Real? Or Really Real? (Post # 49)

With respect to Historically Important Automobiles there is a lot of talk about "authenticity" and "originality."  These are surprisingly tricky words.  I prefer to consider the concepts involved rather than the words, which don't have precise meanings.   

We're trying to keep The Alfatross original but there are a lot of areas where that is clearly impossible.  I think we can all agree that not having the original spark plugs is not too big a disappointment.  Ditto the tires, headlight bulbs, the oil in the crankcase, the gas in the tank, the air in the tires.  At the other end of the spectrum it wouldn't be asking too much for the car to have original paint, exterior trim, interior, engine, wheels, tool kit, and other similarly fundamental items.

Then there's all the bits and pieces in between that are iffy . . . .  

After almost 60 years most of the rubber grommets, seals, weather stripping, and gaskets have given up the ghost.  Of course you can't find replacements at your local NAPA parts supplier.  After 60 years even most stocks of rubber "new old parts" are no longer usable.  Face it: with the possible exception of weather stripping you're going to have to make your own rubber parts. 

Yes, there are a lot of rubber pars in a car, and a lot of different types of rubber to do very different jobs.  Most of it has a a very limited life span compared to metals and even plastics.

Fortunately, molding and casting are not new skills that I have to acquire.  There's a lot of that in archaeology, particularly with objects found in the sea. In warm, tropical waters iron decays rapidly. As it does so a chemical reaction occurs which causes minerals dissolved in seawater to precipitate on the surface of the object forming an encrustation.  Sometimes relatively small objects literally dissolve inside the encrustation, but not before creating a perfect natural mold.      

All you have to do is break the encrustation apart, clean out the black sludge that is all that is left of the original iron object, dry it, put it back together, and inject the cavity with an epoxy resin.  After letting the epoxy set you carefully clean the encrustation off the epoxy cast to reveal a perfect replica of the original object.  

These "artifacts" from a ship that sank in the Turks & Caicos Islands about 500 years ago are actually resin casts made from cavities inside natural molds of calcareous deposits that formed around the original artifacts.  The detail preserved in these natural molds is astonishing.

Here's where the real vs. really real dilemma pops up.  Are those epoxy casts not "real"?  The original object is a black, stinking paste. You could pour it into a jar and save it because it's "really real", but why?  Compare the "really real" jar of sludge with the epoxy cast.  The cast is so perfect that it often includes the first layer of rust that formed on the object when it fell into the sea.  It is far more faithful and authentic to the original object than other iron objects from the same site that dissolve inside their encrustations--but it isn't "real" according to the dictionary.  

The rocks on top of Sapodilla Hill in the Turks & Caicos Islands are covered with inscriptions featuring names, dates, ships, flags, and even buildings dating back as far as 1767.  We made molds and casts of many of them.to preserve the information they contain.   One of these rocks is the original.  The other is a cast.  Which is which?  

We do the same thing on land sites to record ancient inscriptions in stone. We make RTV rubber molds of the inscriptions in the field, then cast them in plaster reinforced with a polymer resin.  The casts are then more durable than the original stone.  We discovered that if you spray them with a thin water-based color coat and let it settle, details emerge that were never visible before.  But the inscription casts are not "real"--they are better than real!  

Back to The Alfatross and its rubber parts.  So molding and casting is no big deal--but there's a catch. Synthetic rubber parts come in all sorts of different compounds: hard, soft, oil-resistant, photo-sensitive, elastic, stiff, foamy, solid--you name it, the variety is endless. So one compound does not fit all.  
The compound has to match the job's requirements.

And that's not the only complication.  The original parts usually can't serve and the "positive" from which you can make a "negative" mold for the casting of the final part because after 60 years they are wrinkled, cracked, swollen, shrunken, or otherwise no longer faithful to the original part.  So you have to make a replica positive that you then use to make the negative mold from which you can a rubber positive.  It's a long, tedious process that's worth while when you are making multiple replica parts, but very inefficient for just one!

What happens to original parts over time and exposure to solvents and the environment.  All these parts are the same.  Only the second from right retains its shape and dimensions.

So I have a lot to learn, and it's going to take another post or several to explain what I've learned so far though a series of experiments.  One thing is clear already: if you can find a reliable source for decent rubber parts, BUY THEM!  Don't try to make them yourself unless there is no alternative!