January 29, 2008 12:08 PM   Subscribe

PISS LASER! How to use urine most efficiently in carving of urinal cake?

In one of those quixotic quests to amuse myself in an office building, I've been attempting to piss in the same place into a urinal cake every day, hoping to carve a hole through. But lately, the sheer numbers of people pissing in another, more obvious place on the cake (I picked mine because it was accessible and unlikely to be hit by as many confounding streams) have been digging deeper and faster than I have.

There have to be tricks of angle, or of motion, that will allow me to cut faster with roughly the same amount of urine. Should I be trying to hold steady on a single point, should I be attempting to hit it head-on, should I be attempting to change the chemical composition of my urine? What are the secrets used by miners with high-pressure hoses?
posted by klangklangston to Grab Bag (33 answers total) 35 users marked this as a favorite
How about Waterpik? You wouldn't be limited by using only your own urine.

Or you could try to get really good at passing kidney stones, although you might just end up pulverizing the suckers.
posted by hydrophonic at 12:21 PM on January 29, 2008

Get your hose as close to the cake as possible. Exercise your bladder muscles, and pinch your hose a bit - constriction = greater force.
posted by yesster at 12:25 PM on January 29, 2008

Drink more water.
posted by studentbaker at 12:27 PM on January 29, 2008 [1 favorite]

Remember - short, controlled bursts.
posted by cashman at 12:27 PM on January 29, 2008 [1 favorite]

A worthy assignment for sure. I'll agree with those who say that its force rather than a steady flow which should erode the bastard. Try the wee-wee equivalent of a glancing blow, as that might weaken it structurally. Oh, and I'd recommend lots of water AND coffee to really get the job done.

Best of luck!
posted by ob at 12:35 PM on January 29, 2008

Response by poster: Waterpik? That's fundamentally against the premise—Piss Laser!

As for more water, sure, though it's really going to be more coffee. But I was looking for ways to increase the effectiveness without drastically increasing my output.
posted by klangklangston at 12:36 PM on January 29, 2008

cashman Remember - short, controlled bursts.

Hhahah. Pew pew pew!

Seriously though, what kind of urinal cakes do you have? If you can't get the brand, do you have details on color, texture, size, shape, etc? It might be difficult to bore a hole straight through, since your urine will end up all over the cake, so I'm thinking the highest pressure is the way to go. Not sure "pinching" as yesster suggests will help, I think that might actually reduce the flow instead of increasing force.
posted by Grither at 12:37 PM on January 29, 2008

Get your hose as close to the cake as possible. Exercise your bladder muscles, and pinch your hose a bit - constriction = greater force.

Be moderate. I won a beer-fueled "piss for distance off the dorm balcony" contest (soundly trouncing yerfatma and another suitemate) and something in there hurt for a couple days afterward. Totally not worth it to destroy a urinal cake or to arc over the grass into the dorm parking lot.
posted by Mayor Curley at 12:45 PM on January 29, 2008

Response by poster: Urinal cake is visible here.
posted by klangklangston at 12:52 PM on January 29, 2008

Oh, man, all bets are off -- it's in a cage. I would venture to say that all the above comments assumed a free-standing cake.
posted by Guy_Inamonkeysuit at 12:56 PM on January 29, 2008

Response by poster: It's in a cage, but I can pretty successfully thread the holes, which I've been doing.
posted by klangklangston at 12:57 PM on January 29, 2008 [1 favorite]

This is a problem of chemistry and physics, and I doubt you can infuse your urine with particulates or acids in quantity enough to make an improvement on its corrosive or frictional power. High pressure seems perfectly logical, and I think a consistent angle is sufficent, in short bursts, though you already experience the benefit of some potential cake breakdown between pissings.
posted by Ambrosia Voyeur at 12:59 PM on January 29, 2008

Since urination is a gravity-feed process, and is not driven in any significant way by bladder pressurization, constricting bladder sphincters will not increase outlet pressure. The only way to increase flow velocity is through harnessing more gravitational energy, which is to say you must piss from on top of a step-ladder.

For rough estimates, pee velocity (V_p) will be proportional to the square root of the height of the bladder above the urinal cake. Actual results will show a more rapid increase in velocity as this estimate does not take into account frictional losses within your internal plumbing.
posted by cardboard at 1:02 PM on January 29, 2008 [1 favorite]

cardboard clearly doesn't know what he is talking about. As amusing as it would be to see you peeing from a step-ladder, you most certainly CAN increase velocity of your urine stream by "pushing" harder. Also, the further away you pee from, the less accurate your stream will be, which goes against your hole-digging goal.
posted by Grither at 1:05 PM on January 29, 2008

You should decide at what distance your stream is most concentrated. Find someone equally enthusiastic about this endeavor to lend you a hand.
posted by studentbaker at 1:06 PM on January 29, 2008

Ah, The base is commonly pure paradichlorobenzene or naphthalene, says wikipedia. Non-water soluable. So your next question might be what you can eat to infuse your urine with benzene solvents.
posted by Ambrosia Voyeur at 1:08 PM on January 29, 2008

Quite the golden thread you've started. "You're in" the running for favorite time-wasting thread =P

I second Burhanistan's ratio idea -- I'm sure there's an optimum distance that accounts for greater momentum via gravity and deterioration of the stream by the air in between release and target, but it would take numerous experiments to procure that information. I also second studentbaker's suggestion to up the intake of water (whereas caffiene is said to have dehydrating properties) and possibly for holding it for longer than usual to gain an optimal natural pressure without the need to strain. I would avoid attemping to produce an arc, as the momentum would be reduced, I presume.
posted by vanoakenfold at 1:42 PM on January 29, 2008

Urine dispersal is a result of turbulent transition in the flow stream. The Reynold's Number (Re) is the product of urine velocity (V_p) and urine shaft diameter (d_u) divided by the kinematic viscosity of urine which will likely remain relatively constant within the bounds of good health. It is acceleration due to gravity which both increases V_p and decreases d_u (bounded as it is by conservation of mass principles). d_u will decrease to the point where surface tension effects become significant enough to break the stream into droplets.
posted by cardboard at 1:51 PM on January 29, 2008

Nix the short controlled bursts unless you have significantly increased your water or gatorade intake. You lose a substantial amount of fluid trying to recalibrate your aim in the interim between bursts.

Maybe just use the bursts to get a nick started, then once an area is exposed, focus on it exclusively.
posted by cashman at 1:53 PM on January 29, 2008

whereas caffiene is said to have dehydrating properties

Because it's a diuretic.
posted by ob at 1:56 PM on January 29, 2008

Forget all the science foofahraw and go for the tried and true volume, volume, volume method.

Start chugging equal parts water and coffee/caffinated beverage. The caffeine is a mild diuretic, which will get the pipes pumping.


And, uh, watch out for the all that Freud in the last sentence.
posted by unixrat at 2:01 PM on January 29, 2008 [5 favorites]

Mod note: a few comments removed, even a great question still deserves its share of decent non HURFDURF answers, no?
posted by jessamyn (staff) at 4:37 PM on January 29, 2008 [1 favorite]

Hm. This Yahoo! answer implies that alcohols help break down 1,4-Dichlorobenzene (urinal cake) more effectively. Get rip-roarin' drunk before you go into work?1

1This may enhance the piss laser, but may degrade the paycheck.
posted by WCityMike at 4:44 PM on January 29, 2008

Also, watch it with the diuretics. You don't want gout.
posted by WCityMike at 4:45 PM on January 29, 2008

Kegels to build up your strength.
posted by plinth at 5:25 PM on January 29, 2008

Here's some stats on alcohol excretion in urine. Apparently if you drink a "moderate amount," you only piss out ~1% of the alcohol you drink. (The rest you excrete some other way, or metabolize into something else.)

Someone who knows more about how solvents work will have to tell us what that means for klanklangston's sobriety and employment prospects.
posted by nebulawindphone at 5:36 PM on January 29, 2008

Since urination is a gravity-feed process, and is not driven in any significant way by bladder pressurization... pee velocity (V_p) will be proportional to the square root of the height of the bladder above the urinal cake...

What!? I suspect that most parents of baby boys would disagree with you.
posted by jpdoane at 8:15 PM on January 29, 2008 [1 favorite]

How do you feel about pumps attached to your cock?
posted by Ambrosia Voyeur at 8:21 PM on January 29, 2008

Response by poster: I'm going to eschew, generally, the "get drunk at work" suggestion, unless I can get someone higher up to take me to a martini lunch. But working with a bunch of recovering alcoholics makes it harder to come in stinking.

I am also opposed to pumps—the purpose of this is to carve sheerly through manpower, as it were. Last time there was a new urinal cake, I was able to drill a hole through in just over a month, but this time, due to personnel changes, there are more pissers focusing on a higher spot, and I want to beat them through, purely by my (our) wit and piss control. Any sort of implement or accoutrement would be cheating, even if they don't know we're in a contest.
posted by klangklangston at 10:05 AM on January 30, 2008

Best answer: Err. I've done this. Volume is the best way to increase your erosion, of course, but I also found that an angle of about 30 degrees (I'm estimating) from perpendicular seemed to get the best results. I also had much better luck hitting nearer the edges rather than the middle. I have no scientific reason for saying this, only personal experience.

You should note that if you try this with multiple cakes to see which techniques work best, your results will be extremely unreliable. Whether it's because of a lack of quality control in the urinal cake industry or inconsistency on the part of the people ordering them, there's a huge variation in the erosion from cake to cake. There've been some that I could barely dent, and some that I could get small chunks to break off in a single session, both in the same kind of cages at the same place.
posted by fidelity at 9:12 AM on January 31, 2008 [1 favorite]

Obviously, the ideal controllable factor is pressure, and pinching or external pumps will probably have minimal effect. Because biology leaves us with little control over the slindle (the technical name for the opening at the end of the penis), the first step is to insert a glass pipette, preferably one whose diameter narrows at the external end. Be sure to insert this as far as possible, as you don't want it to accidentally slip out--the back splash will make everyone think you are spastic upon your return from "the facilities."

And while plastic is an adequate substitute, glass really does function better. If you are concerned about breakage, then I recommend 316-stainless steel. You don't want any rusty damn plain steel or cheap cast iron.

This part only offers hope of a more controllable direct stream. To fully mechanize the operation, you clearly need to insert a pump inside the bladder. I recommend the Geoprobe model MBP470. The advantages over pneumatic bladder pumps hardly need to be stated here.
posted by beelzbubba at 9:04 AM on February 3, 2008 [1 favorite]

I wonder if anyone has every hollowed out a urinal cake and filled it with alka seltzer.
posted by mecran01 at 9:48 PM on May 10, 2008

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