Potting the wire pass throughs in the end caps

Instructions for v2.4

Materials

 * Assembled end caps (except the white flat endcap piece is still not attached).
 * Assembled ROV Internal Structure(for reference purposes)
 * Expando Sheathing for tether
 * tether wire (twisted pair)

Tools

 * Hot Glue Gun
 * wire cutter
 * acrylic cement and applicator
 * electrical tape
 * Hack Saw
 * Some sort of wire stand (see Step 4) to hold the line while the epoxy dries.
 * clamp
 * Loctite 29309 E-90FL HYSOL with applicator

Procedure
In the bundle you should now have: increase its diameter! Tape over each end of the expando sleeving to keep it from fraying 
 * 1) Mount motors onto internal structure using M2 screws and nuts, this only needs to be a loose attachment for these purposes MotorMounting_1.JPGMotorMounting_2.JPGMotorMounting_detail.JPGMotorCableRouting.JPG
 * 2) Mount the battery tubes onto the Shell with zipties loosely with the wires hanging towards the rear of the vehicle
 * 3) Label all the wires! Bundle and label each set of motor wires (port, starboard, and vertical; or left right and top for you landlubbers), as well as each set of battery tube wires PottingWire_2WiresTaped.jpg
 * 4) Insert the internal structure into the OpenROV shell with both the battery wires and the motor wire. make sure you route the bundle of wires through the top. make sure you include the tether wire as a part of the bundle! PottingWire_wholeshot_24.jpg
 * 5) Cut the wire bundle approximately 2x the width of the shell, like so in the picture. Try to keep the bundle taut and together such that they are all cut the equal length PottingWire_3EchassisBundle.jpg
 * 6) Tape together the end of the the massive cable bundle you now have.
 * 3x sets of 3 motor wires (9 wires)
 * 2x sets of 2 battery wires (4 wires)
 * Tether twisted pair (2 wires)
 * 1) insert the bundle into the expando sleeving to keep all the cables tidy and organized. To expand the expando sleeving, simply push down the end to compress it and it will
 * 1) insert the bundle through the starboard side endcap (wire pass-thorugh going to the rear and flat endcap edge facing the bottom. You want to feed the wire bundle far enough such that the wire bundle fits snugly against the internal structure and has enough slack slack for the endcap (with the white endcap piece which you will soon glue on) to be placed flush against the side of the outer shell. You will want to align the hole that the wire bundle exits to be aimed straight back (see pictures below)PottingWire_6FitBundle.jpgPottingWire_7FitBundleTubing.jpg
 * 2) double check that fit and distance, after this next step it will become more difficult to adjust it!
 * 3) apply acrylic cement onto the white endcap piece and glue it onto the rest of the endcap! Make sure the flat notches alignPottingWire_8Endcap.jpgPottingWire_9EndCapGlue.jpg
 * 4) optional to make sure the acrylic cement adheres nicely you can grab a few clamps to apply force while the acrylic cement is settingPottingWire_10GlueClamp.jpg
 * 5) triple check the fit of the endcap and tether length by placing the endcap flush with the side of the shell. Adjust the length to make a little bit of slack so that the electronics tube can be easily removed, but not enough to interfere with the vertical shroud which will be inserted into the top holePottingWire_11CapFitCheck.jpg
 * 6) whip out your hot glue gun and use hot glue to seal the wire pass-through from the outside edge. Inject enough hot glue into and around the wire bundle to make it a tight seal that will keep the epoxy from flowing out. Try not to get any hot glue into the O-ring channel, since you'll need it clean.PottingWire_12HotGlueSeal.jpgPottingWire_13HotGlueSealShow.jpg
 * 7) quadruple check the fit of the endcap. Once you pot it there is no going back!PottingWire_14EndcapFitTestGlued.jpg
 * 8) Now use some sort of rig/shelf/thingie to keep the wire bundle suspended vertically with the endcap clamped flat against a surface. You want to keep the wire bundle perfectly centered in the pass-through hole without it touching any of the sides. You don't want any places where water can tunnel through cracks and spring leaks. You can use tape to keep the bundle tightly together. PottingWire_15PotWires.jpg
 * 9) the next part of potting is a bit hard to describe in pictures so here's a video!

If you have any suggestions for improving the instructions, please email us at info@openrov.com!

Materials

 * Assembled end caps (except the blue triangle and blue servo mounts are still not attached).
 * Assembled ROV (for reference purposes)
 * Sheathing for tether

Tools

 * Hot Glue Gun
 * Razor blade
 * Hack Saw
 * Some sort of wire stand (see Step 4) to hold the line while the epoxy dries.
 * Loctite 29309 E-90FL HYSOL with applicator

Procedure

 * 1) Preparation:
 * 2) Mount motors onto internal structure using M2 screws and nuts, this only needs to be a loose attachment for these purposes MotorMounting_1.JPGMotorMounting_2.JPGMotorMounting_detail.JPGMotorCableRouting.JPG
 * 3) place the outer shell over the motor structure.  place the battery packs at their eventual location, loosely zip-tieing is helpful.  Route all wires through an upper corner as shown in the pictures below.  In this step we are ensuring that the battery wires are the proper length.  They should take the shortest route from the battery packs to joining the other wires.  Tape all wires together to "lock in" these lengths - INCLUDE THE TWISTED PAIR TETHER AS WELL.  It is really helpful to mark which set of three wires goes to which motor.  Electrical tape is good for this.battery_wires_2.pngbattery_wires_3.pngMotorWireLabel.jpg
 * 4) Take off the shell and thread wires through end cap. Make sure it is the correct endcap.  Compare with the photo. Potting 1.png
 * 5) Place wires through the electronics tube as well, placing tube close to acrylic motor structure (see pic below) Potting 2.png
 * 6) Mark wires with a Sharpie where they go through the end cap Potting 3.png
 * 7) Add blue acrylic triangle, making sure you can still see sharpie mark. (Also, add blue acrylic triangle to non-wire pass-through end cap.)Potting 4.pngPotting 5.pngPotting 6.png
 * 8) Add hot glue to mouth of wire pass-through - the hot glue serves as a barrier for epoxy. Make sure to avoid getting hot glue in the gland of the end cap (the area where the o-rings lay) or any area that would interfere with the end cap making a complete seal in the tube.Potting 7.pngPotting 8.pngPotting 9.png
 * 9) Tangent step: Cutting the syringe plunger. (Meaning: doesn't have to be done now, necessarily. But now is a good time because the hot glue is drying.)
 * 10) Using a razor blade, use the outer end of the blue triangle to mark where the plunger should be cut (assuming it's pushed all the way in).Potting 10.png
 * 11) Use a hack saw to sick the plunger.Potting 11.png
 * 12) Sand down the cut end of the plunger.Potting 12.png
 * 13) Set up a stand to hold your wires. We built ours out of wood, but anything that can hold the wires away from the edges of the acrylic circles they protrude from will work. It needs to hold this form for the duration of the epoxy cure time, which is at least 24 hours, so make sure it's in a place you can leave it securely.Potting 13.pngPotting 14.png
 * 14) Add one (not both) of the small, blue, circular servo mounts to the inside of each endcap. Potting 15.pngPotting 16.pngPotting 17.png
 * 15) Prepare the Loctite. Potting 18.png
 * 16) Fill the wire pass-through holes with the epoxy. Making sure to get inside the wire sheath (it's a good idea to slice a hole in the sheath so it's easier to apply the epoxy inside).  Keep a close eye that epoxy isn't leaking out of the hot glue seal. If it is, make sure to wipe it before it can accumulate and harden. Potting 19.pngPotting 21.pngPotting 23.png
 * 17) Put a small piece of tape over the syringe hole inside the servo-mount circle (making sure it's just the one circle, we'll add the second one after the epoxy dries). Fill the servo-mount circle with epoxy - only to the height of the acrylic.
 * 18) While the epoxy is drying, keep an eye for bubbles that may form beneath the surface. Poke potential bubbles with a paperclip or pin. See below photos for an example:Potting 24.pngPotting 25.png
 * 19) After the epoxy has dried, add the second blue acrylic servo mount.