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Posted by: Tom Daniels 9/16/2008 9:15 PM
If you came into the shop 2 weeks ago, and then again today, you'd know that something was different but you might have a hard time putting your finger on it.  That's because most of the work we've been doing has been the detailed, small work that goes into getting everything to fit together nicely.

Take the ballast keel plug.  Karl has been working on it outside because he's doing the final fairing and smoothing.  This involves a lot of sanding and the application of Bondo, the auto body filler (pee yew!)  The goal is to have a perfectly smooth plug for the foundry to use when casting the ballast.



With the ballast outside, it's easier to get a sense of how BIG this thing really is.



After all, it will weigh close to 6,000 lbs when it's cast.  The pink coloring on the wood is Bondo.  It' dries fast and sands like a dream.  Karl sands for a bit, looks for low spots, and fills them with Bondo.  Then he sands again, making sure that the low spot is now filled and blends smoothly with the rest of the ballast.

Once he's happy with the shape, he paints the ballast.



The paint masks the grain of the wood and makes it easier for the eye to follow the curve of the ballast.  This allows him to see any subtle humps and hollows in the shape that previously might have been hidden by the distraction of glue lines and grain patterns.  

He sands this again to get an even matte finish on the paint.



A little more marking, a little more filling, and the shape will be perfectly smooth and even.

Not the kind of thing that smacks you upside the head when you walk in the shop, you know?

More small but critical steps in the next entry!
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Re: The progress that's not immediately apparent    By Kent on 9/19/2008 12:20 PM
Is the comments function on here new? If so great addition!

When you create the plug for the ballast keel, is there any effort to oversize the plug in anticipation of the shrinkage of the casting? Is the shrinkage minimal? I can't remember if you had already noted it, but is the ballast keel going to be cast lead or cast iron?

Re: The progress that's not immediately apparent    By TomDaniels on 9/19/2008 12:25 PM
Kent,
We'll be testing out the comments section to see how it goes. I'll need to approve comments before they get posted to keep spam from creeping in, and if the spam load gets too heavy we may drop it.

As far as shrinkage goes, we ignored it. Some folks (Alan Vaitses for one) recommend adding for shrinkage, and pattern makers even have a special ruler called a "shrink rule" that they use when making their patterns to compensate for shrinkage. For a funky, flowing shape like the ballast, it seemed too complex and uncertain to try to build in shrink rules, so we went with what the lofting gave us. We'll let you know if this was a good idea when it comes back from the foundry!


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