[PSUBS-MAILIST] Minn Kotta 101 - Thruster Reliability

Tue Jul 25 19:30:05 EDT 2023

 This is way too much kinematic viscosity for me at 100 times the viscosity of water.  Manufacturers make a low viscosity silicone oil.  I think we need to be closer to 5 cSt for kinematic viscosity.
I am hoping Emile will send info on what he is using.
Cliff

    On Tuesday, July 25, 2023 at 06:17:28 PM CDT, Jon Wallace via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

  I found SuperLube which has 100 cSt viscosity, but it's pretty expensive at $17 for 4oz.
Silicone Oil | Synthetic Oils

| 
| 
| 
|  |  |

 |

 |
| 
|  | 
Silicone Oil | Synthetic Oils

Super Lube® Silicone Oil is a straight chained polydimethylsiloxanic fluid. This product is available in 100 cSt...
 |

 |

 |

    On Tuesday, July 25, 2023 at 04:18:06 PM EDT, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

 Hi Cliff,thanks for that detailed report.We had discussed WD40 years ago and decided a low viscosity silicone was the way to go. The main problem we discussed was that the WD40 degraded plastics, but yes could imagine it would act on the binder in the brushes.I built a thruster using a 6374 outrunner brushless motor.I had 11 motors made up with 316 stainless shafts to my specs. I also had a mechanical seal. I feel now that I should build again with an inrunner motor. The inrunner has the coils on the outside and can dissipate the heat through the housing whereas with the outrunner, it's inner coils were being cooled by the silicone. It hasn't failed.I found I needed an over-pressure in the compensation system as the silicone was being thrown out of the thruster housing and up the wiring tube.I have been working for a long time now on an over-pressure compensator & recently bought a 3d resin printer to print the compensator body & sealing surfaces.Not far off finishing but have to order 316 springs from overseas. The compensator can be pre set to between 2-8 psi. The idea is that the thruster is oil compensated but pressurized by air. I like oil compensation as it lubricates & cools the parts, & in Minn Kottas I have seen, they don't have a bearing for reverse.Alan

Sent from Yahoo Mail on Android 

  On Wed, 26 Jul 2023 at 6:13 am, Cliff Redus via Personal_Submersibles<personal_submersibles at psubs.org> wrote:   _______________________________________________
Personal_Submersibles mailing list
Personal_Submersibles at psubs.org
http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles

_______________________________________________
Personal_Submersibles mailing list
Personal_Submersibles at psubs.org
http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
  _______________________________________________
Personal_Submersibles mailing list
Personal_Submersibles at psubs.org
http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20230725/b3b2ba31/attachment.html>