There's damp in that thar deck

[dancrane]

Ah, how proud I was of my shiny chrome rowlock-sockets last year. And in fact the chrome is still pretty good...but the machine-screws have rusted horribly...

View attachment 41082

...I begin to get the feeling there's moisture in the wooden core under the GRP! Is my best bet to use bronze screws, or monel, or something else?

 

[john_morris_uk]

Apart from obvious questions about the deck construction and material the machine screws are made from, how did you seal the rowlock when you fitted it? In other words, what bedding compound and technique did you use?

 

[dancrane]

Ah. Thanks Mr Morris. That had occurred to me, but I reckoned I was thinking too hard.

I bought Duralac bedding compound a month ago to seal the new rivets in my spreaders. I'd been thinking there was enough in the tube to last me several lifetimes.

Maybe I'll have a Duralac weekend, going round the boat gradually insulating all differing metals from each other.

 

[Kelpie]

Are the machine screws 316 or A4 stainless? You can get small quantities on a Ebay if you don't have somewhere locally.

On sealing, Duralac us what you need for dissimilar metals, but you should also put something on the screw where it goes into the wood. Un thickened epoxy would be good but varnish is much easier.

 

[prv]

Are the machine screws 316 or A4 stainless?

Mild steel, I reckon, possibly zinc-plated if you're lucky.

You want stainless, Dan!

And some sikaflex (or alternative goop, but not Duralac for goodness sake!) under the plate so that you're not introducing more water into that core.

Pete

 

[onesea]

Dan I know your on a budget but S/S is the way to go. If you find the right Chandler you can buy them individually at the right size for the job. I always buy 2 extra for the bilges and have a tool box with a few spares in that have built enough I often do not need to go to the Chandler.

 

[Seajet]

First, as mentioned check the screws are stainless. Simple silicone sealant from a DIY bodgers merchant like B&Q etc would be fine.

The really infuriating thing about Sikaflex ( A Rolls Royce solution for a BL Marina problem ) is, if one has half Aberdonian ancestry like me, it's truly painful to only use a smidgin of the very expensive stuff then the rest in the tube sets as solid as Stonehenge, unuseable...

 

[pcatterall]

Ang on ..... I thought I read that even stainless in a wet sealed environment was problematic ( could just be old age again)

 

[john_morris_uk]

Ang on ..... I thought I read that even stainless in a wet sealed environment was problematic ( could just be old age again)

The clue is in your reference to 'wet sealed'. Put some suitable sealant in the joint and under the screw head and you will get sealed without the wet.

 

[dancrane]

Thanks for all the replies, gents. The rusted machine-screws were indeed B&Q cheapies, I don't know why I'd thought they'd be sufficient.

I'll certainly replace them with stainless, and I'll fill the hole around each bolt with the mastic I bought to gum-up my leaking self-bailers. If that'll do it...it'd certainly keep them dry.

Pete, I only mentioned Duralac because I had supposed that the bolts' deterioration might have resulted from their damp contact with the nobler metal of the rowlock-sockets...

...but the fact that the starboard bolts are in worse condition than those on the port deck, suggests that more probably it's just the localised damp in the wood core on that side.

I've more or less given up worrying about that moisture imprisoned under the glassfibre. I expect it could be removed, but only by time-consuming work which is hardly vital.

 

[dancrane]

Ooops, accidentally repeated my last post.

 

[john_morris_uk]

Dan I know your on a budget but S/S is the way to go. If you find the right Chandler you can buy them individually at the right size for the job. I always buy 2 extra for the bilges and have a tool box with a few spares in that have built enough I often do not need to go to the Chandler.

A fastenings shop (a proper one!) will almost certainly be a lot cheaper than a chandlers. Or order on line from a choice of several suppliers.

If the deck is a cored deck, it would help a LOT to use a bent nail or similar and get the core (balsa?) out from round each hole and then fill with thickened epoxy and re-drill.

 

[richardh10]

Falcon Workshop Supplies do a lot of marine stainless fittings. They have an ebay shop, or you can ring them and place an order. They do small quantities, and when you see their prices you'll never buy from a chandlers again. Free next day delivery on most things

 

[chrisbitz]

I've used Westfield fasteners in the past.. Seemed cheap, good selection, and no minimum order.

Don't have the link, but put them in google...

 

[dancrane]

Thanks, I'll look at those sites for new bolts and other fittings.