Category Archives: Hack

DIY Store Foam Medieval Practice Sparring Sword


One afternoon, like many others, I found myself engaged in an intense battle with with my son on the backyard grass.  This day’s chosen weapons are blocky foam replica swords from some a slightly popular video game.  I decided I’d had enough with trying to have a entertaining battle with the things – and if they break? Costly at $25 each.  A new, CHEAPER, more realistic design was necessary.

Now, when I was a kid, we rolled up newspapers as tightly as we could, wrapped them with duct tape and did battle in the middle of our street.  Builder skills varied, and so did the quality of the weapons – if you wanted durability, you had to use a good amount of newspaper. In the end, you basically had to swing these heavy things like battle axes to get them going.

While I thought about going back to this design for our duels; my 32 additional years of building experience led me to a simpler, more nimble design.

COMMON SENSE ALERT!  These swords are not toys.  They will hurt you if someone swings it hard and hits you.  I’d imagine in the right hands it could break fingers or small/thin bones.  Build and use these at your own risk!  Be cool. Don’t hurt people.  These can be super fun if used with some common sense – I designed them to be safe should there be the accidental missed block or something… but we can’t NERF the world people!  Kids need to be kids.  As the authors of The Dangerous Book for Boys [ link] said:

I think we’ve become aware that the whole “health and safety” overprotective culture isn’t doing our sons any favors. Boys need to learn about risk. They need to fall off things occasionally, or–and this is the important bit–they’ll take worse risks on their own. If we do away with challenging playgrounds and cancel school trips for fear of being sued, we don’t end up with safer boys–we end up with them walking on train tracks. In the long run, it’s not safe at all to keep our boys in the house with a Playstation.

So don’t sue me if someone gets hurt, ok?  I already told you it could happen.  Have fun, but be smart.

And with that out of the way, let’s get to building!

You’ll be able to find what you’ll need at your local big box DIY superstore:

  • 1/2″ foam pipe insluation – one 6 foot section should be good for two swords
  • 1/2″ PVC pipe (thin!  see below) – a little over 3 feet per sword
  • one (1) 1/2″ PVC four-way junction
  • three (3) 1/2″ PVC end caps
  • clear PVC cement
  • duct tape – I like the cheaper, off-brand stuff for this project – its thinner and easier to work with.
  • spray paint (optional).  You can leave your PVC uncolored if you want.  I chose to go with gold for the hilt to give it a touch of class and honor

NOTE: get the thinnest walled PVC pipe you can find.  The standard schedule-40 stuff that comes in the shorted lengths near all the fittings is way to thick.  It’ll be heavy and really hurt when someone misses a parry!  At my local store, I could only find the real thin stuff in the bulk area in 10 foot lengths.  Don’t say I didn’t warn you!

Hopefully you have something to cut PVC.  These crazy things work really well [ link].  Avoid hacksaws as they make all kids of nasty PVC dust.  You don’t need to breathe that.  Your store will cut stuff for you for a nominal fee.  They might think your cut list is crazy, but who cares… tell them what you’re making and they’ll probably think its pretty cool.

Cut the PVC into these lengths:

  • 1 piece 26 inches
  • 1 piece 5.75 inches
  • 2 pieces 1.75 inches

First, we’re going to use the three shortest pieces to make the hilt.  Dry-fit the pieces (no cement) before-hand to make sure you like the sizes you’ve cut.  Once the cement comes out, you can’t go back.

The hilt will look like the letter ‘T’.  Take the two smallest pieces and fit them into the junction opposite of each other.  Put the 5.75 inch piece of pipe in one of the remaining holes.  This will be your handle.  You can put caps on the ends of each of the pipes.  If you’re happy with the sizing, you can take it all apart and glue it together.  When I use PVC cement, I like to let the brush drain off for a bit and even wipe it along the inside edge of the can to get most of the excess, drippy glue off of the brush.  Then quickly use the brush to coat the inside of three of the holes in the junction, as well as the inside of each of the caps.  I like to swirl the brush once around to make sure I’ve evenly coated the inside of the fitting.  Quickly put all three pipes into the four-way junction first, then put the caps on the ends of the pipes.  When you’re done, it should look like this (note this one is already painted – I got too excited to finish and forgot to photo document this part of the process!)


Now we are ready to work on reinforcing the foam with duct tape so that it doesn’t split when we slide it onto the 26 inch PCV “blade”.  Cut the foam to a length of 26 and one-half inches (26 1/2″) Start with a 6 inch length of duct tape and wrap around one end of of the foam.  Do not apply pressure to the point that it starts compressing the foam.  You should be able to smooth it lightly on to the foam and make sure there are no wrinkles as it wraps around the tube:


For added strength add another piece of 6 inch duct tape over the tape you just applied.

Continue this procedure down the length of the of the foam, butting each new section against the last.  You can overlap a bit between sections if you’d like.  Try not to leave any foam exposed between the tape wrappings:


Before you get to the end, we want to add a couple tape squares as a cap before we wrap the last bit of the end.  Offset two square pieces of tape on the end of the tube.  Fold down the diagonal ends and hold them down with the last 6 inch section of tape:


And an additional 6 inch wrap of tape over the end:


We are now ready to start sliding the foam on to the blade.  Now, note that in these pictures that I took, I was waiting for the painted hilt to dry – so I ended up pushing the foam on to a lone piece of PVC and pressed it against my belt.  You might find it easier to use the hilt handle with pressure against your thighs for this part.

Put the 26-1/2″ long blade PVC into the open end of the taped foam.  While it’ll be easy at first, it’ll take a considerable amount of effort once you get about half way.  I like to switch between pulling on the bottom end an about the middle of the foam section to move further on to the PVC.  Use your judgement – if you pull too hard on a stubborn section, you may rip the foam and have to start over.  Keep working it until you’ve got about all but four inches of the PVC covered with the foam/tape “blade”.


(here I’m using the open end of the PVC against my belt to push the foam on to the PVC)

As you work it down, you may find that some parts get compressed and are wrinkled.  This is ok, just apply more pulling pressure to the bottom of the foam and it should smooth out.


Wrinkles are ok, they will smooth out.

Now that the foam is mostly pulled down, you’ll add some layers of tape lengthwise to the blade.  Rip a section that is almost 26 inches and pull on both ends to keep it straight.  With this method, you should be able to smooth out the tape to run the length of the blade without wrinkles.  Repeat this two more times, slightly overlapping the last layer as you go.


Add one more width-wise 6 inch strip at the top and bottom of the sword to cover up the fact that the last three lengthwise strips didn’t make it to each end of the blade.  On the open end of the foam, I like to offset it a bit over the end so that it will cover the black part of the blade near the hilt:


If you were working like I did from the pictures, swap some PVC cement on the remaining channel of the hilt and press your blade in.  Give it a minute to set up, and pull the foam all the way to the top of the hilt.


I used a hot glue gun to wrap a small section of fake leather fabric to the handle between the end cap and the junction.  You could do the same, or use electrical tape or paint… its up to you.


Now that you’re done, you just need to build one more and you’re ready for some knight-style sword practice!  Remember: be cool, be smart, have fun!

40W Chinese Laser: More upgrades

Made some upgrades over the long weekend:

Took out the stock work holder in preparation for the adjustable Z bed. It is hard to see in the first picture, but all but two of the posts were standing about 10% off of vertical. Even the allen screws securing the original work holder were at an extreme angle:



The LED strip lights got installed. If there is any upgrade that adds instant polish to your rig, its this one. The lights look amazing:




Also removed all of the original cooling system and installed fresh tubing. Added reservoir, radiator, fan and anti-freeze:




40W Chinese Laser: First cuts with open-source toolchain

Now, since I haven’t removed the stock work area, and because of the way the machine homes before the cut, I had to rest the test piece up higher than the normal work height. Outside the ideal laser focus width. Therefore the cut width is a bit thicker than if the material was a proper distance from the lens.

Still, I’m pretty happy with the performance – this is an example of a vector drawing:


Digital source:

Screen Shot 2015-09-04 at 9.17.55 PM

40W Chinese Laser: Public Service Announcement: Clean your mirrors and lenses!

Don’t trust that your mirrors and lenses will be even remotely clean.

Remember when I mentioned I saw some soot on the lens carrier? Well, today I took it out for a closer inspection:


And the mirror wasn’t in much better shape:


I cleaned them up with some alcohol imbibed lens wipes:


40W Chinese Laser: Brain Transplant!


I’m removing the stock controller board. The proprietary software is terrible. It is getting replaced with the Open Source RapRep RAMPS G-Code controller. Thanks to the customized Marlin firmware by TurnkeyTyranny, this gives us several new advantages:

  • open source software chain (thanks again to TurnkeyTyranny and the Inkscape G-Code Export Extension)
  • programmatic control over the laser output power (ditching that terrible manual pot)
  • A slick new LCD control panel
  • I’m surprised I’ve not seen this elsewhere, but I plan to use a thermistor in my coolant tank to monitor the coolant temperature. Hopefully I can hack the firmware to stop firing the laser if the tank temperature rises beyond the set threshold.

    I ordered a new ribbon connector and made a new transfer cable to connect to the RAMPS pins. I was too impatient to design and order a wiring harness board, so I just soldered the cable right to the pins on the connector. I covered the contacts with some Liquid Electrical Tape.


    Below is a diagram of the wiring. Thankfully this was my exact power supply, so I didn’t have to get creative. Now, on the RAMPS, the servo pins are marked 2B 2A 1A 1B and the diagram has A- A+ B- B+. Here is the translation:

    A- -> 2B (ribbon cable pin 9)
    A+ -> 2A (ribbon cable pin 10)
    B- -> 1A (ribbon cable pin 11)
    B+ -> 1B (ribbon cable pin 12)

    It’s also not very clear on the diagram, but the XHOME goes on the first Signal pin on the endstop header and YHOME goes to the third signal pin. Even though it shows the 5v and GND going to the AUX-3/SPI header, you can use any 5V/GND connections on the other AUX or SERVOS header blocks.

    The Y stepper cable connects the following colors to pins:

    red -> 2B
    blue -> 2A
    white > 1A
    yellow -> 1B

    I’m borrowing this photo from TurnkeyTyranny’s git repo and putting this here so I can find it later:


    This is not the greatest photo, but some of the wiring choices can been seen here:


    I made sure to test the steppers and homes before I even hooked up the laser fire and PWM controls to the RAMPS board. Once everything was moving as I expected, it was time to test the laser! Something about this screen preparing to push the button had me feeling like a mad evil genius set to take over the world: “FIRE ZEE LAZOOR!”


    As you can see by the burn, the initial tests were a success:


    Now its time to mount the board and get the wiring cleaned up to make room for more upgrades!

40W Chinese Laser: First cuts!

Today I finally wrangled a Windows XP machine back into shape so that I could run the stock software that works with the stock controller board.

I did the test cuts on 1/8″ thick hardboard.

We immediately see the value in having an air assist cutting nozzle. Without one, the exhaust fan pulls the smoke and heat up and across the work.

No problem – a couple hits with the sandpaper and its clean! Not bad for a machine out of the box with zero calibration!

The RAMPS arrives Monday. That’s when the teardown and upgrade will begin. Honestly, I can’t wait, because the stock software provided is terrible! Perhaps I’ll experiment with different power settings in the meantime.

40W Chinese Laser: Improvements

This is currently just a list of the upgrades I intend to make on my new machine. I’ll add links as I complete each item:

Add LED interior lighting
Remove controller and replace to RAMPS CNC controller
Replace controller panel with RAMPS LCD and switches for cooling, lighting, etc
Change chassis bolts to proper length
Add Air Assist head and pump
Upgrade Water Cooling
Enlarge build area
Upgrade Exhaust Assembly
Add fan to interior of power supply

LINK: Click here for a link to my post that contains a shopping list of parts required for the various upgrades.

40W Chinese Laser: Upgrade Parts List and RAMPS conversion

All of the following links are for items on Amazon. With a few exceptions, all qualify for Prime free shipping.

RAMPS Parts:
RAMPS + Arduino + Stepper Drivers
E-Stop Switch

Power Supply Cooling:
60mm 24v Fan for P/S

Exhaust Upgrade:
Exhaust Fan
Fan Hose
Hose Clamps

Laser Cooling Upgrades:
Water Reservoir
Heat Exchanger
Heat Exchanger Fan
Cooling Hose

Air Assist Upgrades:
Air Pump – hold off on this: waiting for pump to arrive to see if it can produce sufficient air flow.
Manifold – hold off on this: waiting for pump to arrive to see if I can reroute three of the four outlets internally.
Air Assist Hose
Drag Chain for Air Assist Hose

Interior Lighting:
LED Strip
LED Power Supply I chose the 2A model, only slightly more expensive, and the terminals have more substance.

40W Chinese Laser: Unboxing

I ordered mine from the San Leandro, CA facility. It shipped on a Monday via FedEx. It arrived two days later, on Wednesday.

I was surprised at the size of the unit – I had imagined it to be about 75% of its actual size. The wooden box was a bit beat up, half the screws were missing and the lid was otherwise held on by packing tape.

The second (cardboard) box inside was in very good shape.

The entire machine was tightly surrounded by 1″ thick, cheap styrofoam. I’m pretty sure they just broke up the pieces by hand to make them fit in the shipping container, as there were small bits of foam all over the place. Get your shopvac handy to pick up all the snow!

Unpacked. Back of the unit. Covered in broken styrofoam. The cooling hoses are very soft and were crushed and deformed by the tight stryofoam packing. They function ok, but some parts seem to have melded themselves with the foam somehow. Notice the lines are filled with water, so they did actually do some testing before they shipped it out.

Front. Covered in packing cellophane wrap. For some reason the lid is jammed open a bit. Perhaps because of the items packed inside.

Removed the wrapping film and we now see the accessories inside. This bag contained a tube of silicone paste (I’m assuming for lubricating the rails), a roll of cheap double sided tape (the manual mentions using this over the mirrors to check alignment), a DVD-R (containing instructional PDF, CorelDraw and CorelLaser software) and a USB key – I have read elsewhere that this is a dongle that allows use of the Corel Laser software.

USB A to B cable, exhaust fan and aquarium pump (for laser cooling).

Took me a moment to notice the exhaust fan hose (blue, behind the lens head). Hose expands to about 6 feet in length. Also hidden under the platform is the 110v power cable.

Closeup of the cooling hose. Note they are still very wet inside. Some sections are more opaque than others. I’m assuming their test water also had some sort of antifreeze in it, as my pump was also covered in some milky white residue around the outlet connection.

A bunch of styrofoam “snow” trapped in the power connector.

Some of the frame bolts are MUCH longer than they need to be. I will be replacing these with bolts of the appropriate length. Some are so long that they are offsetting the ability for the machine to sit flat on the four rubber corner stands.

The interior of much of the machine was VERY dusty with brown dirt. No telling how long the chassis parts might have sat in an open warehouse or even outdoors prior to assembly.

Laser tube. While a but dusty (probably from the dust falling from the top of the bay door that was pictured above), it looks to be in very good condition.

More styrofoam snow in the back of the power/control compartment. All the wiring is wrapped and appears to be tidy. Not the horror show rats-nest or unshielded wiring that I’ve seen arrive on other Chinese laser builds.

Back of control panel.

Power supply.

They obviously test-fired the laser as there was a good amount of soot on the bottom of the lens carrier. I have yet to remove the lens. I plan to take it out for inspection and cleaning – mirrors too. I’ll add to this post with those details later.

They must slap these things together very quickly. The shield acrylic (in addition to being very scratched up by the stored accessories mounting) is crooked as all get out.

Here’s a shot to show the size of the thing on my workbench. Again, much larger than I anticipated it would be. Pretty crazy for such a small work area of 12″x8″. I’ll certainly be making modifications to make for a larger build area.

I did some checks to make sure the mirrors were aligned (I forgot to take pictures of that process). Turns out everything was in line and I successfully fired my first hole in a piece of thin cardboard!

New owners note: The way the switches work are not very clear in how they are labeled

Power: This is obvious. Nothing will happen unless this in On and glowing.
Laser Switch: This is an up/down locking toggle pushbutton. This essentially arms the laser.
Laser Power needle indicator: This will only indicate the read amperage of the laser *while it is firing*. Turning this, even when the Laser Switch is On, will not result in the needle moving. I suggest no more than a quarter turn clockwise when first test firing the laser.
Laser Test: if the “Laser Switch” is in the on/down locked position, this momentary switch will fire the laser. A quick pulse is usually sufficient.

That’s it for the unboxing.

LINK: Click here for a WIP/TODO post that lists the improvements I’d like to make.

LINK: Click here for a shopping list of all required upgrade parts available on