Anyone know about rebar?

[Bogie]

I wanna cook up some bars for three windows on my garage, along with a couple of side windows in an alley between houses. Those are going on the inside, behind some drapes, and will be easily defeated in event of a desire to exit rapidly. They do NOT need to be pretty.
 
So, what do y'all know about how to tell if rebar is weldable? I have some 3/4" 1018 square tubing that I plan to use for the crossbeam/frames...

[charby]

Rebar welds like carbon steel for me.

[Nick1911]

I've done it before, and it went okay.

I recall reading that the specifications for rebar are very open, so how it goes may just depend on the particular batch you end up with.  Clean well, and use an electrode/wire/filler with lots of deoxidizers.

[Bogie]

Well, the welder is one of the "upgraded" China Fright wire gizmos, but the wire is at least Lincoln... Cutting the square stuff tomorrow night. Going to drill about 1/2 to start, will probably end up reaming to 17/32 if the rebar from Homeless Parking Lot is a little rough.

[Grandpa Shooter]

I made rebar grates for horse feeders out of 1/2" stuff.  Wire welded it and it held up just fine, but you do need to abrade it really well and have a fan blowing the fumes away from you when you do it.

[K Frame]

I've welded rebar a number of times over the years. Just have to clean it well to make sure you get a good weld.