silicone sealer vs rtv

[jb_from_texas]

im in the process of sealing my motor bracket to the transom i wanted to know if Dap Acrylic Latex Caulf with Silicone is adequate for the job.  and what is the significance of RTV.

[Tom Bass]

I am not a marine mechanic but I do know something of home improvement, automobiles. boats and I work on trains.....

Do not use latex caulk with silicone for anything boat related. It's not designed for that!

RTV is a very good sealant but there are different grades for different uses. Contact a marine specialty store for what you need or do a search on-line with 3M.

[Way2slow]

Don't use caulk, stick with the 100% silicone.  They make a marine grade that's recommended but I've never had a problem with GE Silicone II

[ernel]

Never use RTV/Silicone sealant for below water line application. The results are not immediate, but there is a reaction that occurs as the RTV is exposed to water. Over time the RTV breaks down and one of the chemicals in the RTV will give off an acidic compound that can damage/discolor the gel coat. It will also cause problems with the polypropylene products used in the mfg of bilge/areator pumps.

Use only products that are made with polyurethane. 3M's 5200, or 4200 for below water line applications. They also have a clear version for above water line applications. I think it is 5000. You can pick up all three from Wal-Mart for around $5.

[jb_from_texas]

I havent used anything yet but plan to tonight. I dont want to use 5200 because that is as permanent as you can get.

I think I will use Silicone II

ernel/waytoslow:  thanks for the heads up.