Jump to content
rtropp

casting metal parts including cannon

Recommended Posts

 White metal castings do not need a centrifugal casting machine nor does brass or iron. Metal has been cast for century's before that machine came along. Sand Molds or many other types of material can be used as long as the material holds it shape and withstands the heat of the pore. You can even get a casting, if you are tough enough, by using your hand as a mold and pore into it, Like many molds that, hand mold would be for  one time use only and the quality of that casting would  probably not duplicate faithfully  the shape of the mold at the beginning of the pore. . ;)

jud

Edited by jud
Walton likes this

Share this post


Link to post
Share on other sites

Jud,

 

Please note that I said white metal is typically cast on centrifugal spin machines- of course there are many other ways, including using high temp RTV molds and hand casting .....

 

Joe

Share this post


Link to post
Share on other sites

Sorry not my parts so I can't share any secrets about them (as I didn't make them) except to say that they were done in RTV molds and are destined to be pieces in a kit.  A friend shared the photo of the initial run of parts. 

However, I can say with certainty that this quality of parts is able to be done in pewter and RTV molds as I have others on hand cast by another fiend that are just as good. 

Kurt

WackoWolf likes this

Share this post


Link to post
Share on other sites

Please let us know here when the tutorial is posted.

 

Bob

 

Hi All,

 

Just a quick update.....

 

I have the resin casting article written up. I do not yet have photos edited into the article. I hope to have that done by mid-March. Work has me tied up right now, and then I will be on vacation the first week of March, so it will have to wait until I return.

 

Chuck has previewed the text and given it a "Thumb's Up", so I think (hope) you all will enjoy it.

 

-Joe

gjdale, WackoWolf and mtaylor like this

Share this post


Link to post
Share on other sites

If you live by or visit the foreshore you can often obtain cuttlefish bone (the white skeleton).  Cuttlefish bone is quite soft and will retain the shape of objects pressed into it (after preparation). This means by taking two piece and sandwiching the object to be cast and pressing them together until they meet an impression can be made suitable for casting. Cuttlefish casting has been traced back to the Saxons and Viking and is still used today to make pewter and silver jewellery. Although cuttlefish bone seems fragile it can withstand the heat of casting silver. Casting silver it is used once but for pewter or white metal the Mold may be used many times. Instructions are available on the web by typing in cuttlefish casting into Google.

Edited by Bev
janos and mtaylor like this

Share this post


Link to post
Share on other sites

I haven't read through this conversation as I'm pretty busy so please forgive me for missing any info. I cast  model parts in brass. I've just completed another very intricate all brass model for a model RR company. I will have photos in a few days. If you want to see them let me know.

I have a long background in different types of mold making and casting.

 

I'm not sure if it's appropriate to market ones abilities for sale on the site. I do have a website and you can reach me in a personal message.

 

Von Stetina

Share this post


Link to post
Share on other sites

Looking forward to those photos. If you cast brass, you probably have the heat to cast iron, maybe you could expand a bit on what you use for heat and where you get your flasks. What fuel do you use in you cupola?  :rolleyes:

jud

Share this post


Link to post
Share on other sites
On 2/11/2014 at 8:24 AM, JPZ66 said:

Jud,

 

Please note that I said white metal is typically cast on centrifugal spin machines- of course there are many other ways, including using high temp RTV molds and hand casting .....

 

Joe

Not sure if you are speaking of production or general home hobbyist there.

A centrifuge tends to be overkill for general white metal casting for the home hobbyist and for mass production not cost effective for the small operator if that operator is trying to produce multiple copies of the same piece in a timely manner.   

Rather than a centrifuge, a diecasting methodology would be used in commercial application or other forced/pressure system with metal molds.
This allows high detail with efficiency of mass production.

However, Centrifuges are very handy for one-off  and lost wax casting and we see it used especially in the art world of jewelry making.
We also see them used in things like small run figurine casting (popular with the dungeons & dragons lot) - the cost of larger centrifugal casting machines capable of multiple part castings are in the thousands of dollars and not something the home hobbyist would most likely have a budget for.

 

But, the question always comes down to cost of machine vs. production run requirements.



So, "typical" is quite relative.

For the home hobbyist - RTV with free pour or simply using artist quality plaster of Paris as the molding compound is the more "typical" casting set up for white metals - especially pewter.
 

Please see the expose in the postings by Neptune in this thread.  This is the typical way that hobbyists have poured white metal castings over the past 100 years. It also is the far less expensive way to get into casting with very good results possible.

You also will find the system is still used even in commercial production today.

 


-Walton

mtaylor and Canute like this

Share this post


Link to post
Share on other sites

I'll just mention (again) another alternative... if you just have to have brass or bronze, and you'd like to just order parts and have them delivered, it can be done via houses like Shapeways and iMaterialise. These places will take your CAD model, print the part in wax, and pass it on to an investment casting house. Not cheap, but not impossibly expensive either.

 

Some examples:

Pair of deck mounted fire monitors... I had the yokes cast. 2nd pic shows the as-delivered surface finish, an artifact of the 3D printer resolution... be prepared to polish your parts.

 

594d4be395dc1_a7102218-27-20140125_1333041.jpg.fbb9217841e643699c72c3e536bdf2ba.jpg

594d4bf88908a_a7102219-56-20140121_2150551.jpg.ba792fb7a632d25a5996ba51d0189c1f.jpg

 

A passel of Herreshoff style cleats I made, polished, and home-nickel plated:

594d4c12c75cc_a7288704-116-a20141115_1107541.jpg.1be5031a6076cb7b19aeb51f2215ac20.jpg

 

A flag staff socket, polished and true chrome plated at iMaterialise:

 

594d4c2c3b2f1_a10071329-149-20170526_1822191.jpg.88f74fc1adbbaa033c1cc97ede652abc.jpg

 

A deck vent, rough, and then (roughly) polished and home nickel plated:

 

594d4c4caf9ea_a6860197-204-a6859180-78-a20140617_1710401.jpg.83c4f023b56eaff947c321f4eea71eaa.jpg

594d4c5bcc7ab_a6860195-27-a6859183-13-b20140617_2035531.jpg.3387fe39e672b0421974f912b5cdad2b.jpg

 

Share this post


Link to post
Share on other sites

If you wish to cast anything visit and explore this site. I have used their product 320 resin for pressure casting 1/16 engine parts. As with anything you need the correct materials and tools and most of all a good master. RTV silicone can pick up a fingerprint in a mold. Also printed master parts will have the stepped texture that will require finishing versus metal masters that will have a smooth finish.

https://www.smooth-on.com/tutorials/

 

 

The parts below were pressure pot cast with the 320 resin hand poured into silicone molds. The US penny will give you a sense of scale.

594d5bc428e63_DVIICastEngineParts.thumb.jpg.1b4920ba00542c0dd0f01d62b70caf94.jpg

 

594d5bfd8f8e5_CastEngineParts.thumb.jpg.f6e76db88cbcaf69b74dbd31decaa690.jpg

 

594d5c5e91654_DVIIEngineCastParts.jpg.67e4c4f82002caee30407169b0b7d584.jpg

 

 

Share this post


Link to post
Share on other sites
22 hours ago, Walton said:

Not sure if you are speaking of production or general home hobbyist there.

A centrifuge tends to be overkill for general white metal casting for the home hobbyist and for mass production not cost effective for the small operator if that operator is trying to produce multiple copies of the same piece in a timely manner.   

Rather than a centrifuge, a diecasting methodology would be used in commercial application or other forced/pressure system with metal molds.
This allows high detail with efficiency of mass production.

However, Centrifuges are very handy for one-off  and lost wax casting and we see it used especially in the art world of jewelry making.
We also see them used in things like small run figurine casting (popular with the dungeons & dragons lot) - the cost of larger centrifugal casting machines capable of multiple part castings are in the thousands of dollars and not something the home hobbyist would most likely have a budget for.

 

But, the question always comes down to cost of machine vs. production run requirements.



So, "typical" is quite relative.

For the home hobbyist - RTV with free pour or simply using artist quality plaster of Paris as the molding compound is the more "typical" casting set up for white metals - especially pewter.
 

Please see the expose in the postings by Neptune in this thread.  This is the typical way that hobbyists have poured white metal castings over the past 100 years. It also is the far less expensive way to get into casting with very good results possible.

You also will find the system is still used even in commercial production today.

 


-Walton

Walton,

 

I am talking about a Centrifugal casting machine that spins a 9" or 12" circular mold....it is absolutely designed for production work. No, it is not for the typical "home hobbyist". It is THE way to cast pewter for production of small model parts. This not the "broken arm" type centrifuge. 

 

When I was casting small model ship parts, say, 20mm deck guns in 1/350 scale, I could easily get 100 parts per spin in a 9" mold. A spin cycle takes about 2-3 min.

 

My spin casting machine sits right next to a melting furnace crucible pot that holds 150 lbs of pewter. I have other equipment for investment casting. 

 

Joe

Canute, mtaylor, jud and 1 other like this

Share this post


Link to post
Share on other sites
Posted (edited)

I have a lot of experience in investment casting,  the end result is only as good as the mold you want to reproduce in metal.  So here the important part is preparing and making molds.

 

The molds made by xken above really look magnificent.

 

Instead of brass, I like Alpaka, or in the US it's called new German silver, a brass and copper mix.  A kilo costs around $50, which would make for a lot of cannons.

 

Here a 1/25 scale Diesel motor for a Peterbilt truck model I did 2 years ago.  The motor has a lot of individual cast parts, this pic shows the finished assembly.  The silver looking metal is cast nickel, the pale gold is German silver;

 

29968432hi.jpg

 

A ship with a deck full of metal cannons would have considerable weight!

 

The method used by Watson above, would be the way to go for a large number of objects.

 

 

Edited by Mickgee

Share this post


Link to post
Share on other sites
Posted (edited)

Guys, if you don't mind, Richard asked for links concerning casting parts in brass in his original post, the theme of this topic.

 

I've been doing this stuff for some 45 years.  I don't have a link, but from former modeling forum builds I have some pics showing the casting procedure as I know it.  The parts here are for a 1:25 scale car or truck model.  My models are fabricated entirely from metal, excepting the resin or plastic bodies.  Further on I'll show a few pics, the results are truly astounding, very real looking, and real metal motors just look, well real.

 

Here the step by step procedure for investment casting of small parts using the lost wax technique.

 

This is a rear axle housing for a model Peterbilt truck in plastic, as in the kit;

 

-IMG_0199.jpg.fd114746696d957544ee7372b2341b3c.jpg

 

 

The parts have 4mm sprue leads waxed onto the housings.  A Bunsen burner and specific waxes are used to connect the sprue leads.  When heated up, the wax will melt and a tunnel remains where the molten metal will be thrown into with centrifugal force;

 

-IMG_0200.jpg.71f0ce3ca3c032896e10ab818cfc8b61.jpg

 

-IMG_0202.jpg.19afe703c2e8080ce20b737d8caa21c5.jpg

 

The thinner blue leads are for ventilation.   It's hot in there, lots of metal coming in, the voids have to be evacuated to make a safe place for the molten metal.  Another view.  Realize, the axle housing has the front and back already fused together.  Inside is hollow, but it's imperative the liquid investment material can flow into the very last crook and cranny, inside the housing.  If not, a void exists, and this void becomes after the casting procedure a big clump of solid metal!  Not good, and can usually be filed under "failure".

 

-IMG_0204.jpg.b8f6692844d33c78c1759d73eddf4561.jpg

 

Next a ring will be placed around this so that investment material can be poured in.  The investment is a powder and liquid mass that flows readily from a rubber bowl, just dump it in;

 

-IMG_0207.jpg.8e021551d79f441bb1445ff6716cde60.jpg

 

Side view;

 

-IMG_0208.jpg.1920f22eaee1005d75f90f631fff78c1.jpg

 

Here the investment is set, in this case 20 minutes, then pushed out of the ring former.  You can see the small 1.5mm vents at the base.  These are very important, and help to guarantee a high quality and dense metal casting result;

 

-IMG_0209.jpg.12f3c22c831c3cfe363c84b92604e1bb.jpg

 

The funnel shaped hole is where the crucible is slid into place when the form is heated up.  More brass, nickel, alpaka and chrome/cobalt (a steel) the form is glowing red hot.  Same temps approximately for gold, silver and similar metals.  Here a funnel to feed the metal, in this case alpaka, or German silver (very similar to brass);

 

-IMG_0212.jpg.e653a68de3790c79edc9fe20cfd8f29f.jpg

 

A wonderful metal for hobby use.  It does not tarnish when cast, and is hard but still malleable for polishing and working with normal hobby rotating instruments and burs.

 

Here the investment mold in the oven, or kiln as ceramic folks say.  The crucible has to be heated up as well or it will burst when heat from a torch to melt the metal for casting is applied;

 

-IMG_0218.jpg.4bbd4f6af1dd4336ef147e30f02ce626.jpg

 

Here a "broken arm" casting machine, a centrifugal forced method to cast molten metals, with a torch for propane/oxygen gas mix.  Cool enough for lesser metals, hot enough for steels, adjustable;

 

-IMG_0222.jpg.d16407d8a2b04b94712b2508ccf947ef.jpg

 

Ready to go.  The crucible is in the cradle, the metal pellets have been added, investment mold is situated and affixed, the heat is on;

 

-IMG_0233.jpg.8efa362d8367aa90be05bd91828f943a.jpg

 

Done.  The broken arm spins like crazy and throws the molten metal into the mold.  The mols id pulled from the cradle with long pliers and laid away to cool down for about an hour;

 

-IMG_0229.jpg.0b41128276d1a93aaae6e264388aa00f.jpg

 

 

 

-IMG_0231.jpg

 

To be continued;

Edited by Mickgee
druxey and mtaylor like this

Share this post


Link to post
Share on other sites

The cooled down mold is now broken open.  The investment is fairly soft.  Lets have a look to see if everything cast out properly;

 

-IMG_0242.jpg.a01115ef86d44c7f10b0ccdc5971ac26.jpg

 

The mass is just pinched off, then it's best to sandblast the remaining material away.  The dust is quartz and dangerous, do not breathe in.  I have a suction cabinet;

 

-IMG_0246.jpg.3400186b1489663307d672362e60b732.jpg

 

Getting there;

 

-IMG_0255.jpg.20f3e69c6a876af87243315f91a10e37.jpg

 

Great!  No voids, no unwanted clumps of metal.  Let's get moving;

 

-IMG_0256.jpg.41dba16185fadb57e3aa351a59d02908.jpg

 

A high speed handpiece with lots of torque, and a mounted separating disc, cuts off the sprue leads to get the individual parts for finishing;

-IMG_0257.jpg.4d762af2ba063f38ad64dbad2f083161.jpg

 

Here the parts finished and ready for further assembly;

 

-IMG_0268.jpg.7cedd9dd5ce3f6c7bc9f9fd5144456de.jpg

 

The finished product upside down, and it looks pretty good;

 

-IMG_0793.jpg.fe33e30368731fa96979df57d1fcd334.jpg

 

This is meant to be an insight for casting metals using investment for high heat metals.  Not a thing for the regular modeler for sure.  Just with some preparation and a little practice and guidance, an ambitioned modeler could do the prep work and give the mold to a jeweler or dental type acquaintance.  This stuff happens a lot, no problems.

 

I hope Richard you don't mind me posting this sequence.

 

Michael

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

mtaylor, BANYAN, druxey and 3 others like this

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×