My IFB/fibre-blanket furnace build.

Andy, during my torch trails I found if I shut the fuel off and let the air run I had no smoke at all. My torches take about five seconds each to put in or pull out of the furnace.

To light the furnace (this was my second back up plan).

-with only one torch installed in the furnace
- in my right hand I hold the other torch and a propane blowtorch lit, with the flame pointing towards the torch tip.
- with my left hand I turn both air ball valves on
- then, I turn the ball valve for “diesel flow on” to the torch that’s in my hand. And I’m pointing it inside the furnace from the top. It works literally like a 4-5 foot flame thrower.
- then, I turn the diesel on to the torch that is installed in the furnace well shooting the flames from my hand with the other torch. It fires up.
- I turn the diesel off to the torch that’s in my hand...then airflow.
- I install the torch into the furnace turn the air on it then turn the diesel on. It lights up off the other one.

There is very little clearance (maybe 0.015”) from the outside of my burner and tuyere in the brick. The end of my burner stops about 1 inch from the inside of the furnace. I figure I need to be careful as my drip oil feed is the Copper 3/16 brake line. I figured it could probably melt pretty quickly. When I shut down, I turn off one burner fuel, then its air then pull the burner and repeat for the second side.

What I need to figure out now is when I’m taking a crucible out, I just cut the fuel and leave the air running on Half or very low flow.

This is where a day in the shallow end with aluminum will teach me a few things.

 

Sounds good.

When I cut fuel I kill the air to avoid chilling the crucible with cold air. If I continue the air in a hot furnace I get no oil smoke, not so if I kill the air.

If you're leaving the air on that will protect your brake line. I use a brake line but a steel one. My problem with not pulling the burner is coking the residual oil in the brake line.

 

Andy, I’m very sorry to hear about your situation/loss. God bless and stay strong. My father is in a bad place right now and I’m just trying stay strong for the rest of my family.

 

My brake line is out and in front of my blower Air feed, by about a quarter inch. My little torch tips I have a blower behind it producing 150 CFM. I have choked them down at the tip and installed 1/16 copper wire as a spin vain. The copper wire keeps the brake line central as well. It works really well. Somehow I’d like to increase psi, But this becomes a really dirty game between pump, turbine, blower and High pressure blower (or turbo pump).

I know, I am now playing in the amperage game. If you listen closely to the video you can hear when my little mini Air compressor clicks on... and how it affects the turbine air blower on the 15 amp circuit.

 

Aluminium in your boot or down the cuff of your gloves is as unpleasant as you want it be, I've had both. Iron flying around I can't imagine (or want to)

I still go with the laces untied approach but can understand your concerns with the 'oh sh**' situation when holding a crucible.

I ran a mould to the other side of my yard to prop it up when the cope lifted once and thought after how the hell and why did I get away with that (all to save a cast!)

 

For safety shoes, I’ve now resorted to the Walmart Green patch, white patch “workload” shoes for the last three years. I get a shoe budget of $100 a year. I used to buy doc martens, but they’re too heavy and not disposable. With the Oxy-acetylene torch droppings, I found leather shoe guards gave me, pretty much full protection.

10years ago, I dumped the boots for slip on/off shoes... I was chansawing a massive tree and it fell over rode down my shin and pinched my toe into the mud. I screamed for help in the middle of a forest for about a minute. A few minutes later I gathered my marbles, as I knew nobody could hear me. I took another two minutes unlace the boot and left it under the tree. Walked home 5min. without the boot. I came back with leveraging tools, and one muddy foot in a new pair of shoes. I learned a lesson that day. Be able to walk away from your shoes in a moments notice and keep your marbles intact.

Edit; I finalized the editing of the assembly video and lighting.

 

After a few burns, everything seems to be working great except for the upper lid. Some of the hot gases we’re getting trapped under the stainless steel sheet metal.

I figured all add A bit of a chimney hole using some of my offcuts of IFB. I will mortar these together with a hose clamp for good measure.

This should extend the exhaust past the sheet-metal by 1/2”

 

Lids in general seems to take a beating, I guess maybe that is a hot part of the furnace.
.

 

I've got sheet metal over the top of my lid too. The hot exiting gasses around the 4" hole warped it immediately. Not enough to create mechanical concerns with the lid, it just makes it look a little janky. I find the flat lid to be helpful. It's surprising to see how quickly the heat concentrates when you lay something over the edge into the hot gas stream. Your strategy should work for your purposes but may suffer tool abuse in practice. If you're planning on coating your inside lid surface at some then you could coat your IFB chimney too. That might offer some protection for it. Extra junk in the crucible is no fun.

Pete

 

Pete, when I said mortar, I meant everywhere (I had 40 of those little blocks as offcuts, now I’m down to 20).

I’m still leaving the larger IFB’s inside the lid just clamped. I’ve seen way too many problems when guys mortar IFB’s and then they want to take out just one brick for a fix.

The little donut chimney was to fix my screwup. The little chimney is only loose laid trapped by the ceramic wool and a little bit clamped by the sheet-metal.

No it is a bit of a funnel shape. 5 inches tall, the top opening is 5 1/4 flat to flat, The white IFB is 4 inches flat to flat.

 

Well, don’t make the same mistake I did. I thought the mortar I have would react very similar to Satainte. NOPE! I put on about a 1/8 coat. Let it dry for a few hours and then lightly put the torch to it. It started bubbling up right away. One step forward two steps backwards. This stuff became pretty hard. I started at it with a file, then resorted to the Dremel with a carbide bur, then a carbide scriber/pick.

I filled it back in today, and tonight I’m gonna put the light to it.


Afterwords I took a big chunk off the inside of the Bucket and put the blow torch to it just on a metal plate it’s slowly turned from grey to white to glowing red. It cooled back to a very white-ish grey. Sample sitting on top.

 

In my flu-induced brain fog, I though you had made a mini-furnace.
My first thought was "now that is not big enough to melt in".

.

 

In all rights, it is a mini furnace. It is my first. For first furnace builds, don’t most wish they went bigger?

 

Like most other machines or tools
I bought a 20" press, wish it was 22.
I bought a .38, wish it was .357
I bought a 6 cyl, wish it was 8.
It never ends!

 

Well, today I had a chance to run the foundery.

Since today was recycling day I thought I would put the test to 500 soda cans.

The stainless steel crucible took the hot seat. It performed like a champ for the first for the first melt. It didn’t quite like the extra air I gave it in the second melt.

No furnaces were hurt or damaged during this testing!



By my estimate 500 cans x 14.7 g = 7350 g

I only recovered 6309 g. Some is still stuck in the crucible... and who the hell knows where everything else went.

In the end it was a good and bad pour day. Nothing ventured nothing learned.

I did get four decent ignots out of the 350 can melt. And a decent amount of slag. I do have to admit there was a little bit stuck inside the crucible.


But after the second pour and my new trophy that is weighing in at 1685 g.



I can’t count the slag because it’s stuck inside the crucible with who knows how much other good stuff .

It was really sad that she passed during this epidemic. And it had nothing to do with the epidemic at all. She just wasn’t built to handle the heat. May she rest in peace.

 

lol... Nice hole. Clay graphite my friend!

 

yeah yeah yeah, I know! Couldn't walk away without giving it a try first. But the art it created is priceless.

 

So you have discovered first hand that stainless steel is soluble in molten aluminium the same way a friend of mine discovered stainless is soluble in molten solder when he built a radiator soldering tank out of stainless steel. You'll notice it appears to have failed from the inside.

 

Mark, you're 100% correct. It did melt from the inside.

There was no apparent stainless steel loss of the crucible during the first pour. But during the second, I added a little bit more fuel and air. Maybe I was getting greedy, who knows. The first pour took 23 minutes. The second pour, rigged disaster in less than 15 minutes.

I got my aluminum. Now I'm looking for my aluminum bronze.

 

Stainless relies on it's oxide layer passivation, once it gets compromised the problems start. It must have been pretty hot though!, most people get a fair bit of aluminium service before failure.