Date: Thu, 08 Jun 2006 22:41:09 -0400
From: Finn Lassen <finn.lassen@verizon.net>
Subject: Re: [FlyRotary] Re: OT: Concrete forms
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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I did indeed price the Sonotube forms. Regtangular (inside) 16x16 is 
only $27 (per foot!!!) plus outrageous shipping.

Please expand on tying the four verical rebars together. I missed out on 
that story.

Finn

Charlie England wrote:

> Finn Lassen wrote:
>
>> Thanks Bill (and to all others that reponded)!
>>
>> I've had my eyes on these. Haven't found a place to rent them yet. 
>> But I doubt it'll be cost effective. Looks like I'd need at least 6 
>> per column: 36. Let's say they rent as cheap as $6/set, that would be 
>> $200. >From all the data I've gotten on and off the list so far, the 
>> cheapest way seems to be using the 16x16" concrete column blocks. 
>> Either pick up speed in doing it myself (which may well happen by the 
>> time I'm done with my third corner and ready to start the columns - I 
>> *will* learn how to do it) or hire some "illegals" to do it for me.
>>
>> The only problem is that when I placed the rebar in the 
>> slab/foundation I was leaning towards poured columns and placed the 
>> rebar as close to corners as possible. Some of them won't quite fit 
>> in the column blocks so I'd have to cut the inside of some of the 
>> blocks sitting on the slab (of course I could mix and pour the first 
>> 8 inches of those columns). Ah, choices...
>>
>> Remember, I intend to have a concrete truck and guy with a concrete 
>> pump come out to pump the corner blocks and the columns, and 
>> preferably also the lintels and lintel blocks all in one go.
>>
>> Did anybody check Jarrett's numbers? Would I really have to brace the 
>> forms every 3 inches (near bottom) with 2x4's? Any way of reducing 
>> that to, say, every 2 to 3 feet by pouring the columns and corners in 
>> a round-robin fashion, so that the concrete would start to set and 
>> not exert such big pressure on the forms? How would one calculate and 
>> control this? My knowledge of concrete viscosity, plywood and 2x4" 
>> strength is woefully inadequate.
>>
>> As you can see, I haven't completely given up on forms and still have 
>> a couple of weeks to decide. I was hoping to find someone with real 
>> world experience - how thick plywood, bracing distance, etc. Jarrett 
>> seems to come close, but his experience is not really with columns.
>>
>> Finn
>
>
>
> I won't pretend to be an authority, but I suspect that the problem 
> with plywood forms is the same as rectangular mufflers on a rotary: 
> the flat sides. Have you considered using the paper tubes that are 
> made for pouring columns? Slide 'em over the rebar, brace to prevent 
> movement, & pour. Then you just peel 'em off after the concrete sets. 
> Adapting to the round cross section (framing lumber & a powder-charge 
> anchor gun) should be a piece of cake compared to all the work on 
> forming a square column. If you pour in the round, don't forget the 
> circles of rebar to tie the vertical runs together (remember that 
> no-longer-elevated highway in CA?).
>
> Charlie
>
>
>
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