removing fireplace damper

[MrGriz]

You should not have any trouble getting a brush through the ovalize liner. The brush that you want to use with a stainless liner is poly and has some give. There will be a tight spot where the brush passes through the ovalize area, but it should go.

Keep in mind that your are only ovalizing the liner enough to get it through the damper. That should not require compressing the liner more than about 1/2" or so. Also, this portion should only be long enough to pass through the damper opening and then be rounded again for connection to the collar. You definitely do not want to compress or crease the liner when you ovalize it.

As I stated earlier, I have not had any problem with draft from ovalizing the liner. In fact, my situation has three things going against it as far as good draft is concerned. It's an exterior chimney, the liner is not insulated and I ovalize a bit of the liner to pass through the damper opening. Even with the triple threat, I have plenty of draft, bordering on too much in extremely cold temps. I guess in this case I'd rather be luck than good.

 

[Highbeam]

Cross sectional area at the oval is reduced compared to perfectly round. Taken to the extreme an ovalized pipe has no area so anything other than perfectly round has less cross sectional area, a higher perimeter to area ratio, and will be a hindrance to draft. Of course you need to put things into persepective and remember that the 2% difference is no big deal.

 

[HalJason]

Cross sectional area at the oval is reduced compared to perfectly round. Taken to the extreme an ovalized pipe has no area so anything other than perfectly round has less cross sectional area, a higher perimeter to area ratio, and will be a hindrance to draft. Of course you need to put things into persepective and remember that the 2% difference is no big deal.

I believe that as long as the circumference doesn't change from round to elliptical, the cross sectional area won't change either (assuming we're talking about a circle and an ellipse, not a creased circle). I could be wrong, but I don't think I am.

-Hal

 

[Andre B.]

I believe that as long as the circumference doesn't change from round to elliptical, the cross sectional area won't change either (assuming we're talking about a circle and an ellipse, not a creased circle). I could be wrong, but I don't think I am.

-Hal

Far as I know a circle provides the maximum area possible for a given perimeter length. If the shape changes in any way while maintaining the same length perimeter the area will be smaller.

 

[Highbeam]

[/quote]

Far as I know a circle provides the maximum area possible for a given perimeter length. If the shape changes in any way while maintaining the same length perimeter the area will be smaller.[/quote]

Yep, same with volume and a sphere. Anything less than perfectly round or spherical gets a reduction in enclosed area or volume.

Always go to the extreme and consider that if you collape/oval/distort that round liner until it is flat then as you approach flatness you approach zero cross sectional area.

 

[firebuckeye]

This shows some number and what you need if ovalizing.

(broken link removed to http://www.lindemannchimneysupply.com/HTMLobj-2872/vnox_ovalizing_inst..pdf)

 

[begreen]

You got grinder skills for a cave dude!
IM not so sure on that dryer vent as a liner though.

just dont get a flu temp over 150 and youll be fine.

Hey, Its so easy...................... even a Neanderthal can do it!
I was not a happy camper in there grinding & cutting away. I the only thing left white on me was my teeth

:bug: Well I guess the next time you'll wear some clothes while grinding away... or maybe not. %-P :lol:

 

[HalJason]

Far as I know a circle provides the maximum area possible for a given perimeter length. If the shape changes in any way while maintaining the same length perimeter the area will be smaller.

Yep, same with volume and a sphere. Anything less than perfectly round or spherical gets a reduction in enclosed area or volume.

Always go to the extreme and consider that if you collape/oval/distort that round liner until it is flat then as you approach flatness you approach zero cross sectional area.

I stand corrected. Spent the evening geek-chatting with my father and brother and we've come up with enough cases that prove my initial statement wrong, that I'm OK admitting it Glad I had wine in the house.

My apologies

-Hal

 

[Larry H]

I did my Dad's upstairs and downstairs stves just like Hog' and Ojeep did theirs - 41/2 angdle grinder / sawzall combo. Piece of cake. Make sure if you do it you wear a face sheild and or some other PPE. If the installers do it for you then no worries. I recently had an eye injury and it is not a fun thing.

 

[Hogwildz]

You got grinder skills for a cave dude!
IM not so sure on that dryer vent as a liner though.

just dont get a flu temp over 150 and youll be fine.

Hey, Its so easy...................... even a Neanderthal can do it!
I was not a happy camper in there grinding & cutting away. I the only thing left white on me was my teeth

:bug: Well I guess the next time you'll wear some clothes while grinding away... or maybe not. %-P :lol:

Oh wow, is that what I did wrong? You mean if I wasn't nekkid, I wouldn't have had those sparks burning my skin everywhere? And just for the record, I was clean between my cheeks

 

[BurningBrit]

Great discussion. This is precisely the issue I'm planning to deal with. Haven't even purchased my insert yet, but just mulling things over.When I bough the house three years ago, the chimney sweep (from Lotirzo's in S. Philly) told me that it was originally built as a coal burning fireplace, and that if wanted to burn wood, I'd need to widen the throat by taking out the moving damper plate. I've taken out the plate, and after installing a smoke roll out guard it works quite well, as a wood burning fireplace. The damper is still in there ( i mean the bit that that doesn't move). Now three years later, I want to buy a wood burning insert. With the damper still in place, I would have to ovalize a flex liner to about a 4 inch diameter to fit it through the opening. However, if I smash out the damper and frame,, I should have about 8 inches. I cant imagine anyone ever wanting to use the fireplace as a wood burning fireplace again, so I think this is the way I'll go. All 20 or so houses in my street are identical, and most have converted to gas inserts. For some reason, I'm the only wierdo, that wants to put a wood burning insert in. Someone in this thread suggested that the damper and its frame, might serve a structural role. Is this really true. I'm somewhat skeptical.

 

[LeonMSPT]

I cut 'em with a two foot pipe wrench... just take a decent bite and break it out... repeat as needed... get the middle out front and rear, use a wrecking bar as required.

Of course, I am 6'3 and weigh 265 pounds... I broke a grip strength dynamometer at my first job out of school as a physical therapist. New employer just about crapped himself...

"Squeeze it hard?"
"Yeah, as hard as you can."
"Like this?" (spurt, as the brake fluid shot all over the carpet)

"Hmmm, was that old?"

 

[gpcollen1]

FYI - this thread is 2 yrs old.

 

[Green Energy]

Great thread - Needed to widen the throat of my damper plate in my fire place to fit my 6" flex liner. The damper opening is about 6" and I want enough clearance It about 1/4 inch to 1/2 thick cast iron. I cut a couple of notches about a foot apart with a circular saw and a metal cutting disk. I figured I would see if I could get my 7.5 inch circular saw up to the plate. I had to cut at an angle to get the saw in there. After cutting about an inch on each side. I got discouraged because I could not really maneuver the big saw in the small space. Also, I though I was poisoning myself with the smell of the disk and/or the creosote residue.

So I figure I would check with the experts, or at least see what I could learn from other peoples experience. Found this thread. Found someone who said a hack saw would work. Tried a hack saw for about two minutes, slow going, blade probably dull. I also saw some one who said that they wacked at it with a 5 lb sledge. I remember that cast iron is very brittle material, does not bend, it breaks. So I got my 2.5 lb hand sledge and five or so wacks at the notch I cut almost perfectly broke loose the bottom section across to the other notch.

So now I have a foot wide section that is 8" wide. Conclusion, a couple notches with a sawall or hacksaw and some wacks with a small sledge hammer is the way to go. If you use a grinder, eye protection and a respirator is the way to go. I did not wear the respirator and I was blowing black soot out of my nose.

 

[LeonMSPT]

Great thread - Needed to widen the throat of my damper plate in my fire place to fit my 6" flex liner. The damper opening is about 6" and I want enough clearance It about 1/4 inch to 1/2 thick cast iron. I cut a couple of notches about a foot apart with a circular saw and a metal cutting disk. I figured I would see if I could get my 7.5 inch circular saw up to the plate. I had to cut at an angle to get the saw in there. After cutting about an inch on each side. I got discouraged because I could not really maneuver the big saw in the small space. Also, I though I was poisoning myself with the smell of the disk and/or the creosote residue.

So I figure I would check with the experts, or at least see what I could learn from other peoples experience. Found this thread. Found someone who said a hack saw would work. Tried a hack saw for about two minutes, slow going, blade probably dull. I also saw some one who said that they wacked at it with a 5 lb sledge. I remember that cast iron is very brittle material, does not bend, it breaks. So I got my 2.5 lb hand sledge and five or so wacks at the notch I cut almost perfectly broke loose the bottom section across to the other notch.

So now I have a foot wide section that is 8" wide. Conclusion, a couple notches with a sawall or hacksaw and some wacks with a small sledge hammer is the way to go. If you use a grinder, eye protection and a respirator is the way to go. I did not wear the respirator and I was blowing black soot out of my nose.

************
I just use a two foot pipe wrench... iron snaps easily and starting small, nibbling away where I can get a purchase. Just take a gap in the middle of each side and remove the whole mess. It's not structurally necessary in most hearths, it's there to hold the damper.