Butyl Tape for Bolts, ???? for screws?

[Beersmith]

I'm sold on using butyl tape to bed and seal all thru-bolted hardware on deck, including ports.

Do you use butyl for things that are simply screwed onto deck, such as teak trim or other non-load bearing items? It seems that the directions to use butyl always say to not turn the bolt heads, only the nuts so that the butyl remains set. But that is impossible for screwed in items.

If you don't use butyl for screwed in items, what do you use?

[dbruce85]

I did try butyl tape to rebed my genoa track, I had leaks on 5 or 6 of the screws.
Just backed them a bit, applied some Life Caulk and screwed them back down, it solved the problem.
I am now a believer that you should not turn the head after you apply butyl to get a good seal.

[celenoglu]

To have a good seal you have to turn only the nuts. This is the rule for any sealing agent not only butyl tape.

[Beersmith]

Originally Posted by celenoglu

To have a good seal you have to turn only the nuts. This is the rule for any sealing agent not only butyl tape.

I understand that, but screws don't have nuts. what do you do about screws?

and before someone says "you shouldn't have screws, everything should be thru-bolted blah blah", please understand that there are non-load bearing things on deck, and some places where a bolt and nut would be impossible to secure due to inaccessibility.

[mitiempo]

When an item is screwed to the deck the sealant (butyl or other) is between the deck and the item. All holes, for either screws or bolts, should have countersinks so an "O" ring of sealant is created where it is needed most.

[rugosa]

I've factory outfitted over 500 decks (mostly sail - production & custom, some power & 26 government commercial small vessels) and assembled decks to hulls on about the same. Best advise is test products, find the ones you like and 'stick' with them. After using Boatlife, 3M products and a number of others my #1 choices are 3M 5200 for permanent, 3M 4000 for future removal, butyl tape for thru-bolts (ALWAYS turn the nuts/not the bolts), clear silicone for removable teak plugs, silicone for wire feed holes for instrument displays because of the normally soft plastic housings.

ALWAYS counter sink all holes to clear the gel coat to avoid cracks radiating from the hole.

I've seen installers throw away those thin foam gaskets that come with some instruments and install them with with butyl tape. Looks nice on install day but always oozes in the heat. I prefer to use the manufacturers materials & advise (they invested in the research and field feedback). These are the same installers that throw away the manufacturer supplied instrument junction boxes and use an exposed terminal strip in a locker. Sooner or later there's gonna be trouble.

I almost always toss hardware manufacturer supplied fasteners and stick with my regular suppliers fasteners, lessens the risk of cheap fasteners and rust problems.

[rugosa]

What year is your CS27 Brian?

[pdqaltair]

For big things tha are through-bolted--winches, ports, tracks--it can't be beat. It makes it simple to remove the item later and does not harden.

However, I've used it for screws and been disapointed. Part of the problem is the twisting. However, for small parts I like the adhesive quilities of 5200. If I install a small pad-eye or a guard rail for a heater stack, the extra bond of the 5200 keeps it tight and it will come off easily enough later anyway.

My personal feeling is that unless I can through-bolt, I'm better off with an adhesive. Large items, like ports that are screwed on, I may still go with butyl (the hatches on my boat were screwed on and factory butyl, and were still well sealed and tight after 14 years). But sometimes you need to look at each application and make a judgment.

Other than difficult removabilty, the other weakness of 5200 is that it doesn't keep in the tool box. Even with foil under the cap, 3-4 months seems to be the limit. And so I occationaly use butyl where I should not, simply because I always have it. If it's that or silicone, I know it will be easier to remove the butyl later.


Rugosa is dead on, except I question the foam gasket preference on some occations. I can't even remember how many of the those gaskets have failed and leaked over time in both marine and industrial settings, ruining something. I think I would take that case-by-case; some are good, and some are clearly crap. As for the ooze, it never really bothered me, but I'm quite certain it would botter some customers. Perhaps my climate is cooler.

[Maine Sail]

Originally Posted by pdqaltair

However, I've used it for screws and been disapointed. Part of the problem is the twisting.

I have some tricks for this but have been reluctant to share them as the technique is critical and even with my in-depth instructions people still don't follow the instructions as well as they could..

I do seal screws with butyl and it works great for ME but for most folks I would advise a marine sealant as it is easier and less dependent upon the technique used.

[Beersmith]

Originally Posted by Maine Sail

I have some tricks for this but have been reluctant to share them as the technique is critical and even with my in-depth instructions people still don't follow the instructions as well as they could..

I do seal screws with butyl and it works great for ME but for most folks I would advise a marine sealant as it is easier and less dependent upon the technique used.

what sort of marine sealant would be used for non-load bearing deck fitting? 5200/4000, polysulfide, silicon?