Pool Filter Sand

Discussion in 'Sand Casting' started by John, Aug 3, 2021.

  1. John

    John Copper

    This is probably a dumb question, but I have never thought about using this sand, it says it is 20/40 graduations. It looks really fine.
    Could this be used for making green sand?
     
  2. Petee716

    Petee716 Gold Banner Member

    I looked into it before and found it to be unsuitable. To coarse if I recall correctly. I went to a builder's supply and bought a couple bags of the finest they had. Still not great but way more useful than lowes playsand. One fellow here gets sand from wherever and pours it in front of a box fan leaving a 6ft skidmark of nicely sorted sand on a plastic sheet. Ima do that next time!

    Pete
     
  3. Billy Elmore

    Billy Elmore Silver

    I used some in a small batch I mixed up just to try it out...when I opened the bag I realized the grain was too big to have a good surface finish on castings. I used it to cover the ground where I pour my molds.LOL
     
  4. Melterskelter

    Melterskelter Gold Banner Member

    Casting has so many unavoidable challenges that it seems prudent to eliminate as many variables as possible, Suitability for greensand is not solely dependent on grain size as edge sharpness and heat resistance also are significant factors. Do yourself a favor and, if at all possible, start with known proven materials. After your basic setup is working well, maybe then start experimenting. We’ve seen people get so side-tracked and bogged down experimenting that they never get to casting!

    Denis
     
    oldironfarmer likes this.
  5. Mach

    Mach Silver

    Where do you get foundry sand? I've tried sifting my own but the quality is suspect.
     
  6. It amazes me that novices think they can instantly improve on a craft which is thousands of years old and developed to a high art. It actually happens in every field.
     
    Jason likes this.
  7. Petee716

    Petee716 Gold Banner Member

    Could you pass along the type of raw sand you use, its attributes, and your source? That often seems to be the greatest challenge. Speaking to materials suppliers, and even going to sand distributors gets you blank stares.
    I dont think anyone is trying to reinvent the wheel here.
     
  8. Melterskelter

    Melterskelter Gold Banner Member

    I
    I use Olivine 100 mesh as supplied by local foundry supply companies. Silica sand of a similar size can also be used, but I believe Olivine is more durable in the iron foundry. The US Navy Foundry Manual has loads of information about green sand (and a whole lot more) and is an excellent starting point. HT-1 has been shamelessly ;-) promoting it (why should he be ashamed of such a fine resource?). That was the reference I used when I started mixing up green sand a few years ago. It has served me well.

    I have found that using both Southern and Western bentonite in the way they recommend provides sand that works better for me than using Southern alone. For iron I also add in sea coal to prevent burn-on of sand but this is not needed in non-ferrous applications. I have been using the same sand for several years now and it seems to be holding up well.

    Denis
     
  9. FishbonzWV

    FishbonzWV Silver Banner Member

    Yeah, pool sand sucks.
    I had a stack of graduated sieves and ran various sands through them. Playsand in the clear plastic bag had the least amount of undesirable grit in it.
    Winnowing in front of a fan is the quickest way to classify the sand. For good greensand, just use the top 50% of the 'skidmark' (good one Pete). I don't know if a box fan has enough ooomph to do the job, I used a three speed floor fan. The rest can be used for lost foam casting.
    Pic's of my setup here. https://forums.thehomefoundry.org/i...-me-on-sand-greensand-and-lf.1278/#post-29961
     
  10. I was lucky enough to be given a 25kg bag of green sand by a local enginnering copany who invited me along to watch them pour 25kg of cast iron. The sand was a revelation with its fine texture. I would advise anyone starting out to ignore the youtube videos showing how to make green sand from play sand and ground up kitty litter.
    I used the play sand/kitty litter mixtures to re-lay some paving slabs in my garden.
    Lee
     
  11. MortyNTenon

    MortyNTenon Copper

    When you don't have a foundry supplier available Unimin Granusil can be bought at building supply or landscape supply places. Runnings, a regional farm supply, also has it. It's clean, dry, and available in different sizes. The 5020 grade is a good choice. I use 4030 for more permeable cores. Much better than the Home Depot varieties.

    https://www.coviacorp.com/media/rwpdmvx3/granusil_tds_portage_021_0719_bld_eng.pdf
    https://www.runnings.com/uniminr-granusilr-silica-sand-40-50-lb.html
    https://www.brockwhite.com/product/1-0300498
     
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  12. Mach

    Mach Silver

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