Idea for InexpensiveLlong-Radius Elbows

[Dan Case LR]

I'd be surprised if nobody else has had this idea, so I thought I'd throw it out there and find out of it's worth trying.

The idea is to take two standard HVAC elbows--short-radius by default--adjust them to 45 degrees each and put them together to make a longer-radius 90. Has anyone tried this? Did it work? Was the radius long enough to be comparable to "real" long-radius 90's?

While those expensive, smooth long-radius elbows are both lovely to look at and nicely efficient I like the idea of using adjustable elbows, if for no other reason than the reality that "perfectly square" and "perfectly straight" seldom share a sentence with "ductwork" or "Conduit." I like the adjustable LR elbows Oneida sells for around $15, but if I can do the same thing with a couple of $4 elbows back-to-back, I'd love the economy even more.

What say ye? Anybody tried this?

Thanks!

D.

[steven c newman]

Depends. Metal ones? Or, the PVC ones? PVC, get two 45 degree fittings, add a short connector between them.
Metal: One could use the adjustable ones used for DRyer vents....

[Dan Case LR]

Galvanized Metal.

D.

[Dan Hintz]

I used two 45s with a short straight section between for my 90 degree corners... it was nearly as inexpensive, and I'm sure I get better flow.

[Bob Cooper]

Sure. Depending on the two points that needed to be connected I've used 3. 6" galvanized 90's are pretty cheap. Just seal everything which I pretty much did with AL tape

[William C Rogers]

That is how I intend to do my DC pipe.

[Ole Anderson]

Have fun twisting them to get a 45, almost as much fun as a Rubrics cube. Don't forget to run a thin bead of clear silicone along each joint before your install.

[Chris Padilla]

My DC pipe is plastic but I used two 45s over a long-radiused 90 as the cost was much cheaper. I cannot attest to the 2 45s being better or worse in flow/static pressure to a lr 90 but I don't care, my DC sucks fine. :)

[Jim Andrew]

I have used 90 degree elbows twisted to 45 to make a long sweep, they don't look straight anymore, but it works. I don't use caulk in the joints, as it glues them together, and it is hard to get them apart, just use aluminum furnace tape on the outside. DC is not permanent, you are always having to make changes.

[Dan Case LR]

Since I started this discussion, it seemed appropriate to show my results. I stopped by Lowes this morning and found a couple of 26ga 7" elbows in the sea of 30-ga thinness, brought them home and started twisting.

305037305038

Each standard (short-radius) 90 degree elbow easily transformed into a long-radius 45--and when two of those are combined, you get a rather pleasing long-radius 90 degree elbow for under $10. A considerable saving compared to the adjustable (gored) long elbows sold for around $20 by the DC vendors.

The place where I'll save most is on my 45 degree elbows. Around $5 beats $20 and up any day!

BTW, The radius works out to 1.85 times the diameter, a respectable and quite acceptable radius. Now, I just need to buy a cyclone... :)

D.

[Ned Everitt]

I like the idea and the results. Thanks for sharing.

[Kent A Bathurst]

Have fun twisting them to get a 45, almost as much fun as a Rubrics cube.

To quote the Cowardly Lion: "Ain't it da trut. Ain't it da trut." :p :p

I always have to clamp one end to the edge of a table/bench, work one section at a time - duct taping that joint when I think it is right - and then move to the next section. Using gloves with "grip surface".

[Dan Case LR]

To quote the Cowardly Lion: "Ain't it da trut. Ain't it da trut." :p :p

I always have to clamp one end to the edge of a table/bench, work one section at a time - duct taping that joint when I think it is right - and then move to the next section. Using gloves with "grip surface".


I used to HATE messing with gored (adjustable) elbows. Then I learned a method that uses the seams as reference points. If you've got a bunch of elbows you need to set to 45 degrees, you can use dividers to replicate that setting easily on as many elbows as you need. Easier than I ever thought it could be!

D.

[roger wiegand]

Sure, that's what I did wherever I had the room to make the turn.