What's the best Silicone - Sealer ?

[WoofII]

Installing the floor over the gas tank. What's the best silicone or sealer ?
Also what foam do you use over the gas tank under the floor ?
Best places to buy the products?

Thanks

 

[Baylinerchuck]

What do you need the sealer/ silicon for? 3M 4200, or 5200 is made for marine applications. Don't use silicon caulk, it won't last. Still curious as to the application.

Most on this forum get their pour in foam from US Composites. You can find them on-line. Not sure about a foam on top of a fuel tank. Never heard of that.

 

[Watermann]

Welcome aboard, so what are you working on? Not too many guys around here use silicone for much of anything as it's failure rate is about 100%. 5200 is a great sealant/adhesive.

 

[WoofII]

2005 204FX Angler center console boat
Had to remove the floor to access the gas tank. ( had raw gas fumes ). Problem not found yet , hoping Monday after work we can find the problem. We removed a sealant & it was very very dirty. But bought the boat this way. Looking at the tank most of the foam was removed at one point. So what ever they used to seal it back it looked bad with all the dirt stuck to it. I'm 100% sure the factory or boat Mech Would of used something correct. Like to try & do a better job than whoever attempted last time...............

Thanks

 

[Watermann]

Aluminum tank? Either way check the fittings first, if someones been in there before has the tank been removed to be repaired I wonder? Reason I ask about the tank being AL is what can happen is they remove the tank, pressure test it, purge it and weld up any pinhole leaks. Tank gets put back in boat and they sell the boat only to have more pinholes emerge later on.

 

[mr 88]

3m 5200 is pretty much non removable and if its being used over the gas tank that's not a good idea. Go with the 3m 4200/not permanent/ as that will allow you access in the future if the tank/lines/sending unit/wiring develops any more problems

 

[dingbat]

No foam around aluminum tanks. Block with wood and leave open for air flow.

Some advise against the use of rubbber "cushions" between the tank and the wood blocking but mine is holding up very well after 20 years. OEM installation.

Grady White recommends, and I use, GE silicon 2 (almond to match gel coat) to seal the access hatch. Do yourself a favor and lay a piece of monofilament in the joint before chalking. Lines cuts right thru curied caulk when pullled. Makes removing the hatch for your next inspection that much easier.

 

[shrew]

3m 5200: Will be a permanent/semi-permanent installation. Can be used for underwater applications (Not UV reisitant, so not ideal for exposure to sun)

3m 4200: Will be similar to 5200, however the bond will be breakable, so it can be removed for service/replacement. Can be used for underwater applications (Not UV reisitant, so not ideal for exposure to sun)

3m 4000: The same as 4200, only UV resistant. Used for above deck installations (cleats, rail stanchions, rub rails). Will not breakdown or discolor when exposed to UV.

 

[Watermann]

A picture of what your working on would help. If your sealing a hatch then any wet seal will be a pain to deal with in the future. I would think about using a rubber strip type seal that won't be a huge mess if/when the hatch needs to come off again down the road.

 

[dingbat]

A picture of what your working on would help. If your sealing a hatch then any wet seal will be a pain to deal with in the future. I would think about using a rubber strip type seal that won't be a huge mess if/when the hatch needs to come off again down the road.

Installations vary by builder, but this is pretty typical.

3/4-1" thick flat panel recessed into the deck to form a flat surface in the cockpit. My builder uses thin strips of neoprene on the support ledge to help seal and cushion the joint, but the primary means of sealing is the fillet joint around the outside of the panel. Not only does it have to seal, you have cosmetics to deal with thus the recommended color of the caulk.

Removing the hatch isn't bad if you install the mono and use the sealer I noted above. The previous owner used 4200 on the joint and I would have killed him if I could have gotten my hands on him. Took me almost an hour and many expletives to get the hatch off. Twice that to remove the old caulking and residue. That's when I called Grady and got their recommendation.

Tip.....Tape both sides of the joint off before caulking. Fill groove, easier said than done, smooth with finger to level and remove tape once the caulk starts to set up. Nice, color matched caulk job that is easy on the eyes.

 

[Thalasso]

Life-Calk? Sealant is what to use

Life Caulk is poly sulfide based. It is paintable and will flex. It is a good sealant but - it will attack many types of plastic (not gel coat though). Ideal for teak decks, to bed deck and hull hardware, sealthru-hull fittings, and underwater seams. Will bond to fiberglass, wood, metal, glass, and itself.

Life Seal is a combo of silicone and polyurethane and will flex (its seems to be a lot like Silicone Seal). It is NOT paintable, but it won't attack plastics and is also a good sealant.