caulking advice

[jools]

Hi

I am looking to renew some caulking on a 50 year larch planked vessel, the caulking isnt 50 years old just the wood! The bow needs replacing due to previous deteriation from under use and sun.

Any advice on wether to use synthetic or not, or just plain old good advice.

Never done any caulking before but know how to stuff a hole to stop a leak!

Thanks for any in advance

jools

[gonzo]

What kind of construction is your boat: carvel, lapstrake, etc.? What are the dimensions of the planking? Are there see-through gaps in the seams? How are the fastenings?

[jools]

The planking is carvel, larch on oak frames about 5", just a couple of seams let light through but only just. Its more a question about the pros and cons of synthetic caulking. All I have read says cotton. The current caulking 95% of which looks fine is taped then wadded and then stopped. Where the sun has dried out some of the bow this has cracked and opened slightly.

How much should I remove and should I keep using synthetic?

Thanks for the reply.

jools

I have just completed removing a large amount of caulking from my 1964 Egg Harbor 37. I have only been told to use cotton of oakum, or even both. My theory is that if cotton/oakum was good enough for the first 40 years, it should definitely be sufficient for the next. Keep with what's tried and true, then seal with a good poly-eurethane caulk (Sika is well known and proven to hold-up).

[gonzo]

I have been working on traditionally built wooden boats for 34 years. Larch is a soft wood that swells a lot. There are a couple of things to take care off. Firstly make sure you don't pound too much of whatever material you choose to caulk with. If you do, the planking will spring and the sheer will hog. Also, check the fasteners; they may be corroded or loose. When you have see through seams, the best is to reef out all the caulking. Then make sure both edges are square. Cut a dutchman of larch and drive it in with loose fit. Put glue on one side. You will drive the caulking on the non-glued side. Be careful while driving the caulk in, because with soft wood it is easy to drive it all the way through. In any place where it has been driven through you have to put a dutchman in. I assume that the syntetic caulking you reffered to is the putty. Polysulfides are much superior to the old materials. However, the wood has to be cleaned of all loose paint, old caulk and oil. They also make primers that help with adhesion. I hope this helps you.

[abdind]

Wish to introduce ourselves as a manufacturer & exporters of:


MARINE CAULKING THREAD & Caulking Cotton

i.e. Cotton Packing Cord (Twine) in Gulf Area it’s called KALFAT

Using in Wooden Boats for manufacturing and repairing the wood boards joints as a filler.

Packing onto balls, card board tube, Hanks or as per your need.

Besides our other items are:

Braided Cotton Wicks
Cotton Ropes
PP Braided Rope also in other synthetic materials
Elastic Tie Down Belts and Bungee Cord
Cleaning Mops & Mop Yarns


Our URL is:

www.abdind.cjb.net

Awaiting your response.

Best Regards.
ASAD

ABDULLA INDUSTRIES
B-59, S.I.T.E. AREA
KARACHI-75700
PAKISTAN

Tel: 92 21 2570880
FAX# 92 21 2578332

[luke23]

thanks for the offer.