Hi Rusty, yes, 304 stainless is more difficult to weld and the material is more brittle. Not that any of these traits can be overcome but 4130 is just plain more durable and forgiving. That is why it has been used in aviation for so long. Welding stainless properly is an art. Weld pool contamination is generally the most common problem. If you can shield the other side of the weld pool from the atmosphere you will have great success is weld strength.
Doug Mueller
RX-6 13BT
N900DM
Boulder City, NV
 

Russell Duffy wrote:

 Greetings,As I ponder my choices for mounting the single rotor engine, I noticed something that surprised me.  304 stainless is cheaper than 4130 steel.  One thing that's always bothered me about steel tube type construction is the concern for rusting inside the tubes, so stainless is appealing.  There must be a catch here. Is there a good reason I should use 4130 instead of 304?  Either will likely be sized much larger than needed, since I don't have the means to do any proper analysis of the strength. Thanks,Rusty (Autoflight drive supposed to be shipping next week)