technical ? re: 45º offset

[Benchwrench]

It's 7:30 in the morning and I shouldn't be trying to use this much brain power this early but I have a technical question regarding offsets.

I am trying work out a few wrinkles dealing with a rigid install.

I want to see if I can get away with utilizing two 45º offsets, one at the bottom of the rigid liner pipe, and another 45º connector to angle it straight down to accept the new insert.
What I am trying to accomplish is to eliminate the flex pipe from the rigid to my new insert. (if this is possible)
I have a need for roughly a 6" of offset.

so here's my question:

If I joined two 6" 45º connectors, what would the center line difference be? in other words; how far would they be offset?

( I don't have a couple 6" 45º offsets in front of me to measure.)

another question:
can I even consider doing what I am proposing? or do I have to "flex" to the top of the insert?
I would like to use rigid all the way if possible.

Thanks guys.
Bench

 

[bpm44]

I can only answer the second half of your post, and that is yes you can.

Another option, which might make cleaning easier instead of trying to navigate 2 45's would be to use and offset box. Many on the board here don't like them, but they are just the ticket in some situations. The one I have seen and like the best is a Magnaflex Wood Stove Offset Box. It has a gasketed clean-out door on the front. This way you could sweep your chimney straight down and open the door to remove your sweepings and you don't have to pull the insert or remove the baffle every time you sweep. Further, this would allow you to come straight down with your pipe and account for what you are trying to offset with a minimum of difficulty when you are trying to make the connection.

What kind of insert are you installing again?

 

[begreen]

According the the Duravent chart, two single-wall, 6" 45's together should give you a 5 1/2" offset.

 

[Danno77]

I used 45 degree offsets in my last stove configuration. If memory serves me correctly, since I was using the adjustable elbows that can be 90, you could twist either end to give you different amounts of offset. Does that make sense or am I misremembering?

 

[Benchwrench]

I can only answer the second half of your post, and that is yes you can.

Another option, which might make cleaning easier instead of trying to navigate 2 45's would be to use and offset box. Many on the board here don't like them, but they are just the ticket in some situations. The one I have seen and like the best is a Magnaflex Wood Stove Offset Box. It has a gasketed clean-out door on the front. This way you could sweep your chimney straight down and open the door to remove your sweepings and you don't have to pull the insert or remove the baffle every time you sweep. Further, this would allow you to come straight down with your pipe and account for what you are trying to offset with a minimum of difficulty when you are trying to make the connection.

What kind of insert are you installing again?

From the top:
Excellent!
as all I am looking for is 5 1/2" offset then straight down to the stoves' flue collar so I'm hoping that two 45's will gang together. After I look a bit at the different rigid liners, I think it will end up being the rigid duraliner product anyways.
As far as those offset boxes go, I don't know too much about them but after reading what you had to say, it raised an eyebrow. I need to seriously consider that option since it would make this install that much more easier. Thank you jeeper.


I ended up with the only appliance that would meet my btu and dimensios my FP had to offer, I looked at them all and went full circle back to another QF. I can't wait to post some pictures of the progress.

 

[Benchwrench]

I used 45 degree offsets in my last stove configuration. If memory serves me correctly, since I was using the adjustable elbows that can be 90, you could twist either end to give you different amounts of offset. Does that make sense or am I misremembering?

I understand exactly what you mean however I believe the duravent line up offers rigid 45° connectors that won't contort or swivel.

 

[Danno77]

I just realized why my post is wayyy off base. You are talking rigid liner, I was talking black pipe. Sorry for that.

 

[Danno77]

We must have been posting those at the same time...

 

[begreen]

I just used Duravent's offset table, but wasn't suggesting you had to use Duravent brand elbows.

 

[Benchwrench]

According the the Duravent chart, two single-wall, 6" 45's together should give you a 5 1/2" offset.

Thanks BeGreen, you don't know how glad I am to hear that as I am looking for a +/- 6" offset.

 

[Benchwrench]

I just used Duravent's offset table, but wasn't suggesting you had to use Duravent brand elbows.

When going with their liner, I would choose to go with their connectors too,
I need to do a little shopping for all the components.
I like one of this website sponsors website. He has an attention to detail and nice web design too. So I'm starting there.
Thanks so much for all your support,
Cheers,
Bench

 

[Benchwrench]

I called Duravent and was told that what I was trying to do with the 45º (or their 30º) elbows weren't designed.
They informed me that their 45º elbows are for stove top adapters and I would have to use "flex" through the smoke chamber.
I was trying to eliminate flex all together. I guess I was trying to reinvent the wheel or something.

 

[thechimneysweep]

You don't want to use adjustable elbows for this application: they tend to pop apart at the seams during vigorous brushing. Even rigid 45's are problematic, as they add a couple of connections (where they join each other and at the connection to the liner) which can loosen over time and come apart when you sweep the chimney.

When you attach the flex to the rigid, don't use sheet metal screws: use stainless rivets, at least four of them, and be mindful when you're working your brush to ease up a bit when you hit the flex. Or, better yet, run flex all the way and eliminate any joints in the system.

 

[Benchwrench]

Stainless rivets should come with each section of rigid
I still need to look into what type of connector is required to mate flex to the rigid liner.
instead of going the easy route and flexing the whole job, I wanted to install the most durable system that can take long hot temps.
I was thinking that rigid will fit the bill since I bought a large insert that puts out a hefty amount of btu's.
However it seems I am left with no other alternative but flex to the top of the stove for at least 4-5 feet.

 

[thechimneysweep]

I wanted to install the most durable system that can take long hot temps.

Your best bet for resistance to thermal decay and creosote corrosion will be the stainless/titanium alloy 316Ti. Choose a flex liner made of that material and you'll get the durability you're looking for (often backed by a lifetime warranty), along with the peace of mind that comes from knowing there are no joints in the system.

FYI, if you do choose to go with a hybrid rigid/flex system, make sure the manufacturer has a UL listing for that combination. When we researched this several years ago, we couldn't find a manufacturer that had tested their rigid and flex joined together in the same installation.