Tuesday, October 9, 2018

Finishing a pew

Last week Spike's blog post highlighted the completed pews being installed in chapel car 5 Messenger of Peace.  This project included the process of thoroughly documenting the original railroad car pew design and making 10 replicas for exhibit in the Messenger of Peace. This week we are illustrating a little more detail about what was involved in finishing the pews.

First of all, OB Williams did an awesome job of fabricating the pews.  They arrived sanded and all ready to accept finish.  There was some minor sanding involved to catch a few imperfections, and then a thorough vacuuming and wiping to remove wood dust and any other contaminates.  The first of seven to nine coats of shellac was applied using a bristle brush.  (The Museum has experimented with air application of shellac, and the results have not been consistent.  So most finish work is done with a brush.)

One of the most obvious changes that occurred in making the replicas was the color and apparent texture transformation from unfinished wood to finished wood.  Just one coat of shellac deepens the color of the wood and begins the process of sealing.  Initially, the surface feels rough.  Light sanding with 400 grit sandpaper - and more sanding with 220 grit if flaws are found - renders the surface smooth.  However, a unique characteristic of shellac is that is can be redissolved in alcohol.  So any subsequent coats are bonded to the earlier coats.  And subsequent coats can benefit from presanding, but it is not required.

Each pew component was finished separately.  When 7 coats had been applied, the finish was evaluated for consistency.  If any flaws were detected, they were corrected with sandpaper - or, sometimes even 0000 steel wool - and another coat of shellac was applied.  The process was repeated again if necessary. 

A beneficial characteristic of shellac is that it dries very quickly.  However, particularly after several coats have been applied, it must sit for a day or more to fully harden.  If subsequent coats are applied too soon, the surface will wrinkle and it is difficult to correct.  Notwithstanding, the pew project is now nearly complete and the results can be viewed through the chapel car's sanctuary door during regular hours of the Train Shed.

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