Magnaflex offset box

[PLAYS WITH FIRE]

Well, I got the offset box today:-( All I can say is that the only thing that will not leak on it is the clean out door! It looks as if it will pull draft through the box and not through the stove. I can use stove cement and some screws to seal it quite well on 3 sides but not the top. I can only get the cement on the top and that is where I am concerned!
I don't have room to add cement later because once it's in, it's in! Knowing how heat can deform metal pretty good especially with flue temps. When that thing deforms, that will kill my draft and be a creosote factory. I feel confident that cement will hold this together permanently. If I can't think of a way to get a screw to hold it together. This project is on a permanent delay!

I can make my flex pipe shorter but can't make it longer. Not only that but if we don't have wood heat, the wife will kill me! I posted pix see what you think....



Oh and ps, they said this was variable from 15" offset minimum to 21" either I got the wrong one or they are terrible at logic/math. The box is 15" long and the offset at that length is 6". Full extended the box is 21" and the offset is 12".

 

[DAKSY]

Can you take it completely apart? If you can figure out where it's final positioning & adjustment will be, mark it with a Sharpie, disassemble & maybe try to seal it a little better by installing some 3/4" self adhesive tape gasket in the gap locations before you reassemble. I'd probably wrap the entire thing with aluminum tape, but that won't last much more than a season...

 

[Heatsource]

one of the many reasons i hate to install offset boxes!
poor draft- hard to seal
cloggs- and hard to clean properly
etc
Bob's advice is good, flat tape will last far longer than furnace cement!

 

[wkpoor]

I'm really glad you posted on this. I have been want to fab one of these myself because my basement install has the pipe coming off the stove at about a 30 degree angle and I would prefer it go straight up.
As for the leakage issue I have my stove pipe downstairs taped with an aerospace tape. The first joint is less than 12" above the stove top. All three joints have survived 2 yrs of heating 24/7 during winter months, and the pipe has seen 600+ countless times. The tape shows no signs of stress at all. It even has held up from about 6 pipe removals for cleaning. Problem is I can't give you any info as to where to buy and I'm sure it would be very expensive. It sure looks better than that messing looking cement. Also this stuff doesn't get nasty like Duct tape does with age.

 

[PLAYS WITH FIRE]

The cement will work how I am going to use it. I am going to draw the out line of the box so I know where to smear the cement. Then I will slide the boxes together and make a gasket. The way I figure, I will have about an inch gasket around the entire boxes. My initial problem was screwing it together and then installing it in one piece. Well, my neighbor and I checked and actually made a cardboard template to check but we are confident it will work.

As for the draft and cleaning, I am not concerned. My draft right now is strong enough to pull the door closed. Cleaning should be fairly easy as there is a clean out door and if I slide a piece of metal in there. I won't have to remove my baffle to clean out the crap. To help get rid of any " edy currents" in the box I will cut a piece of Roxul to the dimension of the back to smooth the transition.

The benefits of this far outweigh the disadvantages....being able to put 75%+'of the stove into the area is huge! The more I thing about it I may have a friend weld the box together..........problem solved!