green sand

[DAPPH]

I'm about to get ready to make my own super fine green sand to try and cast some brass when I'm able to stand on two feet again .
I've seem lots of YouTube " specialists " running about like idiots with their asses on fires telling the world how good their green sand is but looking at the sand marks on the finished casts it ain't so hot .

I'm also hoping long term to move to photo3d reproduction of the forms then print the plastic item and treat it like lost wax casting with the use of instating powder but that is in the future .
Does anyone have any pointers to getting the very fine green sand made ?
I've a sack 25 kg bag of industrial grade silver sand and will be sieving that through two different fine sieves . I have two 5 kg bags of non clogging cat litter to turn to clay ..it's the turning it to clay powder I'm seeking info on as my lass would have my guts for garters if I used her Kenwood food processor to turn it to dust and burnt it out .

 

[doubleboost]

If you want a real fine finish use silver sand and sodium silicate
My casting sand is what is known as Mansfield red
Comes naturally red coloured with just the correct amount of clay to bind it
The sand gets better with use
Petrobond is a oil based sand that is very good for detail work

 

[jsf55]

I was told a cheap coffee grinder for the job... i never got that far with it tho !

 

[doubleboost]

I was told a cheap coffee grinder for the job... i never got that far with it tho !

I used to use a electric cement mixer

 

[blackolive (Ste)]

Bentonite powder ? You can get it off ebay

 

[brightspark]

If you want a real fine finish use silver sand and sodium silicate
My casting sand is what is known as Mansfield red
Comes naturally red coloured with just the correct amount of clay to bind it
The sand gets better with use
Petrobond is a oil based sand that is very good for detail work

its that good squeeze it your hand and it shows your finger and palm prints . dunno if anyones interested but Mansfield sand acualy comes from Mansfield Derbyshire

 

[bigegg]

Never tried it, but someone on "alloy avenue' suggested dusting with portland cement as a "facing powder" to improve surface finish.
If you make the sand _too_ fine, it won't be porous enough, and you'll get bubbles.

<Edit> maybe try plaster of paris?

 

[Kram]

Xynudu had a video using sand and molasses, tho I cant find it.

 

[doubleboost]

Xynudu had a video using sand and molasses, tho I cant find it.

That would be for making sand cores

 

[brightspark]

cant remember what the mix is but the last core I made was from sand linseed oil and baking powder made in a mold then hardened in the oven

 

[DAPPH]

I used to use a electric cement mixer

@doubleboost .

For grinding breaking the cat litter up ? Or for making the casting mix from silver sand sodium silicate ?

 

[DAPPH]

I've just taken receipt of a kilo of instating powder that jewelers use to make plaster casts of wax forms that will be good if I can convert the model for casting into wax forms.


How I hate this being square wheeled only being able to stand on one leg , I'm raring to get out to the mancupboard and get cracking at the project .

 

[bigegg]

I've just taken receipt of a kilo of instating powder that jewelers use to make plaster casts of wax forms that will be good if I can convert the model for casting into wax forms.


How I hate this being square wheeled only being able to stand on one leg , I'm raring to get out to the mancupboard and get cracking at the project .

Can you 3d print a mould that you can pour the wax into?
Or 3d print the pattern and coat it in latex to make a mould for the wax?

 

[DAPPH]

Can you 3d print a mould that you can pour the wax into?
Or 3d print the pattern and coat it in latex to make a mould for the wax?

I've started to try and design the form for the printer using Fusion 360 , but because of having an addled brain have kept getting stuck when trying to join the whole assembly together on Fusion 360 … persistence & sobriety may help

When / IF , I get back on both feet , I want to try the photographs to 3D printer programme method of making the wooden form into the 3D filament form . Then it will be a doddle to set it up with filler reservoir , venting sprues & lightly coat it in casting investment powder to about 3 mm thick , put it in the BBQ to cure it & melt the filament out . Then set it up in a green sand bed for brass casting . The beauty of it should mean I can increase the physical size of the printed casting form by 2.3% to allow for contraction of the hot brass to get the right size at the end of the day .

Just re read what I've put ..... Yes it might be an idea to make a mould for wax forms on the printer using the photographs as the wax will be a lot cheaper than the lost filament if there is a call for a lot more castings . I could even get to making the wax moulds in cast aluminium .
This could be a very very interesting project for me .

I think that 3DFZephher free 3.702 is a simple free programme to use for 40pictures to be coded onto cura for printing is the place I'll have to be looking into .
https://www.3dflow.net/3df-zephyr-free/

 

[pressbrake1]

The foundry I use that gets good results uses a resin bond sand.

 

[doubleboost]

@doubleboost .

For grinding breaking the cat litter up ? Or for making the casting mix from silver sand sodium silicate ?

For tempering the green sand

 

[Lewis_RX8]

I have used green sand 1 part and 2 part molds before taking shape of something i already have and worked well for hobby. Finish was ok just general cast i would say but wasn't going for nice surface finish anyway.

 

[DAPPH]

For tempering the green sand

How many days did you let it run ?