Mailing List flyrotary@lancaironline.net Message #62447
From: William Jepson <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Welding Update
Date: Wed, 13 Apr 2016 12:00:18 -0700
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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Dave,
Using the propane torch is OK. This is all you can do if the parts are still together. It is also a great idea to preheat many parts if possible. (Super important if you do TIG aluminum welding.) Check some of the suggestions in a welding book for the needed temperature. You might need MAAP gas to get the area hot enough. If you do a fully welded engine mount from scratch it is suggested, (if you use 4130 Chr/moly), to heat treat the full assembly. The need can be overstated, since we are in the era of litigation all literature will suggest the max! The thing is the high strength steels are more prone to notch sensitivity and crystallization. I really like the racing books from Carroll Smith. Great advice and practical too. I love his "Engineer to Win" for down to earth engineering advice. Great metallurgical advice. Amazon has all his books. I love my TIG. The only way to weld!
Bill Jepson

On Wed, Apr 13, 2016 at 11:39 AM, David Leonard <flyrotary@lancaironline.net> wrote:
on gosh,  that adds another wrinkle...  Can I use a generic propane torch?

Dave Leonard

On Tue, Apr 12, 2016 at 5:09 PM, William Jepson <flyrotary@lancaironline.net> wrote:

Dave,
The tig is great. One thing to remember is to anneal the area around welds whenever possible. Tig allows you to weld many metals but annealing prevents cracking right next to the weld later. If it is a motor mount it is a good idea to shot peen as well.

Bill Jepson

On Apr 12, 2016 5:02 PM, "David Leonard" <flyrotary@lancaironline.net> wrote:
Charlie,
Your post below reminded me that I wanted to thank everyone who suggested I get a TIG system rather than some other form of welding set-up.  After getting up to speed on the benefits of the different types of welding, it is clear that TIG was the only solution for my needs (most versatile and most appropriate for the lighter gauge metals used in aircraft).  After spending a couple weeks learning to not destroy everything I touch with it, I can finally create ugly looking things that would loosely fall into the category of a weld.  But is is fun, and great to have the ability to fix a lot of things that were previously thrown out or limped along with JB weld.

I have been able to repair cracks in my exhaust system and beef up my 4130 engine mount, not to mention a ton of projects at home.  

Wish I did it sooner.

David Leonard

On Tue, Apr 12, 2016 at 3:28 PM, Charlie England <flyrotary@lancaironline.net> wrote:
Several years ago, some rotary users tried various flattened exhaust tips, as seen on a lot of European homebuilts. (Supposed to help with making exhaust tone less irritating.) IIRC, everyone found that the rotary would destroy the tips very quickly. Well, while walking through the Fantasy of Flight museum about a week ago, I noticed these tips on (IIRC) a P-40. Looks like they maintained a curved shape but were still able to have the pinched outlet. Don't know if it would actually work with a rotary, but it should have a better chance than the purely flat tips.

Charlie

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