Block arch

[Kacey small scale maple]

I am building a block arch an was looking for any info on them as far as the flue getting thru the block an insulating I am putting it on a concrete pad and ame planning on mortaring it together. Any wisdom would be great thanks 😃

[Thompson's Tree Farm]

Heat will eventually break the block. Line it with fire brick.

[maple flats]

Yes, line it with brick and an inch of ceramic insulation between the block and brick will help the blocks hold up well. Without the bricks the blocks will fail very soon, the insulation (if you chose to use it) will further protect the blocks. You have to realize, an arch is not like a fireplace or any other use. You burn it as hot as you can to boil the fastest possible (and for long periods of time) and by that you make the best syrup. The heat generated far exceeds what a concrete block can handle by itself.

[Kacey small scale maple]

Thanks for the info

[tcross]

u should insulate it with fire brick if you are planning on using it for more then a couple of years! I did a block arch last year and only wanted it for one year before I upgraded and I did not insulate it! I only made 7 gallons of syrup on it, but I did not have one block break... or even crack for that matter! so, for a year or two... you could be ok, but if you can... use firebrick!

[madmapler]

Assuming you're using solid block, You can cut the block with a cheap masonry blade that'll fit in a circular saw. Just plunge the blade into the block and rough out the size hole you'll need for an 8" or 10" terra cotta thimble. If you cut most of the way through you can ussually pop the rest out by tapping it with a hammer. You can get whatever size and length thimble you need at any masonry supply. Then fill in the gaps with masonry cement or refractory cement if you have it. I suppose you could just use stove pipe instead but you'll have to replace it occasionally.

[palmer4th]

I used regular blocks, (not solid) regular fiberglass insulation in-between each course and in-between each block. they are just dry stacked. the fire box portion has fire bricks and the flue section just have red bricks. I have used it for two years still in great shape.

[MapleLady]

Very nice design. Is the front fire door your own design?

[Bernie/MA]

I made a frame to put on top of a block arch for my grandson. He had about 15 buckets so the pan was only 18x36x6" deep. The frame is about 2'x4' with a flue hole on the back end and a hanging door on the front with a grate on the bottom. I can send pics. My email is bearlysane43@yahoo.com. Put sap arch in the title.

[Big_Eddy]

If you look at the block arch thread in my signature, you will see my solution. Mine was never a permanent arch - rebuilt every spring - but what I did was build the arch about 12" longer than needed, then laid a flat plate of steel over the last 12". I cut a "round" hole in it and welded a ring on to locate the base of the stack. For a more permanent installation you could do the same and tapcon the steel to the top of the blocks.

I've played with various other methods - for me this was the simplest and most effective solution. I have since built a few more plates for friends and family.