Delft clay casting knowledge please?!

[Niamh]

Hi everyone,
Im trying to cast a silver spitfire, so far its worked once, but the tail didnt work. Iv made a new mold ready for later but can anyone see anything im doing wrong in the mold itself? If the mold is fine im wondering if it is due to something else. thank you!

[enigma]

If I was doing it I would have the sprue coming in at the nose and the air holes going off at every point, so one for each side of the wings and one for each side of the tail.
If you still have problems then I would make the ones off the tail quite large so that the silver flows through them and cut off after casting.

[handmadeblanks]

Hi Niamh,

Thanks for the pictures, it makes things so much clearer now.

TBH, I can't see anything obviously wrong with what you are doing, I would think it should work. The only thing I can offer is a suggestion based on what I see. It's not so much a solution, but I would try it if I was having the same problem.

It's hard to tell from the picture but it doesn't look like the funnel is sloping down at a nice angle, so I'm wondering if the Silver is pooling at the bottom slightly, slowing its passage down through the sprue?

I would try making the funnel slope down (like a standard kitchen funnel) so that the angled sides of the funnel go right down to the sprue hole.

[Niamh]

Hi Niamh,

Thanks for the pictures, it makes things so much clearer now.

TBH, I can't see anything obviously wrong with what you are doing, I would think it should work. The only thing I can offer is a suggestion based on what I see. It's not so much a solution, but I would try it if I was having the same problem.

It's hard to tell from the picture but it doesn't look like the funnel is sloping down at a nice angle, so I'm wondering if the Silver is pooling at the bottom slightly, slowing its passage down through the sprue?

I would try making the funnel slope down (like a standard kitchen funnel) so that the angled sides of the funnel go right down to the sprue hole.

AH! thank you! i hadnt thought of that at all! Could well be the issue im having! il give it a go! thank you!

[Niamh]

Hi Niamh,

Thanks for the pictures, it makes things so much clearer now.

TBH, I can't see anything obviously wrong with what you are doing, I would think it should work. The only thing I can offer is a suggestion based on what I see. It's not so much a solution, but I would try it if I was having the same problem.

It's hard to tell from the picture but it doesn't look like the funnel is sloping down at a nice angle, so I'm wondering if the Silver is pooling at the bottom slightly, slowing its passage down through the sprue?

I would try making the funnel slope down (like a standard kitchen funnel) so that the angled sides of the funnel go right down to the sprue hole.

I scrapped the plane idea tonight because i didnt feel like it would work, so i tried to make a ring again (my original plan to start with!) and its so close but not completely there! dont have any idea where im going wrong

[handmadeblanks]

I scrapped the plane idea tonight because i didnt feel like it would work, so i tried to make a ring again (my original plan to start with!) and its so close but not completely there! dont have any idea where im going wrong

I think the sprue is still way too long. The Silver has to travel all the way down the sprue, turn 90°, then travel all the way around the ring before it cools down(!). I reckon if you make a deeper funnel so that the sprue is about one third the length it is now you will have a much greater chance of success. I figure the reason I never experienced anywhere near the problems you are having is because of the flasks I'm using. They have a side pouring hole which means the ring can be oriented in a way that the silver flows straight into it rather than having to make a 90° turn.

See this thread: Delft Clay Casting

[Niamh]

I think the sprue is still way too long. The Silver has to travel all the way down the sprue, turn 90°, then travel all the way around the ring before it cools down(!). I reckon if you make a deeper funnel so that the sprue is about one third the length it is now you will have a much greater chance of success. I figure the reason I never experienced anywhere near the problems you are having is because of the flasks I'm using. They have a side pouring hole which means the ring can be oriented in a way that the silver flows straight into it rather than having to make a 90° turn.

See this thread: Delft Clay Casting

Wow handmadeblanks I never thought of that either! I have a lot to learn! This mold iv made just now has 6 air vents, a sprue that’s only 2mm or so from the ring imprint x hopefully it works

[Niamh]

I think the sprue is still way too long. The Silver has to travel all the way down the sprue, turn 90°, then travel all the way around the ring before it cools down(!). I reckon if you make a deeper funnel so that the sprue is about one third the length it is now you will have a much greater chance of success. I figure the reason I never experienced anywhere near the problems you are having is because of the flasks I'm using. They have a side pouring hole which means the ring can be oriented in a way that the silver flows straight into it rather than having to make a 90° turn.

See this thread: Delft Clay Casting

Handmadeblanks thanks for all your advice!! im pretty sure it was the reason iv now managed to achieve this!!!

[Snorkmaiden]

That's stunning!

[handmadeblanks]

Handmadeblanks thanks for all your advice!! im pretty sure it was the reason iv now managed to achieve this!!!

Thanks Niamh for the compliment! It looks beautiful. Now the rings and you can finally get married.