[PSUBS-MAILIST] Castable Rubber

Sat Nov 14 17:57:51 EST 2015

Alan

Over the years we have done a number of connector and cable splices for our ROV systems and other underwater systems and used down to 2000ft or so without problems. I use the 2 part resin which 3M supply with their Scotchcast 82 -A splice kits (don't have resin spec with me at present) but rather than use their 2 piece mould supplied with the kit I use Raychem WCSM heat shrink. A few precautions needed when doing the splice but basically  the heat shrink is heated to shrink one end onto cable or connector, then supported vertical with open end of shrink upper. The resin is mixed and poured into the open shrink leaving enough shrink to later heat and close around cable after resin has set. While resin is still in liguid form and setting, hand squeeze the shrink at intervals to burp any air bubbles. After resin set use heat gun to shrink the excess shrine around cable to close off the splice. It works!
I have attached photo of some cables and connectors I have spliced - hope this helps - the 3M resin product is not cheap but who wants to be cheap at depth.

Cheers
Keith Gordon

On 15/11/2015, at 9:09 AM, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

> Hank,
> further thoughts on the molding...
> if you had a two part mold, you could press a shell of the
> "castable rubber" in to each half to make sure there are no voids,
> then squirt some silicone in to both halves before  clamping it 
> around the cable & fitting (which already has a dried silicone
> layer on it.)
> Cheers Alan
> 
> From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
> To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
> Sent: Sunday, November 15, 2015 8:13 AM
> Subject: Re: [PSUBS-MAILIST] Castable Rubber
> 
> Alan,
> I just bolt an eyelet with a wire to my penetrator and coat it with silicone, it is not pretty, I like your idea a LOT
> Hank
> 
> 
> 
> 
> 
> On Saturday, November 14, 2015 12:08 PM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> 
> Hank,
> that idea may have merit.
> I would just have to be sure the silicone set inside.
> Alan
> 
> Sent from my iPad
> 
> On 15/11/2015, at 2:41 am, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
>> Alan,
>> Are you talking about making a mould with casting rubber that fits over the cable with a void that you will fill with silicone.  Then remove the mould.
>> That  would sure look nice.
>> Hank
>> 
>> 
>> 
>> On Saturday, November 14, 2015 4:38 AM, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> 
>> 
>> Alan,
>> If you go with casting resin, buy small quantities.  Once you open the containers, they don't last long after. 
>> Hank
>> 
>> 
>> 
>> On Friday, November 13, 2015 8:47 PM, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> 
>> 
>> Thanks Hank.
>> I will try the polyeurathane.
>> I have some subconn wet matable connectors, & looking
>> at them closely I can see that they mate the head of the connector
>> to the cable with a thin layer of rubber for at least an inch back.
>> I am not sure whether the rubber head is molded over the cable
>> or whether a layer of rubber is applied some how over the cable
>> head & cable to seal over the entry point of the cable into the connector head.
>> However it seems to lend weight to my idea of applying silicone an
>> inch up the cable. Now all I need to do is track down or make a pressure 
>> Chamber.
>> Cheers Alan
>> 
>> From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
>> To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
>> Sent: Saturday, November 14, 2015 3:12 PM
>> Subject: Re: [PSUBS-MAILIST] Castable Rubber
>> 
>> Alan,
>> I made two through hulls with pipe thread bushings almost the way you are.  I use poly urethane casting resin, I hate epoxy.  I tested my through hulls in my test chamber to 1,500 feet with zero issues.  I just silicone the threaded rod at the bottom to keep the resin in till it cures.   I made a plug connector for my Perry thrusters with casting resin also, that suff rules!
>> Hank
>> 
>> 
>> 
>> 
>> 
>> On Friday, November 13, 2015 5:58 PM, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> 
>> 
>> As this has created a lot of interest, I thought I'd follow up with a
>> couple of drawings of my through hull idea :) (Attached at bottom.)
>> I am using a common reducer fitting to butt or key the epoxy.
>> There are standard reducer fittings with o-rings.
>> I am going to silicone over the outer part of the fitting & along the
>> cable jacket. Then mold over this with the castable rubber to 
>> tidy it up. 
>> The theory is the silicone will compress under pressure on to
>> the jacket (which should itself compress), & seal the jacket better
>> than just epoxy.
>> I looked at a long video of Doug Jackson making through hulls
>> for his rov by epoxying in brass pins. They were failing badly in most cases.
>> I will never trust epoxy again.
>> https://www.youtube.com/watch?v=UDZQIDkWs4w
>> Regards Alan
>> 
>> 
>> From: Alan James via Personal_Submersibles <personal_submersibles at psubs.org>
>> To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
>> Sent: Friday, November 13, 2015 10:52 PM
>> Subject: [PSUBS-MAILIST] Castable Rubber
>> 
>> Was thinking about home made electrical through hulls & came
>> across this castable silicone rubber.
>> How to make a moldable castable rubber (homemade Sugru, Oogroo)
>>  
>>  
>> 
>>  
>>  
>>  
>>  
>>  
>> How to make a moldable castable rubber (homemade Sugr...
>> View on www.youtube.com
>> Preview by Yahoo
>>  
>> Basically it's builders silicone mixed with corn flour about 50/50.
>> There are other recipes with builders silicone & baby powder.
>> My thought was to pot wires inside a suitable bronze or SS threaded fitting 
>> & encase the electrical sheathing where it enters the fitting with straight silicone.
>> Then when hardened, cast the silicone / corn flour mix over the top to tidy it up.
>> The simple recipe may have a lot of other applications.
>> Cheers Alan
>> 
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