Bending Grey Cast Iron

That should work just fine! I bend assorted types of cast metals fairly often for people. Just heat it up good and red and then carefully bend to shape.

Slow cool down is preferable if possible. Bury them in dry sand or kitty litter after the bending is done and let them slow cool if you have conserns.

If you have real grey cast iron, it'll break, no matter how hot you get it. If you have ductile cast iron (hard to see except under a high powered microscope, it'll bend some. If you have cast steel, it'll bend with heat pretty well.

Jack,

I believe that the MP for gray cast iron is somewhere around 2,100 degrees (F).

Therefore, if you wanted to bend the material without breaking off the "ears" you would need to get pretty close to that temp.

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Just my $0.02...

JMAN,

You sound like a metallurgist or like someone that has had experience in a foundry.

My own hunch, which is why I asked for advice, is that any metal that upon breaking shows a crystalline structure, like grey cast iron, is going to break no matter how hot you get it.

Unless a real metallurgist, i.e., someone that proclaims himself as such, chimes in here with advice I am going to solve my problem by collecting some data which I looked for on the net and did not find.

I'm going to go out and find a length of scrap cast iron, get it as close to melting with a torch as I can (Propane no ox) and bend it and see what happens.

My bet is it will break. I will let you all know. Seems my only alternative is going to be to grind off the excess metal and hope enough is left to serve its purpose as a handle.

Like a good scientist or engineer I will let the data speak for itself.

But thanks all for your input.

j.

Jack,

Sorry, but I'm not a metallurgist.

And the closest I have come to working at a foundry was nearly 30 years ago, when I work at a company that beneficiated "low grade" silver from various commercial & industrial sources, into thousand Oz. ingots of bullion grade (three nines or better). Among my other duties, I assisted in the assaying of each "batch" of ingots.

With respect to your mention of crystalline structure, (IMHO) I believe that the closer you get to the MP of a metal, the less crystalline structure there would be, and at the MP (and above) there is no crystal structure, as you are then dealing with an amorphous liquid...

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Just my $0.02...

Jack.

I "r" a metallurgist, more correctly i "were" one; but steel mill not iron foundry.My assignments were in Blast furnace & melt shop, pipe mill labs, and bar mill experience after college in the 1970's. many years. I still have my fingernails.and the first micro I ever made.

If it is malleable iron, might be bendable.

If it is gray cast iron, no I do not think it will bend .

Besides the standard tensile and brinell hardness tests for cast iron in the old days they used to do a rupture test. Basically the rupture test was a form of bend test.

From Making Shaping Treating of Steel,chapterXIII Steel and Iron castings pp556-559 6th edition (one I had in college):

"The modulus of rupture test involves putting a standard cast iron bar on supports 12,18, or 24 inches apart, then applying a specified load and noting the deflection, measured in inches, or loading until deflection occurs and then increasing load till specimen breaks.

MR = (2.546LS)/D^3 where MR equals modulus of rupture, L= length between supports in inches, S= breaking load and D = bar diameter.

Ordinary gray iron brinell hardness = 187/235 range, will take a transverse load of 1800 lbs and deflect .14-.16 inches." end quote.

The section you describe is so thin that you will be unable to achieve a slow cool also, cat litter or not.

Heres how they did it back in the day- again from making and shaping: "In order to malleableize castings by the 'black heart method" annealing cycle is 30 hours to heat to temperature, 45 hours holding and 30 to 35 hours to get cool to 650C then 5 hours to cool to handling temperature. the lengt of time is to get all combined carbon to graphite leaving iron as only ferrite." end quote

( the carbon is not seen as graphite platelets, instead its as blackspots (ie Black heart) in the metal matrix, though near surface it will be absent due to decarburization.

I expect you to get a nice fracture. Wear your PPE!

milo

I'm lucky enough to have a good Mom & Pop bakery nearby.
I also agree that most commercial bread is crap.

I'm betting your pans will break before bending.

Suggest 2 other options:

1) Find some food grade high temperature silicone and try to make a gasket
2) Buy a cast iron dutch oven (with lid) and use it inside your regular oven.

Alton Brown has a good bread making trick for dutch ovens.
http://www.foodnetwork.com/recipes/knead-not-sourdough-recipe/index.html

Good Luck!

I hope I'm not out of line for asking this and if so I appologize in advance. But, were these bread pans extreamly expensive or something like that? I'm just trying to figure out why you are so intent on altering and possibly breaking them in the process. Can't you just buy a couple more that don't have this decorative annoyance? Just curious. If not, I like the gasket idea.

No Bandit. About six bucks each but given the fact that I bought them on the net and the illustrations leave something to be desired and as well that I have the skills, why not make them work.

I won't break them because it is clear they won't bend. Grinding and brazing for which I have the skills and the tools will work.

I suspected I knew the answer about bending grey cast but asked the question anyway when I couldn't independently verify my suspicion on the net.

I could buy two more but run the same risk. Stocks of anything are limited here in Atlanta and if I could find such pans, and I have looked, a lot more money.

Sides which we have all gotten a little entertainment out of this.

j.

Hi Jack,

Have you considered grinding the offending handles off and bronze braze steel components in there place to suit whatever end result you need? If you make a large enough contact area where you braze to the pans it will be plenty strong enough.

I feel it was old Galilio who said it will still break.As you are a guy who likes his bread and hence you will not tolerate any migration of smels,or volatile additives in silicon rubbers.I wll hasitate to suggest,you are baking bread not burning it.Your temp will be such that wooden spacer may do well as carpentry is easier than foundry

Kuchroo,

You are absolutely right. Any gasket, including wood which would probably get hot enough for fractional distillation to start, will taint the product.

I had pretty much, without my little data gathering experiment, decided to do as Garth suggests, grind off enough metal with my $13 Northeast Tools angle grinder so that I get a fit, which should leave enough metal to braze on some additional material so as to drill and fit the lower intended pan with a pair of posts (Just plain old machine screws) so that the top pan, also brazed, will have a couple of holes to just drop into place and being heavy enough will not even require a fastener.

Ed, thanks for the heat treatment information. I thought there might be a process but obviously that process is way beyond my little kitchen oven, an electric which barely gets up to the 450 F. needed to properly do decent bread. That is the reason I wanted cast iron because as opposed to a couple of sheet steel stamped pans cast iron can be pre-heated although even the stamped pans produce a decent loaf of bread.

Milo,

Once upon a time I knew enough about steel mills and blast furnaces to be able to stand off a half a mile, on the outside of the fence, and be able to tell what they were doing.

What I knew was acquired at Brooklyn Tech where in the chem lab we were reducing iron oxide in a test tube (Pretty tough on the test tube) and at the same time in a wonderful course called Industrial Processes we were looking at film of steel mill operations among other things.

Now of course those dirty blast furnaces are gone and it is BOF where anything is left at all. No more Bessemers, no more open hearths.

I would have, still would, love to do a tour of a steel mill. There are some steel mill operations, including basic furnace, still going on West of here (Atlanta) in Indiana although I doubt anybody is going to give me a tour through such a dangerous operation as a steel mill.

I did recently, with my brother who has long experience in the printing industry as do I, do a tour of a paper mill here in Georgia. Just like the films but real and up close.

MJB,

I'll bet that mom and pop bakery is in N.Y. City sides which when you say NY without any other city designation that is usually what is meant. I too am an arrogant, in that way, New Yorker. Used to live on Norfolk Street, Lower East side, surrounded by bakeries, smoked fish, the Delancy Street market just around the corner, all those goodies.

You mentioned cast iron Dutch oven. That is why I got these cast bread pans. I want the regular slices from rectangular loafs rather than from round loaves. As well the cast pans, like the cast Dutch ovens, can be pre-heated, an exercise pretty meaningless with stamped pans..

Could it be that mom and pop produce bialys and god forbid bagels.

Could you be induced next time you are in there to see if they would be willing to provide the flour mix formulas for those products. I think I am getting there on my own but I am matching product to 45 - 50 year old memory.

I am not sure folks understand the very special product memories that New Yorkers who leave spend the rest of their years trying to match and/or replicate. Must have been the same for those people who left places like Bialistoker, Poland, and brought their memories with them to produce bialys in New York.

Any rate you all can see what this quest to bend grey cast iron is really all about, replicating those wonderful bread products I grew up with in New York.

Thanks for your help and suggestions. Grinding and brazing it will be.

j.

This is so obvious you might just be overlooking it. I guess you're talking about something like this:-

In which case: leave the bottom pan as it is and just grind the handles out of the top pan so that it fits snuggly.

Randall,

That is exactly the pans I have.

You are right. I didn't think of that solution.

But if you think about it that solution would require grinding even more metal out of the ears on one pan in a situation where just grinding both pans ears flush with the rest of the pan edge would likely leave little enough metal and might require adding some by brazing.

Thanks for the thought. I like being shown a solution I hadn't thought of even if it is not a workable one. I store the fact that I missed something which keeps me on my toes mentally for the next problem.

j.

If you grind only ONE handle off of each pan, they should fit together just fine. Would that work for you?

MJB,

It is true we don't all see the same way spatially so for a moment I did not understand what you are saying but after a moment I see you mean then to put the pans together with the remaining ears at opposite ends.

That would indeed bring the lips of the pans flush but eliminate a place for my alignment posts.

I would point out that these pans will be preheated to 450 F. before the dough is dropped into the lower one so ease and assurance against fumbling the handling of the upper pan is prudent.

Thanks for the suggestion. Another twist I had not thought of.

j.

If you totally remove the ears from one pan, so that the two will fit together (maybe put clearance notches in the top, now handle-less, pan), you can get the two to stay aligned by any of several methods. For example, four strips of strap iron can be attached to the outside edges of the top pan with machine screws and nuts, giving you a set of lips (yes, bending to fit closely is better, but more difficult). The top pan could get a handle bent from strap iron on what was once its bottom, in order to lift it off. Again, machine screws & nuts will attach, with no more tools than a drill with one bit, a hacksaw, and a file needed for the entire job. [a vise or C-clamp would be nice, too]. The bottom pan, with bread dough, would be unmodified.

Fancier would be to make a set of six-pronged "H" shapes, sort of like the International Harvester logo; bend two prongs up & one down on each side of the crossbar (which should be about as wide as the pan edges), and the results will slip over the edges and align the two pans. Need a closer fit? notch one pan to accept the H's crossbar.

Grinding off all four handles from two pans would let you add L-shaped strap iron handles, again with nuts & bolts (countersunk would be good, but this calls for another tool bit, and maybe a right-angle attachment for the drill to do well). These replacement handles can be below the lip, and can carry alignment features not readily added to the curved ones on the original pans.

Most of these concepts can be used on a mix-&-match basis.

Ron,

This started as a simple project so I could bake NY (Actually old European) style loaves of bread.

Nonetheless, the pans I ordered would not conform to my schemes because of quirks involving the shape of their ears.

Simple, just heat and bend their ears to get the needed clearance except the cautions inbred of the years I have worked in industrial maintenance set in.

Would grey cast Iron bend before breaking. My suspician was no and others have here agreed the molecular structure of the stuff would cause it to break before bending.

That's when we got into this other stuff.

Mix and match it is.

Cut off and grind flush the ears on one pan. Braise to the ends of the pan short rods. Slightly enlarge the center hole in the cast ears of the other pan so that the edge of the hole is tangent to the end of the pan and will thus line up with the rods brazed to the other pan.

Interesting how an uncooperative metal, but necessary to the process, got us into all the rest of this stuff.

Thanks all.

j.

Sounds good. Can you post a photo of the results (preferably including a loaf or two!)?

Ron,

I don't think anybody have yet figured out how to teleport bread-stuffs via email. If they had I wouldn't be screwing around baking my own. I would simply order up some good NY rye bread and some bialys, and perhaps some smoked salmon to go with the bialys.

j.