Questions for all you coopers out there

[Brasilikilt]

Hello everyone

I'm wondering if any of you out there have been successful at being a wet cooper?

I have been wanting to make some wooden beer tankards in the style common on board ships in the 18th century.

Here is an example brought up from the 1758 wreck of the HMS Invincible
This is the piece I will most likely try to emulate.

Judging from the joinery and general craftsmanship, it is thought that this particular tankard was most likely made by the ship's carpenter rather than the cooper.

I've never done this, and understand that coopering is a deceptively tricky trade.

What is a good angle for the edges of the staves to hold liquid and follow the curvature of the tankard bottom.
Is there a kind of formula to determine this, or more of a thing which is figured out by trial and error?

I plan on coating the inside of the tankard with wax which will hopefully seal up any small gaps, but I would still like to get it as tight as possible.

Can anyone direct me to an internet source with detailed coopering instructions, or share their coopering knowledge with a beginning novice?

Any help is appreciated

Iain

 

[paulvallandigham]

I am not a cooper, but I have asked all those same questions of others who are coopers. The angle varies depending on the diameter of the barrel or mug you are making, as well as the width of the staves. YOu have to work it out understanding that all circles have 360 degrees. If you want to use 1/2" staves, and make a tankard that is 4 inches in diameter, you would first figure out the circumference of the circle, by multiplying the diameter( 4) times PI( 3.1416) = 12.5664". Now divide the circumference be the width of your staves, and you see that you will need 25.1328 staves to complete the circle. Now, divide 360 by 25.1328 = and each stave much account for 25, 128 degrees of the arc, and if you divide that by 2, you get 12.564 degrees as the angle for each side of each stave.

Now, if you intend to taper the staves, so that the tankard has tapered sides, then you have to figure the circumference for both the TOP and the BOTTOM of the tankard, as they will be different, and figure the angles for each, Then, taking into consideration the height or length the stave are desired to be, the taper of the sides of each stave will have to slowly go from one angle to the other. Easy!

Remember, you are working with wood. Forming loops often made of steel were used to make the initial circle, and the wood staves were made a little wide so that in the final fitting, the last stave could be trimmed to size. This is often the stave to which a handle is fixed, so compare the size of that " handle " stave to the rest to figure all this out. That last stave wide enough to require being pounded down into place.

Probably the most difficult work for beginners is making the bottom and fitting it to the staves to that the tankard can be made water tight.

Try googling Coopering , or Barrel making to find materials on the step by step process you want. You do need some special tools, and Woodcrafters would be the place to go to to look for them. They may also have a book or three on copperage. Wooden Boat Magazine would be another place I would look for references to this kind of work, since there are so many people trying to restore, or make modern replicas of old sailing ships out on the East Coast.