Going off script right off the bat I decided to start with the construction of the hose. I figured that it would be a good starting point to get brush off the soldering cobwebs and to tackle something I could complete in a weekend.
I started out by following the directions and disassembling the female connectors. The first step is to cut out some electrical tape to isolate the metal spring inside from the casing.
I tried using the method shown in the directions, but wasn't happy with the result.
I tried modelling and 3D printing an insert, but even at the finest quality my FDM printer couldn't print a wall thin enough to work. I ended up printing a template created in Illustrator which I taped on top of electrical tape stuck down to the cutting mat. I could then get accurate inserts with notches cutout to allow it to curve up the sides a bit.
After fiddling with this a bit I got it perfect. Which brings me to my first criticism.
...Connectors and Plunger
The goal here is to isolate the metal spring from the housing allowing the signal from the peddle to work. CD has opted to use glass tape, but recommends electrical tape or heat shrink as well. The problem is that the build order of this means that in the next step you'll be applying huge amounts of heat to the brass connector. This heat, as you can imagine will mess with the heat shrink and electrical tape.
I found this out the hard way as I had to go back and redo the electrical tape after soldering the wire. The build order really should have the electrical tape being the last step.
That said, I also think electrical tape/heat shrink isn't the best solution. If the goal is to isolate the spring, I think a much easier and more effective way would be to apply a non-conductive coating to the spring itself. A coating of liquid electrical tape or rubber would not interfere with the movement of the spring, but would make it so much easer to apply.
The next step is to remove 1/16 of this part called the plunger. It is a tiny metal part that attaches to the spring. The idea I believe is to remove 1/16 of the metal plunger and then extend a 1/16 brass rod from the male connector to connect with this.
Now, I only sort of tested it, but I am not convinced this is going to work that well. The reason is that the part that you take off results in a very small surface area. This means that when the brass tube comes into contact, it must find this little ridge and maintain a strong connection.
These connections are also designed to spin. This is a good thing as it allows the trap to spin around on the hose reducing pressure and keeping the hose free of twists. In one of my initial tests the brass rod slipped to one side not allowing the connectors to spin freely. This could put a lot of pressure on the parts and ultimately cause failures.
My suggestion would have been to either completely remove the fin on the plunger (and extend the brass rod), or increase the surface area of the top of the plunger using another method. This would create a flat, large surface area for the brass rod to find.
Time will tell if this will hold up.
...The Wires... Don't cross the streams
The instructions call for soldering a blue wire to the plunger and a black wire to the connector.
Now, perhaps I am totally screwed up but, it appears to me that CD has this completely mixed up. I've attached a diagram of what the directions call for.
Now, again I might be looking at this incorrectly, but it appears that the wires are reversed along the inside of the tube. Not a huge deal as a wire is a wire, but it had me super confused after I tried troubleshooting a connection only to realize I was working on the wrong wire. My perfectionism makes me want to go back and rewire it, but I'll leave it for now.
As you can see from the diagram above, the directions call for soldering a wire to the barb of the female connector. This is no easy task and brought me back to my days in art school when I got the brilliant idea of soldering together a giant brass lantern. The issue is that to avoid a cold weld (a weld that doesn't actually adhere to the metal) you have to heat the part. The part of course won't just heat up in one spot and will dissipate the heat to the rest of the object, the vise, the leather you're using to hold it in the vise and everything else.
What I don't like about this is that you solder a small wire to the end of an edge, where there is the most amount of flex and strain on the hose. This came back to bite me later when I attempted to insert it into the clear tube and my wire broke off in the process.
I should have went with my gut feeling and dealt with it then and there.
I think a better solution would be to take the wire and wrap it around one of the upper parts on the barb and solder it there. Then, taking a heat shrink tube, cover both the blue and black wire, as well as the barb and solder point.
After shrinking the tube this would lock both of the wires in place and create a strong, flexible stress point at the end of the barb. It would also hold the wires onto the barb not allowing them to pull out as easy with stretching that likely comes while rolling out the trap.
This is really bothering me because I am concerned that black wire will eventually snap in the tube requiring me to take most of it apart and heat up the brass which has already discoloured due to heat.
...We Be Tubin'
With the connections made, it was now time to put the wires in the tube.
An old electricians trick is to use a vacuum or your mouth and suck a piece of string through the tube. Then, you attach the wires and pull it back through. Clever!
The instructions call for slicing the tube lengthwise and manually feeding the wires inside and I wanted to avoid this if possible. The less chance of moisture, mud, dust, and such getting inside the plastic tubing the better.
Hmmm... The problem is that the tube provided in the kit has a very small inner diameter. This means that while the wires do fit, they cannot be pulled through as the friction becomes so great after a few feet that it is impossible to move. I tried doing one wire at a time. I tried different rigs, but in the end I ended up slicing the tube as directed.
To do this, I created a simple little jig.
Using a piece of plastic tube the same diameter, I poked a knife through just enough so it would slice one side. I then taped that knife down to the table.
I could then feed the tube in and pull it the entire length. What I like about this method is that the tube naturally twists meaning that the cut is spiralled along the entire length meaning that it does not easily buckle open.
The inner diameter of the tube once again became an issue when trying to connect them to the barbs at the two ends. To fit them on the ends the tube needs to be sliced, but this creates a really weak connection due to the tube only covering about 3/4 of the diameter of the barb.
Once taped and zip-tied it seemed to hold, but I think this could all be avoided with a more appropriately sized tube.
Eventually you'll need to connect the wires from both sides. This is just a small nitpick, but while the directions show a staggered connection of the wires (meaning they don't connect at the same spot), there wasn't any little notes to point this out. I wasn't thinking and I connected the black and blue wire in the same spot, only to realize that they wouldn't fit into the tube with the addition width of the heat shrink.
I ended up having to redo one of the wires further along so the connection points were not in the same spot. Not CD's fault, but one of those quality of life notes that would have saved me a half our.
...Fosters Male Connection
To shield the connector from electricity, a 3D printed part is inserted into the Foster connectors. Then, a brass rod is inserted, cut to length and soldered to a wire. This allows the connection to be made with the plunger inside the female connector and then through the tube.
The directions say to solder a wire to the end of one of the brass rods, then insert it into the 3D printed part. Then, when 1/16 is poking out the top, glue it in place add some heat shrink and call it a day.
Again, this doesn't sit right with me. Not only am I obsessive about cable management and clean looking parts, but I didn't like that it caused a stress point with uncovered wire. The reason for having to use heat shrink is because once the wire is soldered to the end, it becomes too bulky to fit into the 3D part.
To solve this, I took the rotary tool and a disk and carefully created a notch at the end. Then, I filled this with solder and laid the wire inside. This resulted in the wire coming straight out the back of the brass rod. With a little sanding and scraping with the hobby knife, I was able to create a clean, strong connection.
The best part, is that it could now be inserted into the 3D part and glued in place leaving the wire to come out the end. I think it not only looks cleaner, but most importantly is not stressed.
That said... I am concerned about this part holding up. When the male and female connectors are inserted into each other... Hmmm, err... Well, the little brass rod presses on the top of the plunger and spring. I suspect in the normal operation this pressing action opens the valve. In this case it keeps the two connections tight together. The concern I have is that the spring, which is already super compressed will not have enough give and will push the pin and / or the 3D printed insert out of the Male Foster. CD recommends some glue, but in my experience when you introduced two immovable objects then something has to give. The spring and brass rod won't, but the fragile 3D printed part and the glue likely will.
If it ends up becoming a problem, I may end up replacing the spring and plunger and opting for a connection with larger contact points and a weaker spring. Something that will keep the pressure together for a good connection. Or... I might just permanently wire the thing up as I'm not sure when I would remove the hose anyway.
After finishing up the final steps I put it together, taped up the ends to fit the GB1 style and put on some zip-ties. I gave it one last test with the multimeter and it seems to be functioning as intended. It needs some weathering of course, but I think it turned out quite well.
I am still concerned with the connection points and how they'll hold up over time, but hopefully they don't become an issue.
I think overall this part of the instructions were easy to follow and accomplish. There does however seem to be some mistakes in the directions which could cause issues down the line when troubleshooting. Some quality of life notes in the instructions would make things a little more clear in some parts as well.
I think the solution to making the pedal work is really clever and full credit to Sean for coming up with this solution. I would like to see a few improvements made to assure the connections are more robust.
One of the biggest things I would like to see changed is the diameter of the rubber tube. A thinner one might not feel as hefty, but it would go a long way to making the process a lot more user friendly. It could also mean that the tube does not need to be cut, which would help keep out moisture, dust and other things that could work themselves into the tube and mess with the wires.
Anyway, I had fun!
Three Venkmans out of 5