Stanchion Bases
We have been asked several times how Chris went on with anodizing our various fittings. Some of these photos have already been featured in the blog, so this is a brief re-cap. Immediately above is a photo with a reanodized stanchion base in the foreground and a brand new stanchion base in the background (we had to buy a brand new one in order to find the one we had misplaced that should have gone there). You can see that there is a difference, but it doesn't jump out at you. Above that is a photo of a hinge before and after anodization.
Cleats: above = before, below = after
This is how Chris explained it in the emails he wrote:
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"The aluminum fittings for the Prouts are made by Holt Nautos. I can find all the fittings but the engine cover hinges at UK Marine Chandlers (Import duty to the States is low to none existent) but replacing them all cost too much for our budget. So we polished our original cleats, locker hinges and stanchion bases up to about 1000 grit wet and dry sandpaper.
The anodizing process is then fairly simple.
1) Buy battery acid and dilute to about 50% with distilled water in a PVC container. Lots of people seem to use old coolers, we used a battery box.
2) Make a cathode of approx 1 sq ft area from aluminum bar. Some people use lead as a cathode but this can color the work piece because of impurities.
3) Scrub the aluminum piece to be anodized in warm soapy water and dry.
4) Hang the anode (piece to be anodized) in the bath on aluminum wire from an insulated bar (wood, acrylic)b
5) Connect the cathode (-ve) and the anode(+ve) to a 12v battery charger
6) Leave in the bath for about 12 amp hours per square foot of work piece. ie if a cleat is about 1/2 square ft and it is anodizing at 3 amp leave for 2 hours.
7) Remove and wash the piece (don't touch!) and hang in gently boiling water for 45 mins.
You will see some gassing at the cathode but very little at the anode. If you leave the work piece anodizing too long the current will rise and gassing will start at the anode. Then the piece has reached dissolution point and you should stop the anodizing process immediately.
Our fittings are cast aluminum which is the worst type to anodize as it contains more impurities which affect surface texture and color (can come out with a yellowish tinge). Ours generally came out looking slightly duller than they went into the bath but with a definite sheen and a very smooth finish. They don't look like commercial anodizing but seem to have a very definite protective coating of aluminum oxide.
For more information try http://www.focuser.com/
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~ Blogger has changed the way it behaves and I haven't changed along with it yet. Apologies for the odd layout.
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