By Skye from Seneca, Pa on March 3, 2013
When passing a thimble through a thick masonry wall (foundation block faced with solid brick), how do you fabricate an extension for the thimble?
Will this thimble connect single-wall pipe to double-wall chimney? What adapters/collars are needed at each end to connect flue/chimney?
By Collin C. - NFI Master Hearth Professional on March 4, 2013
Typically, an extension for the thimble is fabricated by using 26 or 28 gauge sheet metal and forming it into an 8 inch diameter circle of the required length. Rivets are commonly used to hold the sleeve together at the overlap.
The transition to Class A chimney pipe occurs inside the house. A stovepipe to chimney pipe adapter must be used. For the MetalBest brand, the MetalBest Ultra-Temp 6 Inch Diameter Chimney Pipe Adaptor - Chimney Pipe
is the required item. This adapter will twist into the end of the chimney pipe, then allow you to mate a single wall stovepipe to the tapered end.
By Stacey from Northampton, MA on October 9, 2012
I have a lined, outside chimney that doesn't have a thimble; it looks like someone built it for a wood stove but then never followed through. I'd like to put in a wood stove with built-in rear heat shield by a sheet rock wall, to keep the look simple and clean, and not to have to put masonry up the wall.
If I use this through the wall, will I be able to back the stove up to the sheet rock with the appropriate amount of clearance, or will I still need brick or tile over the wall?
By Tyler M. - Fireplace Specialist on October 10, 2012
Answer:Depending on the stove you purchase, the required distance to the rear wall can vary. The minimum distance is usually around 12" - 15" without an approved heat shield. This thimble is indeed something you may be able to use, if you choose MetalBest Class A pipe to vent the stove.
This thimble is intended only to house MetalBest Class A pipe with a 6" inner diameter (8" outer diameter) as it passes through a wall into a tee outside.
By jon bliss from lovell, maine on December 7, 2011
Will it work on a 3-1/2" wall or will I have to build out?
By Collin C. - NFI Master Hearth Professional on December 7, 2011
Answer:This thimble can only be adjusted down to a 6" thickness, so it would indeed be necessary to build the surrounding wall out or trim the sheet metal collars on the thimble down to a shorter length.
By Ben from Bedford, MA on October 29, 2013
I need to vent commercial ironer through a wall. According to the ironer manufacturer, the exhaust temperature is approx. 140 degrees F. I'll have a single wall 6" round duct through a sheet rock, CMU and EIFS (2" Styrofoam) assembly. Will this thimble work? If not, what do you recommend?
By Chris on October 29, 2013
By Robert Taylor from Standish, MI on April 24, 2012
I need a wall thimble for a 6" dia. pipe through a 3" wall. Does this exist? I can find it for a 4" wall but not 3". ( mobile home )
By Collin C. - NFI Master Hearth Professional on April 24, 2012
Answer:Unfortunately, there is not a wall thimble in production that is able to be adjusted to a 3" thickness. It would be necessary to use a standard thimble, such as this model, and cut down the overlapping pieces of metal.
It is possible to use the thimble safely, as long as you are able to make a clean cut and allow the telescoping sleeves to overlap properly.
By Thomas from Como, Colorado on October 4, 2013
I'm planning on putting this through an end-wall of a hunting cabin. Can I run single wall 6" pipe through this and be alright?
By Collin C. - NFI Master Hearth Professional on October 4, 2013
I do not recommend using this item to pass single wall stovepipe through a wall. This item is only intended for use to pass double wall class A chimney through a combustible wall. Because of its high surface temperatures, single wall pipe cannot be located any closer than 18 inches to combustibles. The only way to get around this rule is to use a special insulated thimble, such as the Heat-Fab Insulated Saf-T Stovepipe Wall Thimble - For Stovepipe with 5-Inch and 6-Inch Diameters
. Otherwise, the conversion to class A chimney must be made.