Adhesive/sealer for Depth Sounder Oil Pot

[davidmh]

The oil pot on the boats depth sounder has been leaking. It is mounted to the hull with what looks like Plastic Padding, the base padding is thick and has gripped the GRP hull well but where the filled was wiped up the outside of the PVC oil tube the adhesion was not good and oil weeps past, The filler on the tube comes away from the tube easily and looks like it was never sanded for a key first.
Question - What would be the best filler/ adhesive to join the existing filler at the base to the tube. It needs to be quite thixotropic as the tube is vertical. Access is difficult so I would have to apply it with a spatula. It lives in a wooden box so it is not subject to locker contents bashing into it.

David MH

 

[fredrussell]

CT1 or Sika 291i would be my choice. For what it’s worth, I just stuck my transducer to hull with a big blob of Sika, no oil tube. It’s worked well and gives accurate reading.

 

[VicS]

The oil pot on the boats depth sounder has been leaking. It is mounted to the hull with what looks like Plastic Padding, the base padding is thick and has gripped the GRP hull well but where the filled was wiped up the outside of the PVC oil tube the adhesion was not good and oil weeps past, The filler on the tube comes away from the tube easily and looks like it was never sanded for a key first.
Question - What would be the best filler/ adhesive to join the existing filler at the base to the tube. It needs to be quite thixotropic as the tube is vertical. Access is difficult so I would have to apply it with a spatula. It lives in a wooden box so it is not subject to locker contents bashing into it.

David MH

Mine was "glassed" in with chopped strand mat and polyester resin ,( probably after holding in place with Plastic Padding). I may, however, have used some ABS pipe which the resin will adhere to better than it will to PVC. No leaks or other problems with it in over 35 years

An epoxy resin may be a better choice with PVC

.

 

[thinwater]

CT1 or Sika 291i would be my choice. For what it’s worth, I just stuck my transducer to hull with a big blob of Sika, no oil tube. It’s worked well and gives accurate reading.

If it is actual oil, polyurethane sealants have poor oil resistance. We think they are all-purpose, but oil is not one of them. Glycols are generally a better choice for this reason.

"... temporarily resistant to fuels, mineral oils, vegetable and animal fats and oils...." meaning not long-term contact. Only spills that are promptly cleaned up.

If the oil has permeated the material, it is very likely nothing will stick. A lot of cleaning with xylene, followed by acetone, may help.

Silicone and polysulfide are better choices for oil, but read the specifc product tech sheet. Don't guess.

 

[fredrussell]

If it is actual oil, polyurethane sealants have poor oil resistance…

Fair point, but CT1 is not a polyurethane sealant. It’s a hybrid polymer, and has good chemical resistance to oils and greases, amongst other things. Technical Sheet:
https://s7g10.scene7.com/is/content...tion-Adhesive-Clear-290ml~C5586_991099_TECH_0

 

[LONG_KEELER]

I've always used water in depth sounder pots instead of oils. Works fine with an annual top up.

 

[Pete735]

i just used some car body filler that i had lying around when i did mine, that was 5 years ago. I just roughed up the surrounding area plus the lower part of the tube that came with the sensor and put a fillet round the outside. Not sure what the oil was but i think that came with the sensor kit as well (bought from Nasa Marine if memory serves). If it were me I'd cut the tube off as low down as possible using my multitool, use some acteone to remove the oil that has spilt, roughen up the surounding area on hull and tube, wipe down with acetone again and use the body filler again. It may even have been plastic padding I used, but it tends to be what ever I have around at the time for stuff like this as they are all polyesters as far as I know.

 

[Spirit (of Glenans)]

If oil has permeated the material you'll have to grind the whole lot out and start again. Thoroughly degrease and abrade all surfaces and stick down with CT1, as recommended above. For added security I would also glass it in with a couple or three layers of glass matt and epoxy.
The most suitable oil to use, if you are not using it already, is castor oil, as it does not go rancid. If you are anywhere near Dublin I can let you have a half litre of it, left over from a previous boat.

 

[QBhoy]

If it is actual oil, polyurethane sealants have poor oil resistance. We think they are all-purpose, but oil is not one of them. Glycols are generally a better choice for this reason.

"... temporarily resistant to fuels, mineral oils, vegetable and animal fats and oils...." meaning not long-term contact. Only spills that are promptly cleaned up.

If the oil has permeated the material, it is very likely nothing will stick. A lot of cleaning with xylene, followed by acetone, may help.

Silicone and polysulfide are better choices for oil, but read the specifc product tech sheet. Don't guess.

I think his point was that just simply putting the transducer in the CT1 works better well. As long as there is no air in it. If I’m understanding it correctly. I’ve done this numerous times. Works every time.

 

[thinwater]

I think his point was that just simply putting the transducer in the CT1 works better well. As long as there is no air in it. If I’m understanding it correctly. I’ve done this numerous times. Works every time.

Yup, that is what he said.

I assume the reason not is difficulty of removal.