black powder (separately milled/ screened) and wood discussion

[SignalKanboom]

I thought white ash was a very hard wood? It is in the harness scale at least, surprised it works well.

[SharkWhisperer]

I created a video a while back doing a few charcoal tests.

 

Charcoals used were

• White Birch
• Poplar (Silver or White poplar)
• Willow (have no clue which specie)
• White Ash

 

 

The best charcoal for BP was White Ash, only need 8% of shell's weight to lift it.

Willow is my "go-to" charcoal...this year at least because I have a bunch of it and it's super hot. ERC and alder are other local faves. ERC cuz it's simple, cheap, and fast (from Walmart) and alder shingles that make a very hot BP. I was surprised that your willow BP burn, though decently quick, was so sparky. I've never seen that with willow (mostly weeping willow), even slower formulations for core-burners. Almost looked pine charcoal-sparky, which is expected from pine but not really with willow. Maybe it was slightly undercooked and contained a significant fraction of uncooked volatiles? Maybe the particle size wasn't so small? Odd to me.

[MikeL]

I'm finally back on track. I have 375 grams of granulated Potassium Nitrate in the mill along with 35 pounds of lead media.

My first batch of pecan charcoal (relax, I'm just testing) weighed to 147g. I was surprised at how much charcoal I got from a few 1" twigs. I was also surprised by how "fluffy" it is and how it sticks to ev-ry-thing...

 

 

Now that I'm back to making BP let the questions begin:

 

(1) How long should I mill the Potassium Nitrate? I am milling enough to make five 100 gram batches of BP so not that much.

(2) I think I bought 4 pounds of KN0³, maybe only two, should I mill it all or just as I use it?

 

That's probably not all but it's all I have right now

[SharkWhisperer]

I'm finally back on track. I have 375 grams of granulated Potassium Nitrate in the mill along with 35 pounds of lead media.

My first batch of pecan charcoal (relax, I'm just testing) weighed to 147g. I was surprised at how much charcoal I got from a few 1" twigs. I was also surprised by how "fluffy" it is and how it sticks to ev-ry-thing...

 

 

Now that I'm back to making BP let the questions begin:

 

(1) How long should I mill the Potassium Nitrate? I am milling enough to make five 100 gram batches of BP so not that much.

(2) I think I bought 4 pounds of KN0³, maybe only two, should I mill it all or just as I use it?

 

That's probably not all but it's all I have right now

Nice looking charcoal! Mill a bunch to airfloat and store it with desiccant packets--it will absorb atmospheric water whenever allowed--up to 20% of charcoal weight can be water, which will mess up calculations for any composition (including BP) that uses it, Put it in a bag, beat it to small chunks/powder with a mallet and mill it. Personally, if I haven't used a batch of charcoal in a month (airfloat and with desiccant packets inchluded), I'll recook it in the oven for an hour at 250F or so (it will not start on fire) before use. Charcoal grabs atmospheric water easily. Like all powdered charcoal, there is a risk of making a huge mess if you're not careful. Even when being super cautious, I always leave black fingerprints in places that gets my woman's attention (and a scolding, ack!). My life is at risk on blackmatch-manufacturing days!

 

KNO₃. If you bought it milled, it should be fine. If granular like table sugar, then that's about 40-50 mesh and definitely needs milling to powder that you cannot feel granules between your fingers, at a minimum (that's around 200 mesh; finer is even better). I have granular nitrate (like table sugar) for cooking sugar rocket propellant, but usually pay the extra dollar/pound at FWC for pre-milled nitrate. Worth it to me, using hobbyist quantities. I also cook my potassium nitrate (also 250F for a bit, though that's flexible) before storing/using. KNO₃ is moderately hygroscopic (water attracting), too, but not as badly as charcoal. Sulfur for BP is ignored--no worries about water absorption. If you can feel granules between fingertips, your nitrate (and essentially any other chem in pyro) is too course.

 

You can make great BP with both granulated (sugar-like) or pre-milled powder. If you're starting using granulated nitrate, then you'll have to mill your comp longer. No problem, but a time waster. BP mill powder should be airfloat throughout...and it helps if you have finely powdered ingredients to begin with. Not a necessity, but a nicety. And easier to replicate.

 

I always bake my charcoal, potassium nitrate, and strontium nitrate before use, unless having done so within the prior month and stored airtight with desiccant (can't overemphasize utility of desiccant packets. Simple, provides good consistency, and just a good way to avoid headaches.

 

 

edited for clarity...

Edited December 6, 2020 by SharkWhisperer

[MikeL]

Thanks for the details. My gray matter needs it. I need to pick up some desiccant packs. I have some that came with my 3D printer filament but I doubt if they are any good by now. Speaking of that, the professional 3D printer (the kind that make parts out of more exotic filament that need high temperatures) for a living) people dry their filament by heating it to 250 (I need to figure out if they mean C or F. I think they mean C) if the filament can handle it, then put it in a vacuum chamber. Air conditioning and refrigeration people also use a vacuum to removed inerts, moisture, etc. Do you know of anyone in the pyro world that does that? It's not overly expensive and definitely not anymore complicated than turning on a ball mill. Heating is accomplished in a cheap convection oven (not the wife's...).

 

The KNO³ was in the ball mill for about 8 hours. I haven't check the results yet. The charcoal in the pic was in for about 9 hours. I didn't crunch it up first but I will next time. I haven't dumped it yet. I used my spare drum for the KNO³ so I wouldn't have to clean the charcoal out the other one. I think I'll keep them separated. One for charcoal, one for whatever else needs milling,

 

I bought the KNO³ granulated. It was cheaper but was it?

 

Should I wait until I have granulated it to test or test the mix first?

Edited December 6, 2020 by MikeL

[SharkWhisperer]

Thanks for the details. My gray matter needs it. I need to pick up some desiccant packs. I have some that came with my 3D printer filament but I doubt if they are any good by now. Speaking of that, the professional 3D printer (the kind that make parts out of more exotic filament that need high temperatures) for a living) people dry their filament by heating it to 250 (I need to figure out if they mean C or F. I think they mean C) if the filament can handle it, then put it in a vacuum chamber. Air conditioning and refrigeration people also use a vacuum to removed inerts, moisture, etc. Do you know of anyone in the pyro world that does that? It's not overly expensive and definitely not anymore complicated than turning on a ball mill. Heating is accomplished in a cheap convection oven (not the wife's...).

 

The KNO³ was in the ball mill for about 8 hours. I haven't check the results yet. The charcoal in the pic was in for about 9 hours. I didn't crunch it up first but I will next time. I haven't dumped it yet. I used my spare drum for the KNO³ so I wouldn't have to clean the charcoal out the other one. I think I'll keep them separated. One for charcoal, one for whatever else needs milling,

 

I bought the KNO³ granulated. It was cheaper but was it?

 

Should I wait until I have granulated it to test or test the mix first?

If you're milling it, you'll get where you want to eventually. I'd imaging 8 hours of milling granular nitrate has it about as fine as baby powder with most normal grinding media. Never needed to mill charcoal more than a few hours to get airfloat, even with an old hobbyist HF rock polisher. It's just easier to standardize milling times/loads when you use the same starting materials. You can also get your nitrate (and charcoal--separately) to a fine powder in a coffee/spice grinder if you're in a pinch. The charcoal risks making a big mess, though, so be careful and don't open it inside. If you decide to premill in a coffee grinder, please take care to wash it out thoroughly if you're switching between oxidizers and fuels in the same unit, so no chance of accidental ignition. And in models that aren't sealed very well, the airfloat dust can get into the motor. A lot of people use agricultural/fertilizer KNO₃, which comes in prills/pellets that is super cheap but takes time to get to dust--I'm lazy and that doesn't really interest me strictly for the cost savings. I buy pre-milled and call it good.

 

Most desicccant packets are pretty inert and don't really get old (they do get dirty, especially in charcoal containers. I use silica beads inside tea-bag material that contain color-changing beads that go from orange to green when water saturated. Then they just go in the oven for 30 minutes at the lowest setting (or whatever setting I'm cooking other chems), and they're orange and dry again. I mostly use 10g packets easily available on Amazon, but you can find large quantities elsewhere. The dollar store probably has big packets of calcium chloride for hanging in closets in humid environments, but those are both too big for me and a mess risk because they turn to liquid eventually. I'm happy with silica/drierite beads. Probably very similar to what came with your printer filament, except larger packets. You can get them in any size you want. I typically use a 10g packet on top of chems in a liter/quart containers, with good results. A few more packets in larger containers. They work well and you can instantly see if they need replacing. I only use in KNO₃, strontium nitrate and its formulations, all charcoals (after milling), and BP powder and granules. And in my 3-foot mailing/poster tubes containing BM. Not really necessary, for me, in anything else. But clumping BP in the mill drove me completely nuts until I realized the simple fix.

 

I test my BP both fresh out of the mill and after wet granulation. The burn rate out of the mill gives me a very good indication of how fast it'll burn after granulation. On a subjective 1-10 scale (10 being almost like slow flash), I often get 8/10 out of the mill (with willow) and that'll increase at least to 8.5 to 9/10 after wet granulation. Definitely faster burning than the same particle size as Goex or other commercial BPs--they're made to burn evenly and repeatably to propel a ball or sabot, not necessarily the fastest formulation possible. Uniformity is key. For us pyros, too. I like fast--you can always slow it down. The times I've not pre-dried my charcoal (or used it straight out of the retort), I've gotten crappy clumping and slow burn rates (sometimes 6/10 pre-granulation). For lift, you can just use more powder, no problem. For burst, you might be limited in available volume in the shell and want a faster powder. For rockets, you want your powder to be consistent, whether medium or high speed. Else a hot batch will give you CATOs and a slow batch won't launch your missile to a safe altitude. Me? If it burns slower than my subjective targeted minimum of 8/10 (unless it's designed slow, like 60% core-burner rocket fuel), then it goes into fountains and gerbs. Maybe I'll soup it up a little with some metal to prime stars or use it to make blackmatch.

[MikeL]

One thing that helps me here (NM) is the relative humidity is low. 14% in the house. Not sure about the garage.

 

I can't imagine grinding charcoal in a coffee grinder. That stuff goes everywhere The one time that I've been good with mask wearing is working around that and the KNO³ that I milled. I still need to dump last nights charcoal milling results. I'm kind of curious about how it did.

I learned a few things. KNO³ is interesting to ball mill. It was stuck to the lead balls. Not bad but I felt like I was leaving "good stuff" behind. It's got a gray color to it (probably lead), and it made a few balls that were hard to break while it was in there. Like this (the big one looks like a lead ball but it's very light):

 

I combined the three chem's with a 100 mesh screen. This is all that wouldn't pass thru on t he third screening

 

My 100g batch of chems made 93g of BP :/ I'm not sure why 7% disappeared. Some was left on the 100 mesh screen, some may have spilled but not 7g

 

 

And finally, this is the test. I used some cannon fuse to light it. This is literally the dust that I wiped off of the tray that I mixed it on (screen on top of the tray, the tray collected it)

 

BP Test

 

If it'll work for ejection charges that's a good start. My setup is pretty clunky. The workbench is a stack of 2x4's on sawhorses.

Edited December 6, 2020 by MikeL

[MikeL]

This is a shot of the "leftovers" that I got out of the second attempt at milling charcoal

 

 

I tried to crush it with a hammer and it's wood. I didn't cook this batch long enough.

[MikeL]

I just remembered another valuable lesson. If you're going to test BP it's really important to have a way to light the mix or fuse for the mix

I don't smoke... so when it came time to light the fuse I didn't have a way to light it. Thankfully the person that was renting this place before me left an old Bic lighter behind and I had put it in a closet.

[SharkWhisperer]

One thing that helps me here (NM) is the relative humidity is low. 14% in the house. Not sure about the garage.

 

I can't imagine grinding charcoal in a coffee grinder. That stuff goes everywhere The one time that I've been good with mask wearing is working around that and the KNO³ that I milled. I still need to dump last nights charcoal milling results. I'm kind of curious about how it did.

I learned a few things. KNO³ is interesting to ball mill. It was stuck to the lead balls. Not bad but I felt like I was leaving "good stuff" behind. It's got a gray color to it (probably lead), and it made a few balls that were hard to break while it was in there. Like this (the big one looks like a lead ball but it's very light):

 

 

I combined the three chem's with a 100 mesh screen. This is all that wouldn't pass thru on t he third screening

 

 

My 100g batch of chems made 93g of BP :/ I'm not sure why 7% disappeared. Some was left on the 100 mesh screen, some may have spilled but not 7g

 

 

And finally, this is the test. I used some cannon fuse to light it. This is literally the dust that I wiped off of the tray that I mixed it on (screen on top of the tray, the tray collected it)

 

BP Test

 

If it'll work for ejection charges that's a good start. My setup is pretty clunky. The workbench is a stack of 2x4's on sawhorses.

Not to be an arse, but that sees to be some pretty slow-burning BP. The nitrate sticking to your lead media might indicate moisture--I've never experienced that, even before I started baking my nitrate in the soulsuckingly humid southeast. Your nitrate will pick up some lead and turn it grey if you're not using hardened (antimony added) lead balls. I ignore it. Others are more concerned about lead exposure. If your charcoal isn't cooked all the way through, there's going to be a lot of variability in the residual volatiles that are left behind, and in porosity, so aim for consistency (easier if all wood pieces are similarly sized before cooking). I find it faster to bust up charcoal sticks with a hammer in a thick contractor's plastic bag or doubled-up gallon Ziplocks (some use a 2" x 4" and 5-gallon bucket) before milling--if I ever saw uncharred "wood" remaining during hammering sticks, I'd stop right there and consider a re-cook. I certainly wouldn't trust the charcoal I recovered to be at its best. Tis all about learning the nuances, and you're on your way. It's really a simple process, and once you get it it's like riding a bicycle--you'll laugh at yourself for all the efforts you required for it to become second nature. This was just screen mixed after individual component milling, right? Dunno...some folks here love screen mixing and demonstrate using it to make hot BP. Me? Nope--I'll stick with milling all components together (except for star primes and some charcoal star comps--screen mixing is just fine for those). But for reliably hot BP--I always mill together. To each their own, so long as it works for your desired purposes. Good start!

 

[SharkWhisperer]

I just remembered another valuable lesson. If you're going to test BP it's really important to have a way to light the mix or fuse for the mix

I don't smoke... so when it came time to light the fuse I didn't have a way to light it. Thankfully the person that was renting this place before me left an old Bic lighter behind and I had put it in a closet.

You will soon get tired of burning your index finger and thumb when lighting visco fuse with a Bic lighter or similar. At the very least, get a longer 88-cent grill lighter from the Walmart camping section. They're kinda crummy, though.

 

Better, and a great investment, is a basic torch head that screws onto a skinny canister of propane--I have a basic Benzomatic that cost about $15. Fuel is 3-4 $ for a 16-ounce canister. Lasts a long time and great for igniting hard-to-start comps in addition to fuse. No more burnt fingertips from visco spitback!

 

Suggestion to test your BP burn on a sheet of basic white writing/copy paper. You want a fast burn, minimal residue, and no through-the-paper char holes. You're still in the optimization stages until you get to that point, and from then on making good BP will be ingrained and second nature to you.

 

p.s. You're right--charcoal in a spice grinder could be a messy disaster!!!

[MikeL]

 

 

You will soon get tired of burning your index finger and thumb when lighting visco fuse with a Bic lighter or similar. At the very least, get a longer 88-cent grill lighter from the Walmart camping section. They're kinda crummy, though.

 

That happened about the third !^$* that escaped. Holding that damn lighter upside down plus the spitting fuse wasn't fun. I ordered the basic torch head you mentioned.

 

Just to be sure I understand - place x grams of powder on a white piece of paper. Light the powder or the paper?

 

 

 

Not to be an arse, but that sees to be some pretty slow-burning BP. The nitrate sticking to your lead media might indicate moisture--I've never experienced that, even before I started baking my nitrate in the soulsuckingly humid southeast. Your nitrate will pick up some lead and turn it grey if you're not using hardened (antimony added) lead balls. I ignore it. Others are more concerned about lead exposure. If your charcoal isn't cooked all the way through, there's going to be a lot of variability in the residual volatiles that are left behind, and in porosity, so aim for consistency (easier if all wood pieces are similarly sized before cooking). I find it faster to bust up charcoal sticks with a hammer in a thick contractor's plastic bag or doubled-up gallon Ziplocks (some use a 2" x 4" and 5-gallon bucket) before milling--if I ever saw uncharred "wood" remaining during hammering sticks, I'd stop right there and consider a re-cook. I certainly wouldn't trust the charcoal I recovered to be at its best. Tis all about learning the nuances, and you're on your way. It's really a simple process, and once you get it it's like riding a bicycle--you'll laugh at yourself for all the efforts you required for it to become second nature. This was just screen mixed after individual component milling, right? Dunno...some folks here love screen mixing and demonstrate using it to make hot BP. Me? Nope--I'll stick with milling all components together (except for star primes and some charcoal star comps--screen mixing is just fine for those). But for reliably hot BP--I always mill together. To each their own, so long as it works for your desired purposes. Good start!

No worries. It's all an experiment. My ego is nil at this point. Ego blocks the ability to learn. I was underwhelmed by my burn test too. I was hoping for wow and expecting that sucked

.

Definitely moisture in the unmilled stock. I've had it in the garage (sealed) for a couple of weeks and it went from bag to mill. Next batch I'll dry. The milled stuff will need to be dried but I'll wait for the dessicant to get here. I got my media from Woody's so it should be hardened.

 

The charcoal that had the leftovers in it is stuff I made on the last trip home. The BP I made today was made from the first charcoal batch. It was cooked all the way through. I'll break the next batch up before I take the time to mill it.

 

 

 

This was just screen mixed after individual component milling, right?

 

Correct

 

 

 

Dunno...some folks here love screen mixing and demonstrate using it to make hot BP. Me? Nope--I'll stick with milling all components together (except for star primes and some charcoal star comps--screen mixing is just fine for those). But for reliably hot BP--I always mill together. To each their own, so long as it works for your desired purposes. Good start!

 

Here in NM there's no good place to set the mill up for milling it all together. After finishing a batch using the screen mix technique I'm all for using the mill to mix. I think my neighbors would be upset with me if I put the mill in their backyard I'm headed back to TX in a few weeks. The mill is coming with me. I'll mix some BP up that way once I have some breathing room. Plus I can make some ejection charges and play with those using a cheap, sort of, remote control rocket launch controller.

[SharkWhisperer]

I've never had nitrate alone clump up or stick to my milling media, but then again I rarely mill it alone. It can pick up a few % of moisture, but charcoal is a bigger concern because it can absorb a lot of atmospheric water and still look dusty (until you mill it into BP and it forms a rock-hard clump). It can really throw your formulations off because you have a variable % of charcoal in them, depending on how much water it's kidnapped from the air. Low humidity NM and TX are your friends.

 

Woody's has a good rep (I've got a nice rocket tooling set from him) and the hardened balls should last longer than pure lead. That said, I pretty much use plain old lead musket balls and they have lasted years without too much size reduction, so I have no first-hand knowledge about how much lead hardened balls can shed. Guessing even hardened media can lose a little lead, hence your grey nitrate. Others would have a better idea.

 

For burn tests, I typically use a half gram or a gram of BP and stick a fuse in the center of the small pile (or edge...you pick). Sometimes I just fold a small piece of paper in half, add powder, and light a corner while it's hanging over a flat rock or the edge of the workbench. Usually I use fuse. Either way, you'll immediately know how fast your BP is. It should go whoosh and be gone. Visco/Bic burns get annoying quickly---you'll appreciate your torch!

 

You're on your way. Good luck on the next run!

[belmec3825]

I don't know where you got your information because Paulownia does grow in the U.S. In fact, it is considered an invasive species because it grows so fast that it "shades out" native trees. It also is very prolific and is banned in some states. Other names for Paulownia are Empress trees and Princess trees. As far as good wood for making BP charcoal, I have had very good success with either cedar or black willow. I live in northern Missouri and there are cedar tress EVERYWHERE around here. If you want to look for black willow, look around ponds and stream banks. these trees love being around water

I too like the cedar wood. I get all I want from my local yard waste/compost sites. I like how easy it splits to add to my retorts and it doesn't take long to make it into charcoal.

[Sourdough]

How are you measuring how fast you bp is? I use angle iron, place a 30 track 1/8 inch deep in the angle, and then time the burn with a video stopwatch. Other thoughts?

[MikeL]

Most of the time I just put it in the trough of some roofing tin that I pulled off of an old building (actually the building burned down. Not pyro related). Then I relied on more experience here to let me know. The corned powder was so much faster I didn't need a timer. It was just gone. I'm VERY new so take anything I say with a grain of salt (from a 100 mesh screen )

[SharkWhisperer]

How are you measuring how fast you bp is? I use angle iron, place a 30 track 1/8 inch deep in the angle, and then time the burn with a video stopwatch. Other thoughts?

If you want to know your BP burn characteristics to the cm/ms, for that specific grain size (and range, and proportion of subranges), then that's a decently scientific way to compare two or more powders burn rates. But the ambient temp and humidity are appropriately controlled/matched, right? and the exact mass and powder distribution is standardized, right? And there are better electronic means to determine actual burn start/stop times than a stopwatch.

 

While that measure of evaluation is admirable, for most of us whose purpose is to accumulate quantities of relatively uniform performing speedy BP, that degree of evaluating burn rate precision is, while interesting, often not the best use of time. With decent charcoal, fast is fast, and "fast enough" is easy to reproduce consistently, eventually. And sufficient for essentially all pyro needs. If I could stopwatch measure a 30 inch (cm? don't know what "30 track" means), line of granulated BP and it didn't appear to vanish almost immediately from one end to the other--way too fast for me to push a stopwatch button twice (with repeatable accuracy)--then I'd consider that pretty slow BP and go make a few fountains.

Edited January 7, 2021 by SharkWhisperer

[Carbon796]

How are you measuring how fast you bp is? I use angle iron, place a 30 track 1/8 inch deep in the angle, and then time the burn with a video stopwatch. Other thoughts?

Most real pyro's probably are not doing open trough tests. They don't provide any useful applicable information. And, can be unreliable.

 

You should be doing mortar lift tests. If you want useful pyro information. You need to be able to compare its ability to do work ( provide motion )

 

Or timed spolette tests could also be useful. Given that the standard for a 1" #4 spolette with commercial BP is 3 seconds.

[Sourdough]

Thanks Shark - bad typing on my part. I use 30 of a 48 angle. The stopwatch is a video app with an imbedded stopwatch counter on the screen measuring in 1/100th of a second. I just subtract the counter when the flame gets to the beginning of the 30 from the counter when it gets to the end of the 30. I can go forward and back one frame at a time so it can be pretty precise. I test multiple powders made with the same method but from different charcoals, and any comparison tests are done on the same day under the same conditions. The powders are all screened -30+40, and are leveled to a uniform 1/8 inch with a block that slides along the track leaving 1/8 inch behind. They powders are all stored in my magazine so moisture content should be similar.

 

My old eyes just cant tell the difference from lighting a 1/2 teaspoon of paulonia or pine or balsa or grapevine etc... the burn times look similar but the burn rates on the 30 track can be bery different. Im not really trying to determine which is best for which pyro application, im just trying to see which charcoal and method makes the fastest powder for me, and then how it compares with powder someone else makes. Thanks for the replies.

[Sourdough]

30 inch and 48 inch. Apparently the quote marks that were typed after the numbers are not coming through. Sorry.

[justvisiting]

Interesting stuff! In the BP charcoals study in Pyrotechnica 17, Roger O 'Neill used spolette burn times as one measure of BP speed. In order for that method to be reliable, identical amounts of powder need to be compressed at identical densities. He used 6500psi to press the spolettes.

 

A lot of us bat around numbers and testing methods, and often we criticize the accuracy of different testing methods. It's good that we care enough to worry about details, but to get too carried away is not productive. I know from personal experience that my baseball flight times using identical amounts of identical powders have natural differences in the flight times. That's why one flight is not necessarily representative of the batch- or is it? Sure, an average of 3 flights seems more representative, but in actuality, all 3 samples properly represented the batch, because the variation is natural- in my lay opinion.

 

One might say that baseball testing isn't accurate, with flight times that can vary by a whole second between identical samples of the same powder. It may not be the most accurate testing method, but it is the most 'real world' testing method for shell lift. Because of the natural variations, I made sure to include all individual flight times in my BP articles- so the reader can see that. The natural variation in flight times show me that the 1/5 second graduations on my mechanical stopwatch are well within the realm of accuracy needed.

 

Another observation I'm sure many of us has made is that all 3" shells- even of the exact same weight- do not rise to the same height in a display. The natural variations in baseball flight times are in line with the natural variations seen with live shells. These natural variations may be due to wind, the wrappings of shells, the strings on baseballs, etc. One variation that is NOT natural is the variation seen when pouring in powder loosely into for testing lift, ESPECIALLY if more than one test is being done. If you do testing this way, you might as well just be guessing. It's a bad (common) practice. Shells have lift cups. My baseballs have lift cups