Alternatives to Metal Fabrication

Polymer Craft General
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Getting the shredder blades fabricated by a local shop is expensive. So iv been working on a cheaper alternative to create blades out of a suitably hard material (bronze or brass).

So far the project outline looks as follows:
Create prototype pieces>Create vacuum former>Create foundry>Metal casting

Materials needed are:
+ 4 or 5 pieces of plywood
+drill
+ vacuum cleaner (household kind)
+ thermal plastic sheet
+ Wax
+ casting plaster OR green sand
+ a plot of land (Dont have a foundry in an apartment please)
+ (depending on foundry type materials may vary)

Steps:
1.) Create prototype blades and hex bar out of cheaper material
(I used a wood cnc machine for this but, if you are precise enough, it can be done by just using a to-scale printout of the blue prints and carving the pieces out of some soft, medium to high melting point, material with a knife)

(Note: step 2 & 3 can be skipped if you choose sand casting over lost wax casting)
2.) Create Your own vacuum former
This may sound intimidating but its essentially just a plywood box with holes drilled in it. Instructions on how to make this are here:
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– Youtube: XRobots – How to build a vacuum forming machine including my easy heating solution

– Hackaday: DIY Vacuum Former On The Cheap

DIY Vacuum Former On The Cheap


– Georgerockets:  Vacuum Forming
http://georgesrockets.com/GRP/Articles/vacuform.htm
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3.) Create wax molds
The vacuum formed molds we just made can now be filled with wax to create wax molds. After that, you can use a casting plaster or sand casting to create a suitable mold for liquid metal

4.) Create a Foundry
Again, this sounds more intimidating then it actually is. When it comes to design they can be as simple or as complicated as you’d like. I went with a Dakota Fire Pit, which is made typically made for aluminum, but iv been experimenting with using coke ash and fire bricks to increase the temperatures.

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WikiHow: How to build a metal melting furnace for casting
https://www.wikihow.com/Build-a-Metal-Melting-Furnace-for-Casting

Mother earth news: Build your own home foundry

Build Your Own Home Metal Foundry

Youtube: How to make a metal melting foundry. MELT ALUMINUM, BRASS, GOLD, SILVER. Capable of 1800 degrees!

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5.) Casting (Lost wax or sand)
Now that we have our wax molds, our casting plaster (or green sand), and our foundry, we are all ready to go!

Sand casting:
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Youtube: How To: Aluminum Sand Casting at Home, From beginning to end on Budget Part 1

Youtube: DIY GREEN SAND FOR CASTING – CHEAP, SIMPLE and FAST – MSFN

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Lost wax casting:
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Youtube: Bronze Casting: The Lost Wax Process

Inscrutables: Lost Wax casting
https://www.instructables.com/id/Lost-Wax-Casting/
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Thats it! I know it sounds a little complicated and people who do not have land are not going to be able to make a foundry, but if the community got together then there could be a mail based exchange system in place. Someone who made their thermal former could make multiple light-weight plastic molds and mail them out and someone who made a foundry could cast multiple pieces to distribute. Hope this is some sort of useful!

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Hi @calebmadden !
It’s a very good idea ! It seems pretty long but if it isn’t too expensive it’s very cool !

Do you think that you could make video where you show each step ?

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Thanks you a lot @andyn !

I’ll try to look for auction and see prices 😉

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@adrienluitot

Sure: https://www.mtb-recycling.fr/fr/accueil.html

Look for auctions of used industrial machinery, there are often bargains to be found, if you are able to transport them.

5

Thanks @andyn for the informations !
So we can find them in developed country like France ?
And we can use a mono-phase power on try-phase one, no ?

6

The large machine is called a granulator. They are widely used in industry to regrind eg. failed injection mouldings so the plastic chips can be reused. Used machines should be available in developed countries fairly cheaply, there are often auctions of industrial equipment, but they are big, heavy, and will run on 3-phase power.

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Hello @halimwidyakusuma
Yes the machines looks very cool, mostly if it cost 450$. But it looks impossible in a country like France, a machine like that will cost at least 2 000€.
And the unassembled shredder is (very) expensive  if you buy it on the bazar. But if you buy the laser-cuts locally I think it’s about 200$. Some people arrived to have it for free (they just pay the steel).

But if you have a link to this machines (like a shop or a presentation website) I’ll be interested.

8

ok, i got it… the plastic granulates quality in result of the high speed version machine…
looks good, although agressive & noisy, this has nice price: a ready machine priced 7.000.000 rupiahs(in my country) / 416 euro / 485 dollar
this is the same price as the unassemblied lasercutted shredder part
i start interested in this 🙂

9

yes, i agreee calebmadden. in my country the price of an unassembled shredder machine part (dave hakkens design, low speed version) is as the same price as a ready shredder machine (local design, high speed version). but i still haven’t planned on buying the high speed version, it’s very agressive and i don’t know the quality of the result (plastic granulates), i mean how small the granulates is.
I also got another alternative machine… here it is…