Chimneypipe install question

[beekeeper]

I'll admit that I'm afraid I'll sound inept here, but I'm installing two stainless chimneys in my new house and I'm a little uncertain about something. I'm using the Simpson Dura Tech, and I'm a little disappointed in the twist-lock connection. I've put together about 5 sections - some of them twist together perfectly. Others seem to sort of jam, and I have hard time figuring out if the sections are really together tightly when that happens. When they "jam," the connection doesn't look QUITE as snug - but that's just looking at it from the outside. Also they won't rotate very well either clockwise or counterclockwise (the pipes below just unlock when I try to back it up, for example).

To add to the frustration, their instructions say (1) sheet metal screws aren't necessary, (2) but if you use them, they must be 1/2" or shorter. Unfortunately the 1/2 inch screws I bought don't quite penetrate the second section - not talking about the inner liner, just the outer part of the male section.

Has anyone else installed this, and then stepped back and wondered if the joints are really tight enough?

I also discovered some "locking bands" and I'm wondering if I should get these and use them -- if I use the locking bands, would I be better off skipping the screws entirely or won't that matter?

Thanks for any tips! (and Happy Thanksgiving to all).

 

[begreen]

I've put together several lengths of DuraTech 6" pipe. My joints felt pretty good and solid. Look to see if there was there any denting or damage to the mating end that might be causing it to bind. It does take a firm hand, but they should fit together solidly. It also is easier to do with 2 people, especially if joining lengths that are not locked in position. Make sure the pipe lengths are square to each other and not cocked at a slight angle. If still sticky, you might try some silicone spray lubricant on the male end of the pipe before fitting. That may make it go smoother for you.

If you want better security I'd use the Simpson made locking bands, not screws. But be sure the pipe has been locked squarely and fully in place first.

 

[beekeeper]

Thanks BeGreen - I'll order the locking bands. I can't tell that the ends are damaged, so whatever variation in tolerances must be pretty small. I guess doping them with furnace cement or the 600 degree caulk would be a bad idea?

Thanks!

 

[begreen]

There should be zero need for caulk or cement. Try some spray silicone as a lubricant.

 

[beekeeper]

Figured out one trick - by going ahead and stabilizing lower sections with wall ties as I went, I was able to lock/unlock/lock sections more tightly as I installed them. Ran the first flue all the way up and out the top today - I did go ahead and installed 3 screws right at the last joint because I installed it as an 8 foot section and didn't want it breaking apart while I was up in the trusses. All went well and I think clearances are solid everywhere - one spot right where it goes through the roof is right at 2", and I think I'm going to chisel the OSB back to get an extra quarter inch of clearance. I did order the locking bands last night and I'm going to go through and pop those on yet to really make myself sleep easy.

 

[begreen]

There you go, it really helps if one end is solid and captive.