Quality mild steel

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amv8vol

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Some of the parts for my project call for mild steel not 4130 but in 1020, 14 -20ga thickness. The problem is I cannot find 1020 at sheet steel, plenty of 1020 DOM and 1/8" and above plate but nothing in the thinner gauges. Does any one know of an online supplier for quality mild steel?
Thanks
 

dcstrng

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Not being an engineer or metallurgist I could be all wet, but for our size aircraft couldn’t one substitute 4130… I tried to find it as well, but couldn’t… I know we’re on iffy ground to go from 4130 to mild steel without consulting a structural expert, but going the other way I always presumed was safe in small craft…

PS -- like your build-site !
 

TFF

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You pretty much have to accept 4130 as the sub. The other stuff is not available unless you buy a shipping container full.
 

amv8vol

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The problem with 4130 is that some of the parts are to be brazed on and not welded and I believe 4130 should not be brazed.
Thanks
David N
 

TFF

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Two schools of thought on brazing 4130; both have points, and both have parts in service. Cant build a Tailwind from plans without brazing 4130. The mild steel like that just does not exist anymore. You could buy up a wrecked pre WW2 Cub or Taylorcraft and harvest metal but that is the only real way. 4130 put thin 1020 out of business.
 

Hot Wings

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The problem with 4130 is that some of the parts are to be brazed on and not welded and I believe 4130 should not be brazed.
Thanks
David N
There is no reason 4130 can't be brazed. In fact it can make a better joint in some situations as there is no HAZ if the proper rod is used allowing the 4130 to be kept below the critical temperature during the process. Once brazed it can never be welded.
 

Hot Wings

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The ribs on Dyke Delta are thin stainless sheet, silver brazed.
Reminds me that I should have mentioned that what most people, and me when being imprecise :emb:, call "brazing rod" normally melts at above the critical temperature of 4130 resulting in the same HAZ as if the steel had been welded. The material needed to "braze" 4130 at a low temperature is more properly called silver solder. It's generally more than 50% silver with a bit of cadmium, zinc, and nickel in the mix.
 

BJC

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Reminds me that I should have mentioned that what most people, and me when being imprecise :emb:, call "brazing rod" normally melts at above the critical temperature of 4130 resulting in the same HAZ as if the steel had been welded. The material needed to "braze" 4130 at a low temperature is more properly called silver solder. It's generally more than 50% silver with a bit of cadmium, zinc, and nickel in the mix.

...and it is expensive.


BJC
 

BBerson

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image.jpg
Reminds me that I should have mentioned that what most people, and me when being imprecise :emb:, call "brazing rod" normally melts at above the critical temperature of 4130 resulting in the same HAZ as if the steel had been welded. The material needed to "braze" 4130 at a low temperature is more properly called silver solder. It's generally more than 50% silver with a bit of cadmium, zinc, and nickel in the mix.
From my notes, John Dyke told me it is "nickel silver brazing" "CF17 Puddling". See photo.
I haven't tried it, since I prefer welding.

I didn't see that product on a search.
But I found this product called nickel silver. Doesn't list any silver content. Maybe the color is "silver"? http://www.weldingmaterialsales.com/products_2009/RBCuZn-D.htm
 
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TFF

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I think when Indy racers use to actually make their own cars, they used silicon nickel for brazing.
 

amv8vol

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When I had to Braze Stainless steel tube for my trim tab I used Harris Saftey-Silv 56, 56% silver, for regular steel to steel I used Harris #15 bronze rod. And yes, the silver is stupid expensive.
David N
 
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WonderousMountain

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TCupronickel is silver in color,

Brazing has some silver in master alloy with copper, to bring temp down. It's hard substitute for berrylium copper valve seat insert. More durable, but can wear a titanium valve quick if mismatched or bounce from fast operation or aggressive cam.

You don't get to know everything just buy it and do what it says :nervous:
 

WonderousMountain

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Cupronickel is silver in color,

Brazing has some silver in master alloy with copper, to bring temp down. It's hard substitute for berrylium copper valve seat insert. More durable, but can wear a titanium valve quick if mismatched or bounce from fast operation or aggressive cam.

You don't get to know everything just buy it and do what it says :nervous:
 
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