Penetrator Potting Documentation
The Wetlink Thixotropic 80A potting compound has excellent adhesion to a wide range of materials, including our anodized aluminum penetrators and polyurethane cable jackets. This, combined with a high degree of flexibility and chemical resistance, makes it the ideal compound to reliably seal penetrators and retain excellent performance over time. A high degree of thixotropy, or shear thinning property, allows it to stay where applied and minimizes dripping while still being easy to dispense and reduces bubbles. We use and recommend this compound on all of our cable penetrators.
Thixotropic 80A MSDS - Part A (Larger diameter cylinder on cartridge)
Thixotropic 80A MSDS - Part B (Smaller diameter cylinder on cartridge)
|Cartridge volume (2:1 ratio)||50 ml||1.69 oz|
|Hardness||80 Shore A|
|Viscosity||9000 cP at 25°C|
|Working Time||40 minutes|
|Curing Schedule||3 hours at 90°C/200°F, 24-36 hours at ambient|
|Typical depth capability*||1000 m||3280 ft|
*Determined using Blue Robotics polyurethane jacketed cable with appropriate sized penetrator, the below assembly procedure with thorough surface preparation, and oven curing at 90°C for 3 hours. Note that actual depth capability depends on materials and exact procedures used. Due to the nature of DIY assembly and the variation therein, actual performance of self-potted penetrators cannot be guaranteed, though penetrators potted by Blue Robotics are.
Assembled Cutaway View
The Wetlink cartridge is designed to be used with a 2:1 ratio cartridge dispenser and bayonet lock mixing tips for simple dispensing. Potting is easy to do, and there is plenty of time to make adjustment or clean up any drips as necessary. Proper surface preparation with acetone is required to achieve proper performance.
When working with electricity, especially in water, always practice caution. Always ensure that connections are secure and watertight.
Avoid skin contact with the acetone wipes and either part of the Wetlink Thixotropic 80A Epoxy. In case of contact, wash the exposed area thoroughly with soap and water.
- Wetlink Thixotropic 80A Epoxy cartridge
- Mixing tips
- Potting cartridge dispenser
- Acetone wipes- Proper surface preparation with acetone is required to achieve proper performance.
- Paper towels or other disposable wipes
- Small vise or clamp
- Syringe with luer tip (optional)
Step 1: Stripping the Jacket
To strip the wire jacket, please follow the Cable Jacket Stripping Tutorial.
Step 2: Prepping the Wires
Twist the conductors so they will slide through the penetrator.
Step 3: Cleaning Surfaces
Using gloves, thoroughly clean and wipe down the section of cable jacket that will be in contact with epoxy with acetone. The acetone will chemically attack the jacket surface, etching it and increasing surface roughness. This will ensure a good bond. If using Blue Robotics Acetone Cable Preparation Wipes, each wipe is good from preparing one cable.
Step 4: Bring the Cable and Penetrator Together
Insert the cable into the penetrator, stopping short and leaving the cut end of the jacket just above the penetrator head. Take care not to touch the inside of the penetrator or the prepared cable jacket surface with bare skin, oils may compromise the bond.
Step 5: Priming the Mixing Tip
Dispense and dispose of a small volume of epoxy through the mixing tip in order to ensure it is primed with clean and well mixed epoxy.
Step 6: Sealing the Penetrator
Partially fill the bottom of the penetrator hole with the epoxy, covering the bare wires. Move the cable from side to side, up and down, and twist within the hole to ensure the epoxy is evenly distributed and fills any gaps. the epoxy should completely seal the shoulder, and partially run into the throat. Push the cable jacket down into the penetrator to seat the cut end on the inner shoulder.
You can also optionally dispense the epoxy into a small syringe and apply with the syringe if working in a tight space or more precise control is necessary.
Step 7: Filling the Head
Fill the rest of the penetrator head up to the top. Oscillate the cable gently to coax out any bubbles, and wipe off any drips or excess compound.
Step 8: Curing
Use a vise or other method to hold the penetrator upright while the epoxy cures. Place in a 90°C/200°F oven for 3 hours to cure, or leave for 24-36 hours at ambient temperature in a safe place.