Installing a thru-hull transducer

[RichD]

I am installing a thru-hull transducer and would like to hear readers opinion about bonding the backing block to the hull, should I use 3M 5200, a thickened epoxy or any other suggestions. Thanks in advance for replys

 

[David]

5200

is my choice below the waterline. It provides very strong adhesion and it is not as permenant as some have stated. For example, I used it on my propshaft strut, which I had to remove a year later and found a release agent to help removal.

 

[Ed Schenck]

Epoxy, a good one.

Being slightly paranoid I vote for epoxy. I used West System to epoxy two blocks, each 5" x 5" x 3/8" plywood. You want to know that any void caused by the hull curvature is filled. The blocks should be coated top and sides also. After you drill the hole then coat the inside perimeter of the hole with epoxy. Install transducers with lots of 4200 or 101. Let it set up before the last couple turns of the nut.An aside. Those transducers that look and feel like plastic? They are not. A polysulfide caulk is fine for those.

 

[Steve Dion]

Soak the backer in expoy

Rich:Be sure to soak the backer in epoxy. The thru tend to weep after several years. You do not want the wood to ROT. Most any of the quality sealants will work fine when bedding the transducer.My personal choice is to use something that can be removed in the future (transducer & instruments fail). So I would opt for Life- Caulk, 4200, 101 etc. Considering this an underwater usage, so use an appropriate product.

 

[Justin - O'day Owners' Web]

5200

Those who've been around a while know I'm the 5200 evangelist, but below the water line I'd use nothing else. When I redid my through-hulls I used Starboard to make my backing plates making rot irrelevant.Justin - O'day OWners' Web

 

[RichD]

Using Starboard

Thanks Justin for the reply. I also thought starboard would be the answer. I did a little experimenting at home and could get nothing to stick to it. I called Starboard's tech support hot line and he recommended 3M DP8005 and said it is very expensive about $55. I am going with epoxy soaked wood with thickened epoxy applied to the hull.I will also use 4200 as the bedding compound for the transducer.If you know of a product that will stick to Starboard it's not to late for me to use that plan.