> > > <Big Snip>

 > >
 > > > >
 > > > > What alloy do you guys use?  SS (like 321) will

fail much more

 > easily at
 > > > > 1700 than inconel; especially if under any stress

loads.  It gets

 > > > > inter-granular stress corrosion and loses it strength.
 > > > >
 > > > > Al

 >"Del Johnson, North Point Solutions, Inc" wrote:
 > >
 > > Inconel is really costly if you only need small quanitites.
In December I
 > > purchased some aluminum tube bends from a company in Michigan.
I asked the
 > > salesman if they deal in Inconel.  He said that if your only
buying a foot
 > > of tubing for a 90 degree bend it might cost $100 for the raw
material but
 > > if your talking 50 or a hundred feet of the material the costs
comes down
 > > dramatically.  I asked him to give me a price quote on

some 90 degree

 > and 45
 > > degee bends plus some straight material for 10 exhaust

systems and 50

 > > exhaust systems (I guessed on quantities of bends and straight
pieces) and
 > > told him that we might be able to put together a quantity
group purchase.
 > > He emailed me the prices but they don't seem to be in my
inbasket anymore.
 > > The prices were a lot cheaper than Burns Stainless (they only
have a large
 > > radius 120 degree bend).  If there is interest in going
together on a group
 > > purchase I can contact the salesmen and get another quote.  My
problem is
 > > that I'm not at a point of knowing what I/we need for bends.
 > >
 > > I was able to pick up 120' of 1.5" inconel and some filler rod
very cheap.
 > > The guy that does my welding is going to practice on a small
piece of it.
 > > He might be interested in welding up exhaust systems if we could
 > standardize
 > > on the design.  He is an machine shop and welding instructor
at the Lansing
 > > Community College but has his own equipment so he can do jobs
on the side.
 > >
 > > Let if there is interest in a group purchase.  If I get

enough positive

 > > replies I will look get back with the salesmen to see if he
can resend me
 > > the quote which will give us an idea of what 90 and 45 degree
bends cost.
 > > We will have to get a final quote from them if we decide to go
ahead with a
 > > group order.  There are going to be different requirements for
Turbo vs NA
 > > and 13B vs 20B.  The salesmen will give us a cost per

bent/type and the

 > cost
 > > of straight tubing so it doesn't matter if there are

4,5...n number of

 > > designs.  The more bends that they do of the same type the
cheaper per bend
 > > it becomes so if we can standardize on bend radius that would
be helpful.
 > > They can leave whatever lenght straight tail piece that

is needed. Also,

 > > they can bend down to a very tight radius.  He suggested 3"
radius as the
 > > minmum for 2" inconel tubing.

 > I would be interested in a group buy of Inconel tubing/bends.
 > Mark Steitle
 > 20B
 > Austin, TX

Although I don't need it as I am going turbo it might
be nice to have a few lying around so count me in.

Paul Lamar

I would like a couple of straight pieces for the internal stubs.
What  is the wall thickness?
--
Jerry Hey

When we get the number of interested builders together we need to go back
and get a quote based on the volumn of bends, straight pieces, etc that we
as a group want.  They will go to their inconel supplier and get whatever
stock we specify.  I was assuming 0.035 wall thickness based on previous
messages about inconel exhaust systems.

Del Johnson

I think .035 Inconel will do the job if the bend is not too close
to the engine and you don't run it too rich at cruise. Keep the cruise
EGT down to 1450 F or so. Also plenty of slip joints and other
flexible exhaust couplings.
 
Paul Lamar
 
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