Making construction materials out of shredded paper

Here’s my deal: I have a paper shredder. Back when I lived in an apartment complex where someone just came around to fetch the trash, I threw the stuff out and I was okay with that. Now that I’m out in the country, I have to pay for this service and I’m limited by volume. Shredded paper is bulky. So I want to do something else with it.

I bet I can turn this into a construction material. It’s probably one of the cheaper materials I can make, I think. The base material — the thing that makes up the bulk of it — is free.

The Paper

The paper I’m using is shredded junk mail, mostly. I don’t separate it much. The envelopes have the plastic see-through windows on them for the address; that gets shredded along with everything else. Sometimes I shred old CDs (because why would you keep CDs?) or credit cards. Pretty much whatever comes in the mail or whatever I don’t want to just throw out because it’s got sensitive information on it.

I’ve got a very standard cross-cut shredder. I think I got it online for a couple hundred bucks. It works fairly well. I have the shredded lubricating sheets which I use once in a while and I usually bag the shreds. I used to not bag them and it was an awful mess.

The Concept

I’d like to make bags full of compressed paper shreds. I’m really flexible on the result, it doesn’t have to meet very stringent requirements. I don’t want to add too much to it and I want to use standard bags. The shredder bags are fine. Regular plastic shopping bags would work too.

I don’t need a permanent material. I’m not actually building a load-bearing structure. My first need is as a liner for a graywater system. If it works well, I may use it as-is or modify it to do bigger and better things. Mostly, I want to see what the properties of it are.

The Research

My first hit came up with this thing about papercrete. It sounds a little rude but the concept looks like it’s exactly what it up my alley. They’re making blocks that I’m imagining are going to be similar to cinderblocks. They use them for actual construction and there’s no plastic bag liner. They do say that they absorb a lot of water so maybe if I modify the plan to work with a plastic liner it’ll be more water resistant.

Papercrete

The people making this stuff seem like a bunch of people just like me. They have space, tools, access to stuff, etc. and they’re looking to re-use their clean, dry trash for construction materials.

They’ve got a process and it seems like most of their stuff is based on that. I couldn’t find any recipes so I’m going to have to adapt their method to use what I have.

The core of their process is some fancy custom-built shredder thing. It’s quite clever: it’s a trailer that you run behind a truck and it uses the motion from the turning wheels to shred paper and mix it with concrete. I’ve got a cement mixer though, and my paper is already shredded. If I can adapt the process, I think I can make it work.

So he’s got a stock tank of some unspecified volume that’s 4 feet in diameter. For this setup, his proportions are a 3/4 full tank of water, 75 lbs of material and a 94-lb bag of portland cement. I’m going to have to re-scale this and I’m going to have to weigh some of my paper.

As for the tank, I found a similar-looking one on Tractor Supply’s website. It looks to be about 75% as tall and it’s half the diameter, but it’s measured at 23 gallons. Doing some math, I’m estimating that his tank is about 29.6 gallons. Let’s call it 30 gallons. So that’s about 7.5 gallons of water or, by weight, about 1.25 lbs of water for every lb of paper. Similarly with the cement, it’s about 1.6 lbs of cement per lb of water, or 2 lbs of cement per lb of paper. So paper-to-water-to-cement, by weight, should be about 4:5:8.

Modifying the directions and stuff a whole bunch, here’s what my first run is going to be:

  • 30 lbs of paper, pre-shredded by my shredder.
  • 1 60-lb bag of regular Home Depot high-strength Quickrete.
  • a 5-gallon bucket of water, mostly full.

Depending on how much volume 30 lbs of shredded paper takes up, this may or may not fit in my (3-1/2 cubic foot) cement mixer. The actual amount of water was 4.69 gallons, but that rounds well within 5 gallons — a contractor bucket — given the estimation error on this whole thing. Plus, the person who posted the papercrete block article seemed imprecise with the water and I live in a fairly dry climate. I figure that at worst, it’ll take a little time for this to dry. I’m also substituting the cheaper concrete mix for portland cement. I had a roommate in college who was a civil engineer and went to concrete lab all the time. He could probably tell me the difference between concrete and portland cement, or I could look it up. I don’t know if it matters though. 30 lbs is 3.75 gallons of water. I know without even picking it up (again) that a full shredder bag doesn’t weigh that much. I’m probably going to need 2 bags full.

More to come as I get to trying!

Recycling Plastic

I’ve gone back and forth on this extensively and I’ve decided that I’m going to take the leap. It’s a really small leap, more of crossing over a thin line in the sand.

In my new digs, I’ve got relatively few waste options. Sewer is septic and there’s no municipal trash collection. I’ve got a big bin picked up weekly by a small local company. They provide fantastic service but they’re just too small to have a comprehensive recycling program.

So I sort. Right now, here’s what that looks like:

  • Non-animal food scraps get composted. Banana peels and coffee grounds (with the paper filter) are the bulk of this but it includes parts of vegetables I don’t eat like onion skins and celery leaves.
  • A large portion of the cardboard and paper waste I generate can be burned. I’m not running an energy conversion stove for heat or steam but I do like me a campfire and some chopped and tied delivery boxes make a great replacement for fake firewood.
  • Glass will mulched. I like beer, it’s better in bottles, I don’t have a pool (yet) and I have lots of landscaping needs. Mixed glass mulch is very easy to produce and I believe it will work better than rock across the board.
  • Metal will be melted and poured. I also like Diet Coke. I inherited lots of empty used beer cans with the property. There will be a foundry and I’ll be able to make lots of things out of use metal.
  • Inked or clay paper and cardboard are transcycled. Also in this category is anything made out of metal, glass or plastic that I believe may have a use. I’ve already used some styrofoam for insulation. If it looks like someone went through the trouble of forming it into a shape, I can probably re-use it in the same or similar shape. This is sometimes a difficult decision involving cost of storage (until re-use) and meeting a material and shape to a new need. I’m still working on the mental step of always looking for a transcycling opportunity before using virgin material.
  • Excess material, scrap, dross, food waste, etc. is trashed. There’s not much that can be done with leftovers of spoiled chicken or metal shavings. These go to the dump where they’re managed appropriately by professionals.

I want to keep the last category (landfill trash) as small as possible for two reasons. First, it’s the least friendly category for the planet. Second, it costs me money to get rid of that. Ignoring the first (it speaks for itself), I’ve got the regular pick-up option or I can take items to the dump on demand. I’d like to find ways to eliminate the pick-up option and reduce my total landfill trash production to one or two bags a month that I can take to the dump.

Plastic all goes to the trash right now. It’s generally bulky even though it’s light. I get charged mostly on size (unless it exceeds a very generous weight threshold). If I can eliminate or reduce plastic in the trash, I can probably meet my goal straight off.

I’m going to have to learn how to do this.

Introduction: The Radio Project

I’ve had a general-class amateur radio license for a while and I’ve never really used it too much. Now I’m in a better (physical) place where I can experiment so I’m embarking on a new project.

What Changed & What Didn’t

First and foremost, I have space. Previously I was limited to what I could wire up in an apartment. Antennas can get dangerous and between visitors and the cat there was too much work preventing RF burns, tripping over things and just plain ugly.

Also along the lines of space, I have space to experiment. I made a promise of limiting, “dirty,” work like greasy truck parts and that which generates milled metal dust. Electronics work is, “clean,” in that keeping your breadboard neat is a good habit and no one (who I’m likely to have around) can see in the RF spectrum. I’ve got space for tools, leaving projects unfinished and testing away from the cat.

Still on that track, I don’t have many external restrictions. There’s space to put up antenna masts and I can punch holes through walls for feeders to my heart’s content.

On the negative side, I’m now mired in what’s likely to be ten years’ worth of construction projects. It could all probably be done in two years but I’m expanding the schedule to accommodate work, budget and interesting projects. Before I may have been able to find an hour a day to work on this. Now it’s more likely an hour a week over the stretch.

The place I moved into came with lots of materials as well. I’ve got a functionally unlimited supply of some things (sand, glass and aluminum) and good supplies of other things (steel, rocks, electrical wattage). Further, time spent looking will afford the ability to get lots of used and transcyclable parts from scrapped fixtures like cars, electronics and machinery.

Goals

Fast, cheap and good… pick two. I’m picking cheap and good. Those constraints truly limit just about every choice in the project. Along those lines, most of the choices are for either common parts (like feeder cable) and focus on taking the time to build something that may be difficult (like matching circuits).

I’d like to be able to cover several frequency bands with three or fewer antennas. My intuition says I’ll need one good VHF/UHF antenna, a good HF antenna and something that’ll do well on some lower frequencies (I’d like to experiment with MF and LF or even ULF/VLF based on regulation and availability). I’d like to be able to transmit using reasonable power levels. “Reasonable,” here definitely means within regulation but also what can be attained using reasonable parts. High-power transmission is expensive.

Where possible I want to transcycle as much as possible. I assume this means I’ll be reworking quite a number of component parts as I come up with new ideas. This also means that I’m probably going to have to develop (build or buy) solid tooling and measurement for a great many things. I’m an electrical engineer — not a mechanical engineer — so I’ll probably do more guestimation on weight bearing or wind profiling and build better systems to measure things like VSWR and connector loss.

Personal interest will play into everything. I really don’t care much about the history of the Yagi-Uda antenna. Lowering reactive loss per foot of coax and impedance matching is interesting to me. This probably isn’t the same for everyone but it’s my project.