In this project, we’re using equal parts of sand and plaster to make a simple backyard foundry that’s powerful enough to melt scrap metal in seconds.
With this homemade furnace, we have the power to liquefy aluminum in the backyard and cast just about any object we can think of.
You will need some big bag of play sand and some plaster of paris both of which you can find at your local hardware store for under $20.
We are also going to need a 10 quart steel bucket and a tablecloth to cover anything.
For this makeshift refractory lining we need One and 1/3 buckets full of plaster Paris or 21 cups, One and 3/4 buckets full of sand or 21 cups and 1 and 1/4 buckets filled with water or 15 cups.
Mix everything together. It’s really important to get all the dry powder wet and work out any lumps as quickly as possible. And after mixing for a couple of minutes, it should be fairly runny and roughly all the same color.
Transfer the mix to the steel bucket upto 3 inches from top.
We use the plastic measuring bucket to form the center of the foundry.
Let the mixture dry for 3 minutes.
Next step ,we turn an old steel fire extinguisher into a custom crucible. Depressurize the tank and unscrewed the valve from the top to make it safe and easy to cut in half with a hacksaw.
At this point the plaster should be pretty well set. So let’s dump the water from the bucket then use a pair of channel locks to pull the bucket out.
Next step is make an air supply port .Using 3/8 inch hole saw and a metal cutting blade, we cut a hole to accommodate the one inch steel blower tube.
The blower tube is made of one inch steep pipe ,one inch PVC coupling and one inch PVC pipe.Threads on one half of the coupling screw onto the steel pipe and the slip adapter on the other end simply pushes onto the PVC side easily.
Next step is to build a lid to retain the heat.You need a couple of 4 inch U bolts.Make them stand upright into a 5 quart bucket filled with the insulating mix.
To relieve pressure buildup, make a vent hole using a 3 inch hole cutting saw.
This design works great for venting pressure and gives us the option to melt metal as well without even having to take the lid off the furnace.
By the way, if you run out of soda cans to melt, you could try using it as a blacksmithing forge or even a barbecue for summertime grilling.
We evenly place 5 charcoal briquettes at the bottom of the crucible made out of steel fire extinguisher, helps smelt the can faster once we fire it up.
A hair dryer is taped to a PVC pipe and inserted a couple of one inch couplings to connect the steel tub eat one end and give the blower to a quick release feature. This way it’s super easy to take apart and fits into a five gallon bucket for easy storage.
The charcoal is filled it to the top and we breathe life into the steel furnace with a propane torch.The hairdryer is set to the low setting and blow a steady stream of oxygen on the charcoal to really heat things up.
The lid we made keeps the heat inside so it conserves energy while it’s bringing up the temperature. The coolest part is that the crucible lines up perfectly with the hole in the center.
The container is three inches wide, which is the perfect size for melting standard size soda cans like these and at temperatures over 1000 degrees Fahrenheit .
In order to isolate aluminium, first we remove the crucible making sure we have got a very secure grip with our tongs and slowly pour the liquid into a steel mold.
The Soda cans are molded in the form of ingots.The purpose of an ingot is to keep some pure metal handy for when you want to make something cool.
- How to turn Dirty-water/Salt-water to a clean fresh drinking water by building a simple Water distillation systemThis project goes into the build a simple Survival water purifier that can turn salt water /sea water into fresh drinkable water .This purifier is portable, easy to make and is very inexpensive. It works by the principle of desalination .When sea water/ salt water is heated to its boiling point, the water turns into steam which leaves the salt behind. Condensing the steam back into water ,it is purified. The materials you need to build this desalination unit are a simple non insulated stainless steel bottle with a steel lid , copper tubing , stove or heating source, bottle for collecting the condensed water, soldering unit, right angle compression fiting. The condenser of this desalination unit is made from one quarter inch copper tubing. Remove the lid and the gasket from the bottle . A hole is drilled using a drill press at the top of the lid to accommodate the quarter inch copper tubing . Before soldering the copper tubing , clean the surface of both copper and the stainless steel lid with the help of a sandpaper. The copper tubing is pushed through the hole just enough to stick half an inch from both side. It is then soldered securely in place. Once this is completed , the silicon gasket is then re-installed in the lid and lid is screwed back on to the bottle. A right angle compression fitting is pressed into the lid at the copper tubing opening . The extension tube at the other end of the compression fitting is removed and replaced with a rubber gasket for better seal for the lock nut. The copper coil for the re-condensing the steam when the water is boiling is made by wrapping the copper tube up tightly against the stainless bottle . Eight or nine turns of the tubing is ideal. The ends of the coil are bend outwards so that when one end is pressed into the fitting on the bottle, the other side will be sticking straight out. The salt or sea water is added to the bottle and reattached to the lid which is hanging over a heat source such as a wood stove or camp fire. The other end of the coil is placed near a collection container to collect the distilled water. To produce more condensed water out of the copper tubing ,we need to cool it down. Otherwise the production of steam will outweigh the production of the condensed water. To cool the copper tubing , wet put a wet piece of cloth soaked in cold water and wrap it around the coil or dip the whole bottom half of the copper coil into a vessel filled with cold water. https://www.youtube.com/watch?v=PT6cjp_zThw
- How to Recycle Old Used Laptop Batteries to make a DIY 24V 72AH Emergency Backup Battery SystemThis project goes into the build of a 1.72kwh emergency backup battery system out of old and used laptop batteries and an old military surplus ammo box. The materials you need to build this project are lithium ion 18650 batteries from old laptops, 4X5,3X5 cell holders, ammo can, 40 Amp BMS or Battery management system, spot welder, fused nickel strip, heat shrink, kapton tape. First we determine how many batteries that we can pack inside the ammo box. In our case, we have 2 packs of 91 18650 cells , a total of 182 cells. We take the 4 X5 and 3 X 5 cell holders and connect them to make a couple of 7 x 13 cell holders. To make this 24V lithium ion battery , we need a 7S ( 7 cells in series connection) combination . A single lithium ion cell has a nominal voltage of 3.7V . To make a single long 7S configuration battery , we connect 7 groups of 26 cells in series to get the 25V nominal voltage. The cells used in the build are Samsung ICR18650 - 28A with a capacity of 2800Mah .The cells are rewrapped with heat shrink and added an insulator disk at the positive side of the cell for safety. The cells are installed on the holder in such a way that the first 26 cells are in a same polarity and are connected in parallel. Next 26 cells are installed with opposite polarity and is the connected in series with the first 26 cells . The rest of the cells are connected in the similar way to make a final 7S 2P ( 7 series and 2 Parallel ) configuration with max capacity of 26 X 2.8mah or 72.8 amp hours. A four wide fused nickel strip is used to connect the batteries in series. The nickel strip is placed over the first 4 cells and spot welded in place using the sunkko spot welder. Each cell is individually fused in case there is short circuit or malfunction. The nickel strip connects the first two rows in parallel and then connects the next two rows in series . Similarly, to complete the series connections, the nickel strips are placed and welded on the opposite side of the pack in such a way that it wont short out the connection by coming in contact with the most negative side of the battery. We take 0.15mm standard nickel strips to connect the positive ends of the whole pack together. The last 2 rows of most positive end are connected together using the nickel strip . Small pieces of nickel strips are placed across these two rows to connect them in parallel . The pieces are bent so that it can be connected to a separate copper busbar. The separate 2 battery pack of 7 X 13 cells are connected together by the nickel fuse strip in such a way that one of the pack is flipped on top of the other. The nickel strip that connects the first 3 connection on the 1st pack is bent to connect the 4th connection on the other pack. A 90 degree bent on the last row of the 4p fused nickel strip is welded on to the first battery pack. A piece of kapton tape is placed over the nickel strip to insulate it and hold it together. The bent nickel strip on the first pack is placed on the other pack is such a way that the fuses are perfectly aligned . Then it is welded using a spot welder. A one sixteenth inch ABS plastic is placed in between the two packs. The second pack is now slowly folded over the top of the first pack. The whole pack is then wrapped around with the kapton tape so that it doesn't move around. The last three unconnected terminals on one side of the battery pack is connected to the single row of unconnected terminal on the other side with help of four nickel strips. The 4p fused nickel strip is cut to connect the 3 sides and the other side. To connect the main negative and the positive tabs , we attach a THHN copper wire across the both the terminal ends. The extended nickel connections are folded across the wire to hold it into place and soldered . The terminal wires are then connected together with XT90 connector. Next step is to connect the BMS or Battery management system to the pack . This is a small circuit board which is used to protect each cells of the battery pack from overcharging and becoming unbalanced and getting damaged. It stop the over draining when the cells are fully charged. The BMS used here is a 7S 24V with charge current of 20A and discharge current of 40A. It has two negative leads, one connecting the battery and the other for charging and discharging. The BMS also has 8 sense or balancing wires which are connected to each series connections on the battery. The black wire is connected to the most negative terminal of the battery. The first red wire is connected to the first series connected group of cells, the second red wire is connected to the second series connected cells and so on. The last red wire is connected to the main positive terminal of the battery. A heat shrink is wrapped around the whole battery pack for added safety . Before inserting the battery pack into the ammo box, a hole is drilled on the back side of the ammo can to allow the cables from the battery to pass through. Also a small piece of one sixteenth inch ABS plastic is placed at the bottom of the ammo box as a support and insulation. The battery is slowly dropped into the box . The BMS is placed on the top and is connected to the XT90 connector and the balance wires from the battery. The B- terminal on the BMS is connected to the XT90 connector on the battery. The black wire on the BMS is the charge and discharge lead. To provide extra insulation between the battery pack and the the ammo box ,we attach two pieces of the insulting ABS sheet on either side of the box. The lid is put back on the box and the battery build is complete.
- Cool DIY Video : How to run a Gasoline Engine on Waste Vegetable oil / Used Motor oil .