Install Butyl Cones
Step 4 - Strip some more butyl tape and make another round string. Wrap the string around the bolt threads or shoulder. Knead and work & twist the cones into the threads of the bolt and shape them like a cone.
Apply Butyl Tape To Hardware
Step 5 - Apply butyl tape to the rest of the base. It is perfectly ok to stretch and pull on the butyl while laying it on in order to make slightly thinner. For this project I used 1/2" wide by 1/16" thick gray Bed-It Butyl Tape. I make it available for purchase to readers if this site.
Press Hardware Onto Deck
Step 6- In colder climates you may want to pre-heat the butyl to soften it some. After pre-heating, with heat gun on the warm setting, line up the bolts with the holes and press the hardware firmly onto the deck. I will often stand on the fitting, if possible, to partially displace and seat the butyl.
For illustrative purposes clear polycarbonate was used in place of a deck, another Compass Marine first, but don't worry one of the magazines will surely rip this idea off in no time. (Wink).
This photo allows you to see what actually happens when you bed with butyl.
Apply Backing Plates & Tighten
Step 7 - Install the backing plates, in this case I just used fender washers, and begin to tighten. Please use suitable backing plates. These fender washers would not be the best choice in a stanchion or deck cleat as they are far to thin and a little on the small side diameter wise for a cored deck.
You will be best to have two people or a good way to keep the bolt from moving. Ideally you do not want the machine screw or bolt to spin, but if you absolutely have to, you can slightly soften the butyl with a q-tip and some mineral spirits and go for it.
*****IMPORTANT, IMPORTANT, IMPORTANT*****
Tighten a little bit at a time as the butyl will ooze out slowly because the consistency is quite thick by design. Tighten, let sit, tighten, let sit etc. etc.. When little to none squishes out & the bolt & nut become tight you can stop. This can take DAYS of small tightening events or weeks if you want to spread it out. It does not cure so do not rush it..
If you have a wood deck core DO NOT crush it by over tightening, better yet bore out some core and pot the hole with thickened epoxy. Unlike the "two step" method you are not waiting for the butyl to "cure" or change consistency but you do need to allow it to slowly displace out from under the fitting. This compression & squeezing forces the butyl into every nook and cranny and makes for an excellent seal..
Here I have taken pictures of the underside and the top side of the fitting.
Use Proper Backing Plates!
As I mentioned in the last photo please use properly sized backing plates!
This is a prime example of DIY boat work gone bad. Ouch!! This stanchion base had NO sealant of any type installed. No polysulfide, no a polyurethane, no butyl and not even the dreaded silicone.
As a result of this unbelievably poor installation the core turned to mush. The thin fiberglass deck skins, combined with dinky little washers, could not withstand the forces applied on the 24" lever attached to the stanchion base, and ........ rip!
Butyl Will Squeeze Out
After tightening, the excess butyl will squeeze out around the edges. The easiest way to clean it up is to pull or peel it away first. Use some of the excess butyl to make a small ball that you can then make quick stab & pull motions at the remaining oooze around the fitting. This quick stab & pull with a butyl ball in hand motion will get about 85-90% of the butyl cleaned up.
Clean Up Butyl Ooze
Step 8 - Peel away excess ooze and clean with Meguiars cleaner wax, or a rag slightly dampened with mineral spirits. Do not saturate the rag with mineral spirits as it can creep under the fitting, just damp.
I find a ball of already "peeled" butyl works well at pulling away excess using a stab and pull motion. Stab the ball into the joint and pull away. The butyl will stick to the ball first and usually peel away from the joint. Alternatively you can use plastic razor blades or scrapers.
Contrary to popular myths about bedding all the Bed-It Tape does not squeeze out from between the surfaces even after the fitting is fully tight. This is the magic of Bed-It Tape, but it does take multiple small tightening events, ideally without letting the bolt spin, to get the vast majority of the butyl to squeeze out. If you do spin the bolt a little don't fret about it. Butyl does not harden of change consistency, like in the two step process with a marine sealant, and can take some spinning without causing a leak. Still the less spinning the better.
*****IMPORTANT, IMPORTANT, IMPORTANT*****
I know I may sound like a broken record but people keep emailing me about this issue and the ONLY reason is because they did not fully read or comprehend TIGHTEN SLOWLY..
DO NOT try and tighten the hardware to fully tight right away. Butyl relies on a slow compression to do it's job and seal properly. It takes TIME for it to compress, displace and move into every nook and cranny. The larger the deck fitting the MORE TIME it takes for this process to take place. Because of the density it takes time for it to get displaced and squished out the edges of the fitting. When it stops you can stop making small tightening adjustmensts.
Bed-It Tape is pretty dense, and the perfect consistency for bedding marine deck hardware, but you must be patient when tightening the hardware. Remember you're not waiting for the butyl to change consistency, harden or cure so these tightening adjustments are not time constrained at all. If you can't get back to it for a month just pick up where you left off.
I sometimes take about two to three days of small tightening events to bed the hardware. Yes this is more labor intensive but the finished product, when done correctly, can still be bone dry beyond 30 years as it has been on over 80% of our own boat. Yes, over 80% of the deck hardware on our boat is still un-rebedded at 33 years old and still NOT leaking.
In colder weather butyl flows slower than in warm so just adjust the tightening adjustments based on temp and how fast it is displacing..
View of Butyl O-Ring-/ Seal After Tightening
This is a view after tightening to full tight, and then removing the nut and washer. You can see how well it actually seals and also the o-ring seal of very thick butyl created by countersinking & butyl cone. The butyl o-ring created by countersinking the deck side is evidenced and can be seen by the darker colored ring of butyl around the bolt.
Bed-It Butyl Tape
This is Bed-It Tape and it was developed after this article was originally written. I started to get nasty emails saying the butyl did not behave or perform as I had described. I went ahead and began ordering butyl and testing it. I quickly discovered the butyl tapes of today, thanks to EPA standards, were not what they had been in the 70's. The products were so horrible I was forced to develop a true marine quality product for this purpose..
Bed-It Tape is 1/16" thick by 1/2" wide X 50' long. It is specifically engineered & formulated for bedding marine deck hardware and best of all it is manufactured right here in the US supporting US jobs!
Many builders used to use butyl tape, CS Yachts and many others did, but they all stopped because butyl in a production environment is significantly more labor intensive despite being a better mouse trap.
The benefits of butyl tape are numerous:
#1 It never hardens and remains at the same thick consistency for well over 30 years.
#2 Because it never hardens it always remains flexible.
#3 It is multiples more flexible than a cured polyurethane.
#4 It sticks extremely well to clean gelcoat, plastic, aluminum, bronze or stainless.
#5 It's NOT a glue, and for through bolted deck hardware you do NOT need a glue.
#6 You can easily remove hardware bedded with butyl tape in the future without destroying your decks.
#7 Bed-It Tape is specifically formulated to resist cold flow or creep once properly tightened.
The Original Butyl at 29 Years Old
As I mentioned a quality butyl tape is VERY, VERY flexible. This photo represents well over 1000% elongation of the original squished thickness and this pre-EPA butyl is still stretching and much of it has not yet failed.
You will also notice that it is still perfectly adhered to the deck and the cleat and never let go of either despite its very low 10-20 PSI bond strength, when compared to some polyurethanes gelcoat destroying 700 +/- PSI adhesion.
Butyl tape also cleans up easily. Remove the fitting and clean the surface with mineral spirits and a rag. That's it!
Because butyl can be softened with mineral spirits the one place I won't use it is on fuel fills or fuel vents. If you normally clean your decks with potent solvents, doubtful, then just be careful around the butyl bedded hardware.
No Leaks After 29 Years! Bone Dry Core!!
Here is a look at the below deck view of that cleat pictured above.
This cleat had been bedded 29 years prior to this photo with butyl, and frustratingly, with no beveling of the holes. Despite the lack of countersinking/beveling it was used for 29 years covering over 50k+ nautical miles. Butyl is an exceptional sealant and the deck, even after 29 years and 50k+ miles, was still 100% bone dry, not delaminated and confirmed dry with a moisture meter and soundings.
You can see the pure white core and no signs of moisture damage.
No Signs of Leaking at 29 Years!
Anyone who has been around boats for a long time knows what the back side of a deck looks like when the backing plates come off and the fitting has been leaking. Butyl tape, a deck cleat that sees tremendous loads, no countersinking and yet 29 years of service later and BONE DRY! No rust, no brown goo, no signs of any leakage.
I re-bedded much of our 2005 Catalina in 2006 and the vessel already had multiple deck fitting leaks. This was a BRAND NEW BOAT!!! Properly installed butyl tape, in my humble opinion, is a far superior deck sealant than any of the polysulfides or polyurethanes currently marketed.
Though with any of them, butyl, polysulfide or polyurethane they will all work very, very well IF properly installed. IF PROPERLY INSTALLED being the key words.
All deck hardware will eventually need re-bedding, no matter how good your sealant is. Why make things more difficult than they have to be in the future by using Satan's Glue (AKA 5200) that can have as much as a 700 PSI bond strength? Why do this when a product with just 10-20 PSI will achieve the same, and often better, results or outcomes.
It is good to keep in mind that 5200 can actually bond to the gelcoat more strongly than the gelcoat is bonded to the fiberglass substrate. Unnecessary bond strength? Absolutely! The Satan's Glue marketing mavens at 3M have probably driven millions of dollars in repair revenue for boat yards. They have actually spawned & supported an entire business dedicated to selling polyurethane/ 3M 5200 removal products! Again, this is absolutely ridiculous. This level of adhesion for THROUGH BOLTED deck hardware is 100% unnecessary.