Replacing Teak Trim Boards Around Cockpit...

[gsteiner]

Hey Everyone,

First post here to the forums, and it's what I hope is an easy one.

I've removed all of the old rotted (and previously sanded to within 1/16th of an inch thickness) from around the cockpit of my 1976 Gulfstar Ketch. Removing it was quite a chore. Not sure if these were the original factory trim boards or if they had been replaced sometime in the past, but in addition to screws holding down the boards, it looks as if the underside was completely coated with an adhesive like 4200 or similar. While removing the boards, it not only ripped up patches of gelcoat, but also the top layer of fiberglass!

Not a big problem. I've already repaired all the fiberglass, but was wondering:

Should I repair the gelcoat as well, or just level out and install the teak boards?

I'm using 1/2" thick boards which will be completely covering all of these damaged areas. Originally I was going to cover the repaired fiberglass with gelcoat before installing the boards, but since I'm planning on sealing the perimeter of the boards with Butyl tape as well the obligatory dab of 4200 on each mounting screw hole, I'm wondering if there's any real benefit, or if I'm good just leaving the repaired fiberglass as is underneath the new teak trim boards.

Anyone have a similar experience that could offer any insight (pros / cons)?

Thanks!

 

[Joe]

I think it'd be easier to paint it with a decent quality, epoxy, topside paint. I like Interlux Brightside, the two part stuff like Interlux Perfection is awesome paint but kinda unnecessary for your application.. just my opinion though.

 

[gsteiner]

Probably would be a bit easier, but I have a can of gelcoat from another project. I'm really wondering if it's worth putting anything at all over the repaired fiberglass since it's going to be covered anyway. That would certainly be the easiest

 

[Gunni]

Fair it with an epoxy thickened with a sandable filler (microballoons). Seals the fiberglass core better than gelcoat.

 

[njlarry]

Why use 4200? They will need tobe replaced again some day so why make it hard again? Butyl around the fasteners is all thats needed. The gelcoat damage is one reason polyurethane 5200 and 4200 should never be used on above waterline parts that may need to be sperated someday. Especially on non structural trim pieces.

 

[kloudie1]

Welcome aboard !
Since the gel coat peeled, there are small places where it has pulled free from the 'glass underneath.. the perimeter of the peeled place should be sealed; and since ya have the stuff to seal it, a quick coat on the exposed glass itself would be good.... either a coat of resin, or gel or paint.. since this will be covered, it needn't be visually pleasing, so what ever is easiest to do is appropriate.. The wood moves a lot so a permanent water-proof seal behind it is not so permanent usually.
Again, Welcome to the forum.

 

[gsteiner]

Thanks everyone for the input.

Based on the input, my plan will be to finish fairing out the surfaces that will be covered by the new teak boards, and then install the boards with screws (using the original screw holes), plug, and finish. I have read that the recommended procedure would be to put a dab of 4200 over each screw hole before attaching the board, so the screw is threaded through the 4200.

I have noticed that there are additional unused screw holes under the boards (which leads me to believe it has been replaced at least once in the past) which I will also add a dab of 4200 to (even though they will be unused this time around) just to make sure it is completely water tight. (I have been told that when you wrap butyl tape around a fastener like a bolt, you should not turn the fastener or it will allow gaps to form around the shaft. In other words, don't use it on a screw, only on bolts which you tighten by turning a nut rather than turning the bolt.. if that's not correct, by all means correct me!)

Last question:

Which do you think would be a better: Adding a strip of butyl tape around the underside perimeter of each board before installing, or caulking the perimeter of the board after the board is installed?

I haven't worked with the Butyl tape before, but it certainly seems like that would be the simpler method, but not sure if that's recommended or not.

 

[LeslieTroyer]

I’m a fan of butyl even for screws. The important thing is to give your holes a good countersink. This allows the material to stretch more with expansion and contraction with out failing.

Mahalo

 

[Stu Jackson]

it looks as if the underside was completely coated with an adhesive like 4200 or similar. While removing the boards, it not only ripped up patches of gelcoat, but also the top layer of fiberglass!

Isn't this a perfect reason to NOT use 4200 again? Butyl's perfect for this, as Les said. Also, you shouldn't put anything at the low edge, it could just trap water behind the wood. Let it drain.

 

[gsteiner]

There more I look at the adhesive, the more I suspect it may be 5200 rather than 4200.
But regardless, I do like the idea of Butyl rather than adhesive. I was just wondering if there's a reason that there should be adhesive in addition to screws since I don't have any real world experience with this type of installation.

It makes sense to leave the low edge, in this case the outboard edge, open for drainage (provided all the holes underneath are properly sealed.) The original wood was so degraded it was impossible to tell if it had any type of caulk, etc around the perimeter originally. I would have thought that if the butyl tape was completely around the perimeter of the boards, it would prevent any moisture from getting under the wood in the first place. Would that not be the case?

As for counter-sinking, the fiberglass on the horizontal surface where the boards are mounted is fairly thin so there's not a lot of depth to countersink. In fact the front piece is over the companionway and is mounted on a plastic cowling which can't be more than 1/16" thick... The fiberglass area where the wood is mounted is definitely thicker than that, but I'm guessing maybe 3/16".

I do like the idea of putting a 1" square of butyl tape over each of the mounting holes before screwing the wood down on top of it rather than using caulk or adhesive... Does butyl tape have any adhesive quality, or is it just a sealing product like plumbers putty?

Again, I really appreciate all of the input!

 

[dlochner]

Does butyl tape have any adhesive quality, or is it just a sealing product like plumbers putty?

Yes it does have some adhesive qualities, but not nearly the same as a polyurethane or polysulfide caulk.

 

[Ken Cross]

If you look for expert advice look right here.
https://forums.sailboatowners.com/i...-deck-hardware-with-bed-it-butyl-tape.117172/

Once you finish MainSail's post I think the procedure will be clear to you. This guy really does a great job explaining it. as for sealing the parameter of wood, wood is porous. It benefits from the air. don't seal in moisture.

Best of luck.
Ken

 

[Daveinet]

If you have not purchased the wood, you may want to look at IPE. Tougher than Teak, but looks similar. It is way cheaper and generally considered a better wood. I used it several years ago to make grab handles for my previous boat. You need really good tools to cut it. It must be pre-drilled, as you can not screw wood screws into it without breaking them - trust me, I learned the hard way. The wood is dense, and has a lot of oil content, which protects it from moister. It is also very heavy.

 

[gsteiner]

Ken,

I read through the post you linked, and while it's very informative, it doesn't address one particular fact I'm dealing with: My mounting hardware is not bolted on. There are no nuts holding the hardware in place. They are simply screws turned into the deck from above...

It seems to me that if you screwed 'through' butyl tape, the threads of the screw would tear up the tape and leave a spiral channel that could allow water intrusion. All of the information I've found on Butyl, including that very informative post, show the butyl applied 'around' a bolt just under the head, and make a point to indicate that the bolt should not be turned once inserted through the countersunk hole, only tightening the nut from below.

Is there a way to use the butyl tape on regular screws which do not have a backing plate/nut without negating it's seal?

It seems plausible that if you place a 1" square piece of butyl over a mounting hole, than screw through the butyl into the hole, that it would seal and eliminate any water intrusion coming from the sides... Since the screw heads will be countersunk into the teak and plugged, then varnished, it's is unlikely that water could come straight down the shank of the screw (unless the varnish was neglected and the plug failed) but it still seems like it could present a possibility of leaking.

Has anyone had specific experience using butyl with screws, and if so, did you use any particular technique that differs from the ones outlined for bolt through hardware?

I'd hate to do all this work, then find out that it leaks because the screws chewed up the butyl and didn't make a proper seal...

 

[gsteiner]

UPDATE:

Ok, so a bit of google searching, and our good friends over at Sailrite had a video showing two different ways to use Butyl tape with regular screws to achieve a good seal... so Butyl tape it is!

Looks like my idea of using a 1" square over each countersunk mounting hole will work perfectly.

So the FINAL question for this project:

Are all Butyl tapes created equal? I've seen many different brands, and was going to order some from Amazon, but before I do I thought I'd check with the experts! What should I look for in a Butyl tape to do the job right? If anyone has any particular brands they prefer, let me know (and why).

Thanks!

 

[dlochner]

Are all Butyl tapes created equal? I've seen many different brands, and was going to order some from Amazon, but before I do I thought I'd check with the experts! What should I look for in a Butyl tape to do the job right? If anyone has any particular brands they prefer, let me know (and why).

All butyl tapes are not equal. For a variety of reasons, buy the tape from www.MarineHowTo.com. MaineSail gives much to this forum and sells butyl tape. It is good quality stuff. Get quality tape and support a very generous member. He has an article about using the tape too.

 

[glaufman]

I've only used"bed it" butyl. It's working great for me.

 

[Ken Cross]

Now you got it. I have successfully used butyl tape with regular screws. Having the large piece of tape causes it to squish around the threads especially if the hole is countersunk. I'm also a great fan of the lack of mess when doing it this way. Tubes of goop seem to have a way to get onto everything. I even did some sealing on commercial airplanes, the same problem there goop gets on everything.

Ken

 

[LeslieTroyer]

+1 on MaineSails butyl

 

[Mark Maulden]

Now you got it. I have successfully used butyl tape with regular screws. Having the large piece of tape causes it to squish around the threads especially if the hole is countersunk. I'm also a great fan of the lack of mess when doing it this way. Tubes of goop seem to have a way to get onto everything. I even did some sealing on commercial airplanes, the same problem there goop gets on everything.

Ken

Glad to see I’m not the only on. Stuff is like a virus. Maine’s tape is great. I store it in a food saver bag with the air sucked out. If you try this, you will have to interrupt the vacuum process before you have a single glob of tape..Dont let the process finish vacuum process.