A thin hotface medium/low mass beer keg (drum size) furnace for melting Iron

Of course it will work! Maybe better than you planned or worse than you planned but it will work.

Looking forward to seeing some melting going on!

 

I like that.

Well easy for you to say.

I must say I am a bit nervous about the "big melt".
I have a lot of blood, sweat and tears invested.
While melting iron to some is as simple as ironing a pair of pants, I don't have that confidence yet.

With aluminum, I can relax, kick back, enjoy the show, and basically expect a 99.99% success rate.

With iron, its always been a white knuckle affair, and most of the time a failing affair for me.
I will have to get my confidence up with iron.

I need to try a sodium silicate mold, and also a greensand mold, both with iron, and that is uncharted water for me.

I need a motivational video, to get psyched up.
This is one of my favorites.
It gets the blood pumping at 3:10:



.

 

The other song you should definitely play when you light er up:



That song can be like an ear worm when the iron is melting and red flames are flaring from every crack and crevice...

Denis

 

I need to set up some speakers and a sub-woofer outside while I am casting.
The neighbors would probably not approve, but they have really been pretty understanding with the flames and noise that I make in the backyard.

It is showering on and off today, so no cast work.
I will have to look at the weather forecast for the week.

.

 

Weather looks pretty good today.

I am going to start setting out equipment; pouring shank, crucible stand with hard fire bricks, lifting tongs, leathers, boots, gloves, faceshield, ferro, calcium carbonate, scales, sand, flasks, patterns, flask weights, clock, skimmer(s), stirring rod, scrap iron, charging tongs.

Lots of stuff to gather up and organize.
What I wouldn't give for a nice covered shed (obviously not the cost of a shed, but I can dream).

I watched ironsides sand video last night (thanks for that, its a great help).
I may try out my new concrete mixer, although it is not really set up as a muller yet.

It seems much easier at night to see how the burner is operating.
I fired the burner the other day in direct sunlight, and I could not see any color temperatures at all.

I am going to try and set up my new dash camera, if I can figure out how to use it.

.

 

Got the dash camera working.
Resolution looks good.
Now I need to find a 12 VDC power supply.

.

 

Which sand video are you referring to above?

I use one of these for 12V DC power:
https://www.amazon.com/gp/product/B00D7CWSCG/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

I have also used power supplies harvested from desktop computers, but the above supply is in a lot nicer package and easier, therefore, to setup. Saves a lot of time. Robust.

Denis

Added: It runs a "20V" leaf blower and a 12V automotive fuel pump. It has the capacity to do a lot more if desired.

 

A car battery will work in a pinch.

 

Here is ironsides latest video about sand. (Great stuff, thanks ironsides):


For now, I am going to pull the car into the back part of the driveway.
Hopefully I won't burn up the car, but at least it won't be the wife's car.

And I am having to do the dreaded cleanup; there is no more thankless task, but the driveway does not clean itself unfortunately.

I broke up some iron (old motor end bells) with a sledge hammer.
Boy that is some real work there. I much prefer pushing a mouse all day.

It is still quite hot here, but not raining.
I am also moving the furnace over into the shade; I guess I will become a "shade tree caster".
I just can't melt iron in the direct sunlight without melting myself.

 

Thanks much. I appreciate the thought.

I got the driveway cleaned, the furnace moved and set back up, the sheet metal form and bricks trimmed at the back so the lid can close, got out the ferrosilicon, and did a few other miscellaneous items.
I got the crucible charged, and used cardboard beneath it, plus a layer of powdered graphite on top the plinth.

I am using a taller plinth this time.
I think this new one is 5" tall.

I got out the new concrete mixer, and am contemplating trying to mull some sand with it, using an iron weight inside.

Seems like a waste to pour iron ingots again, so I will have to decide if I want to do a dry run tonight and melt some iron, or wait until tomorrow and try to get a decent mold made.
I will probably try a dry run tonight and make sure I can melt iron.
No sense making a mold if the iron is not going to work.

I need to do a walk-through of all the steps before I start the burner.
I see from the photo that I have not laid out the skimmers yet.
There is nothing worse than trying to find something in the middle or worse yet at the end of a pour.
This will probably be a night pour so I can judge the color temperature better, and it is really important to get everything laid out perfectly for a night pour.

A few photos of today's setup.













Edit:
I think fire ant bit me on the hand.
It was a little sucker, but it got my attention when it bit me.
Not much swelling, but I have never had an ant bite me before, so I am guessing fire ant.
Its not the ants I am worried about, its the iron splatters rolling down inside the gloves.
.

 

PatJ,

That is, indeed, a very fine video made by Ironsides. The best I've seen on the subject. Many very useful points made. He uses a bit more bentonite than I do---he said 7.5% (presumably Southern bentonite) and I have been using 5%. I think I will try using 7.5.

I have found 4% coal to work well which is essentially the same as his 3.5. What is more nebulous for me is how much to add back after a pour. Recently I have been adding 1% back or 8 ounces per 50 pound batch and that seems to be working. I wish I knew better how to judge that.

With respect to the hard work of breaking up grey iron, I agree it is strenuous. But, if the hammer pictured above is your breaking hammer, you are using too small a hammer. A six or 8 pounder will work much better. Also, supporting the workpiece on each end on a hard surface as opposed to laying on grass or gravel works better. I would bridge the workpiece end bell on two other bells (or 1/2 x 6 steel plate scraps) so it can't sink into soil. Then all the momentum is sharply rather than gradually transferred from the hammer to the workpiece. It makes a big difference. It is the peak impact that does the breaking not the overall summed impact, if that makes any sense at all.

Right now, I hope you are tending your furnace and watching glowing shards dripping molten metal and sparks of carbon streaking out of your chimney! " You smell that, son? I love the smell of *diesel* in the morning!"

Denis

 

LOL, yes I can relate to that for sure.

I have two hammers.
One has a long handle, and one has a shorter handle.
The trick is to hit it hard enough to break, but not so hard that the piece flies off at the speed of sound and sheers off your shin or kneecap.
And definitely don't want to swing the hammer into your foot or leg. I was very careful to avoid contact with the hammer head.

The melt went very well with a few minor glitches.
The iron got very hot, and I had the burner set correctly.
I finally understand what is going on with iron.
It is just like ironsides says, with a few exceptions.

The sand was not so much a success.
I mulled my greensand, and got it into pretty good shape, but my surface finish turned out pretty bad.
I got spoiled on resin-bound sand.

Photos and videos tomorrow.
I need rest.

Edit:
I got video this time.
The dashcam seemed to work pretty well.

Edit02:
Looks like I melted about 18 lbs of iron in 60 minutes, using 2.64 gallons of diesel.

 

That is a fast melt. Any idea how hot you were? And did you have to add to your charge or did you just load your crucible and blast away?

With respect to the green sand and poor finish: I'll be interested to see pics. Were you able to include coal dust or ground coal in your sand mix?

I am with you on needing shin guards. Those pieces of CI can and do come off at high speed and are extremely sharp and jagged. I am going to get some soccer shin guards to wear when breaking it up as more than once it has hit me in the shins and broken skin. Youch!

Denis

 

The melt was extremely hot; when I did the final skim, the metal looked like it was boiling, and I have never seen iron do that.
It was so fluid that I did a bit of an interrupted pour because the sprue would immediately drain out, and I will have to remember to pour much faster.
It was like pouring ice tea.

I started with an initial charge, which was as much as I could put in the crucible without the metal protruding over the top of the crucible.
When the initial metal finally puddled, I added one piece of scrap at a time, holding each piece in the flame for about 15 seconds to let it dry out and preheat at bit.
As I dropped each piece in, I pushed it under the slag, and that worked like a charm.

I added about 7 pieces towards the end, dropping them all in before pushing them under, and they were completely melted within about 2 minutes.
These pieces were about 1/4" thick, and I avoided adding the thicker pieces of iron towards the end, so as not to chill the melt.

I put graphite on half the mold.
I will have to get some photos of the casting in the light, but it looked last night like what I have experienced with aluminum and petrobond when the metal was too hot, and it sort of burned/eroded its way into the surface of the sand.

I did not use the coal dust, ferrosilicon or calcium carbonate.
The mold was not good enough to use for a good casting, so I just used it for a test casting.

The burner worked flawlessly, and once I adjusted the combustion air at the beginning, I did not touch and settings again for the entire hour.

I am going to summarize why things went so well last night, compared to previous melt attempts (some successful, but most not).

Need to upload photos and videos today.

I finally have figured out how to melt iron.
The description provided by ironsides is accurate; ie: start with an initial charge, let that melt, then press additional pieces through the slag and under the surface of the metal.
I did not skim until the end, and the metal was so fluid that it was easy to tell what was slag and what was metal, and easy to separate the two.

I glanced at the video last night, and it seems like at the end, the metal was sending off a lot of sparks; which I assume meant it was very hot (and it was).

I believe I can walk out on any given day now and melt iron without any problems.
The key is knowing the correct burner setting, and pushing the added scrap through the slag and under the molten surface, so that it does not oxidize while it is melting.
The scrap I used had heavy paint on two surfaces, and that did not present any problems at all.

The heat is very intense when melting iron, and it pushes the limits of the crucible and furnace.
I had an issue with the lid leaking at one area, and it almost overheated my lid stainless shell in one area. I will talk about a solution for that in a minute.
The pressurized furnace really exacerbates any leaks anywhere in the furnace, and each leak acts somewhat like a cutting torch.

Edit:
I had intended to add ferrosilicon, and porositymaster recommended adding it while the crucible was in still in the furnace with the burner running (that is how he does it).
I did not use the ferrosilicon last night, but when I opened the lid and turned off the burner, the metal was super hot, and there was absolutely no need to keep the burner running at that point.
The iron was as fluid as aluminum when aluminum is at 1400 F.
.

 

The Navy Foundry Manual (Chapter 17, page 245) mentions that "A bubbling action can be observed at 2,800 F".

That is what I saw last night at the end of the melt, and I have no doubt I was at 2,800 F given how fluid the pour was.
I really felt like I overheated the melt, and most likely would have gotten a much better surface finish at a lower pour temperature.

I think I could have poured sooner with less melt time.

.

 

The dash camera seemed to work well.
I had it sitting on the hood of my car.
It takes videos in 5 minute increments, which is really helpful in storing files and locating things.

The resolution seems very good, and the night visibility seemed pretty good too.
I think I got a 128GB card, which is probably good for 8 hrs (+) of video.
Not bad for a $200.00 camera (Street Guardian #SGGCX2).

.

 

Here are some photos.
I will get some daylight photos of the casting today.

I went with melterskelter's suggestion and make a variety of skimmer types; some straight rods, some rods with a foot, and some with handles to keep the gloved hand out of the exhaust stream.
The larger skimmer worked pretty well for coarse slag removal, and the smaller one then cleaned up the smaller amount of slag.



The rod with the yellow handle has a graphite rod attached, for stirring in the ferrosilicate.


The furnace before the melt started.


Here is an iron ingot that was created when my old lid lifter failed on my first furnace, which jammed the lid partially open, and caused a #30 of iron to go cold.
This ingot weighs perhaps 70 lbs.


I wrapped the ingot in bubble paper and taped it, to prevent it from pounding the mixer tub.
I added water to my very dry greensand, and the weight actually worked pretty well.
I used a boat paddle as a temporary scraper, and that actually worked pretty well too.
The boat paddle tended to jam occasionally, but that was no big deal since the rpm is so low, and it just turns the boat paddle slowly, so no big deal.


The sand seemed to mull up well, with good green strength.
I had three 5-gallon buckets of green sand in the mixer, which I consider a lot to be able to mull all at the same time.


Here is an aluminum casting of a flywheel that I used for a pattern.
I filled the drag, and then stepped on top of the pattern, to drive it into the sand.
I scrapped away the excess sand down to the parting line.














I cut the runners (normally they would have dead ends in them, but I knew this was not going to be a production piece), and coated half the mold with graphite.
The graphite did not seem to have any effect.


Here is the furnace in operation.





The lid had a few leaks, and the L-shaped bricks at the top channeled the hot gasses onto the lid stainless shell, and began overheating it.
I stuffed some ceramic blanket in the gap.
I will have to cut the top part of the upper IFB's off, and trim the top section of the stainless shell down so that any leaks at the lid/furnace junction can blow straight out.
I think I can reduce the oil flow and cut back on the combustion air and still get a decent melt time, and this will reduce the pressure inside the furnace and reduce the lid leakage.

I started the burner with compressed air and oil only, and then started the blower with the dump valve fully open.
I then slowly closed the dump valve to put 100% of the blower discharge into the furnace.
I adjusted the needle valve very slightly at the beginning to lean the burner out slightly, since there was a slight excess of flames out the lid.
I did not have to touch the burner controls again for the duration of the melt.


The multi-flow valves worked well, but as I anticipated, now that I know the various flow settings and what they look like when the furnace is operating, and the associated combustion air dump valve setting (I ran the dump valve fully closed), I no longer need the multi valves.


Here is the combustion air dump valve in the fully closed position, which is where I ran it.
The blower was run on its lowest speed setting (variable speed Toro leaf blower).


Here is the furnace immediately after the pour.





Here is the mold immediately after the pour.


Here is the ingot I poured into the grass.
I had a steel ingot mold pop on me a few melts ago, burning my hand, so I decided to pour in a little trench in the grass.


A few post-pour photos.


This is my daughter's boyfriend, and his smile perfectly captures the feeling of the moment, which was definitely ecstatic.


Photos of the casting.
The top of the casting was not bad, and I think would clean up ok.


The bottom of the casting did not turn out well, and I think would probably render the casting unusable.
There was one hole in the hub, but normally I would use a riser at the hub and I think that would eliminate the hub problem.
I did not use any vent holes in the high points of the mold, although I normally do vent the mold.
The next casting will use sodium silicate-bound sand, and we will see how that works.
I am not too keen on the greensand, just because of the amount of work required to mull it, plus the fact that it took three 5-gallon buckets of sand for one flask, which made for a very heavy flask.

 

One thing about melting iron is that it tends to put a maximum stress on everything, including the furnace lining and shell, crucible, skimmers, burner, gloves, leathers, faceshield, etc.

It seems to be similar to driving an automobile on the Autobahn at 100 mph for an hour at a time.
While many/most automobiles in good condition are fully capable of driving at this rate for this period of time, any weaknesses such as poor tires, bad bearings, improper engine combustion, lack of adequate lubrication, poorly functioning cooling system, etc will stop the journey very quickly.

It is the same with an iron furnace.
Everything needs to be in excellent condition, and it all has to function well in unison for an hour at a time.

I will take some photos of the interior refractory shell, plinth, and crucible today, and see how well they held up.

.