Casting kit business?

[GreenTwin]

But what about castings from CNC or 3D printed patterns, do they have any soul? certainly can still have all the faults and problems you find on other castings. I'm enjoying machining some castings from my CNC cut patterns but equally happy to CNC cut parts from solid that you would be hard pushed to tell if they were cast or not once painted.

As I said on another forum where this is being discussed the Woodpecker kit used to sell for about $400. So lets be generous and say it would cost you $300 to have parts cast, print out drawings and all the other overheads that means you could make $100 gross profit. But at the asking price you would have to sell 240 kits to cover the capital outlay before you could say that $100 becomes net profit and that simply is not going to happen.

I don't think Doug even produced any castings from some of those patterns he bought up. For example the little VJ Monitor he go 3 or 4 kits worth of castings when he bought up the rights and that was all he sold, one of which I bought so he would not even be able to say what they sold like.

So is this an original engine, one from a set of castings or barstock?

I had a vague recollection of JasonB building this engine, but I could not really recall much about it.
But looking at the flywheels yesterday, I decided that obviously he had found some used flywheels off of an old engine.
The only way I can tell the rest is not cast is because I make castings, and so I always look for parting lines.
This engine really had me scratching my head though, and so I had to research it.

Not cast, but dang that finish looks right out of 1890, as do the flywheels.
The lettering on the side and overall look are indeed very deceiving, and if I did not make my own castings, I would not have suspected this engine was not cast, and old.
I have reached the conclusion that JasonB builds these pieces for the sole purpose of torturing the casting folks of the world.

Well done for sure.
.

 

[Jasonb]

Just different tools really and used for when they are best suited for a particular job. No castings in that engine, flywheels are iron but cut from solid slices off a bar, CNC cut frames, Silver soldered cylinder, welded base. As for parting line that's really just down to how much you want to fettle the castings, you won't see any on my engines built from castings

Back to the topic there is a very good post by Todd of Littlelocos over on MEM where the same is being discussed.
https://www.modelenginemaker.com/index.php/topic,10868.msg251565.html#msg251565

 

[AndrewW]

But what about castings from CNC or 3D printed patterns, do they have any soul? certainly can still have all the faults and problems you find on other castings. I'm enjoying machining some castings from my CNC cut patterns but equally happy to CNC cut parts from solid that you would be hard pushed to tell if they were cast or not once painted.

As I said on another forum where this is being discussed the Woodpecker kit used to sell for about $400. So lets be generous and say it would cost you $300 to have parts cast, print out drawings and all the other overheads that means you could make $100 gross profit. But at the asking price you would have to sell 240 kits to cover the capital outlay before you could say that $100 becomes net profit and that simply is not going to happen.

I don't think Doug even produced any castings from some of those patterns he bought up. For example the little VJ Monitor he go 3 or 4 kits worth of castings when he bought up the rights and that was all he sold, one of which I bought so he would not even be able to say what they sold like.

So is this an original engine, one from a set of castings or barstock?

Hi Jason. That embossed lettering adds a really nice touch. Very convincing.
Cheers Andrew

 

[Shopgeezer]

I watch the development of direct to metal 3D printers closely. I dream of the day when I can simply print out the castings without all the fuss and complexity of burning out plaster molds. I would gladly trade some soul for that convenience. Of course you would still have to machine them, source out springs and pins and bolts and washers and so on. It would be no fun at all to have a machine print out finished engines.

 

[dazz]

Hi
I am currently drawing plans to build a miniature engine that has a part I cannot produce in a realistic manner. It has internal details that are too complex and too small to use a core. My plan is to have this particular part 3D printed, but I expect it will be $$$.

This is a bit like the difference between injection molding and 3D printing plastic. It will always be cheaper to inject rather than print beyond a certain production quantity.

The ability to economically 3D print patterns for metal casting has significantly shifted (reduced) the time/effort/cost of producing castings compared to alternatives. Similarly, the ability to 3D print metal has already provided an option that is within reach of hobbyists. So I think as 3D metal printing goes from specialist to commodity, then it will be a more accessible and affordable option. It is entirely possible that a 3D metal printing machine will join the traditional tooling seen in hobbyist workshops. It will open new possibilities.

 

[William May]

Hi
I am currently drawing plans to build a miniature engine that has a part I cannot produce in a realistic manner. It has internal details that are too complex and too small to use a core. My plan is to have this particular part 3D printed, but I expect it will be $$$.

This is a bit like the difference between injection molding and 3D printing plastic. It will always be cheaper to inject rather than print beyond a certain production quantity.

The ability to economically 3D print patterns for metal casting has significantly shifted (reduced) the time/effort/cost of producing castings compared to alternatives. Similarly, the ability to 3D print metal has already provided an option that is within reach of hobbyists. So I think as 3D metal printing goes from specialist to commodity, then it will be a more accessible and affordable option. It is entirely possible that a 3D metal printing machine will join the traditional tooling seen in hobbyist workshops. It will open new possibilities.

Well, one thing you could try is modeling the part in 3D printing, then cast an outer shell with plaster in sections. Then take the plaster sections apart, reassemble them, and fill them with metal such as in a jeweler's lost wax casting. Many jet engine parts are made this way. It all depends on the complexity of the part, but you should keep in mind that you can always insert plaster cores for internal areas of detail, and then after casting, throw the casting in water and wash the cores right out, leaving you with a perfect molded part you can machine. With lost wax molding, you can get INCREDIBLE detail and interior features that would be virtually impossible any other way.

 

[dazz]

Well, one thing you could try is modeling the part in 3D printing, then cast an outer shell with plaster in sections.

That is what I plan to do with other parts.

With lost wax molding, you can get INCREDIBLE detail and interior features that would be virtually impossible any other way.

For the part I have in mind, just making the wax pattern would be a challenge. I don't know if I can get wax filament that will work with my Prusa printer. I am not setup for investment casting, and to do so would cost me too many $$$$.

I will look at all options to make the part.

 

[littlelocos]

Paul Jacobs, back in the 1980's produced several steam engine designs that were basically silver-soldered structurally., and then wiped with soft solder to round fillets and give a casting look. His designs are VERY pretty, and you could not tell they were not made from castings. So such a thing is possible. It's just a different kind of work you have to do.
Also, look at the engine designs for the a "NASH 25", by Doug Kelley It is all silver-soldered, and looks like it was cast.
'

Paul published one of them, "Scrapbox" in Live Steam. Another design, "The Green Mill Engine" was never published. I have the original design sketches, article manuscript, and prototype for the Green Mill Engine and have rendered it for release as a collaborative construction article. I also have the original, Scrapbox design and plan to release it as a casting and/or material kit sometime in the future.

Enjoy,
Todd.

 

[littlelocos]

I don't know if I can get wax filament that will work with my Prusa printer.

Here are two filaments to consider. I'm currently setting up for lost wax to do small detail parts for my engines. This is in addition to the oil-sand process we're currently set up for.

https://stacker3d.com/product/i-beam-blue-wax-pla-casting-filament-for-3d-printers-1-75mm-1kg/
https://us.polymaker.com/products/polycast
....and an interesting article: Investment casting

Enjoy,
Todd.

 

[GreenTwin]

Am I missing something? The "Green Mill Engine" is gold in color?
Perhaps it was built by a Mr. Green? Good luck with it. Very nice looking engine.

I have a sample from a "lost-PLA" casting process in iron, and I must say, the result is remarkable, with flawless quality.
The thin casting drills easily.

A filament like "PolyCast" or something similar is suppose to burn out more cleanly, but I must say, the sample I saw from the "lost-PLA" casting in iron is of superb quality.

Here is where I saw the lost PLA process, and I actually got one of these castings and was able to see it up close, and drill it.
This is the future of casting work in lieu of using wax, in my opinion, for a backyard person.

I have seen some lost-foam backyard work, but I am not that impressed with the quality.
The commercial foundries that do lost foam castings in iron use expanded poystyrene beads, which burns out cleanly when the metal is poured into the mold.
The backyard folks use hardware store foam, which does not seem to burn out cleanly.

The beauty of the lost-PLA method is that you don't have to make a permanent mold, such as what is required for either lost-wax, or for expanded polystyrene bead casting. You can make changes/revisions to the 3D model at any time, and then just 3D print the revised part, to be used with the lost-pla process.

Here is the lost-PLA video.



3D printed molds are also taking hold in industry, and the advantage of a 3D printed mold is the same as the lost-PLA method, ie: you can change the 3D model, and the changes are immediately reflected in the 3D printed molds, with no tooling changes.
The turn around time for a 3D printed mold is extremely fast.
You can send your 3D model to the foundry over the internet in the morning, and have a very complex gray iron casting sitting on your desk that afternoon. I am not aware of any other casting process that is this fast or flexible.

.

 

[abby]

"You can send your 3D model to the foundry over the internet in the morning, and have a very complex gray iron casting sitting on your desk that afternoon. I am not aware of any other casting process that is this fast or flexible."
I agree that wonderful things are happening through technology but I think there is a bit of wishful thinking in this statement.
Printing time for even small objects is quite slow and it is very unlikely that the printer is sitting there waiting for work . Commercial printers are very expensive and tend to have full work loads.
Ceramic shell moulds require several dips with a drying period between each , although I haven't had any ferrous castings done recently it used to take about a week from receipt of my wax patterns.
Dan.

 

[fltenwheeler]

I am building a CNW Mikado in 1.6 scale. I have used almost every technology used in casting to make my one of parts.
Tim Meyer

 

[GreenTwin]

"You can send your 3D model to the foundry over the internet in the morning, and have a very complex gray iron casting sitting on your desk that afternoon. I am not aware of any other casting process that is this fast or flexible."
I agree that wonderful things are happening through technology but I think there is a bit of wishful thinking in this statement.
Printing time for even small objects is quite slow and it is very unlikely that the printer is sitting there waiting for work . Commercial printers are very expensive and tend to have full work loads.
Ceramic shell moulds require several dips with a drying period between each , although I haven't had any ferrous castings done recently it used to take about a week from receipt of my wax patterns.
Dan.

I have not kept up with the 3D mold printing machines and speed, but I did read in a casting magazine that one company in the US was adding 3D mold printing capacity.
I would guess that a well connected company like Boeing could get a prototype part mold printed/cast in a day.
Us mortals would have to get in line.
Definitely not for mass production, but would be so very handy in prototype work.

Here is one video I found on 3D printing the sand molds.




The cool thing about 3D printing your sand molds is that there is no pattern required.




They call it "rapid prototype casting".




I don't have time to study these videos, but at some point I will look at them in greater detail.

 

[GreenTwin]

The larger printers appear to be able to print multiple molds or cores at once, which would save a lot of time.

 

[GreenTwin]

The lost foam castings seem to be a good way to mass produce products, but of course this method requires a permanent metal mold inside of which you expand the polystyrene beads.
So any changes to the design would require a tedious remanufacture of the molds.




Here is a good lost foam process video:

 

[GreenTwin]

The versatility of stacked 3D printed molds is pretty impressive.
Not for mass production, but nice for limited runs and prototype castings.

 

[GreenTwin]

It is quite an interesting technology.
I could see a one day turnaround on a cast part, assuming as Dan said that the 3D mold printing machine was not occupied.

 

[methuselah1]

No-one has pointed out that with just a little forward planning, a 3D printer can be left running overnight...

-Andrew UK

 

[GreenTwin]

I am not sure if the printed 3D sand molds will ever make it down to the hobby level (never say never though).

The 3D modeling and 3D printing have certainly made a big impact at the hobby level, and that is how I design all my engines now, and make the patterns for them.

I have not got into the lost wax/pla thing because I don't want to buy the ceramic slurry, and I don't want to go through the numerous sets including burnout etc.

I have had very good luck with resin-bound sand, which I discovered the art-iron crowd using to great advantage.
Here is a video that demonstrates how much post-molding work can be done to resin-bound sand (this is the same bound sand that I use).

I don't see many if any modeling folks using the resin-bound sand other than myself.
Not sure why, but then again I did discover it pretty much by accident (when attending an art-iron cupola pour a few years ago).

See 5:30 onward. Once the sand sets, you can drill it, saw it, cut it, sand it, cut runners, risers and sprues in it, etc.
Very versatile stuff.




Here is another good video showing what can be done with resin-bound sand.

 

[darwenguy]

Hi Greentwin, do you have any pics of the casting you make with the resin sand? Also what sort of resin do you use? Is it just typical two part epoxy? And can the sand be reused? Interesting to see different methods.

Ive seen some of the videos on youtube were they use molasis as a binder for molds, cores but that seams to need baking, i guess it would smell nice though.

I use petrobond myself and a 3d printer to make all my matchplates, i add all the runners and gates to the matchplate and that saves lots of time making the molds, although my 3d prints still tend to need at least 3 layers of sanding and painting to get to a nice smoothe finish. Here is some of my patterns and parts..


Luke.