DIY 110 V Portable Arc Welder - with DC!

I needed a more portable arc welder so I built this unit 110 V unit that weighs 40 lbs. It is made entirely of scrap parts. The frame is wood, the welding and power cables are from appliances, and the transformers/wiring are from microwaves ovens.

It is made form 3./4" plywood scraps. It uses a piece of EMT tubing as a handle. It is easy to pick up with one hand to tote around. I can not say the same for my other welder.

 

Schematic:




The unit has infinite welding current control and can do around 60 amps max. It uses a massive light dimmer type circuit to control the welding current. The circuit controls a triac which varies the input power to the transformers.

 

The transformer primaries are put in parallel so both are energized with 110 volt. If welding too long at max power it will pop the breaker on a 20 amp circuit. Running slightly lower output works great. The transformer secondaries have been cut off and rewound with 12 gauge copper wire, and then put in series to generate approximately 50 volts AC. This then goes to the bridge rectifier.

 The bridge rectifier is rated at 60 amps and converts the AC to DC, multiplying it up to 75 VDC open circuit, which goes to the filter choke. Another microwave transformer core that was completely rewound with 12 gauge wire (50 turns) serves as the choke to smooth the welding current before it goes to the electrode.

The ground clamp is a battery charging alligator clip. The rod holder or "stinger" is a standard model that cost $10.  The ground and electrode welding cables are made from 3-conductor, 12-gauge appliance cables with the conductors in parallel to give 60 amps + capability and minimize voltage drop. Also this makes the cables very flexible.

I was able to weld with 1/8" rod without trouble, you can see my first test bead above. Both 1/16" and 3/32 rods also would work. Due to the high OCV of the welder, I am able to start the arc very easily.

Emergency Bacon Candles

We always save bacon grease in old pickle and jam jars in the fridge. Its a great flavoring for cooked vegetables. We had more than we needed so we decided to try making bacon fat candles. They are extremely easy to make and only took us about 5 minutes, and are bacon scented already!

I made this wire tool for inserting wicks into the soft bacon grease. It is bent and has a small notch filed into the end. It took me about 1 minute to make with a pair of need-nose pliers and a file. Unlike wax, bacon grease is fairly soft even when refrigerated. A piece of steel coathanger or stiff copper wire would work fine too.

The wick is simply cotton kitchen twine. I dipped the wick into liquid bacon grease hot from the pan and let it cool. This is the jar we are storing the new grease in, it remains liquid until it cools. Later I skipped this dipping step when making another candle and it worked just as well.

I cut it twice as long as the height of the candle. Then I push it down into the fat using the wire tool. So you end up with two strands sticking up to make the wick. Then I cut them to length with scissors.

 

Voila! Couldn't be easier - they've been burning for hours without going out, and the house smells like wonderful bacon all day! My wife made a larger wick as an experiment by braiding 3 strands of the kitchen twine together - it works even better and allows for a brighter candle.

This must be the quickest way to make a candle there is! This works because bacon fat, being saturated, is solid at room temperature. Unsaturated fats like vegetable oil will be liquid at room temperature so wouldn't be able to support the wick. Is there anything bacon can't do??

DIY Electric Predator Fence

A grey fox killed and ate one our hens recently, and was able to enter our yard where they free-range. Originally we had found where he was digging under the fence to access our yard, so we reinforced the bottom portion to prevent that. However, we found out the hard way that grey foxes can climb. As a result we decided to retrofit our fence by electrifying it.

We used a low-impedance 75 mile charger for our fence even though it encloses less than an acre. Its important to use a low-impedance type that can do at least 5,000 volts when trying to keep out predators because they have thick fur which high impedance and lower voltage types cannot shock through reliably.  Modern fencers usually shock on a 1-second interval for safety reasons. This unit is no different.

Since we added high voltage wire to the top of the fence, and because the animal that we are defending against is a fox which climbs the fence, we can not expect to use the ground to complete the loop. This is because the fox will not be touching the ground and the fence at the same time when he climbs, and will not complete the circuit to receive a shock.. As a result the welded wire fence itself it grounded, and there are alternating energized/grounded wires on the top. A ground system is still important to discourage deer from entering, since they will likely stand on the ground and touch the fence with their body or nose. It also is required to prevent interfering with nearby electronic equipment, since electric fences are not much different than early radio transmitters.

The Insulators

Electric wires on fences need to be isolated and secured to the fence by an insulator, if they are to work. Iron T-posts and regular wood posts have commercially available insulators that allow simple attachment. However, the posts in my fence are made from U-shaped stamped steel and none of the insulators fit on them readily. Also, the posts are only 4 feet high, and I would like to attach the electric wires above the fence, effectively making it taller. So, I built my own insulators out of PVC pipe. I have found that bare PVC pipe lasts a very long time and is not readily destroyed by UV rays. Initially I thought about painting these green so they would not stand out so much, but because they will be energized at over 10,000 volts, is probably better if they are more visible. Also, I added warning signs to the fence wire:

To make the posts, I cut 2-foot sections of 3/4" PVC. I used the 480 PSI rated pipe because it has a thick wall and is very strong. There is cheaper 200 PSI pipe sold but its much thinner and I was concerned about it being too flimsy or cracking. There are  6 inches of overlap with the fence post to make it easy to attach, so each insulator extends 18" above the mesh. The fence itself is grounded by a wire intertwined between the mesh along the entire length.

The insulators are attached easily with exterior deck screws. Galvanized would work too and would be cheaper - but this is what I had laying around. Each peice fits into the "U" of the post and is screwed in place. I did not pre-drill these holes, which saves time and allows for a perfectly tight and strong bond.

The wire I used is 14 gauge galvanized for the grounding, and 14 gauge aluminum for the hot wires. Most guides for electric fences tell you to use the same type of wiring throughout, since it will otherwise corrode connections between the two types of wire. However, since the hot and ground wires never connect in my system, it shouldn't be a problem. I decided against polywire/tape because it degrades more readily in UV than these metals do, does not carry as much current, and is not as smooth for my homemade insulators.

To keep tension on the wire through seasonal variations I used galvanized springs on the corner posts. These can be attached on a corner post and then secured to put tension on the wires. I put a small bend in each wire and attached the spring to each - this allows the current to flow between the wires without breaking the connection, and the springs themselves are energized as well. For the aluminum wires this represents a dissimilar metal, so will see if they corrode or not at the junctions.

The fence is up and running, I purchased a 10kV tester and it measures reliably at just over 10,000 volt at the far end of the fence. So far so good!

Homemade Bulletproof Armor v1.0

This is attempt #1 at building homemade bulletproof armor.

This armor is constructed by layering multiple plies of fiberglass cloth called woven roving. This is a heavy weave of bundled glass fibers that is very strong, cheap, and available from boat building suppliers. However, when not cured with a resin, it is very flexible and unravels/frays when cutting using ordinary household scissors. Instead I am using a utility knife to cut it on a wooden board, this works well. Scotch tape applied first along the cut line holds the strands together on the freshly cut edge.

After cutting to size, the sheets are layered, soaked with polyester resin, and pressed together using pieces of 3/4" plywood with clamps until cured. The pieces are 1 inch larger in both directions than the final size of the plates, to allow for final trimming.  In this case the final armor plate are to be 12"X10", so the plywood peices are 13"x11".

The plywood needs some sort of mold release applied (I used saran wrap), otherwise when the resin is cured the plywood peices would be glued permanently to the armor. The resin is mixed with the MEKP catalyst in the proper proportions according to the directions, but I added slightly less catalyst to increase the working time. Each sheet was layed in place, brushed with resin to saturate it, and then a new sheet was added. I am fairly sure that every other sheet could have been saturated to save time, with a dry sheet in between. The pressing action of the plywood distributes the resin throughout the layers well, which I tested by leaving the last sheet dry before pressing.

Once the sheets were put in place, I clamped around the perimeter of the plywood "sandwich". The excess resin leaked out on the edges, so I put some newspaper underneath to catch that. It was left overnight to cure. The polyester resin makes heavy fumes so needs to be used with good ventilation.

The result is this once curing was finished:

The saran wrap peeled off easily from both sides of the armor.  I was very happy with how well it worked as a mold release. The resulting plate is very strong.

It is 3/8" thick. It contains 23 layers of the woven roving cloth and used a pint of polyester resin. I think that probably 1/2 to 2/3 of the resin could have been used instead since so much squeezed out. The armor may have too much resin in it - commercially available fiberglass armor used for buildings is more opaque than what I produced, indicating (I would think) less resin saturation, which will help with de-lamination. It could also be that commerical operations add something to the resin making it opaque, but not necessarily for appearance.

Final trimming would need to used a diamond grit jigsaw or circular saw blade because the plate is extremely tough.

One note here is that fiberglass armor stops bullets by de-laminating to absorb the energy. The layers "catch the bullet" in the same way that a soft kevlar vest does. As a result, epoxy resin should not be used. It is much too strong to allow the sheets to separate and the bullet will more likely punch through the armor. In this thickness, the plate hopefully will be able to stop most shotguns and pistols.

I will update with results after testing.

Tire Slow Leak Fix

A few days ago I looked out my window and noticed one of my car tires was pretty low. I pumped it back up using my compressor, and everything seemed okay. The correct tire pressure is found on a sticker in the driver's side door jam of most vehicles, (mine is 32 psi), seen here. I always refer to this so I don't have to remember.

Two days later the tire was down to 5 psi and looking decidedly flat. I had a slow leak. Not wanting to cough up the change or time for a professional fix, I decided to fix it myself. So I bought a tire repair kit at an auto parts store, these are much cheaper. I have radial tires so this type of fix can be used, in theory. I had seen these kits in stores for years but never had the opportunity to try one. Now is that time! It only cost $10, worth a shot, anyways.

The kit consists of a rasp, a threadable needle, and several strips of sticky rubber strips along with a tube of rubber cement. The kit I bought can repair 5 punctures. There were a few brands and sizes at the store, I grabbed the 8-peice one. I'd recommend getting at least the T-handles since you have to use a lot of force and it makes it much easier to get a grip. It comes with instructions on the back but hey, figured I'd show you how its is done since I am doing it for the first time!

First step was to block the wheels and lock the breaks, set car in park, etc. Don't want it going anywhere when we jack it up, do we?

Next step was to "crack" the lugnuts loose prior to jacking, just a 1/2 turn or so. Otherwise the wheel will just spin in the air if it is jacked up when you apply a lot of force to the nuts:

Then I jacked up the car so I could safely remove the tire. I used my 2-ton hydraulic jack. I hate scissor jacks, they are chintzy and a pain to use. When jacking a car you need to find the right spot, my car has these welds in the frame near the tires that stick down and will support the weight of the car:

Once the tire was clear of the ground, I loosened the lug nuts all the way, put them in a safe spot and removed the tire for inspection:

With the wheel off I set about looking for the problem. Slow leaks occur because whatever caused the puncture is embedded in the tire, forming a seal, albeit a crappy one. Eventually I found it, it looked like a nail:

A little tug with my pliers and I could hear air escaping, yep, this is the culprit!

Pulled that $&^%er out of there. Looks like a finishing nail. Hooray. Tire is now hissing loudly from the hole.

Now to the repair. First, the rasp tool. It helps to spin the tool while getting it in there, makes it easier to push it in. Other more expensive kits at the store had a spiral groove in the rasp - now I know why. I Pulled the rasp in and out 10-20 times. This will clean and abrade the rubber as well as make the hole the right size to install the strip. Tire really started deflating after this.

Then I threaded one of the tar strips into the needle tool, slathered on some rubber cement, and jammed it in there about 2/3 of the way, then yanked out the needle. Probably didn't need as much rubber cement as I put on there. Then I cut off the stub with a box cutter:

Reinflated the tire to 32 PSI and checked if I could hear/see any leak. Nothing. Then I put the tire back on the hub, and tightened the lug nuts in a star pattern till they were snug with the wrench. Then I lowered the jack, removed it, and tightened the lug nuts all the way.

That was easy! All in all, it took me about 45 minutes. Now the part where we wait and make sure it worked, it was a slow leak after all. I'll report back in a week.

I highly recommend going this route. In the past I have gone to tire shops and paid $50 or more to have it fixed, and they use a similar system to do the repair. On the back of the kit it claims that this fix is only temporary and the tire should be taken to a professional shop for a permanent fix, but I noticed that all of the tire repair products mentioned this on the labeling. This sounds like a load of baloney to me, it is probably just there for legal reasons. I seriously doubt that it will fail before the tire needs replacing.

Wireless LED Throwie Transmitter

Wireless LED throwies require a power driver to run the coil loop from which they receive energy to light up. This transmitter has a 555 oscillator that controls the gate on an N-channel MOSFET which alternately turns the power to the coil on/off at a high rate, creating an alternating magnetic field at around 18kHz.

The coil loop is made from 24 gauge wire or less and is wound on a square or round form made from brads hammered into a wooden board.


The basic schematic is here:

The transmitter PCB artwork and component overlay is provided here on a 8.5 x 11" sheet for simple generation using my toner transfer method, it is scaled already so is ready to print:




Parts list:

555 timer IC
7805 Voltage Regulator
IRF540N (or any N-channel MOSFET)
16V 10 uF Capacitor
16V 1000 uF Capacitor
1k resistor, 1/4 watt
5k resistor, 1/4 watt
27k resistor, 1/4 watt
1nF ceramic cap
24 gauge or thinner magnet wire (coil)

More updates soon with a video description!

DIY Broody Buster

Our alpha bird, Queeny, went broody. Since we are not planning on getting fertilized eggs for her to sit on, or to use the late-night egg/day-old chick swapperoo, we need to break her of the broodiness. Broody hens don't lay eggs, and it can really stress out a bird to remain this way since it can last for months given nothing ever hatches to break them out of it. 

So I built a broody buster, which is a fancy name for a mesh-bottom cage that you can keep the broody hen in for 3-4 days until she snaps out of it. The mesh on the bottom lets air get to her underside, which convinces her hormonally that she needn't be broody anymore. That's the theory at least - the wire cage could also block the transmissions from the mothership making her a demented finger-pecking menace.

 

This is made with 2"x4" mesh fencing and the bottom is 1/2" wire mesh. It features a fancy carrying handle that I found in the trash.The cage opens on one side and the door held closed by a spring-loaded wire catch, the spring was from the junk bin and the catch is simply bent fence wire.

The trick is to have the cage up off the ground  to let the air get underneath. I put a couple of bricks on the ground to raise it up, with some food and water for the crazed bird. The other hens are helping her get used to the chicky slammer (and by helping, I mean, eating her food and drinking her water).

Shouldn't be long now...

Update: After 4 days, the hen is no longer broody! She is back with the flock and acting normally. The Broody buster is a success!

DIY Automatic Chicken Door

Where I live, chickens generally need to be closed into a predator-proof coop at night. Then they need to be let out in the morning. This can be a tedious chore and hazardous to the chickens if forgotten.

I wanted to automate this process so the coop door closes up in the evening and opens in the morning without any manual intervention. Here it is in operation from the outside:

This basic design for the circuit comes from this guy.

However I did build a printed circuit board with some more advanced features, such as the ability to raise/lower the door with a switch in a sort of "manual mode", as well as regulated battery charging. Also I built in a battery and power disconnect switch in case the thing goes haywire during testing.

The premise is to sacrifice a cheap cordless electric screwdriver to perform the lifting/lowering and to use a motor-reversing relay and some limit switches as the brains. The unit basically opens the door when AC power is applied and then closes it when AC power is switched off. The schedule for when this occurs is provided by a cheap holiday light timer in my case, however it could be a light swith is one used a switched outlet, etc.

Here is the cordless screwdriver taken apart with the battery and directional switch. The switch is can actually be used for this project if the manual up/down feature is desired.The important part to save here is the battery and the motor unit. I disconnected the wires leaving a little extra so I could crimp on spade terminals.

The screwdriver attachment is glued into a piece of wood which is glued into an old plastic wire spool, with a length of rope attached. The round wood piece was made using a hole saw that was close to the same size to give a plug. Then the screwdriver bit as hammered and superglued into place. I spun the plug on a drill and sanded it until it fit the plastic spool tightly. Then I inserted it into the spool and glued it in place. I drilled a hole in the side of spool to feed the rope through and keep it anchored.

The door I originally had on the coop didn't slide very well in its tracks, especially when the weather changed - the wood in the door frame would swell and bind the door making it difficult to open/close. So I built a new door with wider channels that wouldn't bind.

The door is very simple to build, it is made from 1x4 pine. It consists of a inner box with a dado to act as a track for the cutting board. Then the side facing out is trimmed with 1x4s to give a nice look and act as a flange to install in the coop wall. It is glued and tacked together with a brad nailer.

 

The cutting board can slide up and down in the track which is 1/2" wide. The cutting board is only 3/8" so this prevents binding. The cutting board is some sort of plastic so it doesn't warp at all. It is 12" x 18", but this is really much larger than needed for the chickens I have. Two chickens can fit through the door at once. Some larger breeds may need it though.

I gave the door a  coat of exterior primer from a spray can. Then I brushed on a coat of latex semigloss white, which is what I had flying around. The only critical part is to avoid runs of paint in the channel so the door will not have risk of binding in its track.

I cut the caulkng with a knife and ripped out my old door as shown here. I found a ant nest underneath it. This door was held on with a few nails that I had painted over. The hole in the side of the coop need only be slightly larger than the internal box so that it can poke through and the flange will lay flush.

 The new door is built to the same size so it drops into place. I nailed and re-caulked it. One other thing I had done with this door was angle the bottom piece of wood so water will tend to run out instead of in if it rains. I had considered building a small roof for the door to keep out all rain but it is not really needed. 

Then I reattached my ramp with old hinges. A ramp really isn't required on a coop as the chickens can typically jump up onto the ledge of the door with ease. But I have one anyways. Sometimes the chickens hang out under the ramp during inclement weather, or if dustbathing.

The mechanism inside the coop to open and close the door. The powered screwdriver is attached to a piece of wood and then to the coop wall with screws.There is a second track assembly that sits above the door which has the limit switches.  It is built identically to the door but is thinner and has no trim on the front. The limit switches are bypassed with capacitors to cut down on the amount of sparking when a contact is broken, since they carry the full amount of current form the motor, which is well beyond their DC rating.

 The door raises and lowers perfectly. It's fairly loud but the chickens don't seem to mind it at all.