Mounting a transducer plate

[Steve H.]

I just upgraded my sonar/GPS from a 5" Lowrance to a 9" Garmin on my Lund Fury 1400. Part of the project is to add a poly transducer plate using epoxy (or similar) so that I'm not drilling more holes into the aluminum. (I'll need to fill the existing holes from the Lowrance.) I've purchased some 3/4" poly material to use for the plate.

I've watched a few vids on YouTube and have seen different approaches to this. I think I'm going with 3M 4200 unless someone can steer me clear of this. Also, after scoring the aluminum on the transom, is it required to use a 'self-etch' primer to condition the metal before applying the adhesive? Or is it sufficient to just score the aluminum (wire brush?) as well as the poly?

 

[nytebyte]

I did something similar and used a locktite marine sealant from Menards. Its holding great but I also used the holes from the old transducer to hold the transducer plate on. Short screws from the inside of the transom and the adhesive sealant over primed aluminum.

 

[LDUBS]

Just a thought to give the epoxy or whatever you are using more bite with the HDPE (poly) transducer plate. Consider drilling some shallow holes in the back of the HDPE (poly) plate. Drilling them at an angle is even better I think. Completely fill them and the back of the plate with whatever adhesive you are using.

 

[maintenanceguy]

I used a piece of 3/4" thick PVC and 5200 adhesive. 5200 is considered forever but if I ever need to remove the PVC plate, I can cut through the adhesive with a guitar string.

Some adhesives bond with a very thin film. Marine adhesives need a thicker film to work. When you press the block against the transom, don't press all the adhesive out. I try to leave 1/8" film thickness.

 

[FuzzyGrub]

If there is access to the back, I use two SS bolts (recessed into the king starboard), nuts, and washers, along with 5200. There will be no need to take it off. With today's large transducers, want to make sure that it stys there.

 

[Steve H.]

Just a thought to give the epoxy or whatever you are using more bite with the HDPE (poly) transducer plate. Consider drilling some shallow holes in the back of the HDPE (poly) plate. Drilling them at an angle is even better I think. Completely fill them and the back of the plate with whatever adhesive you are using.

This is a good idea and I've seen the commercial products (stern saver?) have holes with ridges so that the adhesive can have better purchase on the plastic material. To duplicate that, I'm thinking about drilling some 1/2 holes and then "tapping" a bolt into the plastic to achieve the same result.

 

[LDUBS]

Just a thought to give the epoxy or whatever you are using more bite with the HDPE (poly) transducer plate. Consider drilling some shallow holes in the back of the HDPE (poly) plate. Drilling them at an angle is even better I think. Completely fill them and the back of the plate with whatever adhesive you are using.

This is a good idea and I've seen the commercial products (stern saver?) have holes with ridges so that the adhesive can have better purchase on the plastic material. To duplicate that, I'm thinking about drilling some 1/2 holes and then "tapping" a bolt into the plastic to achieve the same result.

That's where I first saw the concept too. I actually met the stern saver guy at a boat show. Told him TB might be a good place to advertise his products.