Author Topic: Problems with the sand mix?  (Read 4158 times)

Offline shipto

  • Hero Member
  • *****
  • Posts: 643
  • Country: gb
  • Redditch, UK
Problems with the sand mix?
« on: March 08, 2016, 03:38:44 PM »
I have added a few pics of the results of my attempts to create a green sand mold but despite putting plenty of powder the sand is sticking together.
I first thought it was too wet so added a bit more sand to the mix and tried again, the results of which you see in the pictures.
I am now thinking that maybe there isnt enough clay in the mix but would like to see if anyone thinks its possible. I origionally used approximatly a 10 to 1 mix but that was before adding the extra sand.
The drag? actually turned out pretty well concidering I forgot the powder on the pattern it pulled away a little (circled) and the core? pulled away too but i think I need to increase the angle on the pattern for that to work.
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
https://myshedblog.wordpress.com/

Offline awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 5427
  • Country: gb
  • East Sussex, UK
Re: Problems with the sand mix?
« Reply #1 on: March 08, 2016, 03:48:20 PM »
Do a 'squeeze test' on the mix. Take a handful and clench your fist with it in it. Relax your fingers to a flat hand. The sand should take the impression of your fingers, but the bit you've squeezed should be able to be picked up. Holding both ends with thumbs and two fingers, bend the sample. It should break cleanly showing exposed edges like cracked cast iron.

Too much clay and moisture and it won't leave your hand cleanly.

Too little clay and it'll crumble and not break.

Moisture content should be about 4%   by weight
Andrew Mawson
East Sussex

Offline shipto

  • Hero Member
  • *****
  • Posts: 643
  • Country: gb
  • Redditch, UK
Re: Problems with the sand mix?
« Reply #2 on: March 08, 2016, 04:00:19 PM »
I did try to take a pic of the squeeze test too but trying hold sand in one hand phone in the other and press the button with my nose didnt work out too well  :lol:
However mine was much more crumbly than that so more clay may be in order will try it tomorrow.
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
https://myshedblog.wordpress.com/

Offline NeoTech

  • Hero Member
  • *****
  • Posts: 828
  • Country: se
    • Roughedge Hobbyworks
Re: Problems with the sand mix?
« Reply #3 on: March 09, 2016, 04:02:05 AM »
And to much clay it will stick to everything and just not let go. =)
Machinery: Optimum D320x920, Optimum BF20L, Aciera F3. -- I have not failed. I've just found 10,000 ways that won't work. http://www.roughedge.se/blogg/

Offline shipto

  • Hero Member
  • *****
  • Posts: 643
  • Country: gb
  • Redditch, UK
Re: Problems with the sand mix?
« Reply #4 on: March 09, 2016, 04:38:10 PM »
Added more clay tonight and got much better result on the drag but I need to mix it more I think the cope pulled a big lump away but it was very rich with clay where it happened. This is the problem with having to work for a living you rush stuff.
Anyway car has to go in for new brake cylinder on friday so I am going to take the day off and can spend the full day in the shop getting it right which usually means it goes right in a short amount of time, if so I might even try for a part. Fingers crossed.
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
https://myshedblog.wordpress.com/

Offline awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 5427
  • Country: gb
  • East Sussex, UK
Re: Problems with the sand mix?
« Reply #5 on: March 09, 2016, 05:20:29 PM »
How are you doing your mixing?

The idea is that each grain of sand has a very light coating of binder (clay) with the whole body being uniform in texture - I'm a bit concerned to hear one area was 'very rich with clay' as that implies it's not mixed well enough.

Not always possible, but if making your own sand mix (rather than buying Mansfield Sand for instance which already has clay in it), then start with dry sand and dry powdered binder - bentonite clay for instance - and mechanically mix it (cement mixer or a paint stirrer if on a small scale) .

Only add the water to temper it when it is already well mixed
Andrew Mawson
East Sussex

Offline shipto

  • Hero Member
  • *****
  • Posts: 643
  • Country: gb
  • Redditch, UK
Re: Problems with the sand mix?
« Reply #6 on: March 09, 2016, 05:44:27 PM »
by hand but I will get it mixed just need to keep at it. Not possible to mix it dry now unless I waste the big bucket I have made up.
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
https://myshedblog.wordpress.com/

Offline chipenter

  • Hero Member
  • *****
  • Posts: 707
  • Country: gb
Re: Problems with the sand mix?
« Reply #7 on: March 10, 2016, 03:43:21 AM »
Jeff

Offline awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 5427
  • Country: gb
  • East Sussex, UK
Re: Problems with the sand mix?
« Reply #8 on: March 10, 2016, 04:18:26 AM »
Yes, that's identical to the paint stirrer I used to use for small mixes  :thumbup:
Andrew Mawson
East Sussex

Offline mattinker

  • Hero Member
  • *****
  • Posts: 991
  • Country: fr
Re: Problems with the sand mix?
« Reply #9 on: March 10, 2016, 08:57:19 AM »
by hand but I will get it mixed just need to keep at it. Not possible to mix it dry now unless I waste the big bucket I have made up.

You don't have to waste your big bucket full to mix dry, spread the mixture out on news paper, as thinly as you can, crush when dry (anything will do to crush, a hammer, a piece of wood) and remix with a mechanical stirrer or by hand when dry. Use a mask when mixing dry sand, watch out for dust!

Regards, Matthew

Offline shipto

  • Hero Member
  • *****
  • Posts: 643
  • Country: gb
  • Redditch, UK
Re: Problems with the sand mix?
« Reply #10 on: March 10, 2016, 10:03:48 AM »
I have one of those stirring things somewhere will search it out.
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
https://myshedblog.wordpress.com/

Offline shipto

  • Hero Member
  • *****
  • Posts: 643
  • Country: gb
  • Redditch, UK
Re: Problems with the sand mix?
« Reply #11 on: March 10, 2016, 03:53:20 PM »
My patent pending drying system  :lol: Had the heat setting on while I was sat in there but switched it to just blower mode for the night and left the extracter which I installed to help stop the condensation in the shop on permanent.
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
https://myshedblog.wordpress.com/

Offline tom osselton

  • Hero Member
  • *****
  • Posts: 819
  • Country: ca
Re: Problems with the sand mix?
« Reply #12 on: March 10, 2016, 04:11:34 PM »
I've just been using a tarp to mix my sand with powdered bentonite from the potery shop I'd really like a small muller, I've found a piece of 25" round plate that should be able to do some small batches.

Offline shipto

  • Hero Member
  • *****
  • Posts: 643
  • Country: gb
  • Redditch, UK
Re: Problems with the sand mix?
« Reply #13 on: March 11, 2016, 01:41:39 PM »
What a difference dried, crushed and sieved and the results are amazing especially the drag still need to round the corners on the cope impression but it seems like I am very nearly good to go.
Was amazed at how little water was needed only added a cupfull of water once it was done.
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
https://myshedblog.wordpress.com/

Offline shipto

  • Hero Member
  • *****
  • Posts: 643
  • Country: gb
  • Redditch, UK
Re: Problems with the sand mix?
« Reply #14 on: March 12, 2016, 11:34:35 AM »
 :ddb: My first ever successful casting  :ddb:
Thank you all for the help   :beer:
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
https://myshedblog.wordpress.com/

Offline mattinker

  • Hero Member
  • *****
  • Posts: 991
  • Country: fr
Re: Problems with the sand mix?
« Reply #15 on: March 12, 2016, 12:33:57 PM »
Looking good! Were these the parts that you were thinking about a steel mould for?

Casting is such fun! Regards, Matthew.

Offline awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 5427
  • Country: gb
  • East Sussex, UK
Re: Problems with the sand mix?
« Reply #16 on: March 12, 2016, 03:12:46 PM »
well done Sir  :thumbup:

Nice when a problem gets solved  :beer:
Andrew Mawson
East Sussex

Offline shipto

  • Hero Member
  • *****
  • Posts: 643
  • Country: gb
  • Redditch, UK
Re: Problems with the sand mix?
« Reply #17 on: March 12, 2016, 05:07:49 PM »
Yes Matthew I decided it was a waste of time in the end, if these things take off then I will need to invest some money into some proper di's so I can get them dicast. While the quantity needed is low I am willing to spend the time making sand molds I am in the process of making 4 flasks so that should suffice for now.
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
https://myshedblog.wordpress.com/

Offline Toolshed

  • Jr. Member
  • **
  • Posts: 78
  • Country: us
Re: Problems with the sand mix?
« Reply #18 on: May 04, 2016, 09:38:23 PM »
HEY!!!  Another fellow metal caster!!  Awesome!

I do the "Mulling March" with my greensand.  Lay it out on a tarp.  Stomp the crap out of it.  Add liquid.  Stomp the crap out of it.  Do a squeeze test.  Stomp the crap out of it.  Adjust with more liquid or dry sand....Stomp the crap out of it.

You get the idea. Stomp the crap out of it. Stomp the crap out of it. Stomp the crap out of it. Stomp the crap out of it. Stomp the crap out of it.

You're obviously pulling up the sides of the tarp after each iteration of "Stomp the crap out of it" to make a good mixture, pile in the middle of the tarp and then flatten, make a pile, flatten, make....Oh for pity sake, you get the idea.  BAHAHAHAHAHAHAHAHAHAHA
No matter where you go....There you are....

Metalworker
Woodworker
Metal Caster

Google Map of members.  Send me your city/state/country and I will get you added in!
https://www.google.com/maps/d/edit?mid=1yzP6dM2C2yeti0msljLA5Ny_pwQ