porcelain casting for dendritic steel

Dan Gray · Jul 19, 2005

finally I got my 4 gals of porcelain slip the other day

lets make some dendritic steel haha

I'm going to mess with using it for casting other things too
in lost wax casting..

I know David Boye has his done by a custom foundry now..

have any of you tried it or have info on it..lets talk about it..

Terry_Dodson · Jul 19, 2005

Dan, what is "dendritic steel"? I just got a 25 lb block of porcelin clay the other day to clay coat blades with. I found out it has to be DRY before putting it in the forge

pop, pop, pop, pop, etc

i redid it, i put some wire around the blade, then put the clay on 1/4" thick, and dried it in the toaster oven at 200 degrees for about an hour, filled the cracks, then dried in the oven a couple hours in the oven at 200 degrees, then upped it to 350 degrees for another hour, then in the forge, seemed to work pretty good that way, after a quick ferric etch the line followed real close.

Dan Gray · Jul 19, 2005

Terry_Dodson said:
Dan, what is "dendritic steel"? I just got a 25 lb block of porcelin clay the other day to clay coat blades with. I found out it has to be DRY before putting it in the forge pop, pop, pop, pop, etc
i redid it, i put some wire around the blade, then put the clay on 1/4" thick, and dried it in the toaster oven at 200 degrees for about an hour, filled the cracks, then dried in the oven a couple hours in the oven at 200 degrees, then upped it to 350 degrees for another hour, then in the forge, seemed to work pretty good that way, after a quick ferric etch the line followed real close.

Hi Terry that's not the same as the slip..
this is from Francine's site
http://www.francineetchings.com/dendritic-steel.htm

Dendritic Steel is a term first used by knifemaker David Boye to describe the cast 440c stainless steel he developed in 1981. This revolutionary blade technology has proven superior to most other cutlery alloys in both edge holding capability and ease of sharpening. The process used to produce it, investment casting, transforms the original steel into one infused with microscopic crystals which create tiny serrations along the blade edge. These micro-serrations enable the blade to stay sharp from 10 to 50 times longer than a conventional blade. It also has a better "bite" (the ability to grip and cut into slippery objects --a tomato, for example) than conventional steel blades. It cuts like a razor blade by microscopically sawing the object, thereby achieving a finer and faster cut.

Boye's innovation was the first application of investment casting in modern times. Over the years Boye Dendritic Steel knives have been put through "torture tests" by Boye himself, as well as several knife periodicals, and the knives have always stood up to whatever stress they had to endure. For over 20 years Dendritic Steel has proven itself to be superior to most other varieties of blade steel in edge holding as well as sharpness.

Dendritic Steel also looks different from other types of steel when it is etched. Etching causes the chrome carbide crystals to appear on the surface of the steel, and this reveals each blade's uniquely crystallized pattern. Blades etched with designs have a distinctive multi-textured look to them--a smooth, shiny foreground, with a dramatic crystaline frosted patina in the background. It was these fern-like crystal patterns that inspired the name "Dendritic" (Greek for "fern-like").

it's cast knife steel named so by David..

you make a wax model of what you want..
dip it in the slip and let the layer dry then keep dipping it again and again
then once the coats are thick enough you bake it at cone 6 in the oven
(I'd heat it up side down at a lower temp first to melt the wax out first)
once it's set it will be a mold for the molten metal, once the metal is poured and solidified (still hot) you quench it, this will brake the mold.

hocus pocus with the magic wand,, you have a knife with very little grinding needed, with guard, bolsters or what ever you fancy..

butcher_block · Jul 19, 2005

is it true porcelin or stoneware there are a few different kinds of clay
i used to be a potter and still have some clay around

Terry_Dodson · Jul 19, 2005

What i got was a light gray color clay, and they guranteed me it was porcelin. isnt slip just the clay watered down? So all i have to do is make a modl, then melt some steel and pour in it? What kinda steel?

Ed Schempp · Jul 19, 2005

Most high alloy steels when slow cooled from the molten stage grow a fernlike platial carbide crystals. I believe industry considers this a problem. If the piece is cast to shape the crystaline structure is parallel to the surface; a factor of cooling. This is not a bad crystaline formation for edges. This is the same reason that factories were limited to the amount of vanadium in the alloy. If the alloy content exceeded 1.5 % Vanadium they could not keep this dendritic growth from happening. This is a very directional material. You might try resmelting some CPM Vanadium steels from Crucible; they should all be very prone to this process. This material is not very ductile; these blades are for cutting, never prying. David's original product was 440 C, it formed Chrome carbides. I believe he is using a cobalt alloy that he achieves the dendritic effect with other alloys with higher carbide hardness. S30V or 3V austenize below 2000 degrees F and would be good to experiment. If you get this process figured out with high Vanadium steel; I want some...Take Care...Ed

Dan Gray · Jul 21, 2005

Terry I don't dought you have porcelain,
it just has to be thin as far as I know so far.

it goes on in thin coats and sets until each coat is dry
I'm told it can take weeks to get a shell thin enouph to fire, remember
if you heat it to dry it to high the wax will melt..I'll bet a food dehydrater would work to make it faster, I think the thin sets,( sets, as in each time it's coated) may keep it from forming cracks.?

Ed, Thanks a bunch for that information, it's stuff I'm looking for.

I just happen to have some S30V

THanks to Mike F

without me looking it up, do you happen to know the melting temp of S30V?

I really want to see if I can get this going in 154CM..
and do fine casting in brass N/S and what have you for fixtures.

and play with some of the 5160 too..I know it won't be the same but I'm looking at the molding..

butcher_block · Jul 21, 2005

btw you do have to make for sure the clay is dry
since your dipping the form in slip you shouldnt hav eto worry about air in the mold
air pockets + kiln heat = pop or boom

Terry_Dodson · Jul 21, 2005

Didn't Bruce Evans do some fancy castings a while back, like horse's heads or something like that? Maybe he has some helpful info?

Dan Gray · Jul 21, 2005

butcher_block said:
btw you do have to make for sure the clay is dry
since your dipping the form in slip you shouldnt hav eto worry about air in the mold
air pockets + kiln heat = pop or boom

I agree
it's two different methods altogether..
as I see it..

casting, as in reg ceramics,
I'm told, the form or plaster mold (for lack of the right name for it right now)
pulls the water out faster than the air will for the initial set, then fire it after some time air drying?.

were talking now about
clay work.
plaster casting molds
and dip lost wax molding

dip molding for lost wax molding is what were talking about here it can't be confused with the others.....

the dry time is helped by the thin layers
because you don't have the benefit of plaster sucking the water out here.

Dan Gray · Jul 21, 2005

Terry_Dodson said:
Didn't Bruce Evans do some fancy castings a while back, like horse's heads or something like that? Maybe he has some helpful info?

I think Bruce used investment plaster or similar?
this stuff stands more heat I think and will be almost a finish product when done, no voids to mess with.

mete · Jul 21, 2005

Butcher block , investment casting refractory is permeable to air an you don't have to worry about air causing problems [you don't normally need risers for venting.].Sand is added to the clay to make it permeable. It's the moisture in casting that really causes serious problems. Depending on the material you need to thoroughly dry it at least and perhaps bake it and preheat also.For safety - NO moisture !! Learn all about it at www.investmentcasting.org

butcher_block · Jul 21, 2005

mete said:
Butcher block , investment casting refractory is permeable to air an you don't have to worry about air causing problems [you don't normally need risers for venting.].Sand is added to the clay to make it permeable. It's the moisture in casting that really causes serious problems. Depending on the material you need to thoroughly dry it at least and perhaps bake it and preheat also.For safety - NO moisture !! Learn all about it at www.investmentcasting.org

thanks for the link i wasnt sure what all transferd
i just know that we used to do 2 firings and yes i have had some projects blow up on me

the parents did slip mold forming and i did the hand molding and potters wheel for a few years

the possum · Jul 21, 2005

Well, I can't comment on casting steel, but since non ferrous stuff was brought up I thought I'd mention a few things.

From the way you're describing this dipping process, it sounds like regular investment casting would be much easier. (for non ferrous metals) You just mix up the investment and pour it around the wax model all at once. Bubbles are taken care of by spraying the wax model with anti-bubble stuff, (I forget the name) and by vacuuming the mold full of wet investment. Bubbles shouldn't give you much trouble with simple shapes, like a simple guard, but you may have to vent it. The stuff I've used is fine enough to cast fingerprints you left in the wax.

How do you plan on getting the metal into the mold? Do you have a centrifugal casting setup, or do you intend to just pour molten metal from a crucible into the mold? If you're just pouring it, you're really opening yourself up for disappointment, but may have success. There are a couple other low tech methods to improve your odds if you don't want to bother with all the equipment.

One more tip-
My metalsmithing teachers were excellent craftsmen. I've seen 3 of them on TV, on the history or learning channel. But I remember when it came to the casting part of the course, our teacher said he never does his own anymore. It's more reliable to just have it done professionally. (I think I still have the list of recommended casters somewhere.) If you just want to do this for your own satisfaction, and you're not spending much time on the wax model, I say go for it. But you don't want something to go wrong after you've spent 20 hours intricately carving a piece of wax.