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Help with a Dirk


Joshua States
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Every failure is a learning opportunity. Today I learned that I need some additonal lathe tools. I was using something too large for the job and it caught the handle.

 

OOPS (1).jpg

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“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

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Third time is the charm they say. A nice piece of Bubinga.

 

3rd time (2).jpg

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“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

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Today I played around with the idea of casting a bronze pommel cap. I made a little wax carving 

 

Castings (2).jpg

 

I finally got to use one of those casting flasks I made .... like 2 years ago?

 

Castings (3).jpg

 

The first pour didn't have enough bronze and I only got half the cap. The second try came out OK I guess.

 

Castings (8).jpg

 

I'll spend some time turning it to round and cleaning it up a bit.

Edited by Joshua States
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“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

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1 hour ago, Alan Longmire said:

Good detail.  Is that just a gravity pour in Delft clay?

Yes it is.

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“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

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3 hours ago, Alan Longmire said:

As if I have time or room,

The benefit to sand casting is the relative lack of equipment when compared to investment casting. I often think it's called "investment casting" because it takes a sizeable investment to purchase the equipment......

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“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

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I had another go at it using a different wax model. Not quite there, but getting closer.

 

Second casting 1.jpg

 

Before cleaning.

 

Second casting 2.jpg

 

Apart from the annoying voids around the center hole area, the outside border frills are not going to work. It is amazing how closely this method copies every detail, including the sloppy shite. I'll need to carve another wax model.

 

Second casting 3.jpg

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

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That looks good already and like a lot of fun.

I love delft clay casting, it is so quick to do and still can give great results, even showing my fingerprints;)

 

If I were you I would try and cast a shape like this from the back, with a larger diameter sprue.

This way you don't have to blend in the sprue in a visible spot, and the metal will fill the mold more evenly.

Do you have channels for the air to escape? a few tiny channels on the lowest point might help prevent those bubbles in the surface.

 

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Posted (edited)

Good questions and comments. Stuff to think about, especially for anyone thinking of getting into casting. Methinks Pieter has a lot more experience with this than I do. I did try casting it from the backside, but ran into a problem. The center of the model is thinner than the edges. This led to an incomplete pour no matter where I put the sprue. I either lost the center section or part of the perimeter. So here is what I ended up doing.

 

Sprus & Vents.jpg

 

The diameter of the model is about 1/8" (~3mm) larger than the wood handle at that end. I was planning on turning it down on the metal lathe and wasn't so concerned with the clean up on the edge. I did offset the sprue toward the backside though, thinking I could file it off and turn it flat later.  I put two vents at the top so that the air would escape and the form would fill. (I had a problem with the sprue hole filling before the rest of the mold) Maybe I will try a vent or two at the bottom and center on the next one, and a larger diameter sprue. Thanks for the tips!

Edited by Joshua States

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

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So I made a third wax model, and set about trying to cast it again. After getting some pointers from @Pieter-Paul Derks and someone I didn't know on IG, i managed to make something I think will work. The IG thing was an interesting event. I tagged my last attempt with #sandcasting. It had a few thousand posts and I figured, why not? Well this guy called Heinrichsmade gave me some pointers and a link to his YT channel and a video he did. Good stuff, and we now follow each other.

Networking on the 'Net I guess.

 

Anyway, a bigger pouring sprue thingy and proper placement seems to have done the trick. It still needs some clean up, turning on the lathe, and some decorative texture.

 

Final pour (1).jpg

 

Final pour (2).jpg

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“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

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I'm a bit late, but here is a type of rigging system I would recommend.  Super quick and dirty.  The runner is tapered, and should be radiused where possible.  The taller the sprue, the more head pressure to fill nooks and crannies (but too much will start to penetrate the sand making a fuzzy part).  Of course, a central sprue can then act as a riser/feeder, especially if you put a few arms radiating out toward the edges, but that is more clean-up.  Here the parting line is either the middle of the disk, or the back of it.  either way, a scratched vent at the end of the disk opposite the sprue will be a good vent.  Even better would be essentially a second sprue.  

image.png

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I am always glad to help! Your casting is looking a lot better, certainly usable.

Most of the delft clay casting I've done was jewelry in precious metal, so a bit different than casting a much heavier pommel cap.

When casting a few grams of silver the most important part is to get it to fill the mould as quickly as possible because the metal with solidify in an instant.

 

Like Jerrod above me, my advise for the next one would be to make the transition between sprue and part more ''fluid'' by scraping away a bit of sand from the mould.

 

 

 

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The IG guy also suggested a horizontal pour and a set up much like what Jerrod posted. I was a little dubious of the sprue placement as the mold has some details along the edges that I really wanted to cast with no interference. So I set about doing it with the model face up and undercutting the channel (B) so it would fill from the backside. Even though I cut a 1/4" channel, it clogged very quickly at the 90* bend area. So i went back to the vertical configuration that gave me the best results previously, left the sprue (A) in the location under the back side and ended up with what I have. Enlarging the pouring sprue (I used a Sharpie marker for a form) made a huge diference.

 

Jerrod's idea inked.jpg

 

To imagine what my set up looked like, take Jerrod's image, lower part B so it is under the model, and turn part A so it is in line with part B. Stand it up on end and pour.

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

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I should clarify that none of my model was dimensioned, it was just a rough concept of principles. 

 

Foundry terms:

Cope: top part of a horizontally parted mold

Drag: bottom part of a horizontally parted mold

Cheek: center part(s) of a horizontally parted mold (not all molds have cheeks)

Sprue: where you pour your metal in

Vents: channels for the gasses (including/especially air naturally in the mold cavity) can escape out of the mold cavity and away from the metal

Gate: where the metal enters into the part itself

Runner:  connects the sprue to the gate

Gating:  the combination of sprue, runner(s), and gate(s)

Feeder/Riser:  Extra metal in the mold position to be the last to solidify and continue feeding liquid metal into the cavity as the part cools and solidifies

 

Some things can serve multiple purposes.  For example, you can have a sprue connecting directly to the part, thus you have no runner and your sprue is also a gate and (potentially) a riser.  All risers are also vents.  

 

In general you want your critical details to be in the drag.  This is because things like oxides float, thus your cleaner metal is in the bottom.  You can even do a lot of good by having the gating such that the runner is "longer than necessary" and goes past the gate connection.  This washes some of the bad stuff in the sprue and runner into somewhere other than the part (the extra runner space), and pre-heats the gating system.  If the gating system is designed well, the system will completely fill with metal well before the end of pouring (ideally before metal even gets to the part), and oxides and such will stick to the top of the runner and thus be skimmed out before getting to the part.  So ideally you want to be able to instantly fill your sprue, then have that fill up the gating system, then get to your part.  The whole time you want the metal to move as smoothly as possible (no splashing/sloshing).  

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I had to read that three times........

 

32 minutes ago, Jerrod Miller said:

If the gating system is designed well, the system will completely fill with metal well before the end of pouring (ideally before metal even gets to the part), and oxides and such will stick to the top of the runner and thus be skimmed out before getting to the part.  So ideally you want to be able to instantly fill your sprue, then have that fill up the gating system, then get to your part.  The whole time you want the metal to move as smoothly as possible (no splashing/sloshing).  

 

This definitely happened. I noticed something that I have never experienced in the limited casting I have done. Then again, this is the largest single pour I have ever attempted, and the gating was set up very differently than I had done previously. What occurred was the spue filled completely, dropped and filled again, all while I continuously poured. This happened on two or three attempts.

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

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1 hour ago, Joshua States said:

What occurred was the spue filled completely, dropped and filled again, all while I continuously poured. This happened on two or three attempts.

 

Sounds like you need more venting to get the air out of the mold as you fill.  And your sprue needs to be substantial enough that it never completely empties during the pour.  

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1 hour ago, Jerrod Miller said:

Sounds like you need more venting to get the air out of the mold as you fill.

Well, the vents were pushing smoke....

 

1 hour ago, Jerrod Miller said:

And your sprue needs to be substantial enough that it never completely empties during the pour.  

It never did empty fully. It just filled, dropped a little and then filled again.

 

However difficult it was to do, I did it anyway. I screwed it up in the lathe. I'll have to pour another one. I need to cut a chunk off my bronze ingot and I need more sand.....

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

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55 minutes ago, Joshua States said:

Well, the vents were pushing smoke....

Believe it or not, that doesn't really mean anything.  Your vents need to be substantial enough that all the gas can get out of the mold cavity at a leisurely rate.  Some say they should have the same cross-sectional area as your gates, assuming the vents are open all the way out of the mold, more if not.  Otherwise you get back pressure, and that is not a good thing for filling.  

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Posted (edited)

Yes. I thank you for your insight. The bottom line is did the mold fill completely, no?

If it did, the venting was adequate. If the mold did not fill completely, the venting was undersized. At least that is how my mind puts it together.

And the vents filled with metal. That tells me they worked.

Edited by Joshua States

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

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16 hours ago, Joshua States said:

Yes. I thank you for your insight. The bottom line is did the mold fill completely, no?

If it did, the venting was adequate. If the mold did not fill completely, the venting was undersized. At least that is how my mind puts it together.

And the vents filled with metal. That tells me they worked.

That is very far from accurate.  The best analogy I can think of off the top of my head is a car engine.  Just because it turns over doesn't mean you're ready to race with it, or even go to the store.  You could be firing on only half your cylinders, broken pistons, out of oil, no coolant, etc.  Sure it is technically running, but it is not doing it's job.  

 

The old adage on venting is "Vent, vent, and vent some more.  When you think you have enough, double it.  Now you almost have enough."

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That's the "best" analogy you could come up with? Not only is it bizarre in it's correlation, it is completely absurd from an automotive mechanics viepoint.

 

But Thanks anyway.

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

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Kind-of-sort-of working, but not doing what it is needing to do.  The engine is technically running, but you aren't driving anywhere with it.  Your vents had gases going through them, but not enough to prevent problems.  That is what I was trying to illustrate, and I think the analogy holds.  And I have seen engines run with all of those conditions, so it is definitely not absurd from a mechanic's viewpoint either.  

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You really don’t know when to quit do you?

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

https://www.facebook.com/dos.gatos.71

https://www.etsy.com/shop/JStatesBladesmith

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