4130 Elliptical Tubing

Ted

Ted

The pilot formerly known as Twin Engine Ted
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The step is broken on the 310. I can have the tubing on there re-welded, but would be happier buying new tubing so it can be welded cleaner. Only problem is finding it. I may be using the wrong term, but I'm pretty sure it's not streamline and it's definitely not circular (see picture).

It's 4130, but it's elliptical/oval, which nobody seems to have. Dimensions (measured) are 2.292" x 1.138", 0.1" thick. I'd like about 3-4 ft, but probably only need 2 or so.

Any leads appreciated.

IMG_00000108.jpg
 
I've welded a lot of 4130. I don't know how much of it you have done, disregard if you have your own process.

I always pre and post heat. For tubing maybe 200-250 degrees pre-heat and a slow cool with maybe a blanket to finish. This isn't called out for thin wall, but I have seen too much cracking from 4130 hardening not to.

Use gas or tig (slowly). I never use mig on 4130, guaranteed cracking IMO.

I use ER70S-2 mild steel rod. The lower carbon content keeps the weld more flexible and prevents cracking. You still have 70KPSI so no issue on strength.

I never have any issues with 4130 hardening or cracking using the above.
 
I have no welding process and am a crappy welder, so I try to avoid welding anything that matters. I was going to pay someone else with a TIG to do it and do it right.

Maybe I need to mail it to you, Alex. :)
 
Ted DuPuis said:
I have no welding process and am a crappy welder, so I try to avoid welding anything that matters. I was going to pay someone else with a TIG to do it and do it right.

Maybe I need to mail it to you, Alex. :)
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If it's UPSable, I'm glad to do it for the only price POAers believe is acceptable for such work.:)

Seriously, no problem if I can help you out.
 
Henning said:
Neat stuff, but that's not what the 310 uses, it's just an oval. Louisiana Steel has his stuff.
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Maybe not.

We manufacture elliptical steel tubing in a wide range of sizes including 2.000” to 12.000” major axis and .750” to 10.000” minor axis with wall thicknesses ranging from .049” to 1.000” thick. Elliptical tubing can be produced in a variety of materials including carbon, alloy, stainless, and exotics.
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Sounds a bit large for the application.
 
3393RP said:
Maybe not.



Sounds a bit large for the application.
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It's 4130, but it's elliptical/oval, which nobody seems to have. Dimensions (measured) are 2.292" x 1.138", 0.1" thick. I'd like about 3-4 ft, but probably only need 2 or so.
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We manufacture elliptical steel tubing in a wide range of sizes including 2.000” 2.292" to 12.000” major axis and .750” 1.138" to 10.000” minor axis with wall thicknesses ranging from .049” .1" to 1.000” thick. Elliptical tubing can be produced in a variety of materials including carbon, alloy, stainless, and exotics.
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How so? These numbers fall right in there from my reading.
 
Last edited:
Well! I misread the OP's post. I try not to appear as a dumb*** with my posts but didn't succeed this time.

:rolleyes:
 
Henning said:
Louisiana Steel does stuff like that, www.louisianasteel.com
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Well, they had nothing in inventory even close to what I needed, and said that I'd be subject to their setup fee of $3,000.

So that would make the new part look cheap. Back to square one...
 
Ted DuPuis said:
Well, they had nothing in inventory even close to what I needed, and said that I'd be subject to their setup fee of $3,000.

So that would make the new part look cheap. Back to square one...
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Ted-

Let's see some more pictures. Is it repairable with a sleeve? Would mild steel work?
 
I'll take some more pictures of what I have at home tonight. It's about 2 ft long, bit more. Issue is the shape needs to be kept consistent and I don't want it looking like crap once installed back on the plane. Also, steps are contoured to the arm.

What one person had suggested was to put a round tube in that would fit snugly, and get some more welds to help give extra support. I like this idea, but it also can't be too much heavier, or else the step will be too heavy to retract.

I think mild steel would be fine, just need to be painted to keep it from rusting.
 
Ted DuPuis said:
I'll take some more pictures of what I have at home tonight. It's about 2 ft long, bit more. Issue is the shape needs to be kept consistent and I don't want it looking like crap once installed back on the plane. Also, steps are contoured to the arm.

What one person had suggested was to put a round tube in that would fit snugly, and get some more welds to help give extra support. I like this idea, but it also can't be too much heavier, or else the step will be too heavy to retract.

I think mild steel would be fine, just need to be painted to keep it from rusting.
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4130 will rust also. If mild steel we could coat inside and out with u-pul weld through primer (good stuff), then with a good topcoat it should outlast both of us.

The other idea was aluminized oval exhaust tubing. I just don't know if you can it that small.
 
Ok, here are a few more pictures that shows you what I'm dealing with. Obviously the bad end will need to be ground down some to make a good mating surface.

Also, two of the steps have cracks in them that should be welded now. May not be visible in the picture.

IMG_00000111.jpg
IMG_00000112.jpg
IMG_00000113.jpg
 
Hmm. Now the real question is whether that will fit...
 
Ted DuPuis said:
Ok, here are a few more pictures that shows you what I'm dealing with. Obviously the bad end will need to be ground down some to make a good mating surface.

Also, two of the steps have cracks in them that should be welded now. May not be visible in the picture.

View attachment 32503
View attachment 32504
View attachment 32505
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Why not call around the junk yards and see what a whole assembly will cost to just stick in there since your's is kinda busted up?
 
Alexb2000 said:
So it's a little hard to tell, was that step repaired before? The end looks pretty rough.
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I was thinking the same thing. If you can find a replacement step that is reasonably priced that might be your best option.
 
Pretty much all used steps will be pretty rough.

Here's the other issue, of course - Cessna changed the step over the years, my guess is because I wasn't the first to have one fail. Compared to that one, mine has some extra metal for support. The R has more still. I need to look at the plane this weekend and see if I think the R step would fit, that might be my best bet.

I'm also going to call a few other salvage places today and see what I can find.
 
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