I know I suppose to get them at MCmaster, but I can only find the page for stainless. I've been trying to look for the page for mild steel but got no luck. Can anybody help me out? Thanks.

 

Search McMaster for "steel butt-weld". It'll list a few things, expand the "Steel Pipe Fittings" selection. Click on the "Steel Pipe Fittings" link. That should get you where you want to go.

 

are those "black seamless steel" ok to use?

 

My mistake. Click on the link for "Unthreaded Steel Butt-Weld Pipe Fitting-Schedule 40". That should get you where you want to go.

 

I'd suggest calling local plumbing supply stores / distributors. I can get sched 40 mild steel elbows for $3-4 retail around here and if you're ordering a lot of them, the shipping really adds up. Plus, I hate waiting

 

mcmaster took 1 day to get to me. (granted same state).

click on "pipe and pipe fittings" on main page.

then click
"Stainless steel pipe fittings and pipe"
then click "tee" or "elboe" to get your log manifold tubing

inside those, you want Female butt weld x butt weld

 

Catalog page 11 and 12 in Mcmastercarr.TRy a local plumbing supply place.Much cheaper when you buy in bulk.