Simple Brick Furnace

I put a little foam sprue on mine then wrap the foil around. It keeps the sand out but is not as pretty as yours.



I did spill some metal on the top of the sand in my rush to keep the cone full. Second pour went better in that respect.

I'll try to make up some tape cones in advance and see how they compare.

 

I made the swivel piece for my pre-heat tray today. I couldn't find my paraffin so I just used straight wax ring wax.



Fillets in open areas were easy to do, not so easy in the tight places, I think I need a heated tool.

Another successful lost foam casting.



That defect on the web isn't much, I didn't notice it until the picture.

I'm gaining confidence now with my beginner's luck.

It swivels and flips up.



It's ready for a handle now, which will double as a counterweight.

 

Keeps the weight off the lid bricks.
I like it.

 

I was thinking baked potatoes.

Yes, the brick is soft and I don't want to be using it. I really need to give it a thin coat of mortar just for protection.

 

I see that I posted above (#24), but sadly I have no recollection of your furnace build.
Maybe I tuned into this thread after the furnace part. For much of this year I have only had time to quickly skim a few of the posts here.

But there you have done exactly what I was considering, which is to cut fire bricks for the lid to that they can be domed.

And you have an excellent solution for the tuyere entry, which is the cast brick for that.

This is a great thread.
You have it going on for sure.

Are you doing iron work?
If not, are you headed that way?

 

There's a lot of stuff to digest, isn't there.

Thanks for your kind comments.

I was seeing lots of furnaces losing their arch into the firebox so wanted to have an arched arch. Now I realize there are very many furnaces which operate well for a long time with a flat arch. And I really did not want steel in close proximity to anything over 600F (limit for steel pipe in refinery service) so I needed my support to be a ring outside insulation. The metal ring gets to about 200F with 2,000F in the firebox. It should be proportional within small limits. I would expect roughly 300F with a 3,000F firebox.

So far I've cast aluminum and made a few brass pours and one copper melt and pour into ingots. The burned blue hose (IT piping) is very fine wire and made a lot more ingot than I expected.

Who in their right mind does not want to cast iron (and steel).

Who in their right mind casts in their back yard?

I rest my case.

 

..

 

Amen brother.

 

Finally made some aluminum bronze. The old furnace cooked it's 200th load today. Shooting the oil to it will get it hot.



By pointing the burner down a little I'm getting a full 360 out of the flame before it starts to come out the flue.

I know it's getting hot because it melted the end off my steel scraper. It was thin, but I was gently mixing the aluminum in and saw something bright. It was steel burning. That made a lot of slag and I came up a little short for the pour on my hammer pattern



But it looks ok, from the bottom, not so good from the top



No porosity



I got goosey and added a riser on the inlet gate



It was great watching the metal rock back and forth between the riser and the sprue (near side) and the casting came out well



I don't think I needed the riser, I think having a full pour would have done the trick. My core is smaller than the core print and I'm too lazy to modify it. I also extended the end of the small end of the hammer because I was scared of shrinkage, but again I think it was all lack of metal.

 

That is a nice looking hammer.
Nothing quite like getting out and firing up the furnace.

 

Thanks! I've been making aluminum hammers for some time. They are great for pounding on machined shafts.



Then I made a couple of brass ones but haven't done more yet.



I've been very fortunate to be able to fire my furnace most days. Sometimes I just melt aluminum to clean it up and make ingots. I know that's wasted effort but I love doing it and they store neatly. 75# per bucket, here's 450# of aluminum.



Makes me feel wealthy.

 

Nice hammers... Zap has been after me to dump my old trusty steel hammer for one made of bronze to break out shells.

 

Furnace update. After a couple of iron firings I'm seeing deterioration on the 2,600F firebrick. Not unexpected. I have 3,000F firebrick to replace it with. It has Satanite on the hot face but not on the top. I'm assuming some iron got on the melted spots and started deterioration. New brick will get Satanite top and face. The underside of the arch looked great.

 

Iron temperatures are not kind to the lower temperature rated fire bricks.
Mizzou is your friend.

.

 

Iron itself in contact with refractory promotes breakdown of the refractory. (Makes me wonder if it has higher affinity for O2 than aluminum and so robs the O2) I have seen just what you photographed—drips of iron seem to eat into refractory materials. The less dense the material the more the iron dissolves it.

Satanite helps slow the process but seems not to be adequte for prolonged iron contact. So, on the floor of my furnace I troweled a 1/2” layer of dense castable. The iron does not seem to erode it appreciably. I am surprised at how well the castable tolerates after-the-fact application. There is no way I can approximate the recommended slow initial heating schedule. So, I have dried it at 120 deg with a light bulb in the furnace and then just “fire away” and it seems to adhere and vitrify just fine.

Denis

 

With iron temperatures everything is a consumable. The flame temperature we need to get superheated iron is around 3300*. For oil fired furnace the flame is around 3600*. I haven't found any castable, let alone insulating firebrick, that will take those temperatures for very long. It ends up needing a periodic rebuild when the sealing surfaces break down too much. I have been locked into the diameter of my Gingery, and could only improve the insulating properties of the furnace enough to have the skin temperature stabilize at 700* when the melt is at 2600*.

 

One of my goals in building a brick furnace was to avoid castable refractory and the required dryout. As long as I was melting aluminum the 2,600F brick was adequate. I did buy a box of 3,000F brick to use as a liner if and when the 2600 brick proved unsuitable. These brick are just set in the furnace and can be replaced in about two minutes.

Since this is above the top of the crucible I'm going to try some Satanite wash over these brick and see how they last short term. I'm not expecting to cook iron every time so they may last a while. These brick have Satanite on the fire side. Since they are 2,600F brick I was not going to be surprised if they were starting to sag but so far they look good.

My floor is covered with a layer of oxidized aluminum and brass slag. It's about time I clean it out and inspect the hearth.

My furnace has two layers of firebrick, then a layer of wool. The outside was over 150F when I had the iron melted. This brick is set in precisely because it was intended to be a consumable. (and the 55 gal drum was too big with one layer of brick.) This lining has around 150 hours at temperature, that's less than a week for an industrial furnace, but it's a lot of melts for me.

 

After the damage noted with the iron melt it seemed appropriate to clean and inspect the furnace. Floor was full of trash anyway.



That's mostly aluminum oxide from spilled slag trying to skim a completely full crucible.

The floor looked good under the trash.



Burner enters on the lower right and swirls clockwise because I'm left handed.

I covered the spots on the brick with Satanite. Those spots may be from brass flux. I'm not sure I spilled any iron in the first pour.



Some of the mortar had fallen out of the flue





I put some sairset mortar in the hole and in the holes on the brick, then put a thin layer on the floor and fired it later that day. A couple of aluminum melts and it looks good.

The floor was in such good shape I realized the trash layer was probably protecting it. So I recovered the floor with loose aluminum slag. The aluminum oxide does not melt so I don't think it will hurt. It melts over 3,700F or 2,000C. I regretted discarding the precooked material.

Decided I should have a poker for aluminum, one for brass, and one for iron so I made two more, and a handle for another SS spoon.