pdp1@EARTHLINK.NET on sun 1 feb 04
Hi Ivor, all...
Right...
Yet, the 'porcelainized' or enamelled Exhaust Manifolds were
common on many better Cars in some previous decades...
My little 1954 Nash I drove in hischool had a humble version
of a porcelainized exhaust manifold, ( a 'tube' more or
less, as ran along the one side of the side-Valve Engine,)
and certainly most or all of the upper Series G.M. and other
make large Series Cars did before the War...or through the
early 'thirties anyway.
I did read up on all this long ago and I do not remember the
particulars of the general formulas, or the patience of the
methods, which likely were proprietary anyway in detail,
but, in essence, the concern of the differential expansion
was very well answered, and many such Manifolds held up
nicely for many years, if not decades of use...eventually
spalling or flaking to some extent...or not, but only after
many decades or much use, when they did.
I almost bought a 1931 LaSalle awhile back, whose Exhaust
manifold was PERFECT and brilliantly glazed in a dark Green
I think, and, had never been redone, but had sat since 1947
in a shed...
My '33 Buick has a porcelainized (on Cast Iron) Exhaust
Manifold (in five sections I think, oweing to it's over
three feet of length) and , showing 84,000 miles, and
seventy-one years, has spalled about 60 percent of it's deep
Green 'glaze'...
Too, at four-to-one, or, four-and-a-half to one, five-to-one
even, the exhaust heats may have been someways kinder than
with more recent higher compression ratios...which I think
would have helped retain the compatibility of the Glaze or
porcelainization in use.
Best wishes,
Phil
Las Vegas
----- Original Message -----
From: "Ivor and Olive Lewis"
> Dear Pat Wehrman,
> Even if you fired the clay to the steel and it adheres and
did not
> spall during processing I think differential thermal
expansion
> between the two materials would cause serious problems.
> Best regards,
> Ivor Lewis. Redhill, South Australia
Ivor and Olive Lewis on mon 2 feb 04
Dear Phil,
Your Knowledge and Experience are appreciated.
Saw Bathtubs being done once at a factory in Scotland.
Do the Porcelain Enamel the bore of the tube?
Is the exterior coating to prevent the ravages of Oxidation?
would Plasma Spraying with some of the newer composite ceramics be a
better and cheaper option today?
Best regards,
Ivor Lewis. Redhill, South Australia
pdp1@EARTHLINK.NET on mon 2 feb 04
Hi Ivor, all...
Beeeeeelow, amid...(and not long either...)
----- Original Message -----
From: "Ivor and Olive Lewis"
> Dear Phil,
> Your Knowledge and Experience are appreciated.
Thank you...
> Saw Bathtubs being done once at a factory in Scotland.
Cool...what fun!
Had they a Kiln as the Tubs ran through on a conveyor? Or
were the Tubs loaded into the Kiln and a door closed and so
on , as with usual fireings? I think it was done both ways,
the conveyor Kilns being of the larger Mfg'rs method...or
eventually it was...
> Do the Porcelain Enamel the bore of the tube?
Oh, on my little Nash long ago? I do not know, I never
looked inside the 'tube' it had for an exhaust manifold (
being a side valve, the Manifold was like a 'Flute' in that
Nash design)...but, if I had to guess, I would guess not. I
would guess it was only on the outside...
> Is the exterior coating to prevent the ravages of
Oxidation?
I believe so. Or, if not the ravages, then at least the
appearance being more pleasant without the conspicuous and
tenacious
oxide, more than that the Cast iron would care so far as
it's
holding up over time. As the Cast Iron would tend to oxidize
more for being so often heated, than if not, my impression
is that the use of Enamelling was to allow the exhaust
manifolds to retain a clean pleasant appearance. Non
Enammelled exhaust manifolds would last forever anyway, but
would tend to look grungy, as they indeed do!
Too, many Intake manifolds used to be Alluminum or it's
alloys, then, as to cut some costs, the use of Cast Iron
became more common for them. In the 'twenties, and some in
the early 'thirties, most
(originally medium priced and 'up') Cars I have had any
experience with, had cast Aluminum Intake manifolds, and,
porcelainized Exhaust Manifolds...a very nice appearance for
these things to have...but the Iron Intakes soon were the
norm, and then the ubiquity.
> would Plasma Spraying with some of the newer composite
ceramics be a
> better and cheaper option today?
I would think it must...or could be adapted to, and with
some range of colors as likely. Whether cheaper or not I do
not know, probably not, as, anyone who can pour piss from a
boot tends to want to make a big deal out of it and get paid
a lot of money for having something someone may want done...
But...
I know nothing about any of that present technology as for
information or
experience...but, I would expect there should be recent
developements as would be excellent for the tasks. I think I
have heard of something as is used inside as well as outside
of the kind of exhaust headers one uses for hop-ups, as are
not (in this
case) Cast Iron, but are thin steel tubes, bent up to
whatever arrangement the lay of the Block's or the Cylinder
Head's Exhaust ports recommends for them, to then gather
into one tube and go on from there.
This is supposed to
insulate them, especially nearest the Engine, from the
Exhausts's heat, and also allow them not to turn 'blue' as
they tend otherwise to do... But I did not hear that the
colors were other than a flat kind of 'silver', so...kind of
boreing...but appropriate for modernish Engines for the most
part, where silver would look good for headers, or for an
exhaust manifold.
> Best regards,
> Ivor Lewis. Redhill, South Australia
Likewise!
Phil
lasvegas
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