Cut out heatform myself?

[Tjm]

Bought some roxul I was going to line the inside of the heatform with but noticed the breathing/ dust concerns on the package so thinking if I use that I should prob block off the original heatform vents after all. Or not use the insulation and just stick with the steel plate/chase. Also think I’m going to ask the installer if they can use a double wall elbow off the back of the stove since that would be the only non insulated point in the whole system.

 

[bholler]

Bought some roxul I was going to line the inside of the heatform with but noticed the breathing/ dust concerns on the package so thinking if I use that I should prob block off the original heatform vents after all. Or not use the insulation and just stick with the steel plate/chase. Also think I’m going to ask the installer if they can use a double wall elbow off the back of the stove since that would be the only non insulated point in the whole system.

There is no reason to use double wall there. And double wall isn't rated to be buried or listed for use with the liner system. It you block off air flow in your case where the back wall is not exterior I don't see a benifit to insulating the cavity. If it was an external chimney then yes absolutely

 

[Tjm]

There is no reason to use double wall there. And double wall isn't rated to be buried or listed for use with the liner system. It you block off air flow in your case where the back wall is not exterior I don't see a benifit to insulating the cavity. If it was an external chimney then yes absolutely

I was just thinking it might be one more layer of protection since I cut out a 3/16 plate and I technically don’t know how thick the masonry is behind.

 

[EbS-P]

Not yet… Chimney was tarped off for rain after they poured the crown and I realized in a hurry without the draft sucking out the dust it was even more dirty than before! Got some nice sawzall blades to try. Hopefully later today. Also probably going to grab my pneumatic 3” cutoff tool or body saw back from my buddy to do the back side-to-side cut.

I put a box fan up top and it was quite effective. Almost so dust.

 

[Tjm]

I put a box fan up top and it was quite effective. Almost so dust.

Definitely planning on doing this now… Thank you!

 

[Tjm]

The box fan worked amazing! As did the carbide sawzall blade. Cut like butter. I just clamped the flopped over damper and cut theu that and the upper smoke shelf at the same time. Did the front to back cuts with the sawzall and then for the back side to side cut I scored it deep with the angle grinder and broke it off. I used 1” masking tape to mark the hole. Did t stick too well but it worked… I put the outside of the tape as my final size and then cut on the inside. Scores the outside and bent up that 1” as a flange I can screw to. Sides are bent up. Just have to finish the back.

 

[Tjm]

Think I’ve got a piece of 16 ga galvanized I can just cut and bent two wings fwd. have something to screw to everywhere except the front angles. Gotta either complicate my plate and add flanges or maybe attach a piece of angle on the back side of each side of the existing heatform. Plan is just self tapping screw la I think but guessing they’ll have to be predrilled at a minimum.

 

[Tjm]

just looked it up and I think galvanized is only good to 392F before it off gasses. Doesn’t seem like a good idea.

 

[bholler]

just looked it up and I think galvanized is only good to 392F before it off gasses. Doesn’t seem like a good idea.

It will be fine there it won't see those temps

 

[Tjm]

Bye the way…chimney work done. I think they did a real nice job… One was a roofline up rebuild and other was extended 4 ft to get past the peak of the house without funky chimney pipe. Crown and mortar still a bit wet on the two flue so that will still lighten up more.

 

[Tjm]

Another interesting find when pulling the old uninsulated liner… Mason pulled from above as I fed the ovalized part thru the old damper area and he called down that it was all clear when I was still looking at the liner in front of me. Turns out the liner was two pieces flanged together in the middle but the Self tapping screws used to attach the two pieces hadn’t pierced the inner wall so it was basically just pinched together like a set screw. Seems pretty lucky it never came apart while cleaning I’d say.

 

[begreen]

Amazing. Good thing you caught that in time.

 

[bholler]

Another interesting find when pulling the old uninsulated liner… Mason pulled from above as I fed the ovalized part thru the old damper area and he called down that it was all clear when I was still looking at the liner in front of me. Turns out the liner was two pieces flanged together in the middle but the Self tapping screws used to attach the two pieces hadn’t pierced the inner wall so it was basically just pinched together like a set screw. Seems pretty lucky it never came apart while cleaning I’d say.

That is why screws should absolutely never be used in applications like that

 

[Tjm]

That is why screws should absolutely never be used in applications like that

I’m assuming a liner made from two separate ( 10 ft?) sections is a no-no. Seems ripe for failure.

 

[bholler]

I’m assuming a liner made from two separate ( 10 ft?) sections is a no-no. Seems ripe for failure.

It is perfectly fine if done properly.

 

[Tjm]

It is perfectly fine if done properly.

Ok. Probably would have been fine if the screws cut thru the male pipe I guess.

 

[bholler]

Ok. Probably would have been fine if the screws cut thru the male pipe I guess.

Again no screws. Screws are absolutely not the proper way to do it. The proper way depends upon the type of liner.

 

[Tjm]

Again no screws. Screws are absolutely not the proper way to do it.

Oh I missed that. Just saw the -if done properly -comment. How should two sections be connected?

 

[bholler]

Oh I missed that. Just saw the -if done properly -comment. How should two sections be connected?

With the splice designed for that type of liner.

 

[Tjm]

Bottom went to the stove and top up and out. You can see the crimp on the top collar where screw didn’t penetrate. Looks like it should have had a collar on the bottom side and then something like the screenshot attached To lock them together I’m guessing.
Wow. It’s been like that for 27 years…

 

[bholler]

Bottom went to the stove and top up and out. You can see the crimp on the top collar where screw didn’t penetrate. Looks like it should have had a collar on the bottom side and then something like the screenshot attached To lock them together I’m guessing.
Wow. It’s been like that for 27 years…

View attachment 283421 View attachment 283422

That is heavy wall liner. It is the proper type of liner but should be attached with rivets not screws

 

[Tjm]

That is heavy wall liner. It is the proper type of liner but should be attached with rivets not screws

And correct me if I’m wrong but even back in 1994 should have been insulated for a Masonry chimney with wood/framing touching it?

 

[bholler]

And correct me if I’m wrong but even back in 1994 should have been insulated for a Masonry chimney with wood/framing touching it?

I believe so yes. That's a bit before my time in the industry

 

[Tjm]

Little bit of grinding to clean up my cuts and fits like a glove! Just have to secure it now.

 

[bholler]

Little bit of grinding to clean up my cuts and fits like a glove! Just have to secure it now.

View attachment 283723

Very nicely done.