Wood Backing Plate for Thru-Hull Soft and Rotten

[Kefaa]

I am starting to seem like a Don Casey Groupie...
Yes - you can seal it up.
Fiberglass Repair by Don Casey

[S&S]

Originally Posted by neilpride

I change all the seacocks in my CSY 44 4 years ago, and i find wood backing plates , i rip off all the backing plates and made donuts with a fiberglass panel, very funy, and i use 3m 5200 because is a serious stuff in underwater fittings, another option is to make the donuts with a tick teflon panel.For me is the answer to spread the load in the tru hulls and have a free rot material. Cheers.

Using the glass is fine, but do you use the 5200 to set the seacock too?
If so, have you ever tried to remove one?

A sloppy job with bedding the plate to the hull with 5200 will cause all kinds of fun if the seacock even needs removal.
Cheers!

[neilpride]

Originally Posted by S&S

Using the glass is fine, but do you use the 5200 to set the seacock too?
If so, have you ever tried to remove one?

A sloppy job with bedding the plate to the hull with 5200 will cause all kinds of fun if the seacock even needs removal.
Cheers!

The fiberglass backing plate is glassed to the hull with epoxy, and i use 3m 5200 for the trhu hull , yes i know that 5200 is pain in the ass to remove , 3m 5200 is polyurethane and other ones are easy to work and remove but im just believe in 5200 for a leak proff underwater fitting, my grounds plates also have 5200, many fin keels are trough bolted to the hull with 5200 , and for me , all my tru hulls are a permanent bond!
and i try to bond others stuffs with sikaflex 291, or 3m 4000, much easy, but for a hole in my hull, no doubt, 5200!!!

[cantxsailor]

After recently finding a broken thru hull stiil attached ONLY by its 5200 gasket I think its the ONLY thing to use. How often you plan on removing an item should be the criteria for your choice of sealant not how hard it might be if and/or when you decide to remove it.

If it's a deck fitting that may be removed for painting and such every few years, yes use something like 3m 101. But for something that will only get changed if it breaks use the toughest stuff you can find and 5200 usually fits that bill.

I have found on my boat that if I use a very sharp wedge I can break the seal of 5200 without damaging even light weight frames around hatches.

Oh and NEVER NEVER NEVER use silicone it's the devils smooge.......m

[S&S]

Originally Posted by cantxsailor

After recently finding a broken thru hull stiil attached ONLY by its 5200 gasket I think its the ONLY thing to use. How often you plan on removing an item should be the criteria for your choice of sealant not how hard it might be if and/or when you decide to remove it.

How do you break off one of these?



They are supposed to be bolted/screwed to the hull.
Mechanical fasteners > wondergoo (even really good wondergoo)

[Maine Sail]

Originally Posted by S&S

How do you break off one of these?



They are supposed to be bolted/screwed to the hull.
Mechanical fasteners > wondergoo (even really good wondergoo)

I agree and was wondering the same thing. A properly installed & through bolted seacock is not dependent on the sealant for holding it to the hull.

I have seen 5200 rip gelcoat clean off the substrate many times. Having more adhesion than the gelcoat to the FRP is complete over kill as the gelcoat bond will often fail before the 5200.

I won't even use it on a keel. I have done a re-set and had a few small spots, that I could not get at, of 5200, tear large chunks of fiberglass off my keel stub which then neede to be cleaned, re-laminated and re-faired.

If the 5200 had adctually worked as advertised I would have never had to replace 5 keel bolts and re-set the keel. 5200 good stuff? Not for me...

[neilpride]

Originally Posted by Maine Sail

I agree and was wondering the same thing. A properly installed & through bolted seacock is not dependent on the sealant for holding it to the hull.

I have seen 5200 rip gelcoat clean off the substrate many times. Having more adhesion than the gelcoat to the FRP is complete over kill as the gelcoat bond will often fail before the 5200.

I won't even use it on a keel. I have done a re-set and had a few small spots, that I could not get at, of 5200, tear large chunks of fiberglass off my keel stub which then neede to be cleaned, re-laminated and re-faired.

If the 5200 had adctually worked as advertised I would have never had to replace 5 keel bolts and re-set the keel. 5200 good stuff? Not for me...

Right , is true that 5200 is over kill, a keel hull joint is a permanent bond, but why you replace 5 keel bolts?? a leak?? grounding damaged? corroded bolts? Right now 5200 is the norm for many boat builders, can you tell me another better product to seal a hull to keel joint??
A better sealant for deck to hull joint?
And in the picture looks like a new bronze tru hull, nice when new, but a 10 years olds tru hull is a another history, maybe some galvanic corrosion, some electrolisis in the bronze, or just a 100 pounds diesel mecanic holding their weight in the tru hull, this last hapen to me!!
And finally i think 5200 is a great stuff in the right aplication, just in the right place with the right prep, Cheers.

[S&S]

Originally Posted by neilpride

And in the picture looks like a new bronze tru hull, nice when new, but a 10 years olds tru hull is a another history, maybe some galvanic corrosion, some electrolisis in the bronze, or just a 100 pounds diesel mecanic holding their weight in the tru hull, this last hapen to me!!

So why use 5200 on something that may need replacing in as little as 10 years? Also, if throughbolted, you can stand on these w/o any issues ( I did and i'm closer to 100 kg than 100 lbs. )

[neilpride]

Originally Posted by neilpride

The fiberglass backing plate is glassed to the hull with epoxy, and i use 3m 5200 for the trhu hull , yes i know that 5200 is pain in the ass to remove , 3m 5200 is polyurethane and other ones are easy to work and remove but im just believe in 5200 for a leak proff underwater fitting, my grounds plates also have 5200, many fin keels are trough bolted to the hull with 5200 , and for me , all my tru hulls are a permanent bond!
and i try to bond others stuffs with sikaflex 291, or 3m 4000, much easy, but for a hole in my hull, no doubt, 5200!!!

Sorry i mean 100 kg not a 100 pounds!!!! jejeee

[Cheechako]

Bottom line is a lot of seacocks like that are not bolted. Personally, I would use 5200 on that style of seacock and eliminate the bolts. Less holes in the hull, and I dont think you are going to pry the seacock loose (if the thru hull is corroded away) when you try to turn the handle.... but then again, I'm sensitive to that type of thing, and before I reefed on a seacock to get it closed or open I would try to loosen it up some. 5200 can be removed..... cut away.... drive a chisel under one edge and start slicing the 5200.

[S&S]

Originally Posted by Cheechako

Bottom line is a lot of seacocks like that are not bolted. Personally, I would use 5200 on that style of seacock and eliminate the bolts. Less holes in the hull, and I dont think you are going to pry the seacock loose (if the thru hull is corroded away) when you try to turn the handle.... but then again, I'm sensitive to that type of thing, and before I reefed on a seacock to get it closed or open I would try to loosen it up some. 5200 can be removed..... cut away.... drive a chisel under one edge and start slicing the 5200.

Not saying it's not doable, but it's a PITA. I'd (personally) be creeped relying only on the adhesive. Getting out the threaded theough hull would be more of an issue.

[Cheechako]

Yea... it's funny how these discussions go.... one thread people will defend Marelon plastic seacocks......many of which cant be operated in the bin down at West Marine! the next thread the more traditional of us insist on Bronze through-bolted ones. Everything's a personal decision I guess. I feel very confident in a nice wide flanged bronze seacock 5200'd to the hull. I guess I feel it's a good pragmatic approach. Many Aluminum boats just have a pipe welded in the hull with a valve attached to that. Of course the weld is probably one of the most likely spots for corrosion.... Aluminum being sacrificial to alot of things..... that could be scary. If the fiberglass hull is an inch thick where it's going then I fear the bolts less than I do than if it's 3/8 or half inch thick. Hell, I'll be two boats into the future before some guy in a boat yard is cussing me about the 5200..
So many boats now days have a through hull fitting with a nut and then a common valve screwed on, now that I fear!

[Maine Sail]

Originally Posted by Cheechako

So many boats now days have a through hull fitting with a nut and then a common valve screwed on, now that I fear!

Amen! But 5200 is still the most over rated, ridiculous product ever foisted upon the boating industry IMHO..

BTW my hull deck joint was sealed with butyl tape 30 years ago (10-20 psi adhesion not 700 PSI) and is still bone dry. In fact my entire vessel was factory beded with butyl and approx 80% of the fittings are still BONE dry and have not yet been re-bedded.

Contrary to popular belief the bolts, like your lug nuts on your wheels, are what holds the boat together or hardware to the deck. We don't glue wheels onto cars and we don't need to glue mechanically fastened hardware to our boats either. In a properly bolted hull to deck joint all you need is a seal and even butyl works just fine. My boat is living proof. 30 years, two across the pond trips, South America to Newfoundland, throught the canal and to Alaska and still not leaking one drop and NO 5200 anywhere....

[neilpride]

Originally Posted by Maine Sail

Amen! But 5200 is still the most over rated, ridiculous product ever foisted upon the boating industry IMHO..

BTW my hull deck joint was sealed with butyl tape 30 years ago (10-20 psi adhesion not 700 PSI) and is still bone dry. In fact my entire vessel was factory beded with butyl and approx 80% of the fittings are still BONE dry and have not yet been re-bedded.

Contrary to popular belief the bolts, like your lug nuts on your wheels, are what holds the boat together or hardware to the deck. We don't glue wheels onto cars and we don't need to glue mechanically fastened hardware to our boats either. In a properly bolted hull to deck joint all you need is a seal and even butyl works just fine. My boat is living proof. 30 years, two across the pond trips, South America to Newfoundland, throught the canal and to Alaska and still not leaking one drop and NO 5200 anywhere....

Hi sr, just a question , is this tru hull picture coming from your boat??

[Maine Sail]

Originally Posted by neilpride

Hi sr, just a question , is this tru hull picture coming from your boat??

Yes, and that is Sikaflex 291 (221 PSI adhesion) as I don't use butyl below water and should have clarified that. I still don't have any 5200 on my boat and amazingly she still floats..

I would have preferred 3M 101 but was out of it at the time Sika 291 is my next favorite cartridge caulk after 3M 101. 5200 can be over 700 PSI adhesion. The seacock is also through bolted through a solid fiberglass backing block.