Author Topic: Casting Gun Case Hooks Using Delft Clay  (Read 10530 times)

Offline smart dog

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Casting Gun Case Hooks Using Delft Clay
« on: May 16, 2009, 11:38:10 PM »
Hi Folks,
Some of you might be interested in how I cast a pair of gun case hooks using the Delft clay casting method.  The process is the same as sand casting but uses a fine clay to construct molds rather than sand.  I am building a case for my dueling pistols and needed hooks of a style used in the 1780-90's on English cases.  Peter Dyson (in England) sells them but I wanted to make hooks of my own design.  The Delft clay process worked perfectly for my needs.

The first step is to make the model of the hook. I carved mine from hard green carving wax supplied by Rio Grande Inc.

Simple tool are needed such as course files and carving knives. I drew a pattern on paper and then copied it twice on my printer.  One of the copies was printed as a mirror image because hooks were generally installed as mirrored pairs.


Once the hooks were carved and smoothed (using knives and a burnisher)I prepared the mold for the first casting.



The mold building requires the casting frame (made or supplied with the Delft casting kit), the clay, a straight edge for cleaning up the mold, a hammer for pounding the clay, and some awls for making the sprue holes and gas ports. You push some clay into the bottom half of the casting frame and pound it flat with the hammer.  Clean off the excess with the straight edge and then gently push the wax model into the clay.

Then you dust it with some talcum powder and brush the powder over the model.  Next place the upper half of the frame on the mold, carefully lining up the index notch.



Next fill the upper half with clay and pound it in.


Clean up the clay as before and carefully open the mold.

Gently remove the wax model and use an awl to cut a series of gas vents into the upper half of the mold. Push the awl through the clay to the surface to create holes for escaping gas.  Gas buildup can create back pressure that inhibits the flow of the molten metal.



The next step is to cut the hole for the entry of the metal (sprue hole).  The hole is shaped into a funnel using a carving knife. It connects to the back side of the hook mid way up the shank.


Now you are ready for pouring.  I used scrap brass that I cleaned with a dip in muriatic acid. I heated the metal with a high intensity torch using mapp gas.  You can used a gas welder (I do for bigger pieces requiring a lot of metal)burn out oven, or forge.


The molten metal is sprinkled with borax flux and the dross (scum) is removed with a graphite stirring rod. Finally, when well heated and liquid, I pour the metal into the funnel of the mold.


The mold is left to cool and then opend to remove the hook.


The thin layer of burnt clay is scraped away and the rest is put returned to my clay supply for reuse.



The sprue is cut off and the hook filed and sanded.



Here is the finished hook installed on the case.  The Phillip's head screw will be filed off and shaped into a rounded stud when permanently installed.


I am using a stud to anchor the hook although most hooks of this style were anchored with eye screws, not studs. I just don't like the appearance of the eye screws. Finally, here is my treasure trove of wax models I have made and cast for other guns and jewelry.



The Delft system works well for small projects up to small to medium sized side plates. Obviously, it is only used for nonferous metals. It is not expensive when used on a small scale.  The casting kit cost about $80 and can be used for a lot of castings. You need the heat source and borax and the means to make models.  Models can be wood, metal, wax, plastic etc, or you can copy an existing piece.  Anyway I hope you found this interesting and useful,

dave







« Last Edit: January 13, 2020, 09:55:54 PM by rich pierce »
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Offline Brian

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Re: Casting Gun Case Hooks Using Delft Clay
« Reply #1 on: May 17, 2009, 12:05:54 AM »
An excellent thread Dave.  Thank you for posting it.  Do you think this would work on something as large as a butt cap for a pistol?  Not the large style with "arms" that go up the side of the grip, but more like a heavy butt plate.  About the size of a silver dollar.

Also, where can you get this delft clay ..... or the casting kit you speak of?
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Offline sydney

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Re: Casting Gun Case Hooks Using Delft Clay
« Reply #2 on: May 17, 2009, 12:28:46 AM »
Nicely done--How about some pictures of the case you are building??
      Thanks for posting the pictures and information
                 Sydney

Offline 44-henry

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Re: Casting Gun Case Hooks Using Delft Clay
« Reply #3 on: May 17, 2009, 04:27:54 AM »
We use a very similar sand in our foundry at the university called Petrabond. The stuff is oil bonded and actually looks the same as what you are using and does allow for very good detail.

Have you tried using the investment casting process for your projects? I started using this process in our lab last semester for one of my classes and it would be perfect for the kind of parts you are doing; however, you would, of course, lose your wax models.


California Kid

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Re: Casting Gun Case Hooks Using Delft Clay
« Reply #4 on: May 17, 2009, 04:30:43 AM »
Did you get the kit from Rio Grande? That would be perfect for doing thumbpieces.

Offline Acer Saccharum

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Re: Casting Gun Case Hooks Using Delft Clay
« Reply #5 on: May 17, 2009, 05:00:34 PM »
Dave, love it. I just get so inspired when I see stuff like this. Now I can make all those little doo-dads, soldiers, pulls, christmas presents, etc. Cool beans! Thanks for making such a neat tutorial!

Tom
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Offline Ken G

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Re: Casting Gun Case Hooks Using Delft Clay
« Reply #6 on: May 17, 2009, 08:28:35 PM »
Dave,
Outstanding tutorial.  You made it look so simple even I'm thinking I could do that.   Thanks for sharing you experience and knowledge.!
Ken
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Offline smart dog

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Re: Casting Gun Case Hooks Using Delft Clay
« Reply #7 on: May 17, 2009, 08:37:29 PM »
Hi everyone,
Thank you for looking.  I hope it was helpful. Sydney, I am going to do a tutorial on pistol case building.  I will post it in 3 parts: 1) building the box, 2)internal lay out and installing the partitions, and 3) finishing the case and lining the interior.  The first part is almost ready for prime time. I will post pictures of the case then.  Brian, you could cast a small shallow buttplate (like the one on so-called "Hawken" pistols) but deeper cups would be difficult. It is hard to cast large objects because the mold cools quickly. When casting sideplates I heat the mold in my oven just before pouring to slow down the cooling.

California Kid, I bought the supplies from Rio Grande Inc. You can purchase from them online at www.riogrande.com. The kit includes 4lbs of clay, small casting frame, and an instructional CD and costs $86. You also need a crucible with handle, borax flux, and a heating source. I also made larger casting frames. If you make your own frames you can purchase the clay at $48 per 4lbs bag. Clearly, it is more expensive than sand but the clay holds detail much better than sand. The Delft method is perfect for thumbpieces and inlays.  It would be too expensive for buttplates and triggerguards.  Sand would be better for those although it is harder to retain details.  44-Henry, the Petrabond material sounds interesting.  I'll have to look into it.  I have supplies to do investment casting but I do not have a vacuum or swing arm to force the metal down into the mold.  I have to rely on gravity. That process takes much longer than the Delft clay and is not worth it unless I need to make a detailed piece that has hollows and undercuts (like a large fancy buttcap).  I have not had much success with simple gravity feed but am thinking of trying the "swing it around your head method".   
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Offline smart dog

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Re: Casting Gun Case Hooks Using Delft Clay
« Reply #8 on: May 17, 2009, 08:41:20 PM »
Thank you Ken,
It is simple and with a little practice anyone can do it.  It is the model carving that requires skill and wax is really, really easy to carve.  You could also just use an object you already have (like a favorite inlay) and simply use it as the model. The key is to understand the limits of the method and stay within them.

dave
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Offline smart dog

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Re: Casting Gun Case Hooks Using Delft Clay
« Reply #9 on: May 18, 2009, 02:33:16 AM »
Hi Folks,
I added one more photo showing the case handle I just cast.  I used a home made casting frame (of wood) and a gas welder to heat the metal.  It came out well. Note the wax model.  To add thickness where the hinge pins will go I simply attached a half round piece of wax with melted wax.  Modeling made easy.

dave

« Last Edit: January 13, 2020, 09:56:38 PM by rich pierce »
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Offline Brian Jordan

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Re: Casting Gun Case Hooks Using Delft Clay
« Reply #10 on: May 18, 2009, 02:01:28 PM »
Great Tutorial!! Very informative!!
Formerly known as Melsdad

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