Removing Old Seacocks and Through Hulls

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HopCar said:
Angus is correct, The Groco SV series of seacocks were very well made. What causes them to be replaced is that the rubber plug swells into the water passage when the valve is closed. The rubber eventually hardens into a bump that makes it hard to turn the valve. Forcing it can cause the rubber to break loose from the shaft. The rubber bump can be sanded off but eventually the rubber fails to seal and the seacock must be replaced.

Skipperdude, the type of corrosion you're talking about is called dezincification. It only happens to high zinc brasses, not low zinc bronzes such as Groco and other name brand seacock manufactures use.

Bronzes are suceptable to electrolysis from stray currents, that is why you bond them to sacrificial zinc anodes.

Bronze seacocks are much stronger than the plastic ones. I wouldn't use the old Forespar Marlon seacocks. The newer design they sell to boat builders looks pretty good, if you want a plastic seacock. While Forespar doesn't market them to the aftermarket, they can be ordered.
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hopcar. That's why I said that. Thanks for the term. but I have never been on a boat that had a correct bonding system. If it was it didn't stay that way long. Good chance those 30 year old thru hulls arn't as brassy as they used to be.
 
Parks, do you know of a source for pre made backing blocks?


1983 Present 42 Sundeck
Twin Lehman 135's
✌️
 
Actually bonding is a great way to spread stray current corrosion to your seacocks......

Galvanic action is totally different and about half the world does not believe bonding is necessary for stand alone seacocks.
 
Regardless of the claims for some super bonding goop., sea cocks are designed to be BOLTED in place.

The method for commercial boats is to install the sea cock , then the thru hull as they may need to be pulled for inspection.

3/8 bronze bolts is my minimum and for go fast folks strut bolts are sleeker.

Never ever SS bolts underwater.

GRP sheet up to 1/2 inch is OTS and can be epoxied in as backing block.

30 days of crap electric can pink most bronze ,
30 years is no problem at all if the electrical system on your boat , and alas your slip mates , is proper.
 
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Since on most boats the internal and the slip mates electrical systems can not always be counted on Walla the composite product. For me it was a no brainer on my last four boats composite exercise the handles so they don't freeze and forget about the pink demon.
 
Forklift, If you are using either Groco or Apollo seacocks with triangular bases, Groco makes some really nice ones. We sell a lot of them but any Groco dealer should have them.
 
Parks, it's the round backing blocks that are attached to the inside hull I'm hoping to score. Would take time to make/ cut and a CIRCLE at that.

eyschulman (AKA Doc :)) - those composite seacocks certainly have some advantages. And it wouldn't take much to add Bronze vs Composite to "our" list of debates :)!!
️Galley up/ Galley down. Single/ double. Etc!!


1983 Present 42 Sundeck
Twin Lehman 135's
✌️
 
Most yards just grind off the outside, the heat softens the goop. Hit it with a hammer. Do it anyway you want but bring a grinder. I think psneeld hit on every spot, and yes if you would like to replace them again go ahead and bond them.
 
kulas44 said:
Most yards just grind off the outside, the heat softens the goop. Hit it with a hammer.... if you would like to replace them again go ahead and bond them.
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What if you don`t want to replace the thru hull, but want to blank it off/repair the opening back to solid hull?
In a non cored f/g hull, 1-1.5" thick, what is the accepted repair procedure?
 
kulas44 said:
Most yards just grind off the outside, the heat softens the goop. Hit it with a hammer. Do it anyway you want but bring a grinder. I think psneeld hit on every spot, and yes if you would like to replace them again go ahead and bond them.
Click to expand...


The more I think about this the more sense it makes to stop trying to save the $80. I probably have 2 1/2 hours in this already, and was planning on building a through hull tool on my small lathe this week (at least an hour with my minimal skills) and I STILL have to get it removed. Grinder or hole saw- that will be my approach.




1983 Present 42 Sundeck
Twin Lehman 135's
✌️
 
Accepted best practice for "blanking" a thru hull is to calculate the required scarf area for 1/2 the thickness of the hull and grind out that much inside and out. Relaminate using woven "glass cloth, then sand fill and fair. Epoxy only !!!
 
Don't know if this is the accepted way or not, Bruce, but I found it on the internet so it must be true. :socool:

 
Forklift, Here is what the Groco backing block looks like. They come with threaded inserts so no bolts go through the hull.
BB-PG9-300-SML.jpg
 
That's it!! PM sent


1983 Present 42 Sundeck
Twin Lehman 135's
✌️
 
angus99 said:
Don't know if this is the accepted way or not, Bruce, but I found it on the internet so....... ]
Click to expand...

it is one of many....

goes to show some if not many of the pros use poly or vinylesters resin believing it is strong enough and actually better for repairs as it has many of the same characteristics of the hull where epoxy doesn't and therefore less prone to stressing and failure.

the video then explains "his theory" on how to lay patches which others will strongly dispute with just as little "scientific evidence" as this guy as to which way is truly better.

so...the "Accepted way"?.....can't really say as like many boat repair "options"....it is just one of many ways of doing it. Some recommend never removing thruhulls....just render them in op and as leak proof as possible....not my way..but one of the many.
 
Found what appear to be SS elbows on two bronze below-the-waterline seacocks for sink drains. Lots of powder growing out of the joints and some rust stains on the hull below. All the other transition fittings on the boat appear to be heavy bronze. I'll probably try to pull these two seacock/through-hull assemblies this weekend and decide if I have time to replace all 14 on the boat.

img_304804_0_4b66614ce7ab21d9aed1d52d560e6258.jpg
 
angus99 said:
Don't know if this is the accepted way or not, Bruce, but I found it on the internet so it must be true. :socool:
Click to expand...
Thanks, much appreciated, wish my f/g work was as neat and organized. It`s similar to the osmosis repairs I had done on my boat, they used a dished grinder pad to cut away, filling the dish same way with enlarging concentric circles, finishing with epoxy putty. The guy said due to depth some blisters need grinding right through with forming up on the inside, fortunately not required on my boat, but it will be if we delete the washdown thru hull supply.
 
I agree with the vid in almost every aspect and pretty much that is how I do it. I like to grind inside and out with a 12 to 1 scarf ratio. I ONLY use a 5 to 1 epoxy for this type of repair, and no CSM, only cloth. The opinion of most current and in the know real professionalls is that the polyester resin that your boat was built with had a "waxing" additive (PVA) that allowed it to cure, without which it would remain in a raw state. Poly or even vinyl ester doesnt stick well to cured polyester fiberglass. Epoxy has the best adhesion of any known and easily available product. This whole thing is a time consuming and labor intensive exorcise, with about $20 worth of materials. Dont scimp, use the good $hit.
 
Laminating resin contains no wax. The last coat needs wax added or some other air inhibiting covering.

While epoxy is used a lot....yet vinylester is used by many pros too with very professional results. Some repairs are better off due to the characteristics mating the rest of the shell. The discussion results in adhesion over the scared area is more than necessary for the intended repair.


http://www.jamestowndistributors.com/userportal/show_product.do?pid=2082


TotalBoat Polyester Laminating Resin is used as a first coat for base coat applications. Without wax, this resin remains tacky to hold fiberglass fabric in place on vertical surfaces. Needs no sanding between coats. Laminating resin is excellent for saturating fiberglass fabrics. MEKP Hardener included.
 
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That is correct, but, the last coat is always waxed. Non of the esters has the adhesion properties of even the lowest grade of epoxy. I will concede that poly is easier to work with and even the least skilled person can use it, somewhat successfully. Its kinda like the difference between rivets and welding, anyone can rivet but not everyone can weld, it takes practice and skill. both work but given the choice I would take welded everytime.
 
If you forget the wax you can cover it with plastic wrap and tape it off good. It will stop the air from getting to it and allow it to cure. Basically it does the same thing the wax does. Seals out the air.
 
psneeld said:
it is one of many....

goes to show some if not many of the pros use poly or vinylesters resin believing it is strong enough and actually better for repairs as it has many of the same characteristics of the hull where epoxy doesn't and therefore less prone to stressing and failure.

the video then explains "his theory" on how to lay patches which others will strongly dispute with just as little "scientific evidence" as this guy as to which way is truly better.

so...the "Accepted way"?.....can't really say as like many boat repair "options"....it is just one of many ways of doing it. Some recommend never removing thruhulls....just render them in op and as leak proof as possible....not my way..but one of the many.
Click to expand...

I removed and glassed over 4 thru hulls, and replaced the remaining 2.
I use polyester resin for the reasons above, and I lay out the patches in a similar manner. That is how I was taught. It seems to have worked for me.
 
Any secondary bonding , weather in a new green hull after 3 days or an old 1960s boat REQUIRES 85% of the surface to be ground to clean glass.

Thats the USCG rules when working / building a sub: T boat , so it should be fine for anyone.

Using wax to block air from the last layer of resin went out with resin infusion.

Regardless of cost or allergies EPOXY is the best for repair and modifications , leave the waxed polly resin and Bondo on the shelf.
 
It is my belief that you build boats with polyester but you fix them with epoxy.
When you're repairing a boat you are essentially glueing new bits to the boat. I've never seen polyester glue.
 
My through hull/ POS seacock are out! I went with the advice of kulas44 and as promised, grinding the mushroom head off which heated old glue and bing bang boom. Look at the backing board " glued" down with silicone. Geez.
New parts are already ordered and will be here soon.
ImageUploadedByTrawler Forum1423443519.669464.jpgImageUploadedByTrawler Forum1423443547.286963.jpgImageUploadedByTrawler Forum1423443564.288398.jpgImageUploadedByTrawler Forum1423443581.557020.jpgImageUploadedByTrawler Forum1423443599.041603.jpg


1983 Present 42 Sundeck
Twin Lehman 135's
✌️
 
RT- that's EXACTLY how I felt❗️❗️❗️


1983 Present 42 Sundeck
Twin Lehman 135's
✌️
 
I will be first to tell you that I am an a$$. But, I have been there and done that, got the Tshirt when it comes to boats, especially fiberglass boats. If I say "this is how the best yards do it" or "this is accepted best practice" well,,,, it is. I wont apologize if you did it like the locals do and it worked for you. I also will not bask in glory when , or if, you report that the repair is 3 years later a dismall failure. However, I will advice you again on the "best practice" way to do it. Just sayin :)
 
Roger that. Well noted?


1983 Present 42 Sundeck
Twin Lehman 135's
✌️
 
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