[TowerTalk] Tack welding rebar, need howto

[Grant Saviers]

Flux core is the easiest, cheapest, and lightest way to weld in the 
field e.g. for fence posts in the pasture with a generator on the back 
of the ATV or Gator.  The entry MIG setups also don't have a regulator 
in the kit although the Miller and others have the shield gas plumbing 
and valve inside.

I've owned 7 or 8 MIG welders and IMO the big box ones and HF are to be 
avoided.  Even the Lincoln ones are cost reduced in critical areas such 
as the wire feeder.  If you've ever had a rig with a stuttering feeder, 
you know how aggravating that can be.  Better to spend another 15% and 
buy the commercial version at a welding supplier.  If you buy on-line 
check the model number carefully to make sure it is the commercial version.

My current favorite for odd jobs is the Miller 211, runs on 120 or 240, 
came with a gas regulator and feed reels for flux core if I need to go 
there.  I use gas 99% since the welds are slag free.  My other welders 
are a Miller 250 and Miller Dimension 432 (400a). Just sold my 
Millermatic 130 flux core setup.

Gas brazing rebar has one big problem not mentioned - rebar I've seen is 
far from clean, often rusty, mill scale and some coolant/lube stuff left 
over from rolling.  Most fluxes won't touch that so wire brushing or 
sand blasting is needed as prep.  MIG/stick burns right through.

Re strength, if HD really (I doubt it) sells graded rebar, the lowest is 
40, 40ksi yield.  Annealed steel is well above 30ksi.  One PE told me 
"all the rebar does for a tower foundation is keep the concrete from 
cracking, there is no significant structural load purpose."  A lot 
different than a bridge beam, where high strength rebar, codes, material 
certifications, certified welders, and heavy testing and inspection are 
appropriate.

For wire ties, buy the swivel hook and ties pre looped, that makes life 
easier unless you can rent an automatic tie gun, those and the portable 
hydraulic benders and cutters are really cool but around $2500 each.  
Available at some rental shops and a must for rebar #5 and larger.

Grant KZ1W

On 1/2/2014 5:45 PM, Roger (K8RI) on TT wrote:
> t might reduce the yield strength by 15 to 20%.
>>>
>>> 2.  Gas weld or arc weld?  How big of an arc welder needed?
>>> Can I get away with a MAPP gas torch?
>> A 120v 130amp MIG or bigger with flux core wire will work,
>
> Why flux core.  MIG uses a cover gas and I don't see the flux serving 
> a purpose with steel?
> Rerod's main function is to keep the concrete from breaking.
>
>
> 73
>
> Roger (K8RI)
>
>
>