Blanking off old skin fittings.

[donncha]

The previous owner of our boat was a little lazy when it came to installing new skin fittings. For example in our heads there are 2 defunct gate valves rusting away connected to nothing along side 2 newish ball valves. It's the same story with the raw water intake for the engine, there is an old blakes type sea cock sitting about a foot away from where a "new" gate valve was installed, I replaced the gate valve already, but what to do with the old blakes type?

Would it be sensible to remove the old sea cocks and skin fittings completely and bung the holes up? If so what would the best sealing/bonding compound be? Epoxy would be to brittle but would the bonding sikaflex do the job (292 I think)? Because of the planks swelling would I have to use some special sort of wood? The hull is made of pitch pine and don't think I could easily get my hands on that stuff anymore, would it be all right to use Teak, or would the hardwood cause another problem?

Lots of questions, any answers?

 

[alan006]

I would use a tapered shaped diamond patch. I would seal this with a polyeurathane mastic. I think its best to get a wood as simular as possible to the wood you are patching, so it expands and contracts at a simular rate.
Good luck.

 

[nmiller]

Hi
If they have been fitted to proper backing pads, then bung the holes from the inside with neatly fitted bungs, glued in. Then fit the dutchman to the outside as suggested, however I would glue them in with an appropriate adhesive, so that they contribute to the strength of the plank. If the previous owner(s) was/were lazy and did not fit packing pads, I would go to the trouble of doing so after bunging the hole. The pad will add strength and help to hold the bung in in-case of failure of the glue.

 

[donncha]

Thanks for the advice. I am thinking of fitting an appropriate bung, backing plate and diamond shaped dutchman then.


Would it definitely be out of the question to use epoxy in this situation then?

Also seeing as It would be extremely difficult to get my hands on proper pitch pine, what would be a recommended substitute?

 

[Chrusty1]

Larch would probably be ok, but Robins Timber at Bristol, might be able to find you a bit of Pitch Pine?

 

[donncha]

It would seem that Robins Timber do pitch pine, but it would probably be easier to source something suitable locally. I live in Dublin and it can be extremely difficult finding good timber (or anything else specialized and marine) here.

 

[misty56]

Enough Larch to fill a few bung-holes? How much do you need and what thickness? I might possibly even still have some bits of pitch-pine kicking about, but I'm sure I could rake you up a chunk of good larch. PM me.

BTW IMHO go like for like-- I wouldn't patch softwood with hardwood or vice versa, personally, so I'd steer clear of oak or teak in this case.

 

[oldfrank]

A decent and well fixed backing pad is important to hold your patch in place - and could prove crucial in the event of any kind of failure in the external patch, glue, fixings etc. etc.

 

[donncha]

Is epoxy suitable for this job then, at all? I ask because I can easily get west systems epoxy but to get a good marine glue requires some effort. Would Sikaflex 292 be suitable either? I have a quantity of both already.

 

[alan006]

Sikaflex is better for this than epoxy in my opinion. The sikaflex will allow for slight expansion and contraction better than epoxy.

 

[Tranona]

Consider cutting a bung slightly smaller than the existing hole and the same thickness as the plank, epoxy that to a pad about 50mm larger than the bung alround and bed the whole lot in Sikaflex from inside.

By the way, why no renovate the Blakes. Much superior to both a gate and ball valve

 

[donncha]

[ QUOTE ]
Consider cutting a bung slightly smaller than the existing hole and the same thickness as the plank, epoxy that to a pad about 50mm larger than the bung alround and bed the whole lot in Sikaflex from inside.

By the way, why no renovate the Blakes. Much superior to both a gate and ball valve

[/ QUOTE ]

I will check out the Blakes and see if I can use it somewhere else possibly later. There are plenty of other skin fittings to see to. When using the pad would it be advisable to clench it in with a few copper nails as well or would the sikaflex suffice?

Thanks for the advice everyone by the way.

 

[Tranona]

It will need screwing onto the plank, or screwing from the outside. Although the Sikaflex will act like an adhesive, mechanical fastenings are also needed for security. Clenched nails would be OK, but bronze screws are more effective.. There is also nothing wrong in doing it from the outside except that you will have a pad sticking proud of the plank. Inside looks neater and by the time the Sikaflex has set around the bung and you have painted AF'd the area you wont know its there.