## Pennies in Boxes

A forum for good logic/math puzzles.

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markdennehy
Posts: 2
Joined: Mon Oct 01, 2012 3:31 pm UTC
Location: Ireland
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### Re: Pennies in Boxes

This one seems far too easy. Or maybe it's just easy if you know what the phrase "Irish Mammy" means

Spoiler:
Half-fill a washing machine with boxes. Run whatever is the machine's shortest cycle that involves a hot rinse, omitting detergents and softeners. Remove contents of drum (be thorough), spread on a compost sieve (ie. a frame with chicken wire stretched over it) and shake that over a large basin of water, extracting the pennies which sink to the bottom.
Hmmm.
The average washing machine drum size is about 70-odd litres (the largest that fits in a standard cabinet is 78 litres) or 0.07 cubic metres; that's 8750 boxes, but divide that in half because of packing hassles and because you want space in the drum, and you get around 4375 boxes - lets call it 4000 for a round number. So we need 31,250 cycles which take a conservative 30 mins each between the shortest wash cycle you have (and interrupting it if it's too long) and the compost sieve; that's 15625 hours, or 7.8 years working 8 hours a day, 5 days a week, for a total revenue of \$1.25 million. Mindnumbing work but at an average wage of \$160k per annum, not horribly unrewarding. Besides, after the first month or so, you could automate the whole process...

Alternatively, tip all the boxes out onto the ground, spread them out a bit so that they're in a single layer (touching is fine), then set fire to one corner of your layer and let the fire burn through the boxes in a wave. Just because cardboard burns at a higher temperature than pennies melt (and aren't US pennies an alloy with a higher melting temperature?) doesn't mean that there's enough thermal energy released in burning one small cardboard box (or transferred for that matter) to melt one penny... though I'd test this on one box first So long as all the pennies aren't immersed in a large long-burning mass, the heat dissipates upwards into the air and the damage should be only cosmetic.
Average cost of bonfire fines <<< \$1.25 million

*ahem* Reposted because I missed rule 3 the first time reading them
(And because the math was bugging me so I went back to confirm it)

dudiobugtron
Posts: 1098
Joined: Mon Jul 30, 2012 9:14 am UTC
Location: The Outlier

### Re: Pennies in Boxes

undecim wrote:
freakish777 wrote:
Felix Griffin wrote:Good luck getting a hold of large amounts of sulfuric acid without arousing the suspicion of the FBI...

I'm sure the box itself has already accomplished this.

If the box could get hold of a large amount of sulphuric acid (whether or not this alerts the FBI), then I think how to get the pennies out of it are the least of your worries.

mward
Posts: 121
Joined: Wed Jun 22, 2011 12:48 pm UTC

### Re: Pennies in Boxes

Felix Griffin wrote:Concentrated sulfuric acid doesn't damage copper, does it?
Copper reacts quite slowly with sulphuric acid, but pennies are 97.5% zinc (core: 99.2% zinc, 0.8% copper; plating: pure copper), so once the thin plating has been breached, the penny will dissolve rather quickly.

Tyndmyr
Posts: 11354
Joined: Wed Jul 25, 2012 8:38 pm UTC

### Re: Pennies in Boxes

Spoiler:
Fire is the easiest way to get rid of the cardboard. For a million and a quarter, I'd gladly violate local burning regulations.

That said, by controlling oxidization, I could pretty easily manage the rate of the fire to avoid it getting ridiculous, or melting the pennies. Hell, since I only need to melt the smaller boxes, I can literally just have a small fire going which I toss handfuls of little boxes into.

trickykungfu
Posts: 22
Joined: Tue Oct 24, 2006 7:51 am UTC

### Re: Pennies in Boxes

Just a thought for the folks who are proposing spreading out boxes: this is a ~3 story tall cube. If you perfectly arranged all of the boxes in a single layer, you'd need 10m*10m*500 = 50,000 square meters of space. That's about 12 standard american football fields, not counting end zones.

Same goes for solutions that involve breaking the whole thing down with various chemicals. Just the massive scale of the thing means you'd have a serious hazard on your hands if you were to dump enough acetone on it to dissolve all the cardboard.

And I'm just assuming for the case of this puzzle that you do not live in a mansion; this delivery in fact already takes up most of the space in your back yard. A pretty normal lot size for the cities I've lived in would be about 10 meters wide, and maybe 40 deep. Your front yard and your house take up space, of course, so let's just assume this mysterious package takes up your entire back yard, with a 50 cm border on each side for you to walk around. So make sure your solution doesn't destroy your house, or your neighbours' houses.

Also, be careful how you open the big box! I mean, it seems like an appealing idea to just cut it apart so you can get at the little boxes inside--but then you're risking an avalanche of tiny boxes seriously injuring you, or worse yet a neighbour or passerby who is feeling litigious. (This is happening in the U. S. of A., after all. We're probably going to have to transport the boxes off-site to get them opened, and we're gonna have to do it fast, because who knows when the elements will cause the structural integrity of all that cardboard to break down?

So given those considerations, I'm thinking we've got to rent some serious construction equipment just to open the box and safely get at the smaller ones: let's say, a 12m cherry picker, a chainsaw, a big dump truck, and a chute. You cut it open near the top, setup the chute going down to the truck, and start the box avalanche.

Now, a dump truck holds about 25 cubic meters. Let's assume we get pretty good packing efficiency, and manage to fit the equivalent of 20 cubic meters of perfectly packed boxes per load. That means we'll need 50 trips to get them all, plus a crew of 3-4 people--more once you get closer to the bottom and have to hoist the boxes up into the truck instead of letting them roll down. Since your house is in a residential area, the closest warehouse you could find to rent out as temporary storage for all your boxes was a little more than an hour's drive away, so each load takes 3 hours total to load up, drive to the warehouse, unload, and come back. We're looking at ~400-500 man hours just to get the boxes out of your back yard and keep them from hurting anyone, plus rental costs of the equipment and the warehouse (and it's a pretty big warehouse you'll need, so that ain't cheap either.)

The good news is, now that you're out in an industrial area, you have more options for dealing with all that cardboard. Maybe you could even get a permit for the bonfire? I dunno, I've got some work to do, so this is where I leave off...but maybe someone else can expand on this.

Tyndmyr
Posts: 11354
Joined: Wed Jul 25, 2012 8:38 pm UTC

### Re: Pennies in Boxes

trickykungfu wrote:Just a thought for the folks who are proposing spreading out boxes: this is a ~3 story tall cube. If you perfectly arranged all of the boxes in a single layer, you'd need 10m*10m*500 = 50,000 square meters of space. That's about 12 standard american football fields, not counting end zones.

Same goes for solutions that involve breaking the whole thing down with various chemicals. Just the massive scale of the thing means you'd have a serious hazard on your hands if you were to dump enough acetone on it to dissolve all the cardboard.

Oh, agreed...but it's fairly easy to shove a few bucketfulls off the top, and do a batch, then repeat. It'll take a little while...but for a million and a quarter, I can devote a few weeks to it.

free-bee
Posts: 277
Joined: Tue Nov 20, 2012 1:35 pm UTC
Location: London, KY

### Re: Pennies in Boxes

I'm a couple months late, but whatever.

If you know exactly where in the boxes the pennies are, you can use a saw to cut most of the cardboard off. You can then use a circular saw to cut the pennies out. That leaves you with a small cylinder of cardboard which is more manageable than the larger cubes. You could then sand the rest of the cardboard away without damaging the pennies too much.
my sister wrote:[the sun] can go to Hell and brighten that place up a while.

Yaf
Posts: 8
Joined: Sat Dec 15, 2012 3:11 pm UTC

### Re: Pennies in Boxes

Spoiler:
douse the box in water to make it weak. once weak getting to the pennies should be a whole lot easier

Yaf
Posts: 8
Joined: Sat Dec 15, 2012 3:11 pm UTC

### Re: Pennies in Boxes

alternatively:

Spoiler:
cut the box in half, to get two halves. Then put the two halves together to get a (w)hole. Now just use the hole to get the pennies out.

Jeff_UK
Posts: 66
Joined: Sat Nov 03, 2007 10:38 pm UTC

### Re: Pennies in Boxes

Quite a high risk option:

Post an 'anonymous' tip off to your local police/ national drugs agency that someone has a 10x10x10 pile of cocaine in their back yard, concealed in boxes .... tell them that you know that about 99% of the boxes just contain pennies, to confuse the police. (maybe even tell them they're well sealed, so drugs dogs wont be able to help)

wait for the police to confiscate and search your boxes. and hope that they return them all, or a significant proportion of them, opened

Actually, I'd post on XKCD and pose a ''hypothetical' 'lateral thinking puzzle' and wait for someone much more intelligent than me to come up with an efficient solution ....
"Please only print this post if you really need to"
...hmm....I wonder how much extra energy is required to generate that request...We need a cost/benefit analysis, STAT!

Emperor_Z
Posts: 28
Joined: Wed May 14, 2008 10:39 am UTC

### Re: Pennies in Boxes

Hire that truck to move the pennies to somewhere where I AM allowed to burn the boxes.

EDIT: Aww. In light of the melting points posted earlier, burning the boxes just doesn't work

The Great Hippo
Swans ARE SHARP
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### Re: Pennies in Boxes

Spoiler:
Call an engineer. Explain the problem, tell them if they solve it for you, they can have half!

Also, maybe an industrial shredder + swimming pool (dump the chaff; shredded cardboard floats).

dudiobugtron
Posts: 1098
Joined: Mon Jul 30, 2012 9:14 am UTC
Location: The Outlier

### Re: Pennies in Boxes

Jeff_UK wrote:Actually, I'd post on XKCD and pose a ''hypothetical' 'lateral thinking puzzle' and wait for someone much more intelligent than me to come up with an efficient solution ....

I would laugh so hard if that was the actual motivation for this thread.

...

And I would also want to buy some of the boxes... XD

Xenomortis
Not actually a special flower.
Posts: 1421
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### Re: Pennies in Boxes

Emperor_Z wrote:Hire that truck to move the pennies to somewhere where I AM allowed to burn the boxes.

EDIT: Aww. In light of the melting points posted earlier, burning the boxes just doesn't work

Take the box back to the deliverer and request a box containing the equivalent in coins of a different currency.
Sterling pennies are made of Iron, not Zinc.

Xavion
Posts: 4
Joined: Wed Dec 09, 2009 10:14 pm UTC
Location: Victoria, Australia

### Re: Pennies in Boxes

Assuming that you can somehow actually manage to get away with selling them then that would be the best solution but not selling them as souvenirs or puzzles, sell them for the cardboard. The key difference here from recycling is that you'd sell them to the military or even just patent it yourself as it's a piece of cardboard that takes 2 minutes to cut through, that's way, way stronger then any kind of cardboard I've ever found and almost definitely contains secret reinforcement techniques better than anything currently known.

Alternatively, just slice open the box and get insurance payments for damage to both your house and the world's largest penny collection.

Vytron
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### Re: Pennies in Boxes

Good job Xavion, I actually think you're the first one to mention the possibility that the cardboard is more valuable than the pennies?
Go! Go! You can do it username5243!
Cheers Marsh'n!

THANKS KARHELL!!

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Location: Space Florida

### Re: Pennies in Boxes

ThirdParty wrote:Here's an inefficient brute-force solution that recovers about a third of the value of the pennies without using any chemistry:
Spoiler:
Hire an intermodal shipping company to transport about 1000 cubic meters of little boxes from your back yard to Cambodia. Estimated cost: \$25,000.
Hire 4 million man-hours of unskilled labor in Cambodia, to unpack the little boxes. Estimated cost: \$700,000.
Hire the intermodal shipping company again, to transport the pennies from Cambodia back to your bank. Estimated cost: \$5,000.
Deposit the pennies. Estimated revenue: \$1,250,000.
Cambodian taxes: 20% of profit.
Estimated net profit: \$415,000.
The satisfaction of being a "job creator": priceless.

It's also illegal to export significant amounts of pennies. If it wasn't:
Spoiler:
it would be more profitable to export it outside of the US, melt the whole mess down, and sell the zinc.

For my own solution:
Spoiler:
I would call the police, and report vandalism (that has to be terrible for the 100 m2 expanse of yard, and it's a safety hazard).

The police would quickly track the source of the package (because it's a 1000 m3 cardboard box!) back to an eccentric billionaire who spends his fortune and time setting up logic puzzles (and scruples questions).

The billionaire (of course) would refuse to divulge any information about the boxes, even under threat of prosecution. The people who actually implemented the box would be a different matter. I'd get them to figure out an efficient way of extracting the pennies.
Last edited by Quizatzhaderac on Mon Nov 30, 2015 2:32 pm UTC, edited 1 time in total.
The thing about recursion problems is that they tend to contain other recursion problems.

Superblack
Posts: 2
Joined: Tue Jan 29, 2013 2:27 pm UTC

### Re: Pennies in Boxes

I have a good idea. Use that crusher from Star Wars...
Or more realistically get a crane and a truck to move it to some kind of large compactor, trash or car compactor maybe and then get it to crush the boxes, very unlikely for the pennies to get damaged and greatly reduces "unpacking" time, admittedly thats a whole lotta cardboard you have to sift through but definitely faster
The biggest problem would be finding a big enough compactor, or you could just kinda "pour" all the little boxes in.

Edited because it took me way too long to parse that first line.
-jr

balr
Posts: 54
Joined: Mon Dec 07, 2009 5:29 pm UTC

### Re: Pennies in Boxes

Sell the boxes intact for USD5 each.

Offer a prize of USD1000 for anyone who has purchased two that are identical.

(You'll need to put some sort of buyer-id mark on them to stop box buyers swapping boxes between themselves after purchase).

If your initial sample result (that no boxes two seem alike) is reasonably accurate, you stand to make a lot of money.

Cloud
Posts: 4
Joined: Wed Jan 30, 2013 2:34 pm UTC

### Re: Pennies in Boxes

Short version of the one I cannot post:

Spoiler:
Call the IRS. Explain to them that you have over a mil in American currency in your yard and you want to pay your taxes right away, but you are unable to deposit the money in the bank in order to write a check. "Please audit me. There is soooo much money here. Bring extra agents with you."

The IRS will take all American currency. Now that Obama has hired more IRS employees, there won't be a shortage of staff. Rent a baler to compress the cardboard and hire a trucking company to transport the cardboard to the recycling center.

You will now have money in the bank from both the pennies and the cardboard so you can use your ATM card.

Vytron
Posts: 429
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### Re: Pennies in Boxes

Spoiler:
Suppose you buy a \$1 million helicopter. The thing is that the people that is selling it, also wants to sell it.

They want your money, this is about profits, if you tell them you have one million dollars, they'll want your one million dollars. And if they don't sell to you, you can buy from their competition, which isn't good for them.

So, go and do it. You can even tell them that if they remove that from your backyard, you give them 5% of the profit, which is \$50000. I doubt it costs them more than that to move the thing, so they'll happily accept.

Now, you have a helicopter and got rid of the problem.

You can even sell your brand new helicopter with a \$50000 discount, to someone that would buy it from you cheaper, or to the same company even. They'll wonder why you'll do such a thing, after the deal is done, you've just given them \$100000 for free.

But, you'll have earned \$900'000 without having to deal with the boxes.

There are probably better ways to carry out this idea, but I'd happily walk away with instant \$1.125 million, after all, probably once you have such a capital, getting it back to \$1.25 and more will be a matter of time.
Go! Go! You can do it username5243!
Cheers Marsh'n!

THANKS KARHELL!!

Laeraren
Posts: 11
Joined: Sat Feb 06, 2010 9:39 pm UTC

### Re: Pennies in Boxes

It's simple - use a furnace that allows you to control the flow of oxygen into it, and shovel in a few thousand of the miniboxes at a time. Burn the boxes at a temperature low enough to avoid melting the pennies, whilst still keeping a steady pace, and you could be done in a day or two. After that, it's just a matter of separating the pennies from the ash.

mward
Posts: 121
Joined: Wed Jun 22, 2011 12:48 pm UTC

### Re: Pennies in Boxes

Hire some professional charcoal burners to turn the whole pile into a charcoal kiln, light it up and tend it for a few days until all the cardboard turns into soft charcoal. This happens at temperatures between 300°C, and 700°C: well below the melting point of copper (which is 1084.62 °C).

Sift out the pennies and compress the charcoal into briquettes for barbecues.

krogoth
Posts: 411
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Location: Australia

### Re: Pennies in Boxes

Design gun that fire's the boxed pennies, Sell the gun and penny box's as ammunition most ammunition being more than a penny each, sell to 'murkans with dodgy sales gimmick about implanting people with "in god we trust" quote or something.
R3sistance - I don't care at all for the ignorance spreading done by many and to the best of my abilities I try to correct this as much as I can, but I know and understand that even I can not be completely honest, truthful and factual all of the time.

Posts: 192
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### Re: Pennies in Boxes

once it's shredded by some means this is probably the tool to sort it with: http://www.youtube.com/watch?v=Yu6IQkLH8Rc
I... I didn't do it.
<- he did it, I swear

LocalGenius
Posts: 1
Joined: Sun Mar 24, 2013 11:34 pm UTC

### Re: Pennies in Boxes

1. Tip the massive box onto one of it's corners.
2. Let the box fall apart under it's own weight
3. ???
4. Profit!

Demki
Posts: 199
Joined: Fri Nov 30, 2012 9:29 pm UTC

### Re: Pennies in Boxes

According to the US mint site, 1 cent weighs 2.5 gram. The boxes contain 125,000,000 pennies, that's 312,500,000 gram in copper plated zinc, or 312,500 kilogram, for those of you using the imperial system, ~688,937.5 pounds.
I have no idea how the hell that cardboard box was brought there, unless it was assembled there.
If it was assembled there, find the people who assembled it and make them tell you how to solve this puzzle.
Last edited by Demki on Sun Mar 31, 2013 12:31 pm UTC, edited 1 time in total.

Posts: 1571
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Location: Space Florida

### Re: Pennies in Boxes

Demki wrote:....that's 312,500,000 gram in copper plated zinc, or 312,500 kilogram, for those of you using the empirical system, ~688,937.5 pounds.
Imperial, not empirical. Also, when expressing large masses, tonnes are useful. Both for scale and the fact that the spelling specifies metric tons, which are within 10% of both imperial and US tons.
Last edited by Quizatzhaderac on Thu Jun 04, 2015 9:35 pm UTC, edited 1 time in total.
The thing about recursion problems is that they tend to contain other recursion problems.

shinkyo00
Posts: 4
Joined: Mon Mar 25, 2013 3:40 am UTC

### Re: Pennies in Boxes

If not:

Spoiler:
A) Auction it off as art, for more than the cost of materials and shipping.
B) Build a sealed enclosure around it and dump in silverfish/roaches/whatever eats cardboard and reproduces quickly.
C) If you're allowed to move the box, then put it in water, and let it soak + agitate it to turn it into pulp.

There are probably more ways.

Vytron
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### Re: Pennies in Boxes

Demki wrote:If it be-did assembled there, find the folk whose innermost essence assembled it and make them tell eow how to solve this puzzle.

It's not guaranteed that the people that assembled it knows how to disassemble it.

Spoiler:
Maybe god doesn't know how to destroy the universe.
Go! Go! You can do it username5243!
Cheers Marsh'n!

THANKS KARHELL!!

vvn
Posts: 228
Joined: Tue Apr 02, 2013 8:34 am UTC

### Re: Pennies in Boxes

Find someone that owes more that \$1.25M in taxes. Sell it to him. He calls the IRS and says, "Here is your money."

firesoul31
Posts: 93
Joined: Wed Feb 27, 2013 10:30 pm UTC

### Re: Pennies in Boxes

Construct a large vacuum chamber around your house, and drain all the air out. Melt the cardboard, then collect the coins afterwards. Sell your house (with vacuum chamber) to someone who fully appreciates the value of it, and you have little cost.

Jeff_UK
Posts: 66
Joined: Sat Nov 03, 2007 10:38 pm UTC

### Re: Pennies in Boxes

It's taken me 2 years, but I think I nailed it:

Spoiler:
For at most \$40,000 USD I could have the following machine built to my specifications; or build it myself for quite a bit less.

The boxes are fed into a hopper; a conveyor belt feeds the pennies past some sort of cutting device which removes one side of the box (e.g a bandsaw or circular saw)

The (now open) boxes are fed into a cement-mixer type drum, which has small perforations all around the outside, slightly larger than the size of a penny; this is in turn fitted inside some sort of housing.

Spin the drum for a set period of time, some of the pennies will fall out of the drum and sit in the bottom of the housing. The optimum time period and fill capacity could be found through experimentation, but we’d keep the waste until we knew how many pennies we’ve retrieved, and can ascertain if it’s worth re-sorting the waste pile.

For further automation, another conveyor could take them out from the housing, and send them over a series of sorting meshes, to filter out any final bits of cardboard (one mesh smaller than a penny through which small debris falls, one larger than a penny allowing the penny through but not larger pieces of debris.
"Please only print this post if you really need to"
...hmm....I wonder how much extra energy is required to generate that request...We need a cost/benefit analysis, STAT!

elasto
Posts: 3555
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### Re: Pennies in Boxes

What about running costs? Are you sure that it won't cost more than a penny in electricity for every penny retrieved?

Jeff_UK
Posts: 66
Joined: Sat Nov 03, 2007 10:38 pm UTC

### Re: Pennies in Boxes

You worried me there for a minute as I hadn't factored that in.. but I'm pretty sure the running cost would be negligible, even at consumer rates electricity is only \$0.12 per kwh.

So a 5Kw machine (I'm sure it would be less, Circular saw = 1Kw, Cement Mixer <1Kw, conveyor <3Kw) would cost \$0.60 per hour... and need to process 60 boxes per hour to break even, I see it doing well over \$1/minute when it's up to speed.

you could probably cut out the conveyor and do enough by hand to make it worthwhile, or invest in some renewable energy generation (You have lots of flammable cardboard... you could make a steam-powered generator!)
"Please only print this post if you really need to"
...hmm....I wonder how much extra energy is required to generate that request...We need a cost/benefit analysis, STAT!

elasto
Posts: 3555
Joined: Mon May 10, 2010 1:53 am UTC

### Re: Pennies in Boxes

Hmm. Ok, but what about the running cost of moving the boxes to the machine? Remember, the boxes would fill 12 American football fields when laid out (and if stacked vertically, would be even harder/costlier to manipulate).

I see no way one box per second could be delivered into this machine without additional costs. At the very least it'd need some kind of manual peasant labour.

Also, are you sure your machine could cut that quickly? Remember, as stated, it takes two minutes to open the box even cutting with a knife. Something that sturdy could cause a lot of wear and tear on your machinery at the very least...

Also, all that waste cardboard has to be removed as quickly as it accrues else the machine is just going to get constipated...

SirBrendan
Posts: 4
Joined: Mon Dec 07, 2015 12:30 am UTC

### Re: Pennies in Boxes

Step 1: Have children
Step 2: Raise child responsibly
Step: Make their daily chore to open boxes

Use money collected to afford more children to open more boxes. Seems like an obvious solution:p

Posts: 455
Joined: Fri Nov 28, 2014 11:30 pm UTC

### Re: Pennies in Boxes

The no fire rule is pretty stupid and makes little sense.
1. Ship the box out to some place where bonfires are allowed, burn it down, then ship the pennies back.You just need to rent a freight truck for a couple days.
2. Bring carts of small boxes inside your home, and burn through the cardboard on your kitchen stove. That will take far less than 2 minutes per box, especially if you have a few people to form an assembly line.
3. Surely there exists some industrial facility that would be willing to let you use their laser cutters for a nice payment.

4. As others have suggested, soaking it in a swimming pool would also do wonders. Throw in some appropriate microbes and the cardboard will be falling off in less than a week.
5. A more fun, but also more expensive, option is to bring it into an ice room and dowse it with liquid nitrogen. After it becomes sufficiently brittle, smash and grab.
This is a block of text that can be added to posts you make. There is a 300 character limit.

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Location: Space Florida

### Re: Pennies in Boxes

Cradarc wrote:The no fire rule is pretty stupid and makes little sense.
1. Ship the box out to some place where bonfires are allowed, burn it down,
Apart from local ordinances, melting pennies down is illegal in the U.S.
burn through the cardboard on your kitchen stove. That will take far less than 2 minutes per box, especially if you have a few people to form an assembly line.
To be worth bothering, it'd need to be more like a box every four seconds (nine dollars an hour); faster if you have more people involved. Also, I'm not sure what kind of stove you have, but I don't think I've seen a 20th/21st century stove that's designed to handle more than a trivial amount of ash. A fireplace sounds more conductive to this plan (wider, more space for ash, handles a less controlled flame).
The thing about recursion problems is that they tend to contain other recursion problems.

DanD
Posts: 308
Joined: Tue Oct 05, 2010 12:42 am UTC

### Re: Pennies in Boxes

A large screen, durable mesh sized to catch pennies, (thinking something like diamond tread plate) and a pressure washer. And some fabric (cotton, suitable for inclusion in paper)

And, for environmental and economic reasons a sealed catchment pond (might as well get an in ground swimming pool put in, say 10m x 25m 2.5m average depth, hold off on installing the pumps and filters just yet).

Put the mesh between the box and the catchment pond. (Judicious installation of an in ground water slide or water feature can define your working area).

Put the fabric downstream of the mesh, upstream of the pond.

First, pour the entire catchment pond of water over the box, to get it started softening.

Put the intake of the pressure washer in the pond, just above the any settled cardboard scrap.

Spray cardboard until the catchment pond is full.

The cloth gets jammed up with cardboard. As it does, pull it to one side to dry and replace it.

Collect pennies from the mesh.

Let the catchment pond settle over-night, to drop out any material the cloth didn't catch. The debris can be shoveled out to dry as needed.

Repeat.

Recycle the dried cardboard, which, hopefully will cover most of your set-up costs, and possibly some of the operating costs, based on the calculations on the last page.

Ideally, mount the pressure washer head to a simple back and forth mechanism (I'm thinking water powered, something like a sprinkler), and buy a small bulldozer or snowplow.

I figure if the cardboard is thoroughly soaked first, you invest in a decently powerful pressure washer, and an ideally sized mesh, you should be able to process several hundred to a few thousand pennies a minute fairly easily. Assuming a thousand, it would take you just about a normal US work year to complete (8 hours a day, 5 days a week).