neat idea , just wondering how you can  mount the weights so they still work but cannot get lost .

Cheers

californiamilleghia said:

has a pressure cooker like this been done before ?

Sounds like a neat idea , just wondering how you can  mount the weights so they still work but cannot get lost .

Cheers

You can see the weights in the latest video here:

https://photos.app.goo.gl/bnxNS54E2VLyo7ww9

Going to Ambatolampy next week to check out a few foundries and try and get a few samples poured. 

Oh, earlier in the thread there was asking of where to shop for fire resistant clothing cheap.

https://usedworkclothing.com/collections/flame-resistant-coats-jackets

In reply to Apexcarver :

Oh hell, I'm bookmarking that site

I've dabbled in casting a little, and it's really cool.  I'd like to do it more, but it hasn't yet risen back to the top of the project list.

I bought a complete foundry set-up kit from these guys.  It's actually a pretty nice set-up and has everything you need to get going.

I made a few tools and an ingot mold out of steel bed-frame angle.

One thing I found early on is that even aluminum is HOT!  Like thick MIG gloves don't cut it.  Like they distort and get hard from the heat.

I went for the full Daft-Punk foundry gloves, and the difference is astounding.  Totally worth it.

In reply to Mr_Asa :

I know, right? I use them for coveralls for yardwork and dirty wrenching.

Paul's Garage has a Discord as well and he knows swdweeb and a couple of other youtube metal casters.  luckygen1001 and Windy Hill Foundry are a couple of good ones for cast iron work.

In reply to JFW75 :

Samples turned out well.

Had a long discussion, and made a few changes to the design.

Round 2 of samples should include a functional pot and be ready August 10th.

https://photos.app.goo.gl/z1GhNMCmaJd2UH3b7

JFW75 said:

In reply to JFW75 :

Samples turned out well.

Had a long discussion, and made a few changes to the design.

Round 2 of samples should include a functional pot and be ready August 10th.

https://photos.app.goo.gl/z1GhNMCmaJd2UH3b7

How much do the weigh ?

Check with the post office and see how much it is to ship to the USA  by surface/sea post .

Might be neat for camping and a great back story :)

In reply to californiamilleghia :

Before finishing they weigh about 2.5 kg. 

Goal is to get them down a bit, but got to maintain the wall thickness.

Given the quality of the scrap here, you don't want to eat anything cooked in them. The neighboring countries have banned importing them due to lead and other metals. But the locals here use them everyday. 

No one was injured or maimed at today's round at the foundry.

https://photos.app.goo.gl/ZjJREfhQC2wK2V478

First two working prototypes were tested. Still need some work, but we will get there. Hard working through translators and trying to explain engineering details to folks who can barely use a tape measure. Lots of repeating stuff again and again, but it works. Couple minor design changes to make it more "machining" friendly for them, and to bring the costs down. 

For reference a kilo of aluminum is 12,000 Ariary ($3.07) and he burns 5 sacks of charcoal @ 50,000 Ariary ($12.79) a sack per day running the foundry. 

In reply to JFW75 :

That's a super cool project, though the videos of them pouring molten aluminum in bare feet is so cringe-worthy.  Different standards, I get it.  Thanks for sharing!

cool pics

can you cast up some wing nuts?  or are you going to include  a wrench on a chain !

In reply to californiamilleghia :

Knobs. Probably threaded if I can find an M8 tap here, if not nuts in them. Thingiverse had a bunch that look like they translate well into cast aluminum. 

The wrench and wing nut were his first pass at it. I was going to use a hair pin bent out of rebar and loop to lock it into on the opposing handle. I think a wrench would wreck the target price point here.

Barefoot, no gloves, no goggles, no hearing protection in the shop. It is a different world for sure here.

Mr_Asa said:

In reply to maschinenbau :

You can do a traditional cope and drag with a sand core (great example here, the one thing it looks like he does that I don't recommend is letting the weight of the top half of the mold be the only thing holding it down), you can do an investment casting with a large enough plaster mold, or you can do what I'm planning and do a shell casting.  Each of those has two or three methods that will work. 
The way I'm planning on doing it: dip in a ceramic slurry, let it dry 12-24 hours, repeat two-three times, dip in ceramic slurry, shake fine grain sand over everything, let dry 12-24 hours, repeat 5-6 times, dip in slurry, shake coarse sand over everything, let dry, repeat ~10 times.  Once the final coat has dried, you put it in a furnace to burn out the plastic and cure the ceramic, then while its still hot you pour the metal.

Slush casting probably wouldn't be a good choice as you would have very rough interior surfaces.  

Casting Thread for more questions so we don't derail this too bad?

Maschinenbau, great example of what I'll be doing for my casting here.

https://old.reddit.com/r/interestingasberkeley/comments/pdjust/how_a_3dprinted_object_is_cast_in_bronze/

In reply to Mr_Asa :

I just got recommended that guy and was going to watch that tonight.