Jay Greer
05-31-2006, 12:12 PM
With the advent of modern chemistry new glues, seam and bedding comounds, varnishes, paints and coating systems have flooded the market. Some are of merit others are more cost and labor intensive than their forerunners. And are questionable as to their longevity and toxicity. Unfortuanatly many old formula compounds that were practical as well as inexpensive fall into the black hole of no longer being made. Two such products were Cuhls Elastic Seam Compound and the recently discontinued Jeffreys Marine Glue.
Both of these products were used for traditional the paying of deck seams. One might ask, when there are so many new products on the market why would you want the old stuff? Jeffreys Marine Glue was on the market for 150 years so there must have been something good about it. The reality of the matter is that few boats today are made of wood in the traditional manner and so there is little call for or profit in marketing products for such a specialised niche.
But there are advantages to using a traditional laid deck. Just as the ancient Romans knew that a compression ring around the base a archtetual dome on a building would keep it structuraly sound, so it is with a traditional laid deck. The sheer clamp, shelf and covering boards are a form of compression ring. As cotton caulking is driven into the deck seams the panel becomes a panel in tension and is more capable of resisting strains in a seaway than the modern form of a veneer deck layed over plywood.
As a deck is caulked a keen observer can feel the changes in sound and vibration as the panel "takes up". It begins to feel more solid under ones feet but still has a feeling of life and resliance not to be found in modern forms of construction. It is the cotton or okum caulking that forms the water tight seal of the deck and not the seam compound.
Raw seams should be primed with a mixture of turpentine and bee's wax followed by the driving of the cotton. Then the cotton is primed over with the same mixture. I might mention that taping off the seams is a good way to prevent decks from being stained during this process. Finally the seams are "payed" with hot seam compound. Usually this was done with a "paying ladle" that had a pouring spigot to allow the work to be done more easily. The hot pitch would fill the seams and find its way into the smallest voids.
Once cooled and after a few days of cure, the tape could be taken up and the decks washed down with cold water. Jeffreys glue would resist melting up to 110deg and Kuhls was a little more resitant to melting. After a few years, the seams might begin to show a crack or two if the decks were not sloshed down on a daily basis. But this was or is not a cause for leakage as the caulking is still keeping the decks tight.
The beauty here is that, in order to close up the seam,all that was needed was to run a hot paying iron down the crack. The seam compound will liquefy closing up the crack. Consider this the next time you can't chase down a leak in your deck and because the seams in the synthetic seam compound are starting to seperate from the sides of the seams of your expensive teak veneer and you are faced with a blistering raw knee reefing and repaying job!
JG
Both of these products were used for traditional the paying of deck seams. One might ask, when there are so many new products on the market why would you want the old stuff? Jeffreys Marine Glue was on the market for 150 years so there must have been something good about it. The reality of the matter is that few boats today are made of wood in the traditional manner and so there is little call for or profit in marketing products for such a specialised niche.
But there are advantages to using a traditional laid deck. Just as the ancient Romans knew that a compression ring around the base a archtetual dome on a building would keep it structuraly sound, so it is with a traditional laid deck. The sheer clamp, shelf and covering boards are a form of compression ring. As cotton caulking is driven into the deck seams the panel becomes a panel in tension and is more capable of resisting strains in a seaway than the modern form of a veneer deck layed over plywood.
As a deck is caulked a keen observer can feel the changes in sound and vibration as the panel "takes up". It begins to feel more solid under ones feet but still has a feeling of life and resliance not to be found in modern forms of construction. It is the cotton or okum caulking that forms the water tight seal of the deck and not the seam compound.
Raw seams should be primed with a mixture of turpentine and bee's wax followed by the driving of the cotton. Then the cotton is primed over with the same mixture. I might mention that taping off the seams is a good way to prevent decks from being stained during this process. Finally the seams are "payed" with hot seam compound. Usually this was done with a "paying ladle" that had a pouring spigot to allow the work to be done more easily. The hot pitch would fill the seams and find its way into the smallest voids.
Once cooled and after a few days of cure, the tape could be taken up and the decks washed down with cold water. Jeffreys glue would resist melting up to 110deg and Kuhls was a little more resitant to melting. After a few years, the seams might begin to show a crack or two if the decks were not sloshed down on a daily basis. But this was or is not a cause for leakage as the caulking is still keeping the decks tight.
The beauty here is that, in order to close up the seam,all that was needed was to run a hot paying iron down the crack. The seam compound will liquefy closing up the crack. Consider this the next time you can't chase down a leak in your deck and because the seams in the synthetic seam compound are starting to seperate from the sides of the seams of your expensive teak veneer and you are faced with a blistering raw knee reefing and repaying job!
JG