Drilling Fire Brick

[danno]

I'm rebuilding my grates out of fire brick. Any idea how easy/hard it is to drill fire brick. I've cut fire brick pretty easily over the years to brick a few different arches, but have never drilled the stuff.

I'm looking to drill 3/4" or 1" inch holes with a mason bit to allow some of the ash to fall through, and more importantly, to allow some forced air to come up through.

Any of you guys that have done this, were you able to find pre driiled brick, or did you have to drill it yourself?

[ericjeeper]

why not just use a House brick with holes already in it? They won't last as long, but they are cheap usually.

[Haynes Forest Products]

The slightly yellow fire brick drills like butter. Dont use the hammer drill option because that will cause cracking. H D has hole saws for tile and they will get you a bigger hole. If dust is a problem use a cordless drill and sublerg the brick in a bucket of water and drill the holes. When you drill as soon as the bit shows thru the backside stop and drill from the oposite side it wont blow out on you. Nice neat holes.

[WF MASON]

When I drill them I use a 3/4" cement bit and haul the drill press outside, I made a jig to clamp to the table and slide them along , 1,2,3 , makes it go faster.

[danno]

Thanks guys.

What do you use to support the bricks - when using them as grates. I'm thinking steel mesh. It obviously can't be sheet metal - cause I need air to pass through and ash to fall through.

Do the holes in the brick plug right up with ash?

[Bucket Head]

Yes, what do you use for support?

How many 3/4 holes per brick?

Full or half brick?

Also, out of curiosity, why are there two sizes of fire brick? Where would you want to use a thin one over a thick one, and vice-versa?

Steve

[WESTVIRGINIAMAPLER]

I use 2 pieces of angle iron 1.25" x 1/4" thick welded together and the ends cut off enough to allow the end to sit on the grate supports on my archfront and rear of the firebox. This allows air to flow between the supports and this design actually helps force air up into the holes in my opinion. This allows a nice flat support on top and I run the bricks lengthwise like the arch runs and have one of these supports on each side of a row of bricks and I would think as strong as these supports are and the constant amount of air flowing around them from my blower that they should last forever without any damage or wrapage.

[WF MASON]

I use 2"x2"1/4" going across from brickrest to brickrest , space the brick so you have 1" of the end of the brick sitting on the angle , and the edge of the drilled hole is 1" in so it is free of the angle. The next brick behind it , same thing , sits , butts up to the other brick , 1" on the angle the hole is clear. The ends of the angle is notched to sit down on the brick rest.

[802maple]

Suspicously sounds like WFMason and WestVirginiaMapler do it just like I do. You guys are good students. Everybody back to class. LOL

[WESTVIRGINIAMAPLER]

It's easy to be a good student when you have a good teacher like Jerry.

[Bucket Head]

Do any of you guy's have pictures of the fabrications and completed firebox's and brickgrates? If so, could you post them?

Thank's guy's.

Steve

[802maple]

Steve

I wish I was good in that picture department.

What I do is like Brandon said,except i usually use 2 inch x 1/4 angle.

I remove the the old grates and measure how long it is from grate ledge to grate ledge front to back and add a couple inches so that the angles will be long enough to sit on the ledges. You will also have to cut a notch out of the angle iron so that it will sit down flat on the ledge.

I put the first angle in the center and continue putting them at 4 and !/2 inch centers(as most firebrick are 4 and 1/2 inches wide) until you are out to both edges. This will allow you to have the firebrick laying on the angle by an inch. In my opinion it is important to have the angles going front to back as not to interfer with the airflow.

As far as firebrick go they drill very easy, I recommend 3/4 inch holes, I usally go with 3 holes but Brandon I believe went with 4. The best thing about brick are they are very easy to change if you don't mortar them as that isn't necessary. Plus the forced air grate that you buy from the Maple equipment guys allow to much air thru them as there are to many holes. Tis will give you plenty of air, if you want a hotter and more efficient fire just add air to the top.

This can be done by building a plenum where your blower is at the rear of the arch and putting duct work up through the bottom of your arch where your angle comes up to meet your flues, no matter whether they are dropped or raised flues. In side your arch I would use a piece of 3x3 or 4x4 by 1/4 inch box tubing and weld 2 rows of nozzles above each other of nozzles made out of 1/2 black iron pipe on 3 inch centers no matter what size evaporator you have. I would then insulate your new air injector system with 2300 degree 6lb blanket and you will be good to go.

Also in your plenum I would put some kind of damper system as to control airflow to the 2 places air is needed.

I know pictures will say a 1000 words but I haven't taken the time to figure all of that stuff out. I can turn this thing on and type because I was made to take typing in school but beyond that I headed for the woods

[danno]

Steve - you asked about 1/2 brick. There are a couple places I have used them.

I used them on the top row of brick directly under the pans. As they are thinner - they allow that much more fire under the edges of the pans.

I've also used them as a single layer over my vermiculite in the center of the arch. It's just there to keep the vermiculite from blowing up the stack.

[WESTVIRGINIAMAPLER]

I did drill 3 holes in my brick 3/4" in diameter as Jerry had mentioned above and it seems to put plenty of air from the bottom. I am working on hopefully adding air above and behind the fire next.

[SeanD]

Why put bricks on the angle iron at all? Don't the ash and blower keep the grate from warping?

[mfchef54]

my evaporator has three sets of angle iron for the bricks to fit on. I'm using regular bricks with holes, (like the original owner) . after the first three firings the middle brick broke and I just replaced it. the ash just falls through (what little there is left) Using a blower helps. I think the air flow is good. the original owner said that he was getting 10/hr, with the blower I'm getting18-20

[Bucket Head]

Thank's for the info guy's.

Jerry- I don't mortar my brick's either. I figured it would be better to be able to change them and remove them if I ever move the whole rig.

The square tube manifold would go around the entire firebox? It would not work if it was only on the sides, or on the sides and along the back only?

What about the height of it? My fire box is 17" from the grate to the bottom of the syrup pan. How high up from the grate, or how far down from the pan, should the row of nozzles be?

This whole system is to cause turbulence, and mix the combustion gases. Would there be any benefit to have the nozzles directed at different angles? Say, some pointing right at the fire, some up at the pan, and some down wards?

It's too late to get this system going this year, but I am looking forward to having it operational for next season. I have been thinking about this set-up quite a bit. I'm undecided wether I will plumb the manifold outside or inside of the evaporator. I'm leaning towards outside.

I'm already fired up about the 2010 season with this system in the works!

Steve

[ryan marquette]

Has anyone used firebricks for grates with no blower? I'm building an arch but I won't be able to do a blower this year.

[802maple]

Steve it won't hurt to point them at all angles just don't point any at the pans as that would be a cooling effect. I haven't tried putting them all around the firebox but I have always wanted to give it a try. I try to get them as close to the pans as possible and pointed down at the fire.

Ryan- I would doubt if it would supply enough air through the bricks.

[Bucket Head]

Jerry,

I might only be able to plumb the manifold in a U shape, with just the sides and back wall having the nozzles. Would that be enough air supply? Or should I go the extra and somehow get the manifold to the front too?

I also have given a lot of thought to a bubbler. Then I read what you said about the bubbler on the oil fired rig that kept steaming after shutdown. I think a small system, just in the rear third of my flue pan would make a difference. The boil is not strong at all at the rear.

What size high pressure blower would I need if I were to use one blower for the under grate air, the new over fire air, and possibly a small bubbler? Or, is it even feasable? Maybe it should have different sources, I don't know. I was thinking that if I were to invest in one these blower's, which are a little pricey compared to my freebie furnace blower, I would get one that would "do it all". Maybe even get one big enough to supply air to a steamaway also, but thats a long way off. I'm sure with ducting, and dampers, or diverters of some kind, I could divide up the air from a big blower so it could feed everything.

What size and horsepower blowers have you used, or seen on other rigs?

Steve

[802maple]

If you keep the air to the rear you might not need a high pressure blower. The reason I use the high pressure blower is due to the complexity of the duct system in getting air to our door. A standard blower just won't cut the mustard. If you add a few more nozzles in the rear it would most likely work and the system you say you are going to use will probably achieve that.

I would not supply air to a bubbler form the same source as you want a very protected air source as to not add flavor to your syrup.

[WESTVIRGINIAMAPLER]

Ryan,

I would think that using these type of brick on a stanard arch without a blower would cause the holes to get plugged up and kill the draft. You might get by with 1" or 1.25" inch holes, but you need a lot more air coming thru in natural draft or it won't pull enough draft.

[danno]

Drilling the fire brick was not too bad. Found that it helped to first drill with a 1/4" and then hit it with the 3/4".

[WESTVIRGINIAMAPLER]

Danno,

Good point to bring up and I had forgotten to mention it. It made it a lot easier for me to drill a 1/4 to 3/8 hole first which gave the larger bit a guide and it was a lot faster.

Amazing how soon we forget the little details.