Step 2: Inlet Air Hole

I cut the inlet air hole and welded 2.5" pipe in an angle so the air will swivel and create more heat in the center. I kept the pipe 2" inside that will be the thickness of the refractory in the furnace. I found my welding magnets very usefull for holding the pipe in place. After getting all my welding gear ready the pipe was perfectly welded into place. Small tip: when placing the cylinder on the side place 2 wood battens under it to prevent it from rolling aside when using the grinder on it.
<p>How thin can you cast like this? I'm looking to make cases for devices I make and aluminium would look dope. </p>
<p>is the air hole position crucial or not? Do i have to make it high or low?</p>
<p>Wow, this is the most thorough instructable on a foundry I have seen. I have a cheap one I made, but would love to upgrade to this one day. Nice work!</p>
<p>i like...but im not so sure about attempting to cut a gas bottle open......</p>
<p>Hello! Brilliant instructable, but i'm having some trouble understanding the final section about sand casting.</p><p>How did you get from the 5th to 6th photo? they seem to be very different. Also the 7th to 8th photo seems very different - how do you get from one to the other?</p>
Excellent ible. Trouble is, now I don't know whether I want to make a stove for my workshop or a furnace suing the old gas bottle I have :) <br> <br>I have a question if I may? Do you have any problems with the surface of your castings? I need to make some aluminium moulds (for pouring molten lead into for fishing weights) but they really have to be nice and smooth. Any ideas how I can achieve this? <br> <br>Take care. <br> <br>Kevan
Thank you I am happy you liked my ible. The best way to decide is which one will be more useful in the long run. Most of my&nbsp;&nbsp;castings are very good. I had of course some casting gone wrong but usually the reason is running out of aluminum, bad mould construction, porosity (small gas deefects, air holes) or just doing some experiments. I am using petrobond sand for my moulds and it's great sand to work with and to get very high quality finish.<br> <a href="http://flamingfurnace.blogspot.com/">You are welcomed to visit my blog I have a few projects using sand casting</a>. I believe you can get very good results using this type of sand and you can make a&nbsp;mould&nbsp;for many fishing weights&nbsp;in one pour.<br> Just one thing&nbsp;and this is up to you to decide, I wouldn't melt any lead at all, &nbsp;<u>Lead is a poisonous metal</u>&nbsp;and can cause serious&nbsp;health problems especially among children. Link:<br> <a href="http://en.wikipedia.org/wiki/Lead">Lead health effects</a><br> &nbsp;If you have any questions I will be happy to answer thanks again.
You would have to heat lead up to an insanely high temperature (3180F!) to have any dangerous effects from casting it. Just don't eat it and wash your hands.
I have to tend to agree with 'klincecum' here, sorry 'NutandBolt'. Most people who cast lead fishing weights do tend to do it outdoors or at least with very good ventilation anyway. So there's no real health concerns with it. I suppose there may be secondary risks from using scrap lead though. Unless you know for certain that the lead has not been used with nasty chemicals next to it. I'm thinking lead pipe work that is used for chemical transference. That could cause problems....
Hiya mate. Just noticed something, I am not 'suing' any old gas bottles :) I will be using them of course... <br> <br>Anyway, Petrobond sand. Any idea what makes it special as opposed to ordinary sand. It sounds like a trade name and it's not one that I know of here in the UK. I was thinking of using what we call silver sand. This is a very fine and very clean sand that is used for children's sand (play) pits. It has to be fine, soft and ultra clean because of this. I'll add fuller's earth clay to this to create my moulding sand but don't yet know in what quantities. <br> <br>Lead. Yep, nasty stuff but then so is aluminium fumes. Lead casting is quite common still over here in the UK and I will only be doing it outside. There are still an awful lot of houses that have lead water pipes ours included. Having once been a plumbing and heating engineer I can tell everybody that the danger from lead is real but very much overstated. It's bad if you ingest it in anyway and that does indeed include fumes, hence my proposing to cast the weights out of doors, it's safest that way. <br> <br>Thank you for the health warning though it is appreciated :) <br> <br>Take care. <br> <br>Kevan
Petrobond vs green sand. petrobond is oil-bonded casting sand, theoretically you can leave the sand in a closed container and it will be good for use years later. Also the final casting will be very high quality. The downside: it is expensive in comparison to green sand. Play sand is also good but you have to make sure you make a good mix ratio of the play sand+Bentonite(clay)+water (not too much water). Petrobond is available in the UK and is mostly sold in foundrys and less in hardware shops such as B&amp;Q. I know that&nbsp;because the petrobond I have is made in the U.k. I am not promoting products but <a href="http://johnwinter.co.uk/foundry-products/sands">this is the link of the commpany&nbsp;&nbsp;</a> in case you want to have a look.<br> :-)
Fantastic :) I'll e-mail the company and ask if they can give me a list of stockists (local hopefully as we do have the odd foundry still dotted about). <br> <br>Thank you and take care. <br> <br>Kevan
I know how thrilling it is when you try something and it works so well! What a great feeling. Congrats! But what is petrobond?
Could you tell me exactly what refractory you used? I am having an extremely hard time finding a good tutorial on refractory, and would be extremely grateful.
Try <br>http://makezine.com/2012/04/05/how-tohomemade-castable-refractories/
Great job...! Thanks for the Instructable... I will try out the aluminium forging some day. Make spare parts, machine them, and plate them with copper,nickel, or chrome :) <br> <br> Kjetil
Big fan of the project! I'm thinking about doing it myself. Now, I know you mentioned what size bag of cement you got, but how much did you use? I'm trying to be economical and I want to get the smallest size I can for this design.
Be careful. I heard sometime you shouldn&Acirc;&acute;t use old tanks because of something could explode besides the gas.
very cool u will have to sell ur alimuium and can u melt steel with it or what about gold or silver
learned something a few days back, dont use charcoal briquettes they produce too much ash which clogs up the air flow, use lumpwood charcoal burns nice and hot with much less ash.
I'm digging your hinge design. and the whole thing is very nicely done.
i found the hindge method good as well but i didnt want to reach over the furnace even with gloves. so i made a pedal lift lid<br> <br> <a href="https://www.instructables.com/id/Aluminium-Foundry-From-a-Gas-Bottle/" rel="nofollow">https://www.instructables.com/id/Aluminium-Foundry-From-a-Gas-Bottle/</a>
I have heard that a lot of blues and yellows in paints have cadmium in them, thus their names...
www.backyardmetalcasting.com and the sister site www.alloyavenue.com will provide as much information as you can use and can answer almost any question you may have on the subject !!
Again you rock. I have done 2 melts and poured 24 aluminum ingots. Im going to pour more tomorrow and then I think i will be ready to sand cast. Thanks again.
I've actually done the same thing (with a propane tank that is) Very nice job! I ended up scrapping most of it, because I couldn't get a decent enough mold to make it work. But I've never heard of petrobond. Then again, I built the whole thing for &lt;$50 because I was on such a tight budget...<br><br>One thing I would recommend though is that you modify it a bit and put a propane burner in instead. Much easier than charcoal, and you have a more controllable heat. From the looks of yours, all you would have to do is insert a propane line into the blower pipe, and you're pretty much there. You would just need to add a flame holder, but that's fairly simple.<br><br>Very well done!
For decent molds, I would highly suggest trying out lost-foam casting. You can do it with junk Styrofoam and an X-Acto knife or something similarly sharp, and sand from your backyard. It's just about the cheapest and easiest method to produce fairly high-quality objects.
<br><br>How long is the inlet pipe ?<br><br>Is the length critical ?<br><br>Is the flange important ?<br><br>Great job.....Roger
As for crucibles, I struggled with making a crucible for melting copper. It would melt through every steel crucible I made. I eventually found a site that sells cheap fire clay crucibles and thats what I use now.&nbsp;<a href="http://www.lmine.com/mm5/merchant.mvc?Screen=PROD&Store_Code=LMS&Product_Code=17703&Category_Code=economy_repacks">http://www.lmine.com/mm5/merchant.mvc?Screen=PROD&amp;Store_Code=LMS&amp;Product_Code=17703&amp;Category_Code=economy_repacks</a>
i got mine for around $60 at foundry101.com and it comes with a lifting shank..
Wonderful ible! I just finished making a similar furnace and will be adding a hinge after seeing how nicely yours worked. I used regular portland cement and cured it for 18 days before firing. It is pretty thoroughly covered in hairline cracks after 4 firings and the outside gets terribly hot. I am guessing I will have to recast the cement before too long and am interested in fire cement. <br>How well Is your refractory holding up? How many times have you fired it?
All I have to say it thank you so much. I just built my refractory/foundry almost exactly like yours. All I have left is to get ahold of some refractory cement and Im in business. This is awsome. You rock!
Firstly, what sort of sensor are you using for a temperature gauge, and where is it mounted? <br><br>Second, what are you using as a mold for the ingots? They're all a nice standard size and very professional.<br><br>Third, this is awesome.
<strong><font color="green">The sensor I used is a simple and trusted multimeter that I got on Ebay. All that is needed is to set the multimeter setting to tempature and place the tempature wire in the furnace.<br> As for the ingots, I am using metal muffin tray (not teflon). All you have to do is pour the molten metal into it and you get a nice aluminum muffin. You can also make a container for the ingots DIY style like the one I welded from metal angles. I am using it to make slim ingots for my pipe cruicble.<br> Thank you.</font></strong>
Nice technique with filling the gas cylinder with water! An elegant solution to the problem of flammables.&nbsp;<br> <br> A professional iron worker once told me that cast iron cookware works well for a crucible. There are a variety of pans, pots, &quot;dutch ovens&quot; and other styles to choose from. Maybe there are cast iron muffin pans waiting to be found at a junk sale.<br> <br> <strong>DIY-Guy</strong><br>
<strong><font color="green">Thank you, That is correct I heard the same thing&nbsp;regarding&nbsp;cast iron cookware&nbsp;used&nbsp;as crucible the only thing is finding the right size that&nbsp;will fit into&nbsp;my furnace ;-) </font></strong>
Check out the book by David Gingry. Then you can make your own cast iron cricible
just so you know it's Gingery, not Gingry. :-)
Details, details. And I suppose you want a crucible instead of a cricible?
I have been warned about using cast iron cookware if it has not been cleaned of all rust. If I understood correctly, what I was told is the combination of rust and molten aluminum can form something akin to thermite (possibly thermite itself?). If this is the case it could be very dangerous.
Ferrous oxide (rust) and aluminium do make thermite. Although the exact ratio's are industry secrets for each company they boil down a lot of rust powder and a lot of aluminium powder mainly for surface area considerations (occasionally it is doped with magnesium to help things along). At any level of rust build up on a pot that doesn't affect it structurally I don't think you have much to worry about. I've never had a problem. but if your worried put the offending rusty item in the smelter with it going full bore for a few minutes (be careful cause this smelter can easily melt cast iron if you are using charcoal ... I speak from experience of loosing an entire melt to this whoops(!?!)) by the time the pot has a barely visible glow in normal light there will be no more rust on it.
I can&acute;t see if the refractory partially blocks the air inlet. I'm asking in case that is some kind nozzle, because the area reduction. Thanks
My dad recently got several dead lawnmowers from junk heaps. <br>I repaired the oldest one and we are restoring it but he tore the rest apart for the pistons and such that he uses to make statues.<br>The rest of the mowers were set to be thrown out but I grabbed a large amount of aluminium pieces. Just testing my furnace i threw a chunk in and it melted beautifully and was quite strong when I later pulled it out.<br>I recommend saving them and smashing the cast base into smaller pieces as well as the tougher engine pieces.
cool <br>
Great instructible!! <br><br>you might find this interesting. It's a link to a catalog website that has all sorts of antiquated methods for making things at home. pretty interesting. This page particularly deals with a book that you can order that shows you how to make a crucible. <br><br>http://www.lindsaybks.com/dgjp/djgbk/cruc/index.html
Would it be possible to use extremely strong industrial epoxy to stick the pipe in if we cannot weld? Or maybe solder in some places of it and then fill the rest in with cement?
<strong><font color="green">If you mean the inlet vent hole I dont think epoxy will take the heat, we are dealing here with temaptures over 1000C. You also dont want to use material that will melt and might realse toxic fumes. You can use metal screws with angle brackets that way you&nbsp;dont need any weld.<br> Another simple&nbsp;option is using card board or plastic cylinder &nbsp;to&nbsp;form the inlet&nbsp;hole, after refractory is set take the cylinder out.<br> In my image I drew blue line&nbsp;that represent metal angle brackets and the red dots arepresent metal screws.<br> Hope this will be useful to you.</font></strong>
Be careful of the brackets or any other parts that are cadmium plated.&nbsp; It gives off a poison smoke/gas fumes when heated.<br> <br> DANGER:<br> <br> Cadmium is extremely toxic even in low concentrations.&nbsp; The fumes given off by zinc is toxic also when heated.<br> <br> Lots of materials around that we need to be careful we don't breath the fumes it makes when we are heating it.<br> <br> Once it is burned off, you are probably okay.&nbsp; Just remember to not breath any of the white smoke/fumes.&nbsp; They are toxic/poison.&nbsp; If they never get heated hot enough to smoke/cause fumes, there <em><strong>shouldn't</strong></em> be any problems from using cad plated parts.<br> <br> Great instructable!<br> <br> Ken<br> <br> 102410 2029<br>
<strong><font color="green">Thank you for your tip that is very important. I prefer when I do my work with the furnace usually to use respirator and in general to melt aluminum parts with no paint or other impurities.<br> Is there any way to know when melting&nbsp;coated object&nbsp;if&nbsp;the paint&nbsp;contains cadmium?<br> Or the best thing is just to melt clean parts such as car pistons act' ?</font></strong>

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Bio: Couple of years ago I created my metal casting blog and over the years I uploaded many projects, my main goal is to increase the ... More »
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