| Jeff,
I initially used .140" 304 handrail bends for my exhaust system. I always worried about it though, especially when I would see 1850*F, or more on the EGT. It never burned through, but it did turn a deep grey color. I have since built a new tangential muffler using 625 Inconel and it still looks nice and shiny, almost as nice as new. I don't worry about it burning through. My suggestion is to spend a few extra bucks on the exhaust and then don't worry about it when you're cruising along in the teens. You can buy 625 inconel bends on Ebay for about the same price as 321 SS.
Mark S. On Tue, Oct 19, 2010 at 7:22 PM, Jeff Luckey <JLuckey@pacbell.net> wrote:
I thought that people were commonly using 321 for Rotary exhaust systems
because it has a higher temp rating.
It's been a while, but I vaguely remember looking it up, and the max working
temps were something like this:
304 = 1200F
321 = 1600F
So, my question is, are people using 304 successfully for Rotary exhaust
systems. If so, that's great, because it's cheaper & more readily
available.
-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Ernest Christley
Sent: Tuesday, October 19, 2010 07:51
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: header parts source
Jeff Luckey wrote:
> Does Columbia now carry 321 stainless. IIRC, I pinged them about a year
> ago and they did not carry 321 stainless…
>
>
I also bought bends from Columbia. Their service and delivery was
excellent.
I don't see any mention of 321, but I wasn't really concerned about it.
Given the diameter of tube we have to use for
exhaust flow, and the thickness we need to contain the exhaust pulse, and
the corrosion resistance characteristics of
the alloys at elevated temperatures, I couldn't see enough of a difference
to stress over.
>
> ------------------------------------------------------------------------
>
> *From:* Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
> *On Behalf Of *kevin lane
> *Sent:* Monday, October 18, 2010 22:03
> *To:* Rotary motors in aircraft
> *Subject:* [FlyRotary] header parts source
>
>
>
> I have been happy with Columbia mandrel bending. they make their own
> parts, family run, and significantly cheaper than burns.
> http://www.mandrel-bends.com/catalog/
>
> last week I finally got the v-band, another 90°, a flex joint, and
> muffler added to this header.
>
>
>
>
>
> KevinLane Carpentry
> www.KevinLaneCarpentry.com <http://www.KevinLaneCarpentry.com>
>
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