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SS Flex liner vs. rigid pipe

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by wahoowad, Dec 20, 2005.

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  1. wahoowad

    wahoowad Minister of Fire

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    I did not know rigid liner existed until today when my dealer mentioned it would work in lieu of more expensive flex pipe in my installation. This is because my chimney is a straight drop all the way down through the flue and damper. He was originally recommending a copperfield 304 flex pipe but says he could sell me 6x48" sections of 304 stainless rigid pipe. I see at least one online retailer sells this pipe as well as sections of insulation that snaps tightly around the liner. This looks cheaper than the flex liner and allows me to get it insulated as well. Any thoughts on this over flex pipe?

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  2. Hokerer

    Hokerer Member

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    If (and that's always a big if) you can use rigid, you're usually better off doing so. Rigid drafts better (no corrugation), cleans easier (smoother), and costs less. The only reason it's not used more is that it usually cannot be. In your case, with the straight shot, you've got it made.
  3. wahoowad

    wahoowad Minister of Fire

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    OMG, a TSL hokie. boo hiss.

    Thanks for the info! I did not consider that aspect.
  4. elkimmeg

    elkimmeg Guest

    I second the advantages of smooth liners. Just make sure they are stainless steel HT 2100.. Insluated even better.
    You will end up with the ideal situation. Far superior than corrugated. and so much easier to clean better draft. This is a win win situation
  5. Rhone

    Rhone Minister of Fire

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    Are you installing it, and is your opening big enough for insulated? I think my chimney was 8x12 and my installers had a heck of a time getting a 6" non-insulated solid liner down it. Generally if you can use it, then use it. If you're going to be doing it yourself, it will probably take you hours of hard work, swearing, and a lot of muscle. If you have a person helping you from below that reaches up to grab the bottom and tries to pull it down, and you're at the top ramming it down, there's a chance you can ram it on their fingers and cut some off. It is very sharp, wear gloves, and watch out when it nears the bottom that no fingers are lost.
  6. elkimmeg

    elkimmeg Guest

    rhone good safety points. I would get a galvanised cap and install it on the first liner section facing down also attach a rope to control the decent
  7. wg_bent

    wg_bent Minister of Fire

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    O.k. I'll side for the flex liner. Only because it's a single continuous peice. The pipe usually is in sections. Is it a consideration? Probably not, but this was starting to make flex liners across the country feel inferior. They needed some emotional support.

    Look at Ventingpipe.com (there are others if you just search) They've got a pretty comprehensive set of the products listed there.
  8. wahoowad

    wahoowad Minister of Fire

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    I am pretty sure my current inner liner is 8" and I recall no obstructions or choke points from the last time I cleaned my chimney. That means I have approx. 1 inch clearance to drop a 6 inch pipe. I will probably get the version I see at hartshearth.com that has the insulation already snapped around the 6 inch pipe. The insulating jacket looks pretty tight although I will confirm the overall diameter with the vendor before buying. I think I need one more visual down the chimney, or up the flue, to make sure.

    The idea of a cap on it sounds like a good idea. Assuming it fits inside the 8 inch pipe with room to spare I need to figure out how to assemble the 48" sections and lower it. I read I could pop rivet the 6 inch pipe lengths together (or screws) but now I am wondering how I would attach them if this insulated jacket was already around the pipe...?
  9. wg_bent

    wg_bent Minister of Fire

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    My flex liner came with lots of duct tape over the end to prevent people from getting sliced on it. Maybe something as simple as that. But do something, cause this stuff is sharp like nothing you've ever seen. I really don't think Elk was exaggerating when he said "cut fingers off" It's entirely possible!!!
  10. saichele

    saichele Minister of Fire

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    I was going to do the rigid liner, but couldn't figure out how to get the stuff assmebled and down the chimney. Either you're hussleing 25' of tube up the ladder, or you're doing assembly as you lower it down. Given two people at the top of the chimney it might be possible, but it just wasn't happening for me.

    I also found the Ventinox 316 TI flex liner to be light and easy to work with - cuts with standard tin snips, unlike the Homesaver 304. Maybe not as good for going through thedamper, where there might be some rubbing, but much better than 100 lbs of 304. Also was only 20/ft, which was the same or less than the rigid I was able to find.

    Steve
  11. Rhone

    Rhone Minister of Fire

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    They pop rivited mine together as they pushed it down. The pop rivits and screws I believe must be stainless, during a chimney fire aluminum rivits in particular will melt and you don't want your chimney falling apart at that time. Also, you don't want it sticking out your chimney too much. My installers left my liner sticking out almost a couple feet, and during an extremely windy day it, along with the rain cap acting like a parachute grabbed the wind and twisted my liner sideways and broke all the seals and connections at the top of my chimney. I'm waiting until spring to redo my liner installation now. I should've listened to Elkimmeg when he said I needed to trim it down. Craig said once get some stove cement and as you pop rivit each piece of liner together, fill the joint between the two pieces with it. It will help improve draft.

    After visiting the site, it looks like their insulation is snapped on over the pipe. You'd still have to pop-rivit the normal pipe together, than it looks like you snap that insulation over it and push it down.
  12. wahoowad

    wahoowad Minister of Fire

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    Yes, you do have a point about the single piece flex liner. I just thought I could get rigid pipe plus insulation for around the same price as uninsulated flex. I am still in the learning phase - figuring out my options and implications!
  13. elkimmeg

    elkimmeg Guest

    this is a simple process requiring a cordless drill. You can do 2 sections at a time the insulation can be roled back for the connection then rolled forward upon completion of securing the joint place. A cheap galvanized cap on the open end punch a hole in it and attach a ropes. Lower the two sections down then secure the rope or use two ropes that extend out side the line, could be clothes line. Wrap it around the chimney add a section lower it 4' and continue it till you reach the bottom. If using sheet metal scrtews use 1/2' or less not more so they do not protrude that far into the interior of the pipe. You also can caulk the joints does not hurt befors making the connections. When factoring which linner is better, please note the friction of corrugated liner has an effect of reducing draft flow up to 20% . Common sense will tell you smoother is better less friction less chance for cresote build up. Really when you think about not all that much harder to do, mayby easier the wrestling 25' of snake corrugated liner.
  14. wahoowad

    wahoowad Minister of Fire

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    The rigid liner I was looking at (that comes with a insulated jacket already around it) supposedly comes with stainless pop rivets. I have a pop rivet gun. I was told the insulated jacket will slide up/down a bit which allows you to pop rivet or screw the liner sections together, then slide the jacket down over it.

    The concept of adding a piece at a time, sliding it down a few feet on the rope, then adding the next section, makes sense. I am not sure what I will secure the rope to (chimney is way too wide) but I'll figure something out. I can lug a cinderblock up there if I have to!
  15. Willhound

    Willhound Feeling the Heat

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    I helped with the installation of my rigid liner last week, and it wasn't that awkward to handle. Now, granted, we were able to work off of the roof, so weren't dealing with ladders. We pop riveted five 4 foot sections together on the ground, one guy went up on the roof, and the other handed it up to him. My installer actually used a short piece of flex (about 2 feet) at the very bottom to make final alignment and connection a lot easier. The pipe I used was not insulated, so I don't know how much additional weight that adds, but I would estimate that the 22 feet that we were handling was no more than 30 pounds, at the absolute outside. Once on the roof we slipped the flex end into the 8 inch clay liner and it acted as a guide to direct the rest of the solid wall pipe. Total time on the roof was about 20 minutes including pop riveting the top cap on and insulating around the top of the liner and siliconing the top flashing down.

    Willhound
  16. webbie

    webbie Seasoned Moderator Staff Member

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    You already have lots of opinions, but I'll add that each product can be used where best. A straight up chimney should use rigid if possible, you are getting a better and easier to clean product. 304 is fine for wood (316 might last longer with coal), Heat-fab is a great brand...but perhaps a bit more expensive than others.

    Our shop often used flex for the first 6-8 feet and then rigid. This got us through the damper, etc.

    As far as insulation, this depends on a lot of factors. A very cold climate as well as exterior chimneys can benefit from insulation. Many chimneys don't have enough room to allow for insulation. Keep in mind that the liner and the air space around it is a GIANT improvement over what was already there, so there is (as usual) the good job, the better job and the best job.
  17. wahoowad

    wahoowad Minister of Fire

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    Well, last night I took another look up my chimney from the firebox. I was dissapointed to see that it was NOT one straight shot. Instead I have a 2-story straight pipe coming down but with maybe a 3 inch offset for the final 18 inches or so of the flue! I think it is just enough offset to prevent me using rigid.

    Although, as someone already mentioned in this thread, I guess I could use a short section of flex to get me through the flue area. Can I buy a short length of flex? And can I buy small quantities of this insulating wrap I have heard about? I would like to wrap this portion if the wrap is thin. Then I may continue up with either insulated or uninsulated rigid pipe.

    You guys don't know how much I appreciate the input. I really have no on else to discuss this with.
  18. Mike Wilson

    Mike Wilson New Member

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    We installed 20' of flex at my neighbor's home 2 weeks ago, right through the flue. He measured the flue width, which was 5 inches, and then we ovalized the bottom 2.5 feet of the flex to be 5" max. We then put 2 ladders up the chimney, and removed one of the 2 slate caps, placing it on top of the other cap. Then we pulled the flex up, and fed it down, oval side first. So far the whole project took about 45 minutes, including getting the flex through the 20 degree angle at the damper. I was shocked at how fast we got the liner up the ladders and down into the chimney. Then we went inside and killed almost 2 hours getting the flex to mate with the insert, and sealing the damper off. Back on the roof (wow, daylight goes quickly this time of year) to straighten the flex out a bit, and install the stainless flue cap, we used high temp silicon. Tapped and screwed the liner to the flue cap with a few sheet metal screws, and then re-installed the slate on top. Bead of caulk across the center of the 2 slates, and put away all the tools. Total time, probably 4 hours. Let it all set up for the night, and then fired her up the next afternoon over a few beers. Worked like a charm.

    So, its not such a bad job, it does need 2 people, and flex works more than fine. Don't be disappointed that you can't use straight pipe. I have flex at my home as well, also works fine.


    -- Mike
  19. wg_bent

    wg_bent Minister of Fire

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    I also have 20' of flex in my home, and the situation sounds VERY similar to yours. It is a pain trying to get the flex past those bends. Here's what I did. I took a peice of strong nylon string, the kind that looks like hemp twine, but nylon, and tied it tight around the bottom of the flex liner. The peice of twine was 25' long. The other end got a small socket tied to it. I dropped the socket down the chimney into the fireplace. Then as I pushed the liner down the chimney from the roof, my daughter pulled on the string from below. Not really needed till I got to the bend, then it took all she had to pull with me pushing to get that liner through the bend. It helps if you bend the edges of the liner in a bit so it won't catch on any of the edges of the inside of the existing chimney. Once again, be careful about the sharp edges. The instructions that came with mine said to attach the flex liner adapter before shoving it down the chimney, I thought it would get damaged if I did that, and I still feel I'm right. So I pushed the liner down further than I needed and attached once it was down, then pulled it back up as needed.
    The flex is pretty springy, so I also used that "feature" to snap the liner down into the stove opening as I pushed the stove underneath the liner.

    Getting screws into it is the next trick! Get a LONG screw driver.
  20. Rhone

    Rhone Minister of Fire

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    I think most liners aren't 100% solid, I was surprised to hear you may be able to go all solid.

    My chimney offsets a few feet to the right, they put on 5' flex to the end of my 15' of solid liner and lowered it down. They ovalized my flex pipe to fit through my damper, and then attached it to my insert. When I redo the liner, I'm torching an opening in my damper plate like Frank Ivy did so I don't need to ovalize. So, your situation is rather common, just use a piece of flex at the end and straight for the rest. Plus it lets you move things around a little.
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