[Fran] shows us how to build a plastic friction welder. It’s a method of connecting plastic pieces. While it’s new to us, apparently this type of tool was given to kids about forty years ago to use with craft project (when plastic was all the craze).
The tip of the friction welder is a styrene rod. If it’s spun fast enough the friction will cause the material to heat to the melting point, depositing a bead of styrene into the joint. The tool seen here is a cheap DC rotary tool acquired from Harbor Freight. It really did a horrible job, but [Fran] discovered that it was the power supply that was under-rated. When she replace the wire that feeds it and used her bench supply it spit out 16,000 rpm without any trouble. The welding rods can be found at the craft store and fit the chuck of the tool quite nicely. You can see her demo in the video after the break. The seam she’s working on comes out very strong, surviving a slew of violent whacks on the workbench.
We’ve seen a few other methods of welding plastic. One used a tool much like a soldering iron, the other depends on ultrasonic waves and clamping pressure.
Continue reading “Make your own plastic friction welder”
[Doctor Bass] needed to do some welding on his electric bicycle. The problem is that he’s never welded before and doesn’t have any tools for it. As you can see, that didn’t stop him. He used a bicycle battery made from reclaimed DeWalt A123 cells to power his diy welding rig.
He has a huge adjustable resistor which is responsible for limiting the current. 80 Amps seems to work the best with the welding rods he’s chosen. It is worth noting that when he shows off each part of the welder (see the clip after the break) the color of the wire used for positive and negative leads is opposite of convention. His positive wiring is black while his ground connection is red.
To get the welding under way he connects a jumper-cable-like clamp to his work piece which serves as the positive electrode. To hold the welding rod he drilled a hole in a pair of vice grip pliers and bolted on the negative lead. This way the end of the welding rod can be clamped in the vice grips while his other hand guides the tip. So far he’s still practicing, but it looks like he’s nearly ready to take on the job at hand.
Continue reading “Welding with over a hundred A123 Lithium cells”
This kayak to sailboat conversion is well done and makes for an interesting project. But even if you’re not going to be hitting the water on one of your own, the construction techniques are a useful resource to keep in mind. Many of the alterations were done with a plastic welding iron.
[RLZerr] shows off the materials that went into the build right at the beginning of the video which you’ll find after the break. His kayak is made of High Density Polyethylene and he uses other HDPE scraps, PCV parts, and even some aluminum to make everything. To weld HDPE together he uses a plastic welding iron that is like a cross between a soldering iron and a hot glue gun. It has a pad tip that gets hot enough to melt the plastic, but also includes a channel through which additional HDPE filament can be fed to bulk up the connections.
Additions to the kayak include a centerboard, rudder, and mast. The sail is a plastic tarp attached to the PVC mast which has been stiffened with a wooden shovel handle in its core. The rudder and centerboard are aluminum attached to PVC pipes using JB weld. The boat catches the wind easily, but without outriggers [RLZerr] must be careful not to let a big gust swamp him.
Continue reading “Kayak to sailboat conversion shows how to weld plastics”
There are so many good ideas crammed into this project its hard for us to believe this isn’t already widely used for critical welding applications. Traditional welding masks simply filter out light to protect the welder’s eyes. This mask doesn’t have a window in it at all. Instead, the mask includes two cameras on the outside and two LCD screens on the inside. It filters light by processing the video which lends itself to that grab-bag of features we mentioned earlier.
Possibly the best of the system is its ability to selectively filter the brightness of the weld. What this means is that areas outside of the welding arc appear at a normal brightness level, whereas before they would have been greatly dimmed. A demonstration of augmented reality is also shown, where a computer monitors the welding surface, giving the welder a target to follow and measuring the distance between the weld and the filament. The video mentions that an FPGA would be well suited for the image processing, making us think this could be produced at a reasonable cost. After all, they already use X-ray machines for some welds, we’d bet a set of these helmets could be supplied to a crew at a similar cost.
We don’t get to see Blacksmith hacks around here too often. But even if they were rolling in on a weekly basis we think this one would be considered the special expanded edition with full-color centerfold. The sixty-five images in this coal forge build log are all commented and just begging to steal your attention for part of the afternoon.
The build mostly involves fabricating a system for injecting air into the forge and providing a mechanism for evacuating the waste ash. [BillDaCat] starts with a 3″ pipe as the ash dump, adding a latching door used to empty it when full. He then welds together a metal trough with a slotted bottom to hold the fiery fury, attaching the ash dump below. He uses a plasma cutter to add an opening in the upper portion of the ash dump for a blast gate.
If you’re excited about his build you should also check out the metal pour and the induction furnace.
Here’s something that may be of interest to all the reprappers, vacuum formers, and other plastic fabbers out there: ultrasonic welding of plastics. If you’ve ever wanted to join two pieces of plastic without melting them together with acetone or screwing them together, [circuitguru] is your guy.
Ultrasonic welder setups are usually reserved for companies that don’t mind spending tens of thousands of dollars on a piece equipment. There are smaller versions made for heat staking – melting plastic pillars into rivets on the work piece – and [circuitguru] was lucky enough a somewhat reasonable price.
Because the heat staking gun was a handheld unit, a rotary tool drill press was put to work. The end result is a relatively inexpensive way to join two plastic parts without screws, glue, or solvents. The bond is pretty strong, too. Check out the video after the break to see [circuitguru] join two pieces of a plastic enclosure and try to tear them apart.
Continue reading “DIY ultrasonic plastic welding”
This project really puts an end to arguing over who has to ride in the back of the tandem bicycle. We challenge you not to smile while viewing the maiden voyage that [Carlos] and his daughter take on this side-by-side bicycle. The video can be found after the break.
It certainly makes a bit more sense than an over-under tandem, and the fabrication process is really quite manageable. This requires alterations to the seat, handle bars, and pedals, but the majority of the bike (frame, gearing, fork, wheels) is unaltered.
The cranks have been replaced by a custom welded cam mechanism that reminds us of how the pedals on a paddle boat work. Both riders must pedal at the same time and rate. To give each a place to sit the seat post was converted into a T bar to host saddles to the right and left of the frame. Finally, the handle bars are the most complicated of all. Extra framing was welded onto both sides for the front tube to provide a place to mount two pair of handle bars. One of them is fixed in place, the other can be turned, using a lever mechanism to steer the front fork.
It looks a bit awkward to get started, but once both riders are up it seems quite stable.
Continue reading “A bicycle built for… Siamese twins?”