Looking for critiques/tips/tricks on my first foundry!

[Madam Waffles]

Hello all! First off, this is my first post to this site, and I'm super excited to join this community! Recently, I became enthralled with the idea of casting my own waffle iron (hence the name Madam Waffles), so I set off to design my own foundry to cast iron. Below I have briefly described my idea and design up to this point. I would greatly appreciate some feedback on the design! If there's something glaringly wrong, I'd like to know before I start the build. Additionally, my specific questions are as follow:

1. What are the rough calculations you do to determine the size of your foundry? (I don't want to have to go in with the heat equation, material properties, etc. Is there a rule of thumb for the combo of insulation materials I'll be using?)
2. Will this actually get hot enough to melt cast iron? 
3. Is 20-gauge steel over-engineering the outside? Lol
4. Does the little table thing I have for the crucible make sense? Is it necessary?

The Design

I'm planning on making this propane-fueled with a forced air burner. The following screenshots show the bare-bones structure. It is to be made of 20-gauge steel sheets, 1-inch, and 2-inch square pipes. I want to weld those things together (I'm a xxxx welder though--just starting out, so that'll be fun). The weird piping coming off the side is the air blower (I got lazy with the CAD so did rough estimates for layout/dimensions. That's why it's square and then cylindrical.). I did not show the gas line piping, but it'll be a combination of brass fittings with a solenoid valve for safety (connected to the blower) and a needle valve. 

The hook things on the side are for a thermometer. I plan on finding smaller ones, but those were the only ones on McMaster that were close to what I wanted (I wanted the CAD).

Dimensions

Height ~22.5 inches
Diameter ~18 inches
Burner Diameter: 1-1/2 inches

Insulation

I want to have two 1-inch ceramic blankets with 1/2-inch of refractory on the sides (3/4'' on the lid and bottom). Additionally, I want to put a kiln brick(?) (the white bricks that are good insulators--not fire brick) under the crucible on the little table thing in the center. 

Pictures

Final Notes

Sorry in advance for lack of jargon, newbiness, etc. I appreciate and welcome all comments, questions, and concerns! Thank you!

[ThomasPowers]

Casting iron as your first project is highly not recommended!  (Like entering a Formula 1 race when you have never driven a car.)

Most people start with the low temp metals like Aluminum and get used to making molds and working with molten metals and then gear up to higher temp work.  Molten metal is hideously dangerous and the hotter ones really do need the high dollar protective equipment and training to work them safely.

Now as far as melting cast iron; have you looked into a cupola furnace?  Most people I know that do hobby cast iron casting use them instead of  foundries and crucibles.

I notice several groups sponsoring iron pours in NC, (search North Carolina Iron Pour),  I'd suggest tracking down the one(s) closest to you and see about joining  them and learning the art/craft from people actually doing it. (Some groups will have you pouring your own molds even at the first melt!)  I would think that a waffle maker using irons cast from their pour(s) would be a welcome addition!

Now the early Wafering irons and often the ones used in Colonial America were sometimes forged from wrought iron rather than cast, (and so tended to be simplier in design.)

[Madam Waffles]

ThomasPowers,

Yeah. I can definitely see why--cast iron seems intensive given the high melting point. I do plan to melt aluminum and other metals to test out the practice first before moving onto cast iron. Ultimately, it is the goal, so that's why I wanted my foundry to be ready for that from the get-go. However, I definitely will be taking it step-by-step and working up to it!

As for cupola furnaces: There's something about molten metal flowing everywhere and using coal/coke/charcoal that turns me away... That seems like a second iteration-type deal (maybe next summer!). Are they particularly any safer or have other advantages I'm missing? 

Thanks for the suggestion about finding locals. From my quick searches though, it seems like everything through the summer has been cancelled due to the coronavirus. I'd like to get something built and cast before I head back up to New York for school. Definitely something I'll keep in mind for the future though. Also with the uncertainty of the fall, I may end up staying in NC and will definitely head to one of those events.

[ThomasPowers]

New York has pours too; in fact the New York Art Foundry advertises: "Students will learn to make professional sand molds, help build a cupola (iron furnace), melt and pour iron. "

Per pound of pour cupolas tend to be much cheaper and running the iron to the mold is not that difficult compared to using a pouring shank.

Most of the pours I have seen were done through Art programs at Universities; though they did do one at Quad-State one year and there was one done at an Artist Blacksmith's set up here in NM. (Both cupolas again.)  It's quite possible to build a foundry that uses propane to melt cast iron---I know smiths who have done so to melt steel.  It's just a lot of set up and heat time for a very limited pour.

[JHCC]

In addition to ThomasPowers's advice above, I'd just like to point out that you can make a perfectly acceptable waffle iron from aluminum.

Welcome aboard!

[ThomasPowers]

Philistine!   

The heat transfer of Al is a bit different than cast iron so the design may need to be slightly different to get best results.  But it is MUCH easier to cast in ones backyard.

[Madam Waffles]

Going to have to agree with ThomasPowers on this one. There's a reason cast iron is so sought after for cookware . However, I'm sure the first one I make will be aluminum just to test the process. Additionally, I'm not sure about the food safety of unfinished aluminum/I don't know how to make food-safe finishes haha. (Don't worry, not a conspiracy theorist that believes Al is toxic). 

[Goods]

I’ve used a lot of aluminum cookware in my time and I’m fine. Really, I’m fine... we’ll maybe ok...

[SLAG]

Mr. Goods,

So your sample size is one?

Did you start eating or cooking and eating,  in infancy ?  Or childhood?  (when your brain was still rapidly developing).

How long have you done the above 'activities' for.  (that is the total number of years of exposure).

The above questions are a very small number of factors that are relevant,  in order to evaluate your endorsement of aluminum and cooking.

Aluminum exposure from cooking vessels was thought to be a serious factor in diseases such as Alzheimer's etc.  The latest thoughts are that it is not a serious factor, after several decades of research and scientific survey reviews.

But many people still harbor that belief, and that fact should be taken into account.

SLAG.

[ThomasPowers]

I was thinking that Al has a higher rate of heat transfer and so by properly heating cast iron you could ensure a nice crunch along the outer surface of the waffle and a properly done middle where Al might result in more overdone outside to get a nicely done middle.  So many factors in cooking though; even the layout of the indents could make a difference for a stuffy purist.

(I think a set of waffle irons with an aggressive boot sole pattern on them would be fun as I've always heard such soles called "Waffle Stompers".)

[JHCC]

Bill Bowerman made the soles for the first Nike shoes on a waffle iron:
https://www.popularmechanics.com/technology/gadgets/a21841/nike-waffle-iron/

[Madam Waffles]

He's also lowkey responsible for countless running injuries by promoting the heel-toe method with that design.

https://www.youtube.com/watch?v=Xdz6jxscD0w&t=573s
(Not that I completely support this guy's channel, but he does make some interesting points.)

Edited June 24, 2020 by Mod30
Remove excessive quote.

[JHCC]

Not so much that design, as much as later models with an elevated heel. The earliest models were basically flats; the waffle iron design was the solution to the problem of metals spikes tearing up the urethane running track.

[George N. M.]

Re lug soles on footwear:  The first rubber lug soles were invented in Italy in the 1930s to replace hob nails on mountaineering boots.  I first became aware of them in the US in the mid-'60s.  The US Army used a lug sole similar to the mountaineering soles on Viet Nam era jungle boots but found that the fairly narrow lugs picked up and held mud fairly badly.  These were replaced by the "Panama Sole" with wider lugs, so named because it was field tested in the Panama Canal Zone.

"By hammer and hand all arts do stand."

[JHCC]

Here's a great old film showing nailmakers hand-forging the hobnails for old-school mountaineering boots:

 

[Frosty]

MADAM: I'm just catching up on the thread, our wireless router was dying and . . . Nevermind, brand spanking new router is up and connected so I'm catching up.

IIRC about a large coffee mug's worth of molten iron has the same explosive potential as about half a case of 40% dynamite. It makes a joke of understatement of the term "inherently dangerous". 

The annual iron pour held at Art On Fire is canceled this year but were I making a cast iron anything I'd take the class and make the mold supervised by the go to bronze caster in Alaska. Pat was a prime mover at the iron pour youre probably referring to in NM, Thomas. 

Your image of iron going everywhere isn't appropriate for a cupola melter. It IS however appropriate thing to keep in mind regarding an inexperienced caster messing with molten iron. 

My sincere advice is find a caster who works in iron, take a class if possible you'll walk away with your waffle irons AND some necessary skills. WITHOUT the catastrophic level burns, disfigurement and potentially crippling injuries that are oh so easy to get with a minor oversight or mistake. I've been in the same room when a small soup bowl's worth of molten aluminum was blown out of the crucible when a few drops of water got introduced. 

I'm in full agreement cast iron is way superior to cast al. cookware except maybe electric waffle irons where conductivity counts more than specific heat and thermal mass.  I may have to have a waffle for dinner. Mmmmmmm.

It's been a while since I read the article but the link between aluminum and Alzheimer's was discovered to be the die used in studying the brain tissue of sufferers. The die had a high aluminum content which wasn't taken into account in the studies. An oversight.

Frosty The Lucky. 

 

[SLAG]

Folks,

This just in,

Attached please find an article discussing the latest views and understanding on aluminum cookware upon diet, and aluminum in  food and water.

Try.

https://www.msn.com/en-us/news/us/fact-check-exposure-to-aluminum-through-food-does-not-cause-neural-issues-or-cancer/ar-BB15ScSd?ocid=msed

It was posted 8 hours ago. The originally source of the article is,  U.S.A. Today.

(it is a good easy read that is not polluted with jargon and abstruse technical jargon).

The general conclusion,  in this report,  is that trace amounts of aluminum,  that may be found in the above mentioned sources are NOT causes of cancer,  Alzheimer's disease,  nor autism spectrum disorder.

Enjoy,

SLAG.

[ThomasPowers]

There is an annual iron pour at the Highlands College out here in NM; but the one I was referring to was done at CT's shop in Rowe. (At one time the largest blacksmithing shop west of the Mississippi I've been told, an ex-RR shop where the 100# LG is one of the "smaller" powerhammers and there is a 2000# hammer in his bone pile...)

Anyway; there is a surprising number of non-commercial cast iron pours going on in the USA; often connected with University Art departments and a great way to learn the skills fairly inexpensively and fairly safely.

[Madam Waffles]

I'll try to search for some of those, Frosty and Thomas. Thanks! (Won't deter me from my foundry build even if it's for other metals though...) ;)

-Madam Waffles

[Donal Harris]

When I worked in a hospital lab in Gilmer, Texas, we would have a health fair for the community during the town’s annual Yamboree.  One of the members of the community was a guy who had worked for Lone Star Steel. Both of his forearms were horribly scarred. I asked him how it happened. He said a mold exploded early one morning and he was showered with molten steel. Molten steel and condensation are not compatible. 
 

I want to cry like a baby when I have picked up a piece of steel at a black heat. My brain is just incapable of thinking what it must have been like for him. I seriously recommend you go learn from people who know what they are doing. If accidents like this can happen even with professionals, imagine how much more likely they are for someone trying to learn as they go. 

[ThomasPowers]

I met a fellow who was loading more metal into a crucible after the original fill had melted down.  Didn't hold it in the exhaust until it was totally preheated.  Moisture from the exhaust gases condensed on it and when he dropped it in the pool of molten brass; BOOM!

It's funny how steel at forge welding temps is much less dangerous than molten aluminum about 1000 degF cooler. (It's mainly due to being able to exercise a high degree of control over the solid piece of steel vs the liquid Al.)

BTAIM: casting can be a lot of fun and you can do a lot of useful things with it.  I don't want to scare you off of it; just want you to do it safely so you can enjoy it!  (I do oil sand castings to make knife fittings using my forge to melt the small amounts of metal.)

[Frosty]

Thomas's example of moisture emptying a crucible is how the al crucible got blown over the entire hot shop section of metal shop. The only person burned was the joker who opened the melter and put the piece in. It got him suspended for a couple weeks, the melter was one of the pieces of equipment that was off limits to anybody the the shop teacher. 

I've been working with molten metal since jr. high (middle) school and it makes me edgy still. However as much as it frightens me nearly enough it's not safe to handle it I can put it aside while I melt and pour and do it safely. One of the many things Father used to say till us kids got sick of hearing it is as true as it gets. "You have to respect it but can NOT fear it." Just the adage out of context might not make sense but Dad's shop was nothing but dangerous some extremely so.

Like Thomas says I'm not trying to discourage you from learning casting, I want to see you do so safely. There is nothing casual about casting, even lead is life altering dangerous, in the immediate sense of dangerous.

Frosty The Lucky. 

[Irondragon Forge ClayWorks]

I know what ya mean Frosty. In all the years I have cast lead bullets, there were several times I had to go and change my shorts due to close calls. Lucky that I was never seriously injured due to PPE.

[Donal Harris]

Makes sense. There is a big difference between respecting something and being fearful. Fear makes it difficult to think. Part of your brain wants to stay, part wants to run, and the rest wants to just freeze in place. 
 

I do love waffles, but the closest I ever get to them are Eggos which is not really even all that close. 

[Frosty]

Eggos! <shudder> I made myself a waffle for dinner tonight,  Krusteaz wheat and honey mix, duck egg and milk, sausage patty layer of peanut butter and real maple syrup. 

Back when an Eggo, sausage patty and over easy egg were quick and tasty. 

Frosty The Lucky.