All posts by Chuck Thompson

We received some drawings today

These drawings are courtesy of Dr. Owen Geiger at

These are drawings for making the block box press. 


We have photos and a material list in another post.

Dr. Geiger has been involved from early on.  Everytime I would vary away from the original concept he would be on to me to get back on track.  He shares the vision of a manual system that can be used by the semi-skilled under the worst of conditions to create shelter and industry.  Dr. Geiger is now in Thailand working with locals who make CEB’s (compressed earth blocks).

Another day, another compression test

I  took the truck to Pearson Stone and we weighed the front axle weight.  6,800 pounds.  That means 3,400 pounds per front wheel weight.

I went to the shop and put the front of the truck up on wood blocks.  Then I jacked up one wheel and placed a ten pound plastic block under the wheel with a piece of steel on top of the block to eliminate the distortion caused by the tire patch only being on part of the block.

The block compressed about three quarters of an inch with the weight on it.  When I removed the weight the block returned to its original shape.

I repeated the experiment with a nine pound block.  The compression was about an inch and a half this time.

It will take some more tests by those a lot smarter than me to figure out the ideal weight of a block for making walls for a shelter.  As far as I am concerned that is just work that has to be done.  Engineers can figure out how much strength is required.  Then plastic blocks can be tested and we’ll have the information we need.

We did a compression test today

We don’t have access to an academics lab to do testing on the blocks.  So I did the next best thing…

Click on the “more” for photos and more dialog..

As you can see, the block was distorted in our redneck/red truck compression test.

This is a redneck’s red truck that weighs fifteen thousand pounds or so just about any day of the week empty.  Most of the weight is on the front axle when it’s empty, diesel motor and all.  I think an estimate of two ton or four thousand pounds or so would be a safe estimate of weight applied to the block.

One of the neat things about plastic is its resiliency.  If you look close I think you’ll agree that even if the block failed the two ton redneck red truck weight bearing test it will still work just fine in a wall.

Block Press Construction and Measurements

After the camera fiasco the other day we finally found another camera.

This after noon I made another block and feel we have the one we want now.  It isn’t perfect and will still need some tweeking to make it work better.   But it is at a point where others can copy it and start making blocks.  Their experiences along with ours will help us find the final block making machine.     Bob Warner took a picture of the plastic block box machine yesterday and then put down all the measurements on the photo to make it easier for others to copy.

We have a bolt with a 15/16  nut on it so we can use a rachet to turn the Acme screw.  We were given a steering wheel from a bus today.  We might change out the bolt and nut for the steering wheel.  Eveyone that makes a plastic block box machine will find their own way of turning the Acme screw.  I think the steering wheel will be my favorite though. is the part number and source for the Acme screw. is the part number and source for the nut.  A substitute that might be available locally is scaffolding screw jacks. The downside of using them is their length, usually only sixteen inches of travel available.  We’ve found the thirty six inches of travel about what you need.  Less than that will mean repeated compressions to get the pressure needed.

This is detail shot of the ram itself.  The three slots are the wire retainers.  You can see in the block box the wire guides.  The wires can’t be installed after the block is compressed, at least we couldn’t do that.  So we designed the machine to locate and maintain location of the wires during compression.

I welded half of a steel ball to the end of the Acme threaded rod.   I used a piece of pipe and a rounded piece of tubing from a tractor attachement  to contain the threaded rod.  I put in a grease zert to make things work better and live longer.  This gives a wide surface for the pressure applied by the threaded rod.  The grease keeps it smooth.

The threaded nut was welded into a hole cut into a piece of half inch plate that is welded to the back or end of the block box  Care must be taken to insure alignment with the ram as it travels down the block box.

Everyone will find a postion that works best for them when it comes to using the block box.  I find this position just about perfect for me.  It has enough angle so I don’t have to fight the plastic falling out like I did when it was vertical.  And it is easier to keep the plastic in place while loading than when the block box was horizontal.

This little tool was designed by Bob Warner for tying the loops in the ends of the tie wires.  The handle is three quarter’s inch round rod and the shaft is half inch pipe.  The tab is 1/4″ by 1/2″ by 3/4″.  A slot is cut into the end of the pipe to allow post tensioning by twisting of the tie wires if necessary.

The small tab is used to make a ninety degree bend in the tie wire.  We’re using 12 gauge galvanized tension wire.  It is stiff to work with but will last a long time.  It is designed for use with chainlink and livestock fencing.

Then using the tab and the round shaft a loop is made in the wire.

This rod with the slot in it is located at the top of the block box frame.  It’s part of a guide for gauging the length of the tie wires.  After Bob made the trick little tool is was modified to make the loop using the tool.

The ends of the loop are placed in the slot.

Using the tool and the slot the eye is made in the tie wire.  Pliers could be used to do the same thing.  But it wouldn’t be near as easy.  Especially with wire as stiff as the twelve gauge.

This photo shows the three tie wires placed in the wire guides in the floor of the block box along with being properly placed in the ram.

This is loading the plastic before we put on the lid.  As you can see the angle position makes this easier.

I did this by myself and didn’t take pictures of the cover plate in place.  The cover plate was put in place.  Once it was in place I shoved in more plastic, occasionally compressing it with the business end of a sledge hammer.  I did one full compression stroke and then filled it back up.  One more full compression stroke and I removed the cover plate.

This is the compressed block of trash plastic.  As you can see it would be very difficult with this design to install the tie wires now.

This is the tensioning tool.  It’s made using half inch round rod.  The slot on the end is critical.  It was made with a chop saw blade and at about an forty five degree angle.

The end of the tie wire is fed through the wire guide on the end into the block box.  The tied loop in the wire at the ram is placed over the block of plastic.  The loose end of the wire is pulled through the loop.  Then the end of the tensioning tool is placed through the loop about five inches.  The groove is placed over the wire.  The loose end of the tie wire is folded over the handle of the tensioning tool.  The handle is forced towards the bottom of the block box.  When the loop is over the end of the tensioning tool the tool is folded down onto the plastic block.  Excess wire is cut off and the end is loosely wrapped around the tie wire.  This is done to all three tie wires.

The ram is pulled back away from the block.  I find a small lever bar is all that is needed to remove the block from the block box.

These blocks are a nominal 8″ X 8″ X 16″ .  They can take abuse and maintain their shape.  They weigh six to seven pounds each and difficult to compress or distort.  Tied to together with wire and rebar they will make a great wall ready for plaster inside and out.

They are a future based upon our past.

Another day in paradise

Before we bumped the table and the camera fell, fatal screw up on its part….

We were having an awesome day.  After that it was just a really good day for inventing in general.

This is the bottom of the new block box, alpha 2 I guess we can call it.  The two pieces of angle iron or for the future stand that will support the block box.  The three pieces of flat stock welded in the middle are to keep it from spreading when compressing a block.  The angle iron is 2″ X 2″ X 1/4″ .  The flat bar stock is 1/4″ X 2″.  The spacing is even spaces, about eight and  a half inches as I recall.

I cannibalized the ram and screw mechanism from the original block box press for the new one.  Here it is installed and ready for compressing the first block.   The next picture is of the business side of the ram with the wires in place.  The next picture is from the other end.  Notice the wires coming out of the bottom.

This is pre-compression chamber I made.  Basically it smashes the material a bit before I put it into the block box press.  I just put the stuff in there and pound it down with a sledge.  Works great.

With the ram back as far as possible I filled up the box press with plastic trash.  Most of it had been through the pre-compression tool.  Then I put on the cover.  I haven’t put on the permanent lid because I wanted to make sure that the new press worked first.  Once the lid was on I ran the screw down all the way as you can see here.

When I pulled back the ram this is what you could see at the other end of the block press.

I added some more plastic and ran the ram down one more time.

This is the good part.  I removed the cover plate. and pulled the wires up for tensioning with my tensioning tool.

First the wire is pushed through the eye or loop at the ram end of the block.  Then that slot you see on the bottom of the tension tool is pushed through the eye or loop and down the wire about five inches.  The loose end of the wire coming through the eye or loop is folded over the handle of the tension tool.  Then the tool is pushed over the eye or loop towards the end of the block.  This action pulls the wire to the loop tightening it.  When the tool folds the wire over the eye the wire is tight.  If it isn’t the tool can be relocated and it can be done again until the wire is tight.

This is when I broke the camera.  So I don’t have any pictures of the finished block.  First thing, the three wire block is a much better block.  Second thing, removing the block was much easier with the tapered sides.  I believe this design will be the final design.  There might be some tweaks but this thing here works.  I’ll get the top hinged and come up with an exact material list and dimensions so that others can copy it if they want.

I’m getting a lot of suggestions about using hydraulics to make it easier, faster and better.  My concern at this point in time is to prove that a wired recycled plastic block is a viable building material.  People a lot smarter than I am will come up with making the blocks faster and easier.  I’ll leave that up to them.

Good News and Bad News

The bad news is the original press has some issues.  One of the problems is the sides are vertical and that makes getting the block out of the press difficult.  Another is it is difficult to remove the trash from the press between blocks.  And then there’s the wire guides, difficult to use when operating the press, too far apart,  and generally awkward to use.

The good news is

I spent some money for some more materials.  I decided to use three wires for the new version of the blocks.  The size is the same.  But the new press has the outside wires closer inside and then I put in a middle wire to contain the middle bulge we get.

I’m trying to get the machine down in cost material wise.  I also want the materials to be as common as possible so that the presses can be made on site if necessary just about anywhere in the world.  I’m trying 11 gauge 2″ X 2″ square tubing for the floor and base end.  I hope this will be substantial enough to hold up over time.

If you look close you and see I”m using quarter inch spacers between the tubes for wire guides.  I believe this will simplify the compression phase because the tie wires will be lying out of the way.  The tie wires will still have to be attached to the ram.  But we won’t have to fight keeping them in the guides like we did with the original press design.

I’ve decided to put an eighth of an inch taper in each side to make removing the completed block easier.  The top has an 8 ” inside measurement.  And the bottom measures 7 3/4″ inside.

We’ll be making blocks with the new design tomorrow if everything goes right.

We Made Our First Plastic Block Today

Of course the very first thing we did was test it for supporting weight.

It was quite a day.

Remember we started off with a trailer load of number three thru number seven plastic from the recycling center.  It turns out we had a lot of number one and it is more difficult to work with.  We discovered that number five was great.  We didn’thave any number six and seven, what we eventually want to use for the blocks.  Numbers one and two are valuable for recycling.  They give value to our blocks that isn’t desireable or necessary.  As it has been pointed out to me by others there are those out there that would love to find neatly bundled blocks worth thirty or so cents per lb at the street level recyclers.

We first tried to compress a block and then install the wire into the mold to secure the block.  That didn’t work.  Then we tried to install the wire without thinking it all through.  That worked better but it wasn’t any good. either.  The old adage about “learning more from our mistakes than our successes” is gospel when it comes to projects like this.

We learned a couple of  things with those mistakes.  We needed to add more plastic to the mold to make a more dense block.  We also made up the rod I designed for tightening the wire.  That and making the loops in the wire at the ram end of the mold enabled us to tighten the wire very tight easily.

The trick to tighteing the wire is a loop big enough for the tightening tool to pass through.  The trick to the tightening tools is the slot in the end of the tool.  Basically the way it works is the tool is slid through the loop to a point about four inches after the wire has been pulled hand tight.  The groove end is placed on the wire and then the loose end is folded over the handle of the tool.  The tool pulls the wire through the loop with a lot pressure when the tool is pushed over the loop.

It’s so simple.  Yet it’s so efficient.

The finished block is a nominal 8″ X 8″ X 16″.  I beat it with a hammer, bounced it around.  I like it.  Then we drove the pickup up on it to see how it handles weight.

I’ll be the first to admit that the block is one of those things where beauty can only be in the eye of the beholder.  For me it is beautiful.  That’s because I see a solution to two problems facing us today.  Plastic pollution is a worldwide issue.  Another world wide issue is affordable shelter.  This block addresses both of those issues, it takes trash plastic and makes it into an affordable alternative building material.

I have proven I believe that this block can be produced in the third world’s worst circumstances.

Now I want to take it further.

I want to see a manual model of this machine that is self contained and built for durability.  I want to see that machine manufactured and distributed everywhere alternative housing is needed.

I want to see another model of this machine that is automated for use in the industrialized world.

I would love to be part of all of the above and more.  But for me to do so is going to require financial assistance.  Any ideas for that kind of help is appreciated.

More Work on the Block Box

I’m not sure just how much pressure we’ll be using to compress the blocks.  So I’m spending extra time reinforcing the far end.  I would hate to be wrapped up in making a block and have the end fall off.  There’s a formula for figuring out the lineal pressure that is generated by the circular motion of the acme thread.  I’ve looked at it and it makes no sense to me.  Hopefully an engineer will google the formula and then send me numbers and I can pretend I’m smart.  One inch ACME thread 4 threads per inch.

I wanted to attempt a bottle brick/plastic block tonight.  I was just too tired.  I’m going to try to hit it early in the morning and maybe we can get one just to see if it will work.

I tacked in the brace for the ram rod and it’s a little off.  So in the morning I will break the tacks and align it better.  I will add bracing and then attach the ram to the rod.  I still have to make the handle for the rod.  There’s a part of me that likes the idea of a steering wheel.  I’ll probably forgo that though and settle for a slip rod handle

The ram will never make contact with the end of the box.  But to get the density we think we’re going to need the force against this end will be like the ram hitting it.  That’s why I’ve put in all the steel.

Keep in mind that if this thing works this is open source.  So if a company wants to send a thousand of these to Haiti for instance then they can get the measurements from mine, have their smart minds modify it for efficiency and manufacturability, then they can have it made anywhere, India, China, Canada, USA.  Another thing is anyone can modify it and make it better.  I just hope that if they do they share it with the rest of us.