Caulking (Silicone or 4200)?

[Tide Roller]

I am starting to re-bed my deck penetrations and am finding that some are bed with silicone. Random ones to. One chainplate is 4200 caulk another is silicone. I've heard to never use silicone on fiberglass but also that if silicone is preexisting to use silicone because it only adheres to silicone. I want only 4200 caulking. Any suggestions? It's rainy off and on here and some of the penetrations are leaking leaving watermarks in the cabin. I don't really want to re-varnish in the cabin for a year so stopping the leaks is the priority.

-B

[rebel heart]

I use boat life caulk for most every caulking need. Silicone has never really been of any value to me on a boat. Might just be me.

[atoll]

sika flex,3m,life caulk are all great polyeurathane sealants,but expensive.

generic, quality "polyeurathane" sealants can be bought from home improvement/diy stores at 1/3 of the price which are perfectly adequet for marine applications.

silicon is best , used as grease,or powder form mixed with epoxy,or in the gf's breasts on a boat.........

[Tide Roller]

Originally Posted by atoll

sika flex,3m,life caulk are all great polyeurathane sealants,but expensive.

generic, quality "polyeurathane" sealants can be bought from home improvement/diy stores at 1/3 of the price which are perfectly adequet for marine applications.

silicon is best , used as grease,or powder form mixed with epoxy,or in the gf's breasts on a boat.........

What brand of caulk is comparable to 3m? Is DAP or something else the same?

[ElGatoGordo]

I use all Polyurethane from Home Depot. Seems like I use the Locktite brand and the PL Premium mostly. Locktite brand lasts longer in the tube, PL dries faster. Been using them for years and never saw a difference from 4100. I'm not claiming to know they are the same...but $6/tube is my price range.

I have used Lifecaulk also with good results.

[Ocean Girl]

Once you use silicone, it's hard to make the change over to a different caulk formula. No matter how hard you clean up the old silicone, it still has a very big chance that the new caulk won't adhere to the old silicone contaminated fiberglass, even if you use silicone again. **prepping the surface for the new caulk should not be rushed and is paramount for future happiness

Between the two I pick 4200, though I don't think 4200 is the best one either.IMHO.

To prep area: clean the area with razor blade, wipe liberally with 3m adhesive remover while changing rags so you don't re contaminate. Also, acetone wouldn't hurt either. If some of your surface is wood, resist the temptation to sand it first, that will only deposits bits of silicone into the wood. Clean well first. The key is to get the silicone residue all off, or it will interfere with your new caulk.

More options:
These folks claim silicone removal : Marine Formula by DeBond

some say GooGone but never tried it.

For chainplates, I'm a big fan of boatlife lifecaulk:A long lasting, permanently flexible marine polysulfide sealant which can be sanded, painted***, and used above and below the waterline. Tack-free in 1 to 3 days, excellent resistance to teak oils, gasoline, and diesel fuel. Ideal for teak decks, to bed deck and hull hardware, seal thru-hull fittings, and underwater seams. Will bond to fiberglass, wood, metal, glass, and itself. Cures to a firm flexible rubber seal with excellent waterproofing and adhesion qualities. Can be applied underwater for emergency repairs. Can be applied to damp surfaces

If you need the caulk to tack off sooner than 1-3 days, spay it with a mist of water, this won't speed up cure time, just help you from tracking it all over the boat.

Polysulfides can be hard to remove, my trick is to cut the caulk seal with wire or sharp knife to free your hardware or port.

Hope that helps, good luck on your project.
Erika

[biltong]

No to silly-cone. It has limited uses in this modern world. Another product is Wurth's Bond 'n Seal. Right price for the right job

[The Garbone]

We used polysulfide on our antenna mounts when I was in the Navy. Worked great. The MSDS on it was a little startling so I would recommend good ventilation and the proper type of gloves. Forget the glove type at the moment.

[atoll]

Originally Posted by Tide Roller

What brand of caulk is comparable to 3m? Is DAP or something else the same?

i'm in the uk so cant comment on local us brands but when looking for a suitable low cost adhesive sealer what i look for on the lable is :

high performance, polyeurathane, adhesive sealer,suitable for marine use,all weather,over paintable,use white spirit for clean up,solvent based ,fast cure ,automotive use,
etc

the main thing is it is clearly marked as "Polyeurathane"

normally expect to pay between $4-6 a tube compared to the comparable sikaflex product costing $9-12 a tube.

a tip for keeping a tube usable once it is opened is to seal the end immediatly after use with masking tape to prevent air entering.

also store the opened tube in the fridge asap,this way an opened tube can stay usable for weeks once open.

[SVNeko]

I have a rule - no silicone on the boat.

[atoll]

Originally Posted by SVNeko

I have a rule - no silicone on the boat.

i dont mind silicon on the boat,but feel it is a waste if constrained by a bikini top

[jongleur]

I have a rule - no silicone on the boat.

My rule too, exactly.

Girlfriend doesn't need it either.(appropriate emoticon here)

[thinwater]

Originally Posted by atoll

i don't mind silicon on the boat,but feel it is a waste if constrained by a bikini top

a. Silicone grease, powdered siliCA filler. Very different chemistry.
b. I thought someone would suggest polyurethane as a marine up-grade for breast augmentation. No personal expereince.

The only place I use silicone on the boat is for dry below deck bulkhead wire pass-throughs, where that is what the PO used, removing it would be torture, and I don't really want a bond anyway. I cringe anyway. I've even switched to PU at home (PU and Sikaflex), which though harder to work with lasts SO much longer.

[Stu Jackson]

BUTYL tape is what you need. 4200 is an adhesive, NOT a sealant, don't use it. Silicone should only be used on Beckson portlights because that's what the manufacturer recommends. Silicone is not a great sealant.

Try this, great source for butyl tape:

Bedding Deck Hardware With Bed-It Butyl Tape - SailboatOwners.com

[skipmac]

Originally Posted by Stu Jackson

BUTYL tape is what you need. 4200 is an adhesive, NOT a sealant, don't use it. Silicone should only be used on Beckson portlights because that's what the manufacturer recommends. Silicone is not a great sealant.

Try this, great source for butyl tape:

Bedding Deck Hardware With Bed-It Butyl Tape - SailboatOwners.com

+1. Butyl tape is what I use instead of "caulk" for bedding all my deck hardware and ports. I even tested butyl tape on a port the PO had caulked with silicone and was able to get the butyl to stick very well.

You can get it from the local RV store but not sure how to identify the good stuff from the not as good, if there are differences. Stu, any idea on this?