Casting

Oct 2, 2008
3,807
Pearson/ 530 Strafford, NH
Hi all, Anybody ever do any bronze casting or other metals? I was attempting to get into a class but sadly I’m on the waiting list.
 

dLj

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Mar 23, 2017
3,332
Belliure 41 Sailing back to the Chesapeake
Hi all, Anybody ever do any bronze casting or other metals? I was attempting to get into a class but sadly I’m on the waiting list.
Sure, done lots of castings. What are you wanting to do? Create your own little foundry and cast some product? Just get an understanding of the process?

There's a guy with a face book group that does some really interesting work on using a very old casting technique that you can set up on your backyard...

Luted Crucible Metal Casting

dj
 
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DArcy

.
Feb 11, 2017
1,687
Islander Freeport 36 Ottawa
Tom, from the heading I was trying to figure out if you were going fishing, looking for actors for a movie or making metal parts. I half expected it to be fishing since this is a boating forum but bronze parts is good too.

I have not cast any parts myself but I've designed lots of cast parts and been to several foundries. I'm guessing sand casting is what you are going for. There are a lot of different types: die casting, sand, investment, permanent mold, metal injection molding...

Sand casting is great if you are making only one or a few parts, can be good for slightly higher quantities as well. Also very well suited for bronze. I'm sure the courses will go over limitations in part geometry, pour speed, temperatures and all of that. Lots to think about but once you understand the process and have the tools it's fairly straight forward. I've 3D printed patterns for sand casting which was really quick and worked out very well.
 
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dLj

.
Mar 23, 2017
3,332
Belliure 41 Sailing back to the Chesapeake
I've 3D printed patterns for sand casting which was really quick and worked out very well.
This is all the "rage" in casting technology these days. With mold making costing in the 6 digits, 3D printing is providing some cost benefits.

Interestingly, the original lost wax method where you have few parts to cast can still be cost effective....

dj
 

DArcy

.
Feb 11, 2017
1,687
Islander Freeport 36 Ottawa
Interestingly, the original lost wax method where you have few parts to cast can still be cost effective....
I talked to one shop that 3D printed wax patterns for investment casting. They could make some very detailed parts using this technique. Sand casting tends to be cheaper for small quantities but you can't get the same level of detail as you can with investment casting. Of course, if you are doing the work yourself maybe there is no cost difference. I don't know the difference in cost between green sand and investment material. I found some casting printer filament that I could use in my printer if I wanted to try it. Sand casting seems a bit simpler.
 

DannyS

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May 27, 2004
927
Beneteau 393 Bayfield, Wi
Strange to find this discussion at this moment. I’m a fellow sailor and a metalsmith and I teach Metalsmithing at a college. I’m currently sitting on my boat preparing for a 5 day workshop on the casting process that begins today. I teach workshops on the summer and try to teach in places that are shoreside and within sailing distance of where I keep my boat. Lake Superior has several art centers and craft schools that I teach various metalworking processes from. This class happens to be my only workshop this summer and my first public post-Covid class. What types of things are you interested in casting?
 
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dLj

.
Mar 23, 2017
3,332
Belliure 41 Sailing back to the Chesapeake
Strange to find this discussion at this moment. I’m a fellow sailor and a metalsmith and I teach Metalsmithing at a college. I’m currently sitting on my boat preparing for a 5 day workshop on the casting process that begins today. I teach workshops on the summer and try to teach in places that are shoreside and within sailing distance of where I keep my boat. Lake Superior has several art centers and craft schools that I teach various metalworking processes from. This class happens to be my only workshop this summer and my first public post-Covid class. What types of things are you interested in casting?
Well I'll let @All U Get answer for himself as he started this thread. But for me - I'd be interested in learning how do you control quality on a small scale. I work within a large industrial scale and have at my disposal X-ray, ultrasound, penetrant inspection at as broad a scale as needed.

What has always stopped me from doing my own "backyard" castings for structural components has been this difficulty in evaluating the integrity of something I might cast at home. Not a problem for an esthetic piece, but for structural work? That has always put the breaks on for me. It's always seemed much easier, less expensive and more reliable to simply employ a commercial foundry. Now that being said, I have built my own molds and then given them to a foundry to cast the part.

How do you address this aspect in your courses?

dj
 
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Oct 2, 2008
3,807
Pearson/ 530 Strafford, NH
Sounds like new hobby!! This is a class on Bronze Casting for Boatbuilders - The process of patternmaking and casting custom hardware: Bronze Casting For Boatbuilders (thewoodenboatschool.com)
Sure, done lots of castings. What are you wanting to do? Create your own little foundry and cast some product? Just get an understanding of the process?

There's a guy with a face book group that does some really interesting work on using a very old casting technique that you can set up on your backyard...

Luted Crucible Metal Casting

dj
Tom, from the heading I was trying to figure out if you were going fishing, looking for actors for a movie or making metal parts. I half expected it to be fishing since this is a boating forum but bronze parts is good too.

I have not cast any parts myself but I've designed lots of cast parts and been to several foundries. I'm guessing sand casting is what you are going for. There are a lot of different types: die casting, sand, investment, permanent mold, metal injection molding...

Sand casting is great if you are making only one or a few parts, can be good for slightly higher quantities as well. Also very well suited for bronze. I'm sure the courses will go over limitations in part geometry, pour speed, temperatures and all of that. Lots to think about but once you understand the process and have the tools it's fairly straight forward. I've 3D printed patterns for sand casting which was really quick and worked out very well.
From this video it would seem that special footwear is necessary
I had visited the Wooden Boat School years ago and had a curiosity about learning some skills that would prove useful for our cruising lifestyle. I gave them a call to see if I could get into the class and was put on the waitlist. Meanwhile I have watched many U-tube videos of the green sand process and it peaked my interest. I also have an assortment of scrap metal bound for recycling or repurposing. The other interesting idea is using this talent for parts I need for repairs, especially when we’re far from home.

My wife seems to have the thought that I could make some articles for the garden similar to what we’ve seen at the botanical gardens during our travels. This may be her attempt to get me to drop anchor and keep me occupied.
 
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dLj

.
Mar 23, 2017
3,332
Belliure 41 Sailing back to the Chesapeake
I had visited the Wooden Boat School years ago and had a curiosity about learning some skills that would prove useful for our cruising lifestyle. I gave them a call to see if I could get into the class and was put on the waitlist. Meanwhile I have watched many U-tube videos of the green sand process and it peaked my interest. I also have an assortment of scrap metal bound for recycling or repurposing. The other interesting idea is using this talent for parts I need for repairs, especially when we’re far from home.

My wife seems to have the thought that I could make some articles for the garden similar to what we’ve seen at the botanical gardens during our travels. This may be her attempt to get me to drop anchor and keep me occupied.
Building your own parts that are aimed at structural fixtures, I'd suggest contracting a commercial foundry - see my note above.

If you want to make cool garden items, check out the luted crucible link I sent earlier.

Learning about all the various aspects of the casting process is fascinating, fun and could be very useful in evaluating a potential foundry if you are thinking to make structural parts. Learning how to make molds is quite an art. You can spend years enjoying just that aspect of castings.

In the foundry industry, mold making is a specialized area of expertise - the modern application of 3D printing into this area still requires a lot of expertise. But can really facilitate lowering mold costs.

For a hobby, I'd recommend the luted crucible technique. But I'd hesitate to use that for structural work.

dj
 

dLj

.
Mar 23, 2017
3,332
Belliure 41 Sailing back to the Chesapeake
I talked to one shop that 3D printed wax patterns for investment casting. They could make some very detailed parts using this technique. Sand casting tends to be cheaper for small quantities but you can't get the same level of detail as you can with investment casting. Of course, if you are doing the work yourself maybe there is no cost difference. I don't know the difference in cost between green sand and investment material. I found some casting printer filament that I could use in my printer if I wanted to try it. Sand casting seems a bit simpler.
Lost wax casting and investment casting are the same technology. Lost wax is a term that comes from a long time back, it was the original term for this technology. The term investment casting came along later. In both cases, you make a wax mold of the part you want to cast. You then encapsulate that wax in a mold material creating what's called a shell, then melt the wax out creating the cavity in the shape of the part you wish to form. Both the mold and the shell are destroyed in the process of performing the casting process.

Sand casting is done with typically a permanent mold that can be used over and over again. You pack sand around that mold, then remove it from the cope and drag (top and bottom parts of the mold - see the video @garymalmgren posted). In that video, you see the guy putting the mold in the two halves of the mold, then removing it and pouring in the molten metal into the cavity formed. This was a rather primitive mold, typically they are built onto a center piece that fits the top and bottom portions of the mold, aligning the cavity with the mold itself and the process of filling the sand around the two sides is much easier that way. Additionally it provides a better method of setting up the entire casting process. You need to get the liquid metal into the mold cavity, it needs to fill all portions of that mold, and the solidification of the metal must occur such that you don't get what's called shrink in different locations of the casting. This can be a bit tricky depending upon part geometry, casting temperature, alloy cast. In that video, you see the guy making that access by hand after both sides of the mold were built. That's a very inconsistent method.

The difference in cost between reusable sand used in sand castings, and the shell material used in investment casting is a very small part of the difference in costs between the two technologies. In sand castings, you reuse both the mold and the sand (until you can't, that's a long story), in investment casting your mold is used only once and the shell material is also destroyed. So yes, there is an added cost to investment casting due to this, but that is only one rather small part of the economic picture. It's really a question of all the steps in getting a finished product - that is very complex.

All the above said, the old lost wax process is actually quite economical, if you are only making one or two parts. It's when you start getting into producing many parts that the economic complications really arise. When you add in the structural requirements, well, it really snowballs...

The Luted Cruicible technique mentioned before is a lost wax method from thousands of years ago. You can set that process up in your backyard for very little money. Takes a lot of practice to make parts come out of it nicely, but hey, that's half the fun! It's currently used primarily in artistic application, as it should be...

dj
 
Oct 2, 2008
3,807
Pearson/ 530 Strafford, NH
Over the last decade we’ve broken various cabin articles, clothes hooks, clock bases, etc. so that along with a ship’s bell all would be good practice. Then gradually more technical works.

My wife would like this:

6181D30A-A9D2-4EAD-BF87-7B430D056DC1.jpeg

What I have so far is this:

88404B5D-F23F-4465-BA18-9A45767F9BB1.jpeg90F6E132-53C2-4736-800C-31150602354B.jpeg

:biggrin:
 

dLj

.
Mar 23, 2017
3,332
Belliure 41 Sailing back to the Chesapeake
Over the last decade we’ve broken various cabin articles, clothes hooks, clock bases, etc. so that along with a ship’s bell all would be good practice. Then gradually more technical works.

My wife would like this:

View attachment 196124

What I have so far is this:

View attachment 196125View attachment 196126

:biggrin:
That's what I call quite an ambitious first project...

You might want to try these folk:


dj

p.s. Just realized that was not going to be your first project but rather the list of small items - all excellent for the luted cruicible technique. When you're done with those, then you'll realize that archer would be better done in collaboration with a company like UAP.... (I have no vested interest in this company, just known about Dick Polich for many years)
 
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May 24, 2004
7,129
CC 30 South Florida
It came to me that today we have computer 3D printing. In my college years many moons ago I worked in the sand box at a foundry making cylinder heads for HD in Milwaukee and thought there has to be a better way of doing this. Still waiting, but it seems we can now print out a lot of small parts.
 

dLj

.
Mar 23, 2017
3,332
Belliure 41 Sailing back to the Chesapeake
It came to me that today we have computer 3D printing. In my college years many moons ago I worked in the sand box at a foundry making cylinder heads for HD in Milwaukee and thought there has to be a better way of doing this. Still waiting, but it seems we can now print out a lot of small parts.
As far as I am aware no one is doing 3D printing in cast iron which is what your head was made from. I doubt it could be economically competitive in that market.

Cast iron has a number of material properties that makes it a very good material for what an engine head needs to run well over a long time period. 3D printing is very cool technology but it will not displace all metal working technologies, certainly not within the foreseeable future in any case.

dj