Radiator pipe kaput

dreads

Not sure if it's actually considered a radiator but it gives off heat. The other night the exit pipe 1/2in copper where it connects to the rad. gave way. Ultimately I disconnected both lines from the tees at the main pipe and capped them off. It is quite some unit 70" long 6" wide 4" deep, has 3 channels and weighs maybe 40-50 lbs. I believe cast iron.
First question What exactly is it called. I will reuse it but can you still purchase it?
next my thought was to PEX it. I could redo it in the same way but I wanted to try PEX yes/no?
There is a 1/4 turn valve at the one end I would like too replace what kind of valve is it.
On one end there is an expansion fitting on the other the fitting that connects to that valve. Both of those fitting are corroded in good I was thinking to just leave them in? anyone's Thoughts on any of these issues please. Thanks

Jamie Hall

It's called a convector. Don't know if you can still get them. They do heat well, though.

The problem with PEX is that it's upper limit is around 180, and you may be running very close to that at times. Personally, though it's a bit of a pain, I'd rather see copper -- although if you reasonably sure you won't hit 180...

dreads

Jamie thanks I see you can purchase similar, a little pricey. Also I do run close to 180 I believe. I do have one regular slant fin that was PEXed

dreads

Follow up question I am going to redo the failed line in the 1/2 in. copper pipe. The run is about 2.5 ft there are two 90 degree bends that were bent into the pipe. so they are a sweep type bend as opposed to a 90 elbow which I would be using. Would there be a significant flow rate change. Thanks