Comparative Sand Ramming Hardness Test Using a Golf Ball and Tape Measure

Discussion in 'Sand Casting' started by Melterskelter, Jul 9, 2022.

  1. Melterskelter

    Melterskelter Gold Banner Member

    In a recent thread the degree of sand hardness was discussed. It was not possible, however, to quantitate sand hardness without expensive equipment that I think is rarely if ever available to small-scale casters. Even a comparative measurement would be valuable though. This is especially true for folks new to casting and seeking advice of experienced casters. The usual geographic separation of the noob and the caster prevent any meaningful comparison of how hard they are ramming their sand molds. This got me to thinking about an inexpensive, reasonably sensitive, and simple method by which sand hardness might be measured by each party using materials that should be available virtually anywhere in the world.

    My suggested solution is to use a Titleist ProV-1 golf ball. This brand and model being chosen as my golfing friends report it is a very commonly used ball throughout the world. Specifying a given brand and model of ball is necessary as golf balls, surprisingly, are not standardized in weight or dimple pattern.

    The other tool needed is a simple tape measure. To perform the test, ram up your mold, strike off the sand, raise the ball 18 inches off the surface and drop it. Then either measure the diameter of the dent made in the sand or count the number of bumps made by the dimple pattern in the sand. Then ask the other person to do the same or, maybe later if anyone puts up any of their own data, look in this thread to see what others have done.

    I just tried idea out a few hours ago and so I have not done careful multiple drops to prove small scatter of measured results. But, my impression is that it certainly correlated well with thumb-pressure testing and correlated with expected differences in top vs bottom surface hardness levels. I do think it would allow Ian in the UK to meaningfully compare his hardness with Jorge in Brazil if the two subject their molds to this testing.

    Here are a few pics. The contrast of the pics was challenging. But detail was quite evident when looking directly at the sand. If there is any interest I can record future readings more carefully and others should contribute their findings as well. If no one puts up any info, I'll take that as an indication of zero interest and let it die as is.

    Hardness4.JPG Hardness3.JPG Hardness2.JPG






    Hardness.JPG

    Denis
     
    Last edited: Jul 9, 2022
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  2. Tops

    Tops Silver Banner Member

    Interesting and rapid testing!
    Of the 8 dozen golf balls now arranged on my living room floor, none of the are VP-1's.
    Granted, all of them are of legal drinking age seeing when the last time I golfed...
    Some are pretty dirty too. Anyone got casting patterns for a golf ball washer?
    :D
    It would be interesting to see if any variation in the 18" (457mm) drop height +/- .25 inch, +/- .5 inch, +/- 1 inch (6.4, 12.7, 25.4mm) affects the dimple count. If if does you'd have to weld up a drop mechanism that rests on any given flask to reduce the variability.

    PS: Pro V1?
    https://www.titleist.com/explore-golf-balls/
     
    Last edited: Jul 9, 2022
  3. Melterskelter

    Melterskelter Gold Banner Member

    Again, desiring absolute simplicity, a drop "mechanism" that I considered making would be a piece of plastic or metal pipe large enough to allow unrestricted passage of the ball. It would be cross-drilled at 18" and a pin (piece of any stiff wire or stick) passed through the holes. Ball goes on top of the wire. I doubt that 1/2" or even 1" variations in drop height would matter. Pull wire. The ball lands "dead" in the sand and does not tend to roll around.

    Denis
     
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  4. Tops

    Tops Silver Banner Member

    18" tube, Titleist DT 3 ball finger-dropped, used (darker, LH side, ruler right-reading) and new (lighter RH side) Petrobond. 1.5" thick flask sides, parting line faces rammed against mold board and flipped up for ball test. Sand was not riddled. Looks like I need to work my flask sides better...
    tops_golfball_18inch_pbond_old_new.jpg
    tops_golfball_18inch_pbond_old_new2.jpg
     
    Last edited: Jul 10, 2022
  5. Melterskelter

    Melterskelter Gold Banner Member

    It does look like your ramming is on the soft side, especially for a 1.5" thick mold. That is comparable to what I got on a 3.5" deep mold.

    Now what would be interesting is for HT1 and a few other experienced petro users to do a little "goof" ball testing on their rammed sand. My results may not be so comparable as I am using mostly green sand. It IS kinda nice to have a somewhat objective comparison capability. Measuring the diameter of the indentation besides dimple count would be useful especially if the ball models used in the drop testing are different as dimple patterns do vary. But then, in your case, maybe the DT3 is similar in that respect to the Pro-V1 dimple pattern.

    Denis
     
  6. Tobho Mott

    Tobho Mott Gold Banner Member

    I have thought about this before, am I ramming too hard or too soft? I can adjust based on past results and compare what I'm doing against what people describe in posts here and in books and youtube videos made by people who seem to know what they're doing, but have never actually felt for myself how hard a professionally made mold is rammed up.

    I have gotten a chance to press a finger into a few dozen petrobond molds made by first timers over the past several months working at the blacksmithing school though. I've definitely noticed that a certain percentage of them will tap-tap-tap away quite softly to my thinking, no matter what they are told. Their molds sometimes end up harder on the outside than at the parting.

    Should be interesting if we can get a good sample of pictures in both types of sand. I'll try to find one of those Pro-V1's and try to get some pictures from molds made with blacker and redder petrobond. Maybe I'll learn something about how well I'm really maintaining my sand too.

    Jeff
     
    Last edited: Jul 11, 2022
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  7. Melterskelter

    Melterskelter Gold Banner Member

    Jeff, I would have liked the above twice if I could have!

    Denis
     
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  8. HT1

    HT1 Gold Banner Member

    ok your ramming technique is $hit !
    in your pictures there is sand clearly missing around the edges of the flask. which means you are not ramming the edges and the corners of your flask thoroughly, this would be exasperated if your rammer is too big, you need to use the Peen end, that is the smaller side, BTW I used a ballpeen hammer for a rammer for 11 years, great peen , on a very small mold like you have there you may need to use the hammer handle or just a 1 inch dowel to ram your corners , it will take some experience to get good results, you are trying to get all the sand packed uniformly


    [​IMG]

    Thats sand looks like it has Pi$$ poor flowability( kind of common in new petrobond, ) riddling will help with that, and "tuck" the riddled sand in with your fingertips to fill all voids before ramming

    V/r HT1
     
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  9. HT1

    HT1 Gold Banner Member

    if we are going to do this golf ball thing, I want to see dimples on the corners, not just the center, getting the corners welled rammed is where the skill is, not the center

    V/r HT1
     
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  10. Melterskelter

    Melterskelter Gold Banner Member

    I think if people start doing a bit of hardness testing, they will find comers tend to be soft which is not always a fatal flaw. But, another area likely to be soft and possibly more significant, will be “windows” in patterns. This is particularly true in deep patterns as opposed to plaque-like patterns. And those window areas can be quite crumbly if soft. So, as HT1 suggests, it may be useful to check corners for hardness and I think window areas too. Using a tube to guide the drop, as discussed above, will allow pinpointing the drop spot.

    I think there is the potential for us all to learn from comparing our results and hope that anyone who “has the balls,” takes the time to do the testing, make photos, and post results feels they have the groups gratitude. This is a (potentially useful) work in progress. Sand ramming is a crucial factor in determining casting success. But, unless we are working shoulder-to-shoulder, it is mighty hard to compare results.

    Denis
     
  11. Tops

    Tops Silver Banner Member

    @HT1, thanks for the candid advice. I will riddle and use a smaller tool.
     
  12. Chazza

    Chazza Silver

    I use a rammer with two square ends and when that doesn't fit, pieces of flat, or square bar.

    My sand will sometimes drop out in a layer, as I usually fill the moulding box three times. Recently I have taken to scratching the surface of the intermediate layers and this seems to have prevented the problem.
     
  13. Melterskelter

    Melterskelter Gold Banner Member

    I use a tool like this to scratch up the first layer. That helps a lot. I still rarely have had a layer failure. But scratching definitely helps prevent such.

    Chazza, how hard is your sand rammed up?


    upload_2022-7-11_16-23-50.png
    Denis
     
  14. Tobho Mott

    Tobho Mott Gold Banner Member

    This gets the job done too, though I rarely bother to use it.

    20220711_194625_copy_520x1040.jpg

    Jeff
     
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  15. Chazza

    Chazza Silver

    Pretty firm. I haven't done any testing of firmness, as the definition from the pattern is always good.

    I scratch the surface with the point of a small trowel.

    Since converting to a pouring-basin, I have had trouble with cold-shuts on one of my long, thin patterns, which also has irritating larger volume bosses in the middle of it. I am studying good gating techniques now as I sure it is a flow problem.
     
  16. Melterskelter

    Melterskelter Gold Banner Member

    Oh, THAT firm. I see ;-)

    Sounds like an interesting problem. Some of those "interesting" problems can be darn vexing!

    Denis
     
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  17. HT1

    HT1 Gold Banner Member

    OMG!!! scratching, you should not have to scratch petrobond, the only time you use the butt(Big flat end) and not the peen is on the final ram, so the sand in the mold in the intermediate levels will still be quite rough, not flat

    getting in the corners well, teaches you rammer control, so you can deal with "windows" on patterns.

    basically you have to practice once you get good with a hand rammer, then you can move to a Pneumatic rammer, where SMALL mistakes have big consequences (broken flasks and patterns )


    Here this video sound is awful i had no intention of posting it, but its great info that some of you need

     
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  18. Chazza

    Chazza Silver

    Top movie HT1.!

    You do mention the mesh-size on your riddle, but I found it hard to interpret. Is it about 5/16" square?

    I am slowly discovering that much of how I was taught 36 years ago, was not the best advice.

    Interesting to see your gating; the Navy manual says to avoid 90 degree bends and yet some of their diagrams show bends of that nature. Any thoughts? It seems to work perfectly for you and has done for myself.

    Cheers Charlie
     
  19. HT1

    HT1 Gold Banner Member


    Avoid 90 degree bends is WAY too simplified if you are using top gates and a bottom runner, it does not matter at all , what they are trying to encourage is you to try and get the metal to flow gently, with out creating turbulence , so gentle curves are the idea, but are often impossible , or will push loose sadn or the initial dross which is very difficult to avoid directly into the casting,

    in short its complicated


    V/r HT1

    P.S that's a plaque , any dross will be on the back side , and of no consequence, so "great gating" can often be very simplified and still give acceptable castings
     
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  20. Tops

    Tops Silver Banner Member

    Mess with the 'Fro...



    Nice video HT1, thanks.

    Rammed another tonight with a smaller rammer, an old piece of hickory about the size and length of a hammer handle. About 1/3 the area per face as my other one.

    Better, not perfect, less dimples. Riddled, tucked, saved the big face for the end. Pattern needs fillets and smoothing but still fell out of the cope unassisted.
    I think I am going to try to ram the same one once a day for a few days and see if I can learn something.

    tops_baller2.jpg

    Where are the rest of the Home Foundry 'ballers' at?
     

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