Casting question

[DM95]

Have any of you ever done any sand casting with just a wood burning fire.I have heard that it could be done but I wanted to see if anybody does this often or if its even possible.Just to add it would be for aluminum and nothing else.

[Harold_V]

I have not, but it is my opinion that it wouldn't be a good idea unless you could control the fire well. Too unpredictable, if nothing else. I question how you'd support your crucible, too.

Harold

[jpfalt]

Wood will work fine as a fuel. It burns plenty hot enough for aluminum as long as the wood is suitably dry, the right size and has forced air combustion. The only downside is that wood contains hydrogen that is released as water when the wood burns. The hydrogen is bad for aluminum.

The best result would come from converting the wood to charcoal and then melt with the charcoal. If you do melt with wood use a crucible with a lid to try to keep out the water vapor.

[DM95]

I wanna try it with wood atleast once to see if it will work if not Ill go about it another way

[choprboy]

I have used wood, or rather wood-charcoal, to melt all of my aluminum machining/scrap. I haven't directly sand cast, but poured ingots for later use.

I started by making charcoal with old wood (for grilling too), mostly 2x scrap, cut into 4-8in lengths. Built a good roaring fire in an old charcoal grill, cover with the lid, shut all the air vents and let it "cook" for 15-20min or so. You want all the wood fully blackened and "alligatored" to drive off the volatiles and leave the carbon, but you don't want to burn up everything. Having large chunks left is best. Douse heavily with water to put out the fire and set aside for later use (I usually make 3-4 batches and fill a 35gal trash can with charcoal).

When melting, I set the crucible (already warmed to remove moisture) in the center of the grill and surround with some charcoal. Open all the air vents, light it up, and add additional charcoal from time to time. Melt scrap until the crucible is full, add a bit of flux and skim, pour and repeat. Once the fire is up to temperature the melt goes pretty fast.

[RONALD]

I'm mystified by your question, why wood you want to burn wood, even in the form of charcoal, when natural gas is so much simpler, cleaner to use, and relatively cheap. Most properties have NG gas lines, or if not, you can use Propane.

Here is a site where they also may have some who burn wood: http://www.alloyavenue.com/vb/forum.php

If the goal is to replicate ancient ways, then go with wood; to make sound castings quickly use NG.

When I was a kid, I would melt type metal over the kitchen stove open flame, and pour into molds I had made out of Water Putty, made lots of HO Gauge parts that way..

[DM95]

Your right wood is probalbly not the best way but I thought it would be fun to try it.I dont plan on that being my way of doing casting I just wanted to do it just to see if it worked well.

[Harold_V]

I have almost no foundry experience, but many years of furnace experience, as I used the identical equipment in my years of precious metal refining. The difference was I melted silver and gold instead of aluminum or copper based alloys. My comments about not using wood are based on sound experiences as a result. In that regard, I'd add another thought, and it's sure to go against the grain of those who do everything on the cheap.

Don't use a metal vessel for melting aluminum. Buy and use a proper crucible. If you must use a steel vessel, ensure it is coated with a refractory material, so molten aluminum does not contact the shell. That's a recipe for poor quality castings.

Molten metals are strong solvents of other metals. In spite of the fact that you would be working in a temperature range far below the melting point of steel, some gets dissolved, ruining the properties of aluminum.

Sure, it will still cast----and it may not appear to be harmed--but it is.

I fully agree with RONALD. Natural gas is the fuel of choice. Unless you don't have access, go far out of your way to go that direction, as once you have built the furnace, you'll be able to cast copper alloys, too, and you're most likely to go that direction in the end, anyway. It's the natural progression of the home foundry. Some even use a gas fired furnace to melt cast iron, although that's a touchy situation, as the furnace type isn't a good choice. It has a tendency to alter the material chemically, so it loses desirable properties (carbon content is altered by the prolonged heating cycle).

Harold

[Pipescs]

Natural Gas would be nice.

But we do not all have it.

When asked about the possibility of getting a gas line run into our area, the Gas company has told me, "Not in your Lifetime"

I melted a small run of aluminum in my oil fired furnace yesterday using an old bag of charcoal to start it. The plan being to turn the oil on once the charcoal had brought it up to temp. The oil was never turned on as the aluminum melted prior to needing it.

[Harold_V]

Natural Gas would be nice.

But we do not all have it.

And how I wish we did.
I'd had natural gas service all my life, until making the move to Washington State. I used natural gas to fire this furnace, which ran for hours on end, reducing waste materials containing precious metals.

While there's a huge natural gas underground storage facility very near our location, natural gas service is not provided in our vicinity, and, as you suggested, most likely will never be in my lifetime. As a result, I chose oil as a means of heating. I used to pay 72¢/ gallon for oil. Those days are gone for ever.

I melted a small run of aluminum in my oil fired furnace yesterday using an old bag of charcoal to start it. The plan being to turn the oil on once the charcoal had brought it up to temp. The oil was never turned on as the aluminum melted prior to needing it.

Iron can be melted with charcoal---so creating the required heat isn't the problem. Inconvenience and cost is. Not using a solid fuel has distinct advantages. The non-ferrous melting furnace I plan to build in the future will burn oil.

Now if I could solve the house and shop heating issue. Propane isn't an option, as it's just as costly as heating oil. Contains only about 2/3 the BTU's per gallon when compared to oil.

Harold

[Pipescs]

I chose oil as a means of heating. I used to pay 72¢/ gallon for oil. Those days are gone for ever

I went the waste oil route. I get my oil for free from two local suppliers that let me have their waste. One is deep fryer oil the other used oil from a local garage. I keep about 30 gallons around

I will be honest if I had to pay for it I would not be running too often

[oldgoaly]

you could use the wood to generate gas then melt your metal.
http://www.woodgas.net/ plus you can make charcoal also this way. Good Luck and keep us posted!