By Staff
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The following comes from a recent topic on SmokStak, which can
be found on the Internet at: smokstak.cgi. As
ever, various individuals started, commented on and concluded the
following bulletin board thread.

Visiting the Coolspring power museum in Pennsylvania a few years
back, I noticed that most of the engines there looked smooth and
free of any pitting from rust. I was wondering how they make the
parts look so good and smooth; do they resurface the parts or put
some kind of filler on them, or just a really good, thick primer? –

Most likely they grind the castings smooth using a floppy type
grinding disk and then apply body putty over that. Then they use
fill coat primers followed by several coats of paint. As always,
the important work comes well before the pretty paint. – Doug

I’d advise not putting too much effort into smoothing cast
iron engine parts. Some engines do end up more pitted than others
(due to the elements), but original cast iron is supposed to have a
somewhat rough look and feel to it. Its slight imperfections are
what make cast iron from the olden days stand out as original.
Casting outfits these days remake parts a little too perfect.

I’ve seen many engines that have been sanded and smoothed
down to where the cast iron looks like glass. This is about as far
away from original condition for the engine as you can get. When
these engines came off the factory line the cast iron didn’t
look and feel like glass! In my opinion, engines that look like
this have greatly decreased value. These days, collectors want
engines in original condition. An engine that is over restored is
not original and it will not have the same value on today’s

I’ve been to Coolspring, and I’m not sure why some of
their really old/rare engines look so smooth. I do know they are
mostly restored and came from a single collector, so maybe that
person did a little over restoration. However, when you walk around
to the rest of the buildings, you’ll see many of the engines
are in original, unrestored condition and they have that slightly
rough casting.

In my opinion, I’d highly advise against doing what Doug
mentioned unless your engine has severe pitting you want to get rid
of. I believe there is nothing more damaging to a historical engine
than over restoring it to something it never was. Put on too much
primer, put on too much paint, but don’t grind down that
original roughness and putty the whole thing up. You can always
recover an engine from too much paint, etc., but you can never
bring back the original surface and feel once it has been sanded
and ground away. – Jeff

I have an 8 HP Field Brundage engine I bought 35 years ago. At
that time the thought was to sand blast down to bare metal and
start over. I wouldn’t do that to that engine today, as it had
a lot of original paint, even though it did have a tapped hole in
the hopper for 1-inch pipe to circulate water to another tank. The
original finish was smooth, and while sand blasting it you could
see a thick layer of some type of filler used to fill in casting
imperfections. This was a quality engine, and I think most engine
builders made some effort to turn out a nice looking product. I
took the effort when I restored this engine to fill it and sand it,
and it looks smooth, just like it did originally. Don’t be too
quick to judge. -John

‘There is nothing like an old engine all slicked up
sparkling and bright. I just stand there in amazement as to all the
hours of labor it took to get it that nice

There is nothing like an old engine all slicked up sparkling and
bright. I just stand there in amazement as to all the hours of
labor it took to get it that nice looking. That’s on top of
what it has taken to mechanically restore it. My engines start out
all slicked and shiny and I even use car wax on them, but they
don’t look like that for long because I like to run them.
That’s another reason I like them slicked, they clean up
easier. – Ken

I have never been to the Coolspring museum, but I have seen some
pretty big engines (100+ HP) and one thing they pretty much have in
common is they were used inside to power cider presses, line
shafts, pumps etc., and they were permanently mounted. With that
said, it is easy to why they wouldn’t have any pitting after
having spent 75 to 100 years sheltered compared to an FM Z that
spent the last 40 years out in the fence row. Other than casting
roughness, these sheltered engines would appear pretty smooth. –

I have never seen an engine in original, unrestored condition
with castings so smooth they looked like glass. However, I have
never heard (or considered) that original manufactures took the
time to putty up their engines to make them look smoother. I have
seen many an engine with 90 percent original paint, stored inside
all their life and with little wear, and they all have a slightly
rough look and feel.

We have a 6HP Mogul that most likely never sat outside. It has
smooth flywheel surfaces and the oiler and gas tank look like they
were just riveted yesterday, yet the flywheel spokes, hopper, and
base all have a slightly rough feel. We lightly sanded and brushed
off the old red paint (even saw slight remains of the original pea
green paint), applied a light solution to clean off the dust, and
then put on primer and a few coats of paint. The engine looks
great, yet it doesn’t feel as smooth as glass.

I think there might be a mix up about what degree of smoothness
we are talking about here. Original castings are all pretty much
smooth, but they also have a slight roughness to the touch. I
don’t think the surfaces should be as smooth as glass, and I
also can’t imagine that many companies put on a layer of putty
over their castings before painting. Of the 100s of engines
I’ve seen, touched and restored, I’ve only seen a few that
were restored and looked and felt as smooth as glass – and in my
head I thought the engines couldn’t have originally been like
that. – Jeff

I also prefer the original cast look. Remember the ‘help
with Simplicity’ thread that ran March 1? Take another look at
the picture – the black areas have a thick putty-like filler over a
very rough casting.

In the grease protected areas, the paint is almost automotive
smooth over this filler, and on the base flange where I cleaned
away some of the grease you can see the original dark olive

I’m using a side grinder some places and a sanding disc in
others while trying to retain the best cast appearance. This
experience tells me that maybe the engine builders did use filler
to cover rough castings. – Ralph

I agree with both sides -most engines are best restored back to
original condition. For example, I wanted the little Ironwood I
just finished to look like it did when originally finished by some
young boy at Ironwood High School. I did remove the forging
‘frost’ that was under the original paint prior to
repainting and I removed most of the pattern tabs, however. Even
the hopper opening is rough and irregular and it will stay that
way. In this case it is part of the history of the engine. The
builders were not professionals and the engine reflects that. Some
of the expensive engines – including many sideshafts – had a fancy
factory finish and should, in my opinion, be restored accordingly.
– Dean

Some manufactures did not take any pains removing flashing or
pimples, and most engines I have collected needed some sanding and
filling. When I restore an engine, I finish what was probably a
production process of cleaning flashing and grinding high spots. I
do use body filler to slick the finish up, and my reasoning is that
it makes the engine easier to clean and highlights the lines the
engine manufacturer designed into the engine. If you look at some
of the old ads the engines appear clean and streamlined, while in
reality they were not. Looks sell, and I like to see a smooth,
streamlined engine. If people take the pains to do that, then
normally they are as meticulous about the mechanical restoration. I
don’t collect engines to sell, so If I buy it, it’s because
I’m going to keep it. I do slick mine up a bit, but not like a
new car finish. I’m going to keep doing it, too, but to each
his own. Our main objective is to preserve these engines. – Pat

‘I have never seen an engine in original/ unrestored
condition with castings so smooth they looked like

The above messages and many more can be found by visiting
SmokStak on the Internet at

SmokStak is an engine conversation bulletin board with over
46,000 messages on file and is part of the Old Engine series of web
sites that started in 1995 as ‘Harry’s Old Engine.’
Harry Matthews is a retired electronic engineer and gas engine
collector from Oswego, New York, now residing in Sarasota,

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