5200 thru hull question

[Stugy]

Hi all , I would like to get your feedback/help. I replaced the depth sounder thru-hull fitting on my E27 located on the bow.
The original fitting was bronze and replaced with same and used 3M 5200 around the fitting to set/seal and bond it to the hull.
I was just inspecting the boat and getting it ready for spring launch and noticed that water had accumulated inside the boat in that small triangular section where the depth sounder fitting is located and noticed small drips of water coming through the other end (outside the boat) around the thru hull.
I am wondering if the 5200 has gone bad? (It seems soft around the fitting) I wonder if I should re-bed the thru hull? has anyone seen this happen in their boat? My plan is to sand and seal the outside of the hull with resin around the bronze fitting then dry the area inside and apply resing and paint around the fitting to waterproof that area.
I would appreciate your feedback/sugestions on this.
Thanks!

 

[Emerald]

Hi,


A couple thoughts. If you got the fitting bedded properly, there should absolutely be no drips coming through, and if this is really the case, I would remove the fitting and start over, as something went terribly wrong when you beded it down. Make sure you aren't being faked out by a drip running down the exterior of the hull and hitting the top edge of the fitting and looking like it is originating from the fitting.


First, a check list of things.

1) How cold was it and what type of temperatures have you had since, and did you use Fast Cure or normal 5200? You generally are going to need at least 40 degrees for this stuff to work, colder takes longer to cure, and normal 5200 at good temps (something more like 55-60), will take a solid week+ to reach full cure.

2) When you did the beding, are you sure that you had the area, inside and out, completely free of all contaminants and it was totally dry? It should also have been sanded to give a nice toothy surface (of course cleaned after the sanding)

3) Did you remove all paint, where the fitting was mating with the hull? You need to have solid, clean, fiberglass - can't bond to paint and be assured of good seal (water can run between paint and hull)


4) All the old timers I've talked to who have done this for many many years are pretty unanimous on tightening the fitting from the inside - don't want to spin the fitting on the exterior of the hull as you can spin your sealant right out. Tighten on the inside and you should get a nice squish out around the fitting on the exterior of the hull and leave plenty of material for a good seal


I would not make any attempt to patch this with epoxy etc. I think you are setting yourself up for a failure at the worst time possible. If you go to remove the 5200 and can't, put some heat on it -even a high power hair dryer (if you don't have a heat gun) will probably get it hot enough to release -- remember, fiberglass gets unhappy around 200 degrees -so be careful.

As much as a pain as it may sound to pull and start over, if you are really leaking water, this is your best option, and some day when it's blowing 25+, the rain is coming down, you can't see past your bow etc., you'll be damn happy you did


-David
Independence 31
Emerald

 

[NateHanson]

I agree with Dave here. There's no sense in trying to patch a leaking thruhull. If it truly is dripping water on the hard (zero pressure), imagine how much of a leak you might have when you put it under 2 feet of water. I don't know about you, but I wouldn't be able to sleep at home, knowing that a throughhull was known to be leaking.

That said, I would also stress that you should make certain that the leak really is coming through the fitting, and not down the hull. Use tape to create a drip-edge along the outside of the hull above the fitting to eliminate drips and condensation running down the hull and dripping off the fitting. Dry the area completely, and put as much water inside the hull around the fitting as possible. Maybe use plumbers putty to attach a bucket with the bottom cut off to the hull around the seacock inside, and fill it with water. Then watch carefully outside for leaks over some time.

 

[rwthomas1]

There can only be one "Stugy" from Boston, MA. I checked your homepage and we have actually met. I'm the guy from RI that bought the used X400 RC helicopter from you off of RCUniverse! Kinda funny how small the world really is. My wife and I just bought an Ericson 38, our first big boat. Welcome to the Ericson forum. Its a great place with knowledgeable people and tons of info.

I think the responses to your leaking transducer are pretty much dead on. Worst case is you have to remove and rebed the transducer which could be difficult with the 5200. There is a release agent available to help remove 5200, WM, etc. should carry it. Good luck! RT

 

[Mike Thomas]

Not a big fan of the 5200 for thru-hull fittings.

5200 is more of an adhesive than a sealant. Once cured it's a real pain to deal with. So the next poor fella that has to work on that thru-hull (you) may have a fight on his/her hands.

I'm a big believer in polysulfide on bronze thru-hulls. There's no need to grind, or epoxy if the fitting seats good in the opening. Put plenty of caulking in on the fitting and seat it so it just starts to squeeze out. Leave it cure for a couple of hours, then go back and tighten, wrench tight (don't over tighten). Also, bed down the backing plate (you are using one I'm hoping). This will also provide a secondary seal.

If everything is fitted correctly it should seal without cranking down on it and last as long as the bronze itself.

Mike T
E-29
Babylon NY

 

[Stugy]

Thank you for all the replies! and hi Rob! LOL its a small world.(Congrats on your E38!)..After reading all the feedback carefully I have decided I will remove the through hull and re-bed it properly with the right sealant agent(polysulfide?) Never heard of it but will look into it. The leak is very very small, but when I put my finger on the transducer I can draw a drop of water and you are a right I will not be able to sail with a peace of mind knowing water is coming into the boat..

 

[Sean Engle]

Second on Polysulfide

Not a big fan of the 5200 for thru-hull fittings...I'm a big believer in polysulfide on bronze thru-hulls...

I'm in with Mike on the polysulfide (old technology - but a good track record and very predictable). It will present you with the choice (down the road) of being able to pull the valve out when you need to without tearing things up.

I used it in re-bedding my ports and just about everything else as well (with more or less the same approach mentioned by Mike), and would do so again.

//sse

 

[Graham Cole]

I've had nothing but problems with 5200 under the waterline. Now using Sika 291 fast cure. 41 transducers and counting since last yr. 5200 takes too long to cure and is too temp sensitive. Just my $.02

 

[Stugy]

Mike T: You mention a backing plate. Would this be a playwood backing plate? the fitting is just a bronze threaded pipe with a big hex nut for back support. I didn't use any backing plate. Should i make one? if so what should I use? The through hull is exactly like this one execpt it is bronze http://www.dmimarine.com/DMIPIX/DMI THRU HULL.JPG
Thanks !

 

[Emerald]

Hi Stugy,


Backing plates are an imperative. I'd recommend 1/2 or 3/4 inch thick marine ply coated with several coats of epoxy to water proof. You will find there are a variety of opinions on other materials for backing plates, but marine ply is easy to aquire and work with, as is epoxy. If you are lucky, you may be able to get a scrap of marine ply from your boat yard or a local boat builder. Here in Annapolis, friends and I have had great luck getting scraps from Chesapeake Light Craft. Use a large (e.g. 4-5 inch) hole saw to cut the overall pad, and then use a smaller one for the inner hole for the transducer.


Good luck, and keep us posted.


-David
Independence 31
Emerald

 

[NateHanson]

I've used 4200 fast cure for thru-hulls. Solves some of the complaints that people have above with 5200. Sets in a couple hours, isn't quite as permanent as 5200 and remains a bit more flexible, but is more adhesive than polysulfide.

 

[Mike.Gritten]

Last haul out we installed a new log transducer and bedded with 4200 with excellent results.

 

[Loren Beach]

Backing plate idea

http://www.rplastics.com/g10sheet.html

URL for just one of many suppliers of G10/FR4 panels. I use this stuff for backing plate material all over the boat. It comes in many thicknesses. You should find it at any large plastics supply house in most cities -- we have several in our area. Cuts are easy with any fine tooth saw -- use a carbide blade if you are doing a lot of cutting.

Even the 1/8 or 3/16 inch thickness is amazingly (!) strong. I bed it in thickened West epoxy on any clean and abraided FRP surface.
(sorry, I do not know what the resin/glass ratio is for this product, but the specs must be available on line somewhere...)

Loren in PDX

 

[NateHanson]

Do you then tap it for machine screws to attach the seacock flange to the backing plate? Or can you just drill it and put in a short lag bolt as with plywood?

oi! I just checked the price on that link, and it's pretty darn expensive! $200 for a quarter-sheet of 1/4" stuff!

 

[Loren Beach]

I just bought six 5 X 7 inch by 3/16" pads for backing up stanchions at $5.50 each, from a local plastics industrial supplier (phone in and pick up at their Will Call desk a day later). It would have cost me over double that at a large local/fancy retail store...

I first did some cold calling with the Yellow Pages in front of me... it was educational. Quite amazing price differences.
Note that stuff sourced from the 'net is not always cheaper than the local guys, and is often a lot more expensive. (Nothing wrong with that, per se, if you happen to live in the outer boondocks.)

Note also that if you buy epoxy resin and cloth and make your own flat pads, the cost of even your 1/4" thickness piece, made up of a big bunch of cloth layers, will open your eyes wide.

As to attachment methods, note that on our boat all the seacocks are epoxied in, and the bases need no lag bolts. If not glassed in, I would use short lags into a 3/4 or inch thick backer.

Those were just my own opinions and experiences. YMMV.

Loren in PDX

 

[Mike Thomas]

backing plates

Stugy
Sorry about the delay in replying. Skippers meetings and the "monkey suit job" are getting in the way of boat stuff.

Dave and Loren have it right. Plywood soaked with epoxy or composite will both work. The point is that the backing plate will spread the load of the nut to a wider surface area (in the same way a fender washer does) and because you bed it in the same goop of your choice, it will provide another sealing surface. My guess is that if you don't have a backing plate in there now, that is why you are having the leak in the first place. I'm sure if you so a search through the archives you'll find a bunch of threads with pics.

A Pic is worth a thousand words (2k when their my words)

If you cant find any in the archives let me know and I'll send you some.

Mike T

 

[Stugy]

Hi, well I managed to take the thru-hull complety out today and with relativily minor effort. I did buy a heat gun and applied it all around the base of the thru-hull then I put a wooden log on top and pounded it with a hammer and it came right out, now that I have a nice clean fresh start I went looking for marine plywood and haven't been able to find any at my local West marine store and another marine place next to my boatyard. So I went to Lowe's and Homedepot and neither place knew what I was talking about when I asked for marine plywood. Would it be same as pressure treated ply?
what if I was to use regular ply and coated it with epoxy? or teak wood?
Also have NOT been able to find Polysulfide, plenty of 4200 though
Any thoughts if I was to use 4200?
Oh- One more question, do I coat the backplate with epoxy before or after I install the through hull?
Thanks !

Michelle
1978 E27- Cloud Croft.

 

[rwthomas1]

Unfortunately marine grade plywood is usually sold in full sheets, 4X8ft. Ask the shop at your marina/boatyard for a scrap about 5"X5" Wholesale plywood suppliers like Allied Plywood in Providence, RI will have most anything in stock but likely will only sell full or half sheets.

Exterior grade plywood or "CDX" would work as the binding glue is rated for moisture exposure and this is readily available. Interior grade plywood will delaminate when exposed to moisture so be super careful you use the correct thing.

Look at my post "thru-hulls and seacocks on a E38" in the Maintenence and Mechanical forum. There are pics of seacocks with backer boards made of teak&holly plywood which is marine grade.

Polysulfide is IIRC, "BoatLife" brand caulking. I can't believe West Marine didn't have polysulfide product but then again they don't hire the brightest bulbs..... 4200 will work fine too. Yes, you coat the backer board with epoxy and let it set before you install it. The epoxy serves as a waterproofing for the wood so it lasts much longer.

I will make you an offer. If you are interested I will make the backer plate and mail it to you. I have an extra piece of teak&holly plywood leftover from my project. I need the diameter of the transducer/thru-hull and the outer diameter would be handy to or I will just size appropriately. I am a carpenter by trade so this is extremely easy for me to do, take less than 1 minute to make it. If you can take a pic of the mounting location it may be handy to have.

Let me know, RT

 

[Stugy]

Sure

Hi RT! well that is an offer that I can't refuse LOL. here are the dimensions.
The thru-hull itself is 2" in diameter (bronze pipe) so perhaps just slightly bigger? that would be the inner hole of the donut.
maybe 1/4 inch thick? . and perhaps 1" wide all around? The transducer itself fits inside the bronze thru-hull. It has a threaded plastic cap on top and rubber seal gasket at the bottom so no worries about the transducer itself. Here is a link with a picture of the whole thing http://www.dmimarine.com/DMIPIX/DMI-DX300.JPG
So you get a better idea.
Thanks a million!

Michelle

 

[NateHanson]

Polysulfide is Boatlife's "LifeCaulk", and 3M's "101" if I recall correctly. Read the small print, and I'm sure you'll find it at West Marine, or another local marine store.