Filling an AirMar through hull transducer - Mineral Oil or ??

[Ben998]

Hello All,
I have to fit an AirMar through hull transducer. The instructions state that when positioned and fixed etc the body has to be filled with 71ml of mineral oil. I assuming that mineral oil must have the correct properties for the transducer to operate as intended.

The questions are... where can I buy mineral oil or can I use something else instead?

And.. can I sikaflex / silicone the body of the transducer to the inside of the hull or does it have to be epoxied in place ( its not the primary depth transducer, its for a fish finder.. ahem echosounder /forums/images/graemlins/wink.gif ) ?

cheers,
Ben

 

[marcusgillies]

Hi in answer to your question use Baby oil its by far the easyest thing to get hold of and does the job well.
Yes you can use sikaflex to fix the body in place however you will have to wait for the stuff to go off, you will need to abrade both serfaces and remove any oily deposits before you fix it.

Also if you have not found an ideal site yet you can take a clear food type bag and fill with water. Get someone to hold it inbetween the transducer and the hull. There you can check you have good signals before fixing in place permanantly.

 

[Talbot]

I use fresh water with some anti-freeze as recommended by silva - if you get a leak it doesnt create a horrid mess.

salt water can go horrible after a while - hence the fresh.

 

[SvenglishTommy]

I use fresh water as well, and will add antifreeze after readings Talbots post.

 

[Talbot]

make sure that the manufacturer is happy with the use of Anti Freeze (plastic compatability)

 

[oldsaltoz]

G'day Ben,

<<I have to fit an AirMar through hull transducer. The instructions state that when positioned and fixed etc the body has to be filled with 71ml of mineral oil. I assuming that mineral oil must have the correct properties for the transducer to operate as intended>>

I'm confused, a thru' hull transducer usually means just that; the transducer is mounted in a hole thru' the hull.

So I will assume I'm wrong on this and add that transduceres are placed in oil for two reasons.
1- to eliminate any air below the transducer as this effect the signal.
2- because it's mounted in oil it can swing as the boat heels, thus providing a more accurate depth reading rather looking sideways as some do.

As a fixed amount of oil has been indicated I presume this has it's own oil container, it should be wide enough to allow the transducer to swing, some are made to be installed athwart ship (sideways) to give maximum swing.

You can use a sealant but you must ensure no air is trapped. If using a plastic bag to find the best location also wet the floor to eliminate any air, or just add water to the bilges.

Make sure the final location is well protected and the cable is run to avoid damage and water/oil.

Andavagoodweekend......

 

[Ben998]

Ah... sorry to be unclear. The transducer is flush mounted inside the hull and 'sounds' through the hull, so its not a true through hull transducer, more of a surface mounted one.
The transducer itself sits inside a body that is fixed to the inside of the hull. Once this body is fixed in place the transducer is put inside, the body filled with a liquid to eliminate air and then the lid screwed on, hopefully keeping it all together. The transducer itself cannot move inside the body so it will only be a true reading when the boat is horizontal, which is fine for what I need it for.
Thanks for all the advice,
cheers,
Ben

 

[ditchcrawler]

I used castor oil in mine & it worked fine.

 

[gjgm]

I didnt fit an airmar, but epoxied my transducer in. As mentioned, first make sure its getting a clean reading. Second, dont use quick epoxy as it tends to get air mixed into it more easily, which you dont want. Lastly, normal expoy turns out to be a damn site runnier than you might think! You need to make a little ringed wall around the transducer to stop it all running away!

 

[EdEssery]

I user Ultrasound Gel. Being a gel, it's less messy than oil and, if you think about it, it is explicitly designed for the job you are trying to do. It's aavailable in tubes from a number of the on-line pharmacy suppliers for less than £10.