weird Petrobond sand recipe

Discussion in 'Sand Casting' started by HT1, Oct 11, 2020.

  1. HT1

    HT1 Silver Banner Member

    Has anyone tried this guys concoction, it looks promising, BUT he is not doing split pattern work, so the "sand" may have PP green strength... His Hand Muller is also Interesting

    V/r HT1
  2. Melterskelter

    Melterskelter Gold Banner Member

    Have you tried K-bond which was developed at Kent State? Seems like I would trust them more.

    How to make K-Bond sand Named for Kent State where it was developed, K-Bond is an almost smokeless oil-bonded foundry sand. Typically, it’s used for casting zinc, aluminum, brass, bronze and iron. What you need: • 100 lbs. sand - 100 mesh or finer • 6 lbs. bentone clay (such as Bentone 34 or VG-69) • 3 lbs. synthetic 2 cycle motor oil • 0.2 lbs. (3.2 fluid oz) Methanol (dry gas) Mixing: Mix the sand and bentone clay first (wear a dust mask), then blend in the oil thoroughly. Small batches (less than 10 lb.) can be done by hand with good results, but a muller is preferred. The small batches can be done with a cheap kitchen electric mixer. Add the alcohol and mix thoroughly. Tips: • The sand won't seem like much until the alcohol takes effect and become like stiff cookie dough. • The sand will be easier to handle the more you use it over time. • If the sand gets powdery after sitting, mull or warm it before use. • When green strength starts to fade, add in some alcohol.

  3. Melterskelter

    Melterskelter Gold Banner Member

    More on K-bond. I would have guessed bentone is bentonite. It is not.

    If I start casting AL, I think I will investigate Petrobond in a home made formulation. It should not be that hard. (Famous last words)


    Last edited: Oct 13, 2020
  4. rocco

    rocco Silver

    Bentone is a chemically modified bentonite, normal bentonite is hydrophilic, it loves to absorb water, the chemical process that turns it into bentone makes it organophilic so it loves to absorb organic chemicals like oil.

    Anyways, back to the original topic, what strikes me as odd about the recipe in the video, is the very high oil content, around 7.5% by weight, compare that to the k-bond recipe which is less than 3%. Maybe that's because the Bentone in k-bond is organophilic so it soaks up the oil instead of having the oil just adhering to the surface of the sand particles. In any case, I'd imagine all of that oil would make the petrobond from the video smoke and off-gas a lot but that's just a guess on my part and I've never used petrobond bond so I wouldn't know what's normal if I were to try this.

    Do we have any experienced petrobond users here that are willing to try this recipe and give us an honest review?
    Last edited: Oct 13, 2020
  5. HT1

    HT1 Silver Banner Member

    I use petrobond!
    have about 3000 Lbs
    I'm wondering if this guys recipe has any merit because it would be so cheap and allow the new guys to get a quick start.
    I looked up that grout, I can order it from Home depot, deliverd to my local stor $16 for a 50 Lb bag add a quart of oil $4, that is $40/100Lbs ,
    Petrobond is $1.50/ Lbs if you get 100Lbs smaller amounts are $2/Lbs
    so if his recipe is any good at all , it would be great for people with a little interest to get started doing real casting ,

    Sand was one of my biggest early hurdles , It would be nice to help others skip that

    V/r HT1

    P.S. I haev and always hear abouut Kbond , never heard of it in use, I think it is an anomily that just has a good internet presence (shrug)
  6. rocco

    rocco Silver

    Perhaps the guy in the video misspoke but he said it was a 25 lb bag of sanded grout with one quart of oil. If they are 50 lb bags, that would put the sand/oil ratio more in line with other petrobond recipes I've seen.

    Anyways, not only is this recipe way cheaper, the ingredients are much easier for the average hobbyist to find so, I hope you'll give it go, I'd love to see what type of results you get.
  7. Billy Elmore

    Billy Elmore Silver

    Awesome detail in that sand! Not sure how the hot strength is but seems the green strength is great. I figured the oil in the sand would cause an abundance of gas and smoke but have never tried it. Thanks for sharing!
  8. Petee716

    Petee716 Gold Banner Member

    He says its 25 lbs, then says its 50 lb. Several times. In the comments section he writes the recipe 25 lbs sanded grout, 1 qt 30wt oil.
    I bet that mold will flash if opened hot or certainly smoke heavy.

    Billy Elmore likes this.
  9. Billy Elmore

    Billy Elmore Silver

    Will make the finish slick as owl shit but better vent it well! I talked to some guys that have tried similar and they said it is not as bad as I think but did add extra vents.
  10. rocco

    rocco Silver

    FWIW, since my last post, I checked the Homedepot website and the grout comes in 25lb bags and in the video we see him open only one bag.
  11. Melterskelter

    Melterskelter Gold Banner Member

    It would sure be nice to be able to make the K-Bond. The stumbling block seems to be difficulty obtaining Bentone. I have done a fair bit of searching on the web and find nothing so far in small quantities. If ANYONE can find a source I'd like to know it. I'd definitely give it a go. It could be boxed up in large Flat Rate Boxes and shipped to anyone interested at reasonable cost.

  12. DavidF

    DavidF Administrator Staff Member Banner Member

    Bentone is just modified bentonite. I looked into making it awile (years ago) seemed like it was just soaked in ??? Then dried and reprocessed.
    I feel its just some basic chemistry. But need the recipe. I'm certain it could be done at home if you had it...
  13. Tobho Mott

    Tobho Mott Gold Banner Member

    I want to say it was DaveD who uses K-Bond... Going by memory, and not sure where the bentone came from or how often he checks in here though.

  14. Fulmen

    Fulmen Silver

    @David: From what I have gathered Bentone is an organoclay made by modifying bentonite with a quaternary ammonium cation. I believe you are right in that you can do this at home with a clay and a "quat", but getting those quats is probably going to be harder than finding bentone. Also, there can be an almost infinite number of these quats, and I'm not sure if all are suited for our use. Wikipedia mentions them used in anything from disinfectants to detergents and fabric softeners, but I doubt they will be present in large concentrations.
  15. DavidF

    DavidF Administrator Staff Member Banner Member

    I'm heading out to Kentucky in the morning for a few days. While I'm out there I'll do some research and see what I can find out.
    There is alot of bright minds on here, if anyone can pull it off its us..
  16. HT1

    HT1 Silver Banner Member

    Sandrammer got Bentone from Lancaster Foundry Supply, 50 LB bag I believe, you have to call and talk to them

    IFSCO in california sells it for sure , same story have to call

    Here is
    4cylndrfury's comparison

    Ive used Petrobond and petrobond II they are interchangable, and can be mixed together , the detail from sand has to do mostly with the GFN of the sand , Petrobond is normally between 120-160 , I have seen some as high as 190, green sand is often 60GFN , the K-bond formula specifically calls for 100 GFN or higher!!! run the GFN up, and ram sufficiently hard you will get good detail.
    Again, I think Kbond is overrated, because it has a better internet footprint

    Here is the original petrobond and PBII sales literature,

    alot of bitvhes and misinformation is covered in the literature

    Now to the tile grout Petrobond, if we are sure 25Lb bag and a Quart of oil, he is using 4 times the oil recommende d for petrobond , so his sand will be crazy oily, and probably smoke terribly with brass, I still wonder if it might not work, particularly if mulled, who knows perhaps the tile grout contains Bentone (shrug)

    V/r HT1
  17. Melterskelter

    Melterskelter Gold Banner Member

    HT, Thanks for the source recommendations. Looks like IFSCO is no longer in business---phone disconnected. I'll try Lancaster tomorrow. OCL in Portland does not have.

  18. DavidF

    DavidF Administrator Staff Member Banner Member

    But don't Kbond and Petrobond both use bentone as the main ingredient???
  19. DaveZ

    DaveZ Copper

    When's the last time you saw motor oil in a tin can ?
  20. rocco

    rocco Silver

    LOL, I was thinking the exact same thing! My house has been in my family since 1956 so there might be one or two kicking around here somewhere but I can't remember how long it's been since I've seen one in a store.

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