What to cast first??.......

That is the question....

This weekend I want to try a proper casting; something useful that looks more like a "thing" than just a blob of metal. I wanted to start off easy by building a lathe. However there is so many things I'll need for that become a reality, not to mention the various failures on the castings that I will inevitably suffer.

I decided I'm going to try for a 4 jaw chuck as a first attempt, as this will be useful in both the lathe and as the chuck for the 4th axis on my CNC machine. Another good reason to start off with it is that it's quite a complex piece with many slots, pockets, bearing cups and such.

The method of lost foam casting is one very predominantly used in industry today. It basically involves cutting a desired shape out of normal EPS foam (Styrofoam) then dumping that "blank" in some ceramic material to create a smooth surface around the blank, then pouring in the metal, the metal will burn out the foam and fill the resulting cavity with metal and voila you have a metal part the shape of the original blank.

I will use my CNC (Computer Numeric Control) machine to cut out the blanks in foam. I built this machine about a year ago from two old dot-matrix printers and a few bits of MDF wood. It's not the most accurate thing on the planet, but it saves me a lot of effort in creating the blank.

This is the design for the chuck main body I have in mind.

Designed in Rhino 3D
















Hope this gives you some idea of what I'm aiming to do.











Here is a few shots of my MDF CNC machine... this will be used to cut the foam patterns for now.



I'm in the process of building a much bigger and way more rigid machine than this one, but for the moment, and seeing as I work with a very soft material Styrofoam, This cheap and easy machine will do.










Starting the first outline cut for what will become the lathe chuck.

You will probably need to click on the picture to see a bigger one if you can't see the circle being cut out.









My trusty old laptop. This poor thing have really been through the wars. I use it regularly to prop up stuff when grinding, or as a coffee cup coaster, since it's surface is about the cleanest thing on my workbench... Despite it being held together by self tapping screws and coffee stains it still keeps on working.

It's running TurboCNC v4.0 which converts the g-code language to pulse signals to drive the motor electronics.


In a later update I will go through the steps involved more thoroughly. We will also be building the BIG machine together.

Here is a short video clip of the router cutting out the foam blank.

My first Aluminium melt!!!

WOW!!

I know it doesn't look like much, but I actually created my very first aluminium ingot!!

After waiting out the rain all weekend I couldn't hold myself any longer, so I took an old motor bracket I had lying around and after starting up the furnace I dumped it into the crucible.


I wish I could get pictures or a video of the aluminium melting, but it's so hot around the furnace I don't want to risk messing up my cellphone by taking the pics or video... Suffice it to say that it just looks to amazing seeing that bracket turn into a plastic like consistency and then eventually just becoming a pool... It was so cool!!




<--- Note the special safety equipment!!
A pair of "vellies"...

Please don't do this if you build your own!!!
You will get burned!!!!!! badly!!!






I was rather surprised at how easily the aluminium melted, the crucible just barely turned red and it was a pool already, I had that crucible glowing white hot without aluminium and still didn't believe it would be hot enough..... Oh how wrong that was ...



This is the pool, it's not a lot but still enough to get me helluva excited! finally a Eureka moment!

See the slight red tinge to the crucible....

It only took about 5 minutes from when I dropped the piece into the crucible till this pool was made. I've seen the future!! and it is waste oil!







Since I haven't gotten around to actually welding up a proper ingot mould I just dragged my foot in the dirt to make a little "ingot mould" and poured it in ...


Look it's SHINY!!!
The ground was very wet and I could see the aluminium bubbling on top, that was the water underneath boiling and the steam vapors bubbling up through the melt..

Still I managed an ingot.

This will forever go down as my FIRST... and nothing will take away from that fact.. It now has a very special place right along side my collection Ferrari F1 memorabilia.

The lifting tongs.

As the name suggest this is a tool used to lift the hot crucible from the furnace... Trust me a red hot crucible filled with molten metal isn't something you want to tackle "hands-on".. I made these tongs to ensure once the crucible is locked onto it there is no chance of it falling out or slipping and spilling the hot liquid metal.




It might be a tad over-engineered, but hey that's my way.

Centering the burner oil tube

This weekend had been quite a productive weekend. A lot of things got finalized like the lifting tongs, the trolley and the burner.

I had a problem that the oil tube in the burner wasn't aligned exactly in the middle it seems it had a bend in it, and no matter hoe hard i tried I just couldn't center it up by normal bending it in place, so I made a sort of "aim adjustment" setup.... was quite a simple and straight forward idea, but welding those 4mm nuts on was quite a hassle, the normal arc welder I use just burns the nuts away. Just be very careful and it eventually works.



Just 4 nuts and the matching bolts welded to the air tube of the burner. Remember to drill holes for the bolts prior to welding.














Result!!!!

<---- centered oil tube.

No Work done :( ---->But look at it .... LOVELY!!!

Well Like the post heading suggest there is no work currently being done. I was busy making the lifting tongs to handle a white hot crucible filled with molten metal... A very elaborate piece of equipment if I must say so myself. I hope it works! Will update you in a later post.
But for now nothing is getting done.











<---- NICE!!!! Damn I love the rain.



Namibia is a very Arid and dry place. So when the rain do come it's a sort of religious experience for me. Time to sit indoors and reflect.

.... and after much "reflecting" ... I've come to the conclusion ....... I LOVE THIS PLACE!!!! You can stick your 1st world amenities right up your bums!!

Africa is where my heart is.

Johann out!

It really really burns!!

last night I simply couldn't wait to get home from work. There were heavy clouds in the sky, and I wanted to fire up my burner and furnace combo for at least 5 minutes to see if everything will hold up.

this is the result....


This is the setup I'm using now.
This thing is scarily heavy so I "salvaged" a shopping trolley cut the basket off and made a push-cart to move this lump of concrete around.



This post courtesy of Trade Centre pty.(ltd)



I will get around to replacing the bricks holding the burner up for something more permanent..
I'm still looking for a way to modify that blower as well. I blows way too much and having it that far away is just a waste of energy.

This is after all a very "green" environmentally friendly machine. It burns old used motor oil... yeah that black stuff they replace when doing an oil-change on your car. Yep! So the environmental impact stems from the fact that that oil aren't left in some landfill outside town, it gets used to generate heat which does useful work.

Though in all honesty I use it because its cheap!!

Okay here is what used motor oil looks like through my burner... this thing is scary HOT!..


I love this pic. just look down into the very bowels of hell!











another one.


















Tonight I will fire it up for 10 minutes to see if the refractory holds up...

Will let you all know how it goes.

FIRE!!!! Testing the burner.

Right ... Last time we built the burner assembly. Now it's time to test it.

I wish I had the furnace at hand to test the burner, but alas it's still drying... and taking it's sweet time.

So seeing as I don't have the furnace, I'll be using a normal coffee can. Keep in mind it's just to test whether the burner actually work.

I cut a hole in the coffee can, big enough to fit the burner nozzle and then I made a small fire in the can using wood lying around..

After things are heated up properly i open the valve to let the oil in, you can definitely hear the oil is vaporizing in the chamber, it's sort of sputtering to life...

Open the valve a little more ... it's still sputtering, more frequently now, but makes a helluva lot of smoke ... give it more oil!!!



OMG!!!! it's ALIVE!!!! It sounds like i just ignited a rocket engine. there is a definite difference in the ambient temperature around the area, this thing burns!!


NB! Note how far away I had to place the blower away, if I have it any closer it start blowing the glowing embers right out of the can.

Also I didn't hook up the oil tank and the feeder pipe, I simply put the valve at the burner and attached a plastic top to hold the oil... this is just a test to see if the burner ignites.




Another burn picture. See the tank assembly lying to one side... that will be used later.
















If you click on the pictures look at the can you'll see it turned a nice red, and that was after about 10 seconds from opening the oil and finding the right mixture. I immediately shut it off, I didn't want the can to melt through and light the whole suburb alight.


... next i will have to fire with the furnace.

The burner!!!

Okay ... this is the build up of the burner.


What you need to start.



The size of the picture might hide how big this burner ends up being, but the reducer (the top middle part) that is a 2" to 1" reducer. So that should give you some idea of the true size.




Step 1.















Step 2.










Step 3.





Step 4.







Step 5.






Step 6.







Step 7.







Really simple ... isn't it.


....but will it work?

Stay tuned.

Ok I made contact with the clay supplier

Right I've told you that I'm struggling with the clay just cracking apart, and not really setting the way I expected it to.... look at it

















Well I finally got the contact details for vereeniging refractories, the suppliers of this clay. What a surprise, a big company that actually makes time for the little guy, and damn they were quick!! I'd recommend you use their products if you can. they gave me really friendly support... Too bad I didn't get any good news.

It seems that the salesman in his fervor to make a few bucks commission neglected to tell me that this specific clay is not supposed to work as a castable refractory it is meant as a normal construction mortar when building a fireplace. sucks doesn't it!!

Ahh well at least I learned a thing or two...

Oh and don't think I'm planning on scrapping this project... ohhh hell no!! I'll continue with that busted up furnace as it is... will wait and see what happens...


Stay tuned..

The refractory pour

okay I poured the refractory clay today, and I must say I'm a bit scared and surprised at how crappy it came out, it seems to be cracking all over, so I hope that fixing it with more clay after this pour has dried out a bit will work....

Too bad I couldn't get castable cement here in Windhoek.

the clay I used was a Elgin works product made by vereeniging refractories. If anyone knows someone there that I could contact it would be much appreciated.


<---- This is the clay. Apparently one just adds water and mixes to make the clay, but with the amount of cracking it does, I suppose there is a bonder of some kind still needed.








Ahh well I'll push through anyways and hope it works ... I've done things that way for a loooong time... I anyways didn't forsee this time to be any different to any of the other stuff i've done, and they turned out okay.


<--- If you look on the sides you'll see the severe cracking I'm complaining about..












Okay so next thing will be to cut and pour the "Lid".


.....Stay tuned.

The Start02 (10/01/2009)

Okay I found a 20 liter plastic paint bucket This will become the "hole" inside the furnace into which the crucible will be placed ... The crucible holds the metal to be melted down.












In order to hold the bucket centre and also keep it from going right to the bottom of the furnace I have fixed some normal carpentry 90 deg. fixtures flush with the top of the furnace. Since they are all exactly the same length I'm pretty sure the bucket will be centred. The bucket will "hanging" off these four brackets...









<---- Like this......
The next thing I did was to mark out where the best position for tuyere will be in relation to the bucket hanging inside the furnace body. And then to cut the hole. I made it square for a reason which I hope will become apparent in a future update.







BTW. I tuyere is basically the hole where you'll put the burner into. It is the burner that does all the hot stuff.





okay next I fitted the tuyere tunnel. Again I used g-clamps and those brackets to keep everything lined up at close to 90 Degrees, and at the necessary angle.











Right that is the basic structure of the furnace... Sofar there has been no brain surgery involved at all... I hope everything else goes this smooth and quickly...

In the next update We'll start pouring the refractory cement around our bucket.

The Start01 (10/01/2009)

Well first thing a furnace seems to need is a container to keep the refractory in place, I got this really nice hot water boiler tank, which is perfect for this application. As you can see it needed a bit of cleaning up. It seems they pour in some kind of expandable foam to insulate it during construction.





So after a bit of cleaning up, using a normal file, the foam stuff really wasn't as stuck on as I initially feared, only took about 10 minutes to clean the outside.










Okay still here?? well next up I marked the centre of the tank all the way around, I chose the center because that would allow me to make another furnace later on, one that fixes all the mistakes made on this one.... Well that and the fact that even half this tank would make one helluva BIG furnace for my needs.

<--- See the white line in the centre ?? That is what you do If you make your own.




Next thing to do is to cut on the line you marked previously.... See this is not so difficult. But PLEASE!!! pretty please be careful when handling power tools such as a grinder. Wear Safety goggles!!!







Right repeat the white line step to get a sizable chuck off the open end. This will become the lid of the furnace.

Again... Be careful!!!

I also Cut off that odd piece of pipe sticking out the bottom... didn't need it so it was removed.

The Furnace (Introduction)

This is a project I have been planning for a few years now, and recently a friend of mine said he was interested in melting the tin out of the raw ore he mines... the smelters charge a fortune!! His production rate does not justify the insane costs charged by professional smelters..

I on the other hand want one to be able to cast things from metal for my various projects, and Aluminium is easy to melt down, and easily obtainable as scrap from just about anywhere.

So this is my first foray into the world of casting, and foundry work. Hope you enjoy reading about my struggles as much as I enjoy the struggles themselves.