Mounting transducer in hull

[mr300z87]

Not sure if this is the right place for my question but it is related to my electronics so here it goes. I have a 1990 Sea Ray Sundancer, I had installed the transducer for my Chartplotter/Fish Finder in my bilge 2 seasons ago with standard silicone caulk from Lowes. I am using this for depth only and all was working fine, however while winterizing the boat the other day I noticed the transducer was coming loose so I pulled it out of the caulk and scraped the caulk off the hull. I would like to re mount the transducer with something a little bit more robust but still not permanent in case I ever sell the boat and want to remove the system before I do. Can anyone recommend what I should use to mount the transducer in the hull. I was thinking 3m 4200. As always any advice is greatly appreciated. Mike

 

[Grub54891]

Perfectly fine to use 4200. Some use 5200, that is more permanent. 4200 can be removes a bit easier.

 

[alldodge]

Can use about anything, but if the caulk was pure silicone and it came loose, most likely gas came in contact with it or it wasn't real clean, use acetone prior.

 

[mr300z87]

Thanks for the responses. I do not think there was any fuel or oil near my mounting location, and the caulk was stuck to the hull but the transducer can loose from the caulk. It does get a little on the warm side in the bilge on a hot summer day while running a BB at cruise speed so maybe that had something to do with is. It also possible the caulk did not like the plastic of the transducer. I am sure I wiped everything down with acetone before it was installation. Can I scuff the transducer with sand paper to give it some tooth? Going to try 3M 4200 this time.

 

[alldodge]

Shouldn't need to scuff but don't see it hurting either

 

[Grub54891]

Regular silicone won't hold up to anything. When used on a boat, it always fails. 4200 will be fine. Scuff the river if you want, but I've never seen one fail that wasn't scuffed.

 

[Scott Danforth]

I always used 5-minute epoxy for mounting thru-hull transducers

 

[JASinIL2006]

This stuff works well: https://www.iboats.com/shop/vexilar-a-c-e-transducer-epoxy.html

 

[fishrdan]

I would use epoxy as Scott mentioned, not the super mongo industrial strength stuff, cheap epoxy. On my last glass boat I had the ducer epoxied to the hull and never had issues with it reading bottom or coming loose. When I got rid of the boat and removed the sonar, I just whacked the ducer and it popped right off the hull.