Hi! I’m trying to pot the cable penetrators. Problem is the Loctite Marine Epoxy used by BlueRobotics is not available in (or easily available) in Europe. We have bought this https://www.amazon.es/J-B-WELD-Epoxy-Syringe-25-ml/dp/B009EU5ZMA/ref=pd_rhf_se_p_img_1?ie=UTF8&refRID=YFV2FP6W3HRSZ8YYBGJQ but it is not fluid enough and it solidifies in 5 minutes or so. Can anyone help me to find a good solution? Thanks in advance.
We have tested West Systems G/flex 650 and had pretty good results. It looks like they have a couple of distributors throughout Europe (http://www.westsystem.com/ss/where-to-buy/). It should be a good substitute. Let me know if this helps.
Thank you very much for the info. I assume you are using the liquid version, the one that is not thickened or hardned.
We are using the 650-8 “Toughened” version.
And is it fluid enough to be used with a syringe and flow well into the cable penetrators? In some videos I have seen it too dense.
You can use it with a syringe. It is a little difficult to get in the syringe without making a bit of a mess because it is a little thick (it tries to come out of the mixing cup all at once). However, you can apply it with a syringe pretty easily.
I contacted Loctite technical in the UK, they suggested I use Loctite 9483. This is not specifically marine, but it is chemically resistant (salt seems to improve it!).
The advice was on the basis of the potting page in this site - so am assured it has low viscosity (low enough for potting anyway),
I just read the data sheet. It looks like it should work pretty good. The only concern that I would have is the relatively low adhesion to “plastics”, but the marine epoxy doesn’t have a rating on the data sheet and it works great. I’m curious to hear your results. Is there any reason for not using the G/flex?
I had not seen this thread before making the enquiry of Loctite.
I have found that Axminster Tools in the UK stock West 650 9and there is a branch 5 miles from me!).
I will use this I think, as you guys have tested it already, rather than experiment with something new at this time.
Thanks for your help
I receive the G/flex tomorrow and I’ll give it a try.
Don’t for get to also purchase material to thicken the G/flex. I use West 405. The G/flex has low surface tension strength and needs some thickening for good potting.
@Richard, Jonathon doesn’t mention filler in his post above (that is for West 650 though, which is what I have bought).
Not experienced at potting, so keen to learn. I imagine that for potting the cables the outer should form sufficient seal to prevent the epoxy leaking through - and that the low surface tension would improve wetting?
I have my epoxy now - but no syringes as yet!
Still hoping for comment on my idea to common the power rails to the thrusters outside of the waterproof housing hence saving 4 penetrators (if using seperate penetrator for signal and power). Idea being to solder common them (possibly using the supplied PCB, then to pot the whole lot in a 3D printed box (doesn’t need to be pressure tight - it’s only there to keep the epoxy in in place during the posting curing really)
I don’t have any experience using a thickener with G/flex. To keep the potting as neat as possible without thickener, you can super glue the cable jacket to the penetrator. That will seal the top part so that it doesn’t flow out at all. If you don’t use super glue, it will flow out, but not much. I did an experimental attempt at that a while back and attached pictures of the results. I just potted from the top and did not clean up or add more while it was drying.
I do the potting in two steps. First is the top cavity in the penetrator. All your doing here is forming a barrier to keep water from passing through the penetrator into the WTE. I use thickener to keep the epoxy from flowing past the outer wire cover and down the wires past the penetrator. I then turn it over and make a barrier to prevent water that has leaked inside the tether from a cut or tear (shark bite) from entering the WTE. You can get by fine without the thickener, I just like to use it. In either case use a fine tool to push down and up into the epoxy to ensure busting up any air bubbles. Also, if you use thickener you can raise and lower the tether about a 1/4" a few times to ensure there is good attachment where the outer covering ends and touches the penetrator. Being thickened a little makes all of this a bit easier, but certainly not a requirement. The G/Flex surface tension (how it flows) is quite a bit less than the Loctite stuff.
For this kind of potting, i prefer using Polyurethane instead of epoxy.
I typicaly use an Electrolube product : UR5528
it’s a two-part potting and encapsulating compound with excellent water resistance properties. It bond perfectly on PU cable’s jacket. Be careful, it’s very fluid, it’ll find any leaks you missed !. It has just an inconvenient : minimum quantity is 250g ( 50g pack are no more sold )
To pot your penetrators in one operation, you can also use an hot glue gun to obstruct the internal side. But again, be careful to avoid any leaks !
Any updates on this? Getting my equipment soon so in deep need of a potting alternative.
Jonathan, have you tested it to depth of 100 meters? Over time? Multiple dives?
Would be great for an alternative here in europe
There is also a JB Weld marine epoxy available (in Europe), did someone tried this ?