Polishing fire engine

John Gavin <jwgowm [at] aol__com> writes

>Can anyone tell me the correct steps to take in cleaning our 1936
>fire engine? I've vacuumed it and plan to wash it with cotton cloths
>dampened with distilled water. Can I, or should I use some type of
>polish to remove old water marks, oxidation, etc.?

Cleaning the exterior of a vehicle without scratching the finish is
a real challenge. Vacuuming with a soft natural bristle brush is
normally the recommended first step in cleaning dirty artifacts but
in this case the brushing action could grind the dirt and grit
particles into the finish. Sometimes the worst of the dirt can be
blown off with compressed air. The best method is to flood the
surface with water and flow the dirt off, but this isn't normally
possible with indoor collections and there is always the danger of
water working its way into crevices that are no longer weatherproof.
The next best thing is to mist small areas (i.e, one square foot at
a time) with a plant atomizer filled with distilled water and a drop
of liquid detergent, followed by wiping with a damp cotton cloth or
chamois. Use as much water as you see fit; enough to soften and
dislodge the dirt while controlling the run-off. Repeat with a clear
water mist and dry with a clean chamois or cotton cloth. Make sure
they're perfectly clean, otherwise they'll act like sandpaper on the
finish.

You can try a number of products to remove water marks and other
stains. Start with a soft white vinyl eraser (e.g.,Staedtler Mars
Plastic  526 50, or Faber-Castell Magic Rub1954). If that doesn't
work, try a commercial polish designed for acrylic plastics like
Plexiglas. Plexi is probably the most vulnerable surface you'll find
in any industrial collection. As a rule, if a product won't damage
Plexi, it won't harm any finish. (We test the abrasiveness of metal
polishes here with squares of clear Plexiglas, by the way.) Try the
Novus cleaners and polishes (Nos.1 & 2) or Meguiar's Mirror Glaze 17
Professional Plastic Cleaner or No. 10 Polish. The latter are
apparently used on modern aircraft canopies and they're popular with
aviation museums.

As for overall oxidation, you may be better off leaving it alone.
Once you start polishing, you could find yourself doing the entire
vehicle in order to get a uniform appearance. It's your call.

George Prytulak
Conservator, Industrial Collections
Canadian Conservation Institute
Ottawa, Ontario, Canada

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                  Conservation DistList Instance 12:81
                  Distributed: Tuesday, April 20, 1999
                       Message Id: cdl-12-81-008
                                  ***