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Lost wax casting Ottoman/Kozak saber guard


Alex Jemetz

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Good morning , I'm working on a Turkish style saber and just completed lost-wax casting the guard (third attempt at casting first attempt for the guard).  I thought I eliminated the mistakes I made with the first two attempts, baked the mold for at least 5 hours at 500 F and burned out the wax on a propane grill.  I heated the mold for several hours at 500 F before pouring the brass but still had some sputtering and splashing out of molten brass.  MY QUESTION:  the guard came out of the mold with a void at the tip of the quillion, can it be filled with molten brass that will bond to the existing solid brass?  I hope to rescue the cross guard and be able to mount it on the saber...  Also, I think I should've had an additional vent attached to that lower quillion in the mold (let me know if you agree).  Below are pictures of the mold and sprues and casting.  Appreciate assistance and feedback.

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  • You are at least 1000F too cold at 500F.  You didn't get hot enough to really burn everything out.  
  • You should have a dedicated gating system, like the example I showed in your last thread.  You want the metal to enter the mold smoothly but that never really happens, so you want a sprue and gate combo that smooths things out before entering the part cavity.  And always fill the part from the bottom whenever possible.  
  • You cannot just pour more molten brass on a void and have success.  While it is possible to get the part pre-heated just right then add more, it is very difficult to do right.  TIG welding would be the easiest way to accomplish this type of repair.   
  • The vents you have look fine.  The too low pre-heat and bad (non-existent) gating are your bigger problems.  
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Jerrod, thanks for your answer.  I will take your advice and improve the gates and try to get the mold higher in temp the next time I do a pour.  In the meantime I will try to weld a repair.  Can you TIG weld with brass?

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7 hours ago, Alex Jemetz said:

Good morning , I'm working on a Turkish style saber and just completed lost-wax casting the guard (third attempt at casting first attempt for the guard).  I thought I eliminated the mistakes I made with the first two attempts, baked the mold for at least 5 hours at 500 F and burned out the wax on a propane grill.  I heated the mold for several hours at 500 F before pouring the brass but still had some sputtering and splashing out of molten brass.  MY QUESTION:  the guard came out of the mold with a void at the tip of the quillion, can it be filled with molten brass that will bond to the existing solid brass?  I hope to rescue the cross guard and be able to mount it on the saber...  Also, I think I should've had an additional vent attached to that lower quillion in the mold (let me know if you agree).  Below are pictures of the mold and sprues and casting.  Appreciate assistance and feedback.

20231004_214605.jpg

20231004_204438.jpg

20230928_204804.jpg

20230928_204748.jpg

 

Looks like it didn't have enough feeder sprues for the upper part, small piece example but it might help.

DSC00127.JPG

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One recommendation I can give is to first rough grind the cast to the shape you are going to use. If the mould was splashing metal due to remaining wax due to insufficient burn out, there may be more voids that will show up in de finishing process. After you did the initial rough grinding, you have a much better picture of what you have and how to proceed further. 

Jeroen Zuiderwijk

Facebook page: https://www.facebook.com/barbarianmetalworking

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Having only tried casting a few times, would it still be necessary to have the gating set up in the wax when vacuum casting? I'm in the process of building a vacuum chamber/flask setup but have only done strictly gravity casting in the past with mixed results. In any event thanks for sharing the above info!

 

John 

Not all those who wander are lost. -J.R.R. Tolkien

-Shards of the Dark Age- my blog
-Nine Worlds Workshop-
-Last Apocalypse Forge-

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3 hours ago, John Page said:

Having only tried casting a few times, would it still be necessary to have the gating set up in the wax when vacuum casting? I'm in the process of building a vacuum chamber/flask setup but have only done strictly gravity casting in the past with mixed results. In any event thanks for sharing the above info!

 

John 

 

What is gating set up? I have cast pieces on and off over 30 years and never heard the term.

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11 hours ago, DanM said:

What is gating set up?

Gating is the system/path that gets the metal into the actual part cavity of the mold.  This would include the pour cup, sprue, runners, and ingates (AKA - gates) at a minimum, but one could also include vents.  Typically the cavity sections of a mold will have gating, risers/feeders, and the part.  Flow-offs, slag traps, pouring basins, and other flow management features would fall under the general "gating" category, but more specifically are typically considered part of the runners.  

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15 hours ago, John Page said:

would it still be necessary to have the gating set up in the wax when vacuum casting?

You would still need a gating system, but it wouldn't need to look the same.  You have to get the metal into the mold somehow, and that is a gating system.  Generally speaking, the gating system is to be deigned to get the metal into the mold as quickly as possible while exposing the liquid metal to air (mainly oxygen) as little as possible.  There are people that do the whole melt and pour in a fairly hard vacuum to reduce oxidization (mainly for things like difficult Ti parts).  These set-ups can have gating systems that would generally be considered bad because they have removed the consideration of oxidization. 

 

So, depending on your set-up (gravity, pressurized, vacuum, etc.), you design your gating to get the metal in the cavity as fast as possible with the least amount of exposure to air, and with the ingate contacts located such that removing them and cleaning up the contacts is doable.  In some situations you will also want to consider the heat of the metal coming in through the gates for flowing into thin sections as well as heat distribution for shrink/feeding purposes.  

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On 10/5/2023 at 5:27 PM, Jerrod Miller said:

I don't have a TIG welder, so I cannot, but in general it can be done.  

Thank you, going to try and clean the piece well and pour molten brass on the part with the voids in an attempt to rescue the cross-guard.

On 10/5/2023 at 5:53 PM, DanM said:

 

Looks like it didn't have enough feeder sprues for the upper part, small piece example but it might help.

DSC00127.JPG

Thanks Dan, next casting will have more sprues and I hope for a completely solid cast.

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Because I have invested a decent amount of time into the saber guard I am going to try and salvage the work by cleaning up the voids, heating the piece in my forge and trying to pour molten brass into the voids.  I will let you know the outcome...  Here's what it looks like after a little file work, a fairly solid piece with only a 3 places that could use a little more brass...

 

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Thank you for that advice Jim.  I managed to fill one void so far and only heated up the guard a little to ensure the molten brass can pour into the voids...  Looks good so far.  I am going to do some more file work to discover any more voids and try to fill them too.  I will also check for a welder nearby to see if they could do some of the braze work...

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Progress!  I melted a small amount of brass and managed to fill some of the voids in the cross-guard, this makes me optimistic that I will be able to salvage the piece.  Carving a new wax mold, casting it and drying out the mold and then burning out the wax would take a lot more time as I only have a home-built two-burner forge, and a turkey fryer propane burner that I use to burn out the wax mold.  I also managed to fit the guard to the saber last night.  Next steps are to finish the guard and heat-treat the blade.  Comments and advice always appreciated.

 

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