Advice on Caulking

[sw35750]

My friend has to re-caulk his 1956 Norfolk Broads motor cruiser hull. Can anyone give us any advice on what is the best caulking to use for painting over and value for money. The hull is made of Iroko.
Any advice gratefully received

Sally

 

[EASLOOP]

Presumably it is carvel. If so then clean out the old caulking material and re-do with twisted cotton and linseed oil putty mixed with shite lead for above the w/l and red lead for below the w/l. Paint the open seams first to prevent the oils being abosrbed by the wood and drying out. I have a carvel sloop and have completely re-caulked the entire hull with the above mix. For the decks I used Sikaflex DC.
If the hull is clinker built then someone else wil know better than me.

Its a painstaking job to good luck - and don't over-caulk.

 

[LittleShip]

Errr......... I think you mean "White lead" I hope /forums/images/graemlins/blush.gif and I agree with all of it.

Tom

 

[Victorious]

White lead is expensive, and the reason it is used above the waterline is that Red lead tends to leach through the paint and thus look orrid.
However, Paints have improved a great deal in recent years and this is very rarely if ever a problem.
I reccomend using Red lead putty throughout (available in ready mixed form from Traditional Boat Supplies)

 

[EASLOOP]

OOPS! So spell check is a good thing after all, or is it a real word??

 

[Peterduck]

Try to get someone who really know their stuff to show you how to do it, and what good-quality caulking cotton looks like. I've seen some 'orrible stuff at the swindlers being passed off as caulking cotton. The r gfood quality cotton is like a thick, fluffy cotton rope, with about 8 strands. If your semas are narrow, as they should be, you won't require all 8 strands. If they are wide, as many are after a few years of over-enthusiastic caulking, you may well need all 8 strands. There is a definite technique to putting the cotton into the seam which really has to be demonstrated. How firm to be with the caulking mallet is very important so that you don't over-do it.
Peter.

 

[Porthandbuoy]

[ QUOTE ]
. . ., Paints have improved a great deal in recent years and this is very rarely if ever a problem.
I reccomend using Red lead putty throughout (available in ready mixed form from Traditional Boat Supplies)

[/ QUOTE ]

Wahayy! Victorious & Mariposa 2 - Mirelle 1 /forums/images/graemlins/laugh.gif

All the advice given is sound, but I'd add the following. If the boat's been out of the water for a long time she will have dried out a helluva lot, so don't put the caulking in too tight. You can alway firm it up next season once the planks have had a chance to swell up a bit; it's a lot easier than fixing cracked frames or broken fastenings.

 

[sw35750]

Thanks for all your advice - I have passed them on and having read previous forum postings on caulking have managed to convince him to do it the traditional way rather than using Sikaflex.

 

[Mirelle]

Not so fast! /forums/images/graemlins/wink.gif

Dunno about your boat, but mine seems to squeeze the seams a little bit for several years after a hardening down and re-stopping. The act of sanding the topsides levels the seams and of course exposes the seam putty. White Lead = no trouble. Red lead putty has to be “disappeared” again and this involved more coats of paint over what was already a “high spot”.