Bending Radiant Tubing (AlumiPex)

Jerry Fountain

A few on a series of questions I'll be posting, but a quick one to start. I'm doing a radiant thinslab install as part of an addition on our house (bathroom floors). I've read quite a bit of the literature, but a few "practical' matters have come up.

For our bathrooms, I'm going with fairly tight spacing on a thinslab (1.5" thick gypcrete on plywood, second floor) install of 1/2" AlumiPex. They recommend using 4" spacing near outer walls (Chicago area). Due to the size of the room, I was planning on just continuing the 4" spacing all the way across since I'll have plenty of tubing. I know it has a 6" bend diameter and so I had made a bending form from plywood. But even getting a 180 bend to 6" is tough enough to make me sure there is an easier way, especially with the bit of springback it has. I've been looking to see if there is an inexpensive bender similar to that for conduit or small diameter soft copper but haven't found anything.

So, for all the regulars, what do you use for bending this stuff and make installation a bit quicker?

Bill Wright_2

4\" o.c. Yikes!!

Did one job w/ 4" o.c. -- and decided to stay w/ 6" o.c. for close spacing.

That said, there are a couple of things you can do.

1.) Use a bending spring (used for copper tubing) -- works nice but you have to slide it along the entire length of the loop.

2.) "Lollipop" the bends (bigger diameters, but bend past
180 deg) -- then dress up the straight runs to be 4" o.c.

Bill w.

Jerry Fountain

close bends

> 2.) "Lollipop" the bends

> (bigger diameters, but bend past 180 deg) --

> then dress up the straight runs to be 4"

> o.c.


I figured I'd have to do these anyway since they are how the manuals suggest doing it (and you have to have a min of 6" diameter anyway. The spring bender would solve worrying about kinking (which is why I made the plywood form, but I've still got the extreme slowness of hand bending around that form. Even 1/2" is pretty stiff stuff

Jerry

hot_rod

But really!

I can get 3/8 OD down to 4" OC. 1/2" Wirsbo Multi-Cor down to 5".

4" OC?? you won't have much space left for cement 6" OC should be plenty tight, to get you through the night!

REMS make a Curvo power unit that will handle PAPto 40mm or so. They also make a hand bender for less$$$.

www.mupro.com

hot rod

Dana Zaichkin_2

It seems like

If you're needing to go to 4" to meet your heat loss, you really need to consider supplemental heating in the room, either via radiant wall tubing, baseboard or some type of secondary supplement (or additional measures to decrease your heat loss). Beyond the extra installation work, it seems like going less that 6-9" yields diminishing effectiveness - In my humble and novice opinion.

Best Regards

DZ

jay_3

4\" oc

terry if you're looking to cut down on installation cost
and need to work w/ spacing of 4" oc. you may want to consider watts radiant's onix tubing. it's a rubber based
product w/ an inner alluminum oxygen barrier.much easier to work with. especially in the cold, since it doesn't become
rigid. it does cost more to purchase but the installation
(labor) cost will be less.

jay

GH

NEW STUFF

Why not take a look at a product that will establish your tube route for you.
This product is ultra light - precured - WATERPROOF- and easy to install.
Just screw it down .

pat_3

4inch on center no problem

instead of making your runs back and forth,try doing a counter flow spiral ,then the bending capabilities of the particular tubing is not an issue.