Transducer Mounting

akoop

Cadet
Joined
Sep 4, 2003
Messages
22
I have purchased a new fishfinder/GPS combo unit and I need to mount the transducer on the transom. The mounting holes for my old unit are very different, what should I used to fill these old holes?
 

JoeW

Senior Chief Petty Officer
Joined
Nov 8, 2003
Messages
664
Re: Transducer Mounting

I had the exact same problem. I just used some 3M 5200. This stuff seals like molded rubber. I've had no leaks so far. I also used it in the mounting holes for my outboard. You can get it at Wallmart.
 

ThomWV

Senior Chief Petty Officer
Joined
Dec 19, 2003
Messages
701
Re: Transducer Mounting

I always use epoxy resin mixed with West System's number 404 High Denisity filler. I don't use their resin (I get mine from Raka) but I like their fillers.<br /><br />I just mix up a little bit of epoxy and then add filler. I mix the resin/hardner first and take a Q-Tip and dip it in the mix then use it to go in the holes and wet them out. Then mix the filler in until you have a consistance about the same as peanut butter.<br /><br />Anyway the trick is to get it in the hole and to fill the hole. The medical unit where I work gave me a handfull of syringes a couple of years ago. I just use them, with no needle of course, and pack one full of the mix. Then the nozzle tip of the syringe goes into the hole and I blow the paste mix into the hole from the back. Fill it up and real quick stick a piece of tape over the hole. Do them all.<br /><br />Take the tape off the next day and then using a sanding block and some 220 grit paper smooth them out, then hit it with 600 grit paper, then 1,000 and then hit it with some rugging compound and a minute with the buffer and it will look like new. YOu won't have a perfect color match, but it will be white and it will be dead smooth and waterproof.<br /><br />Its really not much work to do. When I mount a transom mounted transducer I like to just go ahead and laminate a block of plywood and then take that block and epoxy it to the trasom. Then I can simply mount into the block and not penetrate the gel coat. It goes a long ways towards not getting transom rot started. I simply do not trust 5200 or any other sealer to stop water intrusion into a transom. If the block starts to rot off you can easily replace it. Put a little paint on one and it doesn't look bad either. The if you have to move the transducer you really don't care much about the old holes, but if you do they are easy to patch.<br /><br />Thom
 

imported_JD__

Petty Officer 1st Class
Joined
Jun 13, 2003
Messages
243
Re: Transducer Mounting

akoop,<br />I agree with the 3M but would also back it up with screws. Is your boat glass or aluminum? If aluminum, definitely use screws too.<br />JD
 

akoop

Cadet
Joined
Sep 4, 2003
Messages
22
Re: Transducer Mounting

The boat is fiberglass, and the holes are very small.
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: Transducer Mounting

Use the 3M for the small holes and you will be fine.
 

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: Transducer Mounting

After you seal your old holes you may want to think about adding a transducer mounting plate. I just glued it on the back of the boat and then mount transducer to it so never have to drill holes in the boat. Take a look at cabelas and search for TRANSDUCER MOUNT. Last time I looked I did not find it here at Iboat.<br /><br /> http://www.cabelas.com/
 
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