A few double wall vs. single wall questions

[Jean-Claude]

So I pulled apart my DSP brand stove pipe yesterday to clean it and realised that the last person to re-assemble it used long self-drilling screws that penetrated both layers. I put it back together exactly as it was and now I've got a few air leaks at the joints. According to the manufacturer I should be replacing it and using the correct short screws.

This doesn't fit into my budget at the moment so I looked at single wall pipe with heat shields. That works out to less than 50% of the DSP materials. I have enough clearance on the straight pipe with a shield (it's a corner installation) but the two 45's up top are a concern. The upper 45 seen in the attached pic is exactly 9 inches from the wall and the lower one looks like it could radiate heat towards the ceiling. Can single wall pipe be used if elbow heat shields are installed?

Thanks for any advice!

 

[lopiliberty]

I wouldn't recommend heat shields. I can guarantee you your are not going to like how it looks. I put a heat shield on my single wall pipe last year and I absolutely can't stand it. I thought when I bought it "its not going to look so bad" but after a couple of months I hated the look. Going to replace it with double wall very soon.

 

[begreen]

Explain the leaks at the joints. Where are they? At the screw holes?

 

[EatenByLimestone]

I think I'd be trying to plug the holes with furnace cement and replacing the pieces as I can. But that's me.

Matt

 

[Jean-Claude]

Explain the leaks at the joints. Where are they? At the screw holes?

Right where two sections of pipe join, between the 3 screws. I'm wondering if a long screw failed to actually get back in the previous hole drilled through the inner pipe and managed to bend/push inner pipe inwards. I'll have time to pull it apart this weekend, again. I'm headed into town today and will price out replacement DSP components at 3 large stores.

Thanks!

 

[Highbeam]

Rather than the goofy metal pipe shield aren't you allowed to build a wall shield? You know, the ventilated type that is spaced off the wall. It would have the exact same function as the pipe shield.

How do you know you have any leaks? Even if you did, are you afraid of smoke leaking out? Is your draft too weak?

 

[begreen]

Right where two sections of pipe join, between the 3 screws. I'm wondering if a long screw failed to actually get back in the previous hole drilled through the inner pipe and managed to bend/push inner pipe inwards. I'll have time to pull it apart this weekend, again. I'm headed into town today and will price out replacement DSP components at 3 large stores.

Thanks!

That sounds entirely possible. This is not a great location for self-tappers. I always pre-drill a pilot hole.

I can't see any reason to replace the expensive DSP pipe based on what you've described. You'll need to take it apart, bend back the interior liner if it was bent in by the screw. Then mark the locations for each screw with a pencil on the outside of the pipe so that when you put the sections together you have a precise alignment. Then take a drill that is a size below the self-tapping screw size and run that through the hole first. Then screw together.

 

[Backwoods Savage]

And furnace cement is your friend. Very low cost too. Easy to work with and clean-up is a snap with a wet rag. No need to buy more pipe.