Best way to seal transducer screws and transom hole?

[tangent]

I'm installing a FF transducer on the transom of a fiberglass boat (Searay 215EC). I used silicone for the screws mounting the transducer and for the cable, drilled a 5/8" hole (1 1/4" long) through the transom, enlarged the hole from the inside until the outside fiberglass was reached, filled with Marine-Tex and drilled through again, then used the standard 5200 to seal the hole for the FF transducer cable.<br /><br />I found that the 5200 would flow right out after a few minutes. I used wax paper with masking tape on both sides for about 24 hours to hold it in place then took it off to let it finish curing. Seems OK, but it still has about 4+ days left to cure.<br /><br />Questions:<br />It's too late now, but would the fast cure 5200 have been easier to deal with? Any reason not to use the fast cure version?<br /><br />Should I have used something else in the hole? Maybe after putting the connector through the hole, fit a small cylinder around the cable, fill the large area around the cylinder with Marine-Tex first and fill the small cylinder with the cable with 5200?<br /><br />Should I unscrew the transducer and use something better than silicone?

 

[Purduebarry]

Re: Best way to seal transducer screws and transom hole?

Don't use sillycone! It will not hold up. 5200 should not be that runny, are you sure it is a good tube? You can let it cure a bit and use tape etc to help it set up. My transducer can with a little cap assembly for the wire. If yours did not you can probably get one at Boat World, iboats...somewhere.

 

[willamettejeff]

Re: Best way to seal transducer screws and transom hole?

My experience has been that the regular 5200 is much more runny than the fast 5200. I regularly install FF's at my friends boat repair facility and have taken to using Fast 4200 instead as there is no need for the strong hold of the 5200 and the 4200 allows for easier removal later as FF's often get changed out over the life of a boat.<br /><br />One important thing on drilling and sealing screw holes in fiberglass is to countersink the holes before installing the screws. This prevents the screw from chipping out the gel coat and also provides a place for the sealant to form a kind of an o-ring around the screw for better sealing.<br /><br />BTW, mineral spirits works great for cleaning up the 4200 and 5200 adhesives and doesn't have the strong smell or attack dried paint and gel coat as does acetone.

 

[tangent]

Re: Best way to seal transducer screws and transom hole?

Thanks for the suggestions. I redid the transducer - cleaned out the silicone, countersunk the holes (more), cleaned with acetone (all I had), and used fast cure 5200 which was not runny. I feel better about it!<br /><br />I'll get some mineral spirits - sounds like a better way. The 5200 might have been runny from sitting in the sun for a bit.

 

[Purduebarry]

Re: Best way to seal transducer screws and transom hole?

Thanks Jeff, GREAT tip on the countersink. I had used a larger bit to smooth the gel chips but not thought to go a tad deeper for the countersink.