Material for block casing

[mariner2k]

I have a number of blocks with bronze sheaves,bearings and beckettes. The casings are falling apart. Any suggestions for casing material or a supplier of casings?
thanks,
kevin

[Todd Bradshaw]

You can mix epoxy resin with a fair amount of graphite powder and get a pretty tough plastic, similar to what is used on graphite fishing reels. On the other hand, why not skip plastic, use the hardware you already have and make some nice wood-shelled blocks. They're not particularly difficult to make, work well and look great.

[ScottO12_3]

In your nape of the neck, err woods, elm should be plentiful and it's traditional. The gnarly grain makes for some tough, good looking blocks. I just made a fleet of blanks that are waiting for a little (lot) of shaping.

Elm will also demand that you practice the art of sharpening.

[Mrleft8]

Hackberry would be a good choice too.

[Jay Greer]

The origional Merriman Wood Shelled blocks used Lignum Vitae for the shell cheeks with an ash separating core.
JG

[woodspars]

Hey, Todd.

Would simple colloidal silica or Cabosil (sp?) do the trick? Or is graphite the only option?

Thanks

-Tyler

[mariner2k]

Thanks,
Is there any info available on making the wood shells?

[Todd Bradshaw]

There should be several old threads here on the forum about block making with photos, etc. so that's a good place to start searching.
http://www.imagestation.com/picture/sraid177/pecf07613f889c161715ad8b59ac25a5a/f33b0bc8.jpg

http://www.imagestation.com/picture/sraid177/pe3a71883ab47cd19fbe8383a05c6d336/f33b0bdc.jpg

Colodial silica would probably work, but might be tougher to shape if you have to do much carving because it's pretty hard. Graphite powder has the advantage that once you get above 10%-15% graphite in your mixture it will stop UV at the surface, so your home-made plastic has less chance of deteriorating in the sun. Sooner or later, it's worth buying a can of graphite powder anyway. For those times when you mix more resin than you find you needed, dump a bunch of graphite into the excess, mix it up and pour it into a small container where it can harden into a block. The angled pads under these winches were made from blocks cast that way in the bottom of a small plastic tub (a cheese spread container, if I remember correctly).

http://www.imagestation.com/picture/sraid122/p7d3bf271f4955813dc1bda8a7d9d42a1/f838f9df.jpg

I don't measure it, but usually use a fairly graphite-rich mix and you can also add some cabosil (maybe 10%) if you want it to be a bit more abrasion resistant. Teflon powder would be neat, too, but I don't have any. The dumb sheave at the top of my Star's mast was built from a graphite/cabosil block and stood up pretty well to the wire halyard and every once in a while you find a use for a small hunk of high-quality plastic stuff, so it's nice to have some sitting around, ready to machine.

[Andrew Craig-Bennett]

Mirelle has elm block shells, because they were "ship blocks" and as such very much cheaper than ash shelled "yacht blocks" when she was built, in 1937. She still has them, now. Its pretty good stuff, and I have found that if you drop them into a can of Deks Olje no.1 for a couple of weeks they soak it all up and seem to stay that way for many years.

I've made some blocks myself, using ash, and also apple, which I have found to be a very good choice - it's tough stuff, and also repsonds well to the Deks Olje treatment. The slightly pink colour is a matter of taste, but I like it.

It is an easy job to make new shells for old internal strop blocks. You should be able to prise the "remains" apart carefully enough to use as patterns for their replacements, and by using two or four thicknesses of stock at a time when sawing out you can "mass produce" them.

Trivial fact - probably the first production line in the world was built by Marc Isambard Brunel, father if IK Brunel, to make wooden blocks for the Royan Navy.