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

Couple things:
1) I use almost exclusively green sand. I agree that petrobond is just about the most forgiving sand there is. Maybe Air-set is easier, but is rarely used in small-scale operations.

2) Virtually all of my patterns in current use are deep enough that two layers of green sand are needed to get adequate firmness. (I love doing the rare shallow, single-layer, simple, cope, and drag patterns that seem so easy by comparison.)

3) I do use a Jet pneumatic rammer on those molds as ramming a few hundred pounds of sand per mold is tiresome. Maybe Jet makes a peen end for their rammers, but I have not found one in my searches and even if I did find a peen end, I doubt I would spend 100 dollars (the common cost of a butt rammer) for one as using the gardening tool linked above does prevent fallout quite reliably. I do, certainly, use a hand peen to initially ram the corners and edges of the mold and then use the pneumatic.

Bottom line is if I don’t scratch up the first layer of sand, drop out is much more likely. I doubt that scratching CAUSES any trouble by itself. The other thing to mention is that if a wide shallow mold seems prone to drop out, a couple of cross bars located at 1/3 the length and 2/3 the length of the mold can make a big difference. They prevent sagging of the sand which stresses the sand and usually proceeds drop out.

I am hoping more people will post some golf ball tests as outlined at the beginning of this thread so we can all compare notes in a semi-quantitative way. I won't be ramming sand for almost a week due ot social obligations. But, when I do, I'll try to make more and better measurements.

Denis

 

I think your idea of just ramming the same pattern repetitively is an excellent way to learn. I think that doing the same patterns over and over has really helped me figure out some things that would have been much harder to figure out doing a different pattern each time.

It looks like the firmness shown in your current mold is very similar to what I have found works well for me.

Hopefully, more folks will test their work so you/we can get a better look at a cross section of common practice.

Denis

 

There are no peens for a Pneumatic rammer , it would not work if there was one because the piston rod can freely rotate . if you are using a pneumatic rammer even in petrobond, you have to scratch between layers of sand , because you will have created a flat compacted surface, and sand will not bond to itself that way , well, so you are likely to have sand dropouts if your flasks are not very well designed to hold sand in place, even then on larger flasks , the center of the mold may drop out ( that one will cause a lot of cursing)

if you watched the video, you can see why scratching is completely unnecessary when hand ramming, you dont need to ram the first or intermediate layers on taller flasks flat, its wasteful of time and energy. you using a pneumatic rammer have no choose but to ram flat, so scratching is a requirement

V/r HT1

 

I think I could use a peen end on the rammer. I'd just have to stay a little further away from flask sides and pattern p[arts as I would not be able to predict the orientation of the peen. I would make my own peen for the pneumatic if the butt were quick and simple to remove. As it is, the butt must be pressed onto the shaft of the rammer as there is no visible pin or screw to remove for interchanging the ends. Some Jet rammers show a bolt to affix the butt. But, I have yet to find the attachment method used for mine. (I have not looked extensively, but have tried to find it a time or two.)

Denis

 

I have been ramming that same pattern about once a day. It was a quick and dirty mock-up of some portlight dogs for another sailor, shown below. Corners are improving, golf ball is impressing less. I kept breaking out on the inside of the eyes where there was no draft on the face and no filling in of the 3D printed pattern. I went after it with the spot glazing compound and a little spray lacquer. Will let it dry overnight before waxing and graphite.

 

I'm willing to bet they draw better with draft! ;-) Sounds like a good exercise.

Denis

 

When I saw those I immediately thought ‘foam follower’. You’ll be amazed by the ease of moulding when you sink them to the parting line in the foam. Absolutely no coping down of the sand.
A new process to add to your foundry skills.

 

I will have to try that sometime. Is it more intended for 1-piece and/or existing object patterns? Had I had the original dogs it would have worked for sure. The ones shown were off the first (and only) time I ran the 3D printed pattern. Sort of surprised myself in that I could drill and tap 3/8-16 UNC on my cheap drill press at home. For actual use the cone end would be smoothed and polished so it can bear against a mating surface almost like a valve and seat.

I must say I have a hankering to make some of those sweet torpedo cleats you do. Saw this on the 'part a snake' thread:

 

The re-drafted, faired, painted, waxed, and graphite-coated pattern pulled better with the current prescribed ramming technique.
Thanks for the input!
Still hoping some others play along with the 18" golf ball drop.

 

Tops,

Your hard work has paid off nicely as those are very clean molds. Well done.

Please do take a couple tangentially lit photos of you indentations and measure their diameter (which should be not very dependent on golf ball make and model) and also count dimples which is rather dependent on make and model of ball. That should provide a data point for others to compare to.

I did some green sand ramming today but left my golf ball at home. I'll do some measurements tomorrow. As the molds are under aluminum foil, the moisture should hold pretty well til tomorrow.

Denis

 

Thanks Denis. Last one. Rammed the drag upside down so cope was not guided well during separation and made a mess so no pics of that.
Drag pics after dropping and doping spots with graphite and low angle light.
Newer Petrobond 130 sand, 1.5" drag, riddled, tucked, small rammer, Ttitleist DT golf ball, 5-12 dimples.

 

I rammed up a couple molds yesterday and drop tested one today. I had closed the first before remembering to do hardness testing. I used the Titleist Pro-V1 and got 12 to 15 dimples also. The diameter of the imprints from balls dropped 18 inches was 7/8" for two drops and 1" for another drop. Fairly consistent. Using a tube to locate the drop is helpful as it prevents errant drops from damaging important areas of the mold.

Your petro molds must be very comparable in hardness to my green sand molds. Like you, I do hope other folks will take a few minutes to roughly quantitate their ramming technique using the dropped ball method. This information is of general interest to me and would be very helpful for new people ramming molds as I recall how clueless I was in the beginning and how "adrift" I felt since there was no way to get a grip on just how firmly the sand should be packed.

BTW, those are very nice clear pics you posted!

Denis