Through Hull Transducer Adhesive

[abg5088]

I'm replacing an old through hull transducer with a 2" hole diameter through the bottom of my 1979 O'Day 30. When removing the old one, I was blown away to see it was sealed with very old and deteriorating silicon. Honestly I'm surprised it was water tight, but it made removal quick and painless (compared to one adhered with 4200 or 5200).

When installing the new one, does anyone have recommendation on what kind of sealant or adhesive I should use? Silicon seems under-powered and risky as a through hull adhesive, so I'm leaning towards 4200. I'd likely avoid 5200 incase it needs to be replaced or is a faulty unit. Thoughts?

[Muaddib1116]

There are two schools of thought on this. One is the group of people who say use 5200 on any thru hull, and use a lot of it. The other are the people who say that the fitting provides the mechanical strength and all you need is a bedding sealant, like life caulk. Something that stays flexible and sealed for a long time.

[GordMay]

Greetings and welcome aboard the CF, abg.
What Muaddib said. I’m in the 5200 camp.

[stormalong]

Originally Posted by GordMay

Greetings and welcome aboard the CF, abg.
What Muaddib said. I’m in the 5200 camp.

I am in the 5200 camp too. Hard to remove, permanent.

And it is silicone, not silicon. Totally different materials.

[Knotical]

I used 4200 to bed my transducers a few years ago, old ones were bedded with 5200 and they were PITA to remove.

[Sun and Moon]

I think the best answer is to glass in the old hole and use a newer transducer that will work through the hull. Of course this answer is also the most work.

[Tetepare]

Life Seal it is then.

[motion30]

I used 5200 on one translucer and eventually it came loose The last one I used the West systems the epoxy resin in a tube

[lk240]

+1 for 4200. Here is the input I received on this same question.

input on replacing knot meter and depth sounder on Caliber 28

https://www.cruisersforum.com/forums...d.php?t=230036

[Jammer]

I use 5200. On a 1979 o'day 30 the transducer will probably last for the remaining service life of the boat so removal is not a consideration.


Even if it were a factor I prefer 5200 because I know I will not have to haul the boat or deal with an emergency due to sealant failure.


I use 4200UV above the waterline.

[roverhi]

Life Caulk has been my below the water line sealant of choice forever. Never had a failure and can remove, though not easily, anything bedded with it. 5200 is great stuff but almost a permanent seal as it's such a good adhesive. Think about the likelihood of having to remove anything bedded in 5200.

[foufou]

I believe 5200 can be easily removed by applying heat with a heat gun. Be careful of surrounding material as polyester resin doesn't like too much heat. This is a bit tricky to get the exact right temperature to remove something without causing damage to the adjacent hull.

[wannacat]

One had mentioned that 5200 was a PITA, yet removable, so why go with anything else!? It is the best and is removable, I've removed lots of stuff bedded with 5200, just have to take your time and wedge, heat, cut slowly around the thing and whatever will come off.

[KadeyKrogen38]

5200 is an adhesive not a caulk. It with rip gelcoat from glass and even fiberglass when attempting to remove. Use Life Caulk or such.

[Knotical]

Originally Posted by wannacat

One had mentioned that 5200 was a PITA, yet removable, so why go with anything else!? It is the best and is removable, I've removed lots of stuff bedded with 5200, just have to take your time and wedge, heat, cut slowly around the thing and whatever will come off.

I don’t think you understand what I was trying to say-

Yes, I was able to remove it as I didn’t have a choice, I don’t know wanna be able to make that decision again.