I am hopeful there are few of you out there who share a penchant to stand out
as different. If so, read on.
When the heat shield kit for the 100-M arrived from Moss, both my restorer and
I felt it fell way shy of the mark. The boards were about 1/2 the thickness of
the originals, were glass smooth and grayish vs buff in color due to the
masonry refractory used today. One of the longer pieces had cracked in
transport, so we had decided to return them for credit and start out making
our own -- that is, until, I walked past the boxwood near our front door.
You see, the original shields have a very nice 'burlap' texture pressed into
the exposed side. I believe from talking with furnace men that refractory
shielding is a slurry of asbestos and masonry (gypsum?) binder which does not
model very well. To keep the air entrained for insulative value, yet achieve a
relative smooth surface, it was necessary to press-mold shielding with a board
backed with several sheets of absorbent, porous cloth. On the BN-2 Healey
shields we took off the M, clearly original, the shields were pressed between
cloth-backed boards,probably paint-sealed canvas on the smooth side, and
absorbent burlap on the other to press out the water with minimal pressure.
What does this have to do with our boxwood? Well, you see, I didn't have time
to send the shields back to Moss and cast about for an acceptable substitute
(we're miles from the nearest Home Depot where they sell Hardy Backer, and the
glass blowing studio which sells board for its blowing furnaces is 75 miles
away), so I decided to work with what we had. Since one of the Moss boards
needed repair anyway, and all of them were too thin, I decided to repair the
one and build the thickness of all by screeting a 1/8" of buff colored masonry
cement on each side, press in plastic bug screen and smooth over. This worked
well, but the texture was a little off.
So how you get a burlap texture. Walking past the boxwood, the answer was
obvious. Afterall, I'm a New Englander and nothing gets thrown away. And even
with the Artic Snap we had in March, it was still time to take the burlap off
the boxwood. A little moldy, but nice texture. I cut up enough in strips, ran
them through the wash, and mirabile dictu, perfect heat shield texture. On all
but the one that goes under the floor board, I pressed the burlap into another
coat of furnace cement, then sponged off the excess to expose the weave.
Lightly sanding, I sponged on two more coats, watered down a bit, until the
surface was identical -- I mean identical -- to the achievements in absestos
of post-war English industrial ingenuity.
Water resistence was confirmed when my wife pointed out several white globs on
the sink and counter where the Tranformation occurred. It took a blunted knife
and several minutes to chisel out the furnace cement, despite copious
applications of hot water -- more than all the steam your Healey Steamer will
generate in a 100 Texas summers.
Proudly displaying the grotesquely deformed shields to my restorer, I received
a silver, but the gold commendation eluded my efforts on the issue of color. A
little too yellow, he opined. This was quickly remedied with high heat paint
of the appropriate buff off-white color, almost identical to the unsmudged
portions of friable asbestos intact on the original shields.
Concerns for rot in the encapsulated burlap on the underfloor prompted a
variation. I applied a coating of cement, then pressed in a damped piece of
the burlap, removing it after a few minutes, leaving the design pressed in.
Light sanding removed the peaks.
This has led to a new obsession: developing the most arcane means of
heatshielding the rest of the compartment. I wanted to keep our carpeting
looking old and mean, with no fat underlayment like you sometimes see. The
idea of shielding the underside of the tunnel and firewall pieces on the
outside is under development. I have laid woven fiberglass cloth on the
concave (outer) side of the tunnel, modeling the cloth and cutting to fit the
curves, the pieces held on the outside by tape. I've bought another furnace
cement, this one with the promising notations "DANGER - CONTAINS FREE SILICA".
The texture is much like asbestos jacketing on old boilers and pipes. You are
supposed to lay this stuff up with dampened rags to help model the surface
without compressing the air entrainment. Sounds really good. I'm half done,
and the result is a shell like a plaster cast which is rigid, and readily
removes with the fiberglass backing intact from the tunnel. When done, I think
I am going to use the more plastic beige cement, and line the exposed (under)
side with tarpaper stuck to the cement for a truly waterproof shield, readily
removable, and provided good clearance from the tranny. If this succeeds, I
will repeat with the moveable firewall piece. My restorer has supplied a
template for the firewall section above the steering tube on the inside, and
we are considering a similar 3/8" insulation piece to fit on the compartment
inside, this time tarpaper facing inward consistent with the original
appearance.
So there it is, simply worded in as little space as possible.
Allen Miller
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