Waterproofing buffer/line driver

To waterproof buffer/line drivers, you will need the following:

• Silicone modified conformal coating - MG Chemicals Silicone Modified Conformal Coating, 55 ml Bottle with Brush Cap
• Dual wall adhesive lined 3/8" heat shrink tubing - DW1S3X-9.5 Dual Wall Adhesive Lined 3:1 Heat Shrink Tubing 9.5mm (3/8") - Black
• Dielectric grease - Permatex 22058 Dielectric Tune-Up Grease, 3 oz. Tube
• Rubbing alcohol
• Heat gun
• Standard 1/2" heat shrink tubing (optional)

If you want better moisture protection and make the whole thing tougher, do optional steps.

1. Cut the pigtail wires to 10mm lenght (~1/2") and remove ~3mm (1/8") of insulation. Twist and tin the wires.

2. Solder one pigtail to PCB. Remember, male pigtail is on the input side, female on the output.

3. Cut 3.5"-4" piece of 3/8" dual wall heat shrink tube and slide on one of the pigtails (there should be ~0.75"-1" overlap on pigtail's jacket.)

(Optional) cut 2" piece of 1/2" standard heat shrink tube and slide it on one of the pigtails.

4. Solder second pigtail to PCB.

5. Cover PCB and wire ends with conformal coating. Make sure everything is covered. Wait 15-30 minutes and apply second coat (3rd coat is not necessary, but always a plus.)

6. Let coating dry for 24hrs.

7. Clean pigtail's jacket ends with alcohol.

(Optional) cover PCB with dielectric grease (small amount on the back, flat end.)

(Optional) slide shorter tube so that PCB is in the middle and use heat gun to shrink the tube. There should be small overlap on pigtail's jacket, ~1/4".

Clean pigtail's jacket ends with alcohol as in step 7, to remove any grease.

8. Slide dual wall heat shrink tube so that PCB is in the middle and use heat gun to shrink the tube. Start in the middle and then do sides. Inner hot melt adhesive lining will melt around pigtail's jacket and will seal it.

9. Finally, apply a thin layer of grease around male connector's gasket.