Is "seam-sealant" off the market?

[Jeff Aitken]

I heard from a wise boat-man, that the best materials to seal wooden-boat-seams with, are cotton caulking or "seam sealant".

I want to chisel in some cotton caulking after the summer, but for now, which product will work best? The "marine-store-man" said, seam-sealant was a great product and it worked, but since it had lead in it, it was discontinued.

Whats my best option for on top of cotton caulking? Just Sikaflex brand underwater sealant?


I know to pick it dry and clean.

 

[tillergirl]

White lead putty above the waterline, red lead putty below. Get ordinary linseed oil glazing putty, a bottle of raw linseed oil, some red lead powder and mix. 2 oz of red lead does 1lb of glazing putty so it goes a long way. Add the linseed oil sparingly to keep the putty at its original consistency after gradually adding the red lead powder. Some nitrile gloves are a good idea.

Prime the seam before the cotton caulking goes in with a caulking iron (some prime again after the cotton is in) and then add the red led putty.

 

[stuhaynes]

I heard from a wise boat-man, that the best materials to seal wooden-boat-seams with, are cotton caulking or "seam sealant".

I want to chisel in some cotton caulking after the summer, but for now, which product will work best? The "marine-store-man" said, seam-sealant was a great product and it worked, but since it had lead in it, it was discontinued.

Whats my best option for on top of cotton caulking? Just Sikaflex brand underwater sealant?


I know to pick it dry and clean.

Red and white lead paste (and powder) are NOT illegal. Google 'Traditional Boat Supplies' in Suffolk (not got the number to hand) Speak to John, very helpful. He's got it in stock along with red lead paint which disappeared from supermarket shelves a LONG time ago.

Lead was never made illegal, but it's not good stuff for the environment. The government, rather than ban it, put a big wedge of tax on it. For wooden boats it's excellent in the seams. Our own boats bilges still show pink lead paint after 60 years.

I'll watch this thread cos we're out of the water in 8 weeks and I'll be interested to see what others have used and how successful it was.

Ring John at Trad Boats, he really is very good. No connection, happy customer is all.

Process
Thoroughly clean out joint
Prime about a foot of the joint with oil based paint
Bang in caulking cotton so that it compresses in the bottom of the joint
Complete the run in this way
Mix lead putty and Linseed oil putty in equal amounts, Add a small amount of 'soft grease' and mix thoroughly. The grease helps the putty not dry out. If you mix a small 'fist full' of paste a 'thumb full' of grease is about right
Paint the joint (again) with oil based paint, just enough to cover, and insert the paste into the joint, smooth off.
That's about it. Paint within a few days and relaunch in a reasonable time otherwise the putty may well over dry and appear to crack.

If you speak to John he'll give you the whole 9 yards!

Good luck, Stu

Edit: I've always used the paste, not powder. If you buy the powder follow the advice in the previous reply. You still should add the grease!

 

[Boo2]

White lead putty above the waterline, red lead putty below.

What does the red/white lead do for the mix ?

Boo2

 

[AntarcticPilot]

What does the red/white lead do for the mix ?

Boo2

I'd imagine it makes sure bugs don't grow in or on it - reason it is no longer used in (most) paint is because it is nastily toxic! Read your "James Herriot" books for accounts of animals getting poisoned by old paint, in the days well before I were a lad. Lead poisoning from old lead based paints was commonplace; it is much rarer these days.

 

[tillergirl]

What does the red/white lead do for the mix ?

Boo2

In relation to ordinary glazing putty - better consistency, retains flexibility longer, doesn't crack as easily and generally tougher. Why white lead/red lead. The red leaches and or shows through undercoat and enamel on the topside so white is used. Why not white all over. Don't know technically but I find it is difficult to evenly mix the white lead as the colour difference to normal glazing putty is only slight.

Artists' paint shops are a good source of red lead. Buy a suitable container and keep the spare to mix up in the future when necessary.