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Angle iron not beefy enough?

Posted: Fri Jul 26, 2019 11:37 am
by fallguy1000
As many of you know, the Skoota is demountable.

The cockpit is supported by two angle irons welded together.

I had a professional ironworker put a 3/4" arch into it and the welding.

But it is giving too much.

Has anyone ever sandwiched a metal core inside fiberglass?

Or do I need a beefier iron setup?

Re: Angle iron not beefy enough?

Posted: Fri Jul 26, 2019 11:44 am
by jacquesmm
That is a question for Richard. He has designed many folding multihulls and must know what is involved. Plus, he knows the design. Many of us can calculate a beam but we don't know what is involved here.

Re: Angle iron not beefy enough?

Posted: Fri Jul 26, 2019 1:40 pm
by fallguy1000
I did a spreadsheet with data from the Machinery Handbook and came up with some numbers.

The angles we used are too light.

There is a big jump in angle strength from 1.25" to 2" angle.

The 2" is 500% less deflection.

There is really no use in glassing the lighter angles.

Re: Angle iron not beefy enough?

Posted: Fri Jul 26, 2019 1:43 pm
by fallguy1000
If I weld two 304ss angles together, can I seal the seam with 5200 or will the ss corrode in low oxygen?

This part is subject to lotsa seawater.

Re: Angle iron not beefy enough?

Posted: Fri Jul 26, 2019 1:48 pm
by jacquesmm
Don't seal SS.

Re: Angle iron not beefy enough?

Posted: Fri Jul 26, 2019 4:21 pm
by fallguy1000
Thanks. I ordered it in 316.

Kinda spendy.

The beam I failed could be used as a 1/3rd of the way support under the helm station.