# My furnace



## 12bolts (Sep 22, 2014)

For those members that may be considering melting metal for fun, it can be a fairly straightforward and simple process to build an effective furnace.
Let me state first, I am not going to get into a bunfight over safety concerns with the materials used. Appropriate safety considerations and precautions were applied during construction.
Mine is an old LPG cylinder cut down for the main body and then the lid was cut off the remaining portion. It is lined with about 50 mm of Kaowool and has a roughly 40 mm thick castable hotface.
A homemade (not my design) oil burner enters tangentialy at the bottom. This design will melt about 2 lt of liquid ally in 30 minutes from a cold start or 10 once everything is hot. Brass & bronze takes about 30 minutes. Other people have used similar designs and can melt cast iron with theses types of set ups. I havent tried CI yet but I think i might get close.
I get my scrap ally from engine/gearbox parts, alloy wheels, old broken cast alloy parts and pieces. Pretty much anything that was cast once makes a good base product. Ally cans do not.
Scrap brass from various sources, taps are good, but lots of dross. Old propellors, bushes, boat bits. Sometimes I will buy from the scrappers if I want good bronze.
My burner runs on waste oil from, mainly sump oil, but pretty much any old oil will suffice, waste vegetable oil is another source that I havent tried yet.






Happy to answer any further questions.

Cheers Phil


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## gredpe3 (Sep 22, 2014)

How do you pressurize the fuel and what do you use to get it burning?
Eddie


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## jpfabricator (Sep 22, 2014)

What do you use for a crucible? Do you do investment casting or greensand molding?

Jake Parker


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## GarageGuy (Sep 22, 2014)

I want to build a foundry furnace someday.  I thought I read that you need to burn oil if you want to melt cast iron because LP or natural gas won't get hot enough?  I'm thinking about using a Babington style oil burner with compressed air feed.  I have an old 15 gallon grease drum that I've been saving for the furnace container.  There is a YouTube channel by "luckygen1001" where he regularly melts cast iron.  His molding techniques are excellent, and he makes some outstanding parts.

GG


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## 12bolts (Sep 23, 2014)

gredpe3 said:


> How do you pressurize the fuel and what do you use to get it burning?


Eddie, I have a 60 lt water heater as a fuel tank. Regulated air to about 50 kPa, adjust to suit the fuel in use and metal you are melting. Just dip a piece of rag in diesel, light and toss it in. Slowly add atomizing air and combustion air and it takes off. Takes about 10 minutes to get it hot enough to close the lid. It uses a blower for combustion air. 2nd pic Top right tapered thing, its just a vacuum cleaner motor stripped down and I made a sheet metal housing for it. The funnel bit just tapers down to fit onto the back of the burner tube.






jpfabricator said:


> What do you use for a crucible? Do you do investment casting or greensand molding?


Jake, I have a few different crucibles, steel pot for melting ally, silicon carbide and graphite for brass and bronze. I just do sand molding so far, trying to learn how to do some other methods.



GarageGuy said:


> I want to build a foundry furnace someday.  I thought I read that you need to burn oil if you want to melt cast iron because LP or natural gas won't get hot enough?  I'm thinking about using a Babington style oil burner with compressed air feed.  I have an old 15 gallon grease drum that I've been saving for the furnace container.


Oil has a higher calorific value than gas but Gas will melt CI. Its all about insulation and getting BTU's in faster than they escape. I know a few blokes that melt Iron with gas. Waste Oil is popular because its cheap, free in most cases, I believe its a bit more fiddly to light than gas but like above, in 10 minutes I am hot enough to start melting from a cold start.

Cheers Phil


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## mattthemuppet2 (Sep 23, 2014)

that's really neat, having your own foundry really is the next step up in what you can do. Be careful of old engine blocks/ gearboxes etc as a lot of them now have magnesium in which can cause nasty fires


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## savarin (Sep 24, 2014)

mattthemuppet said:


> that's really neat, having your own foundry really is the next step up in what you can do. Be careful of old engine blocks/ gearboxes etc as a lot of them now have magnesium in which can cause nasty fires



I had some super light magnesium alloy bicycle wheels that I tried to light just because everyone says they will.
Using the gas torch from my furnace all I could get was a melt that was mainly just a mass of dross with tiny little flares popping off inside the mass.
I guess different magnesium alloys have differing amounts of magnesium in them and they wont self ignite until the magnesium content is high enough.
I have heard of but never seen Volkswagen tranny cases igniting in the pot.
Could someone with firsthand experience of this give a description.


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## Mark_f (Dec 20, 2014)

I have decided to try casting aluminum and I want to build my own furnace. I have a few friends that do it , but it is all new to  me. I am just gathering information right now, looking for a furnace plan , and finding out what I need to get started. I hope to start this when the weather breaks in a few months. If nothing else this should be interesting.

:nervous: Mark Frazier


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## Smithdoor (Dec 20, 2014)

This not hard to do I have pored tons of al over years. 
Try looking at http://www.alloyavenue.com/vb/forum.php
I wish I had this site 40 years when I started
FYI start with lead and sand from your yard Use baby power for parting power 
 FYI it works great

Dave
Good luck



12bolts said:


> For those members that may be considering melting metal for fun, it can be a fairly straightforward and simple process to build an effective furnace.
> Let me state first, I am not going to get into a bunfight over safety concerns with the materials used. Appropriate safety considerations and precautions were applied during construction.
> Mine is an old LPG cylinder cut down for the main body and then the lid was cut off the remaining portion. It is lined with about 50 mm of Kaowool and has a roughly 40 mm thick castable hotface.
> A homemade (not my design) oil burner enters tangentialy at the bottom. This design will melt about 2 lt of liquid ally in 30 minutes from a cold start or 10 once everything is hot. Brass & bronze takes about 30 minutes. Other people have used similar designs and can melt cast iron with theses types of set ups. I havent tried CI yet but I think i might get close.
> ...


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