The local Furnace supply didn't have any half-thickness firebrick. They said I should just go ahead and cut them down with a tile-saw/ceramic-cutter/cement-saw, etc.

I have a diamond saw blade (7-inch diameter) that I could mount to a circular-saw (electric,) or, I could mount it to a large 8-inch pneumatic (air) grinder, and apply a continuous spray with a garden-hose to it while I cut.

Of course, I'll wear a particle-face-mask, eye-protection and gloves.

They are standard 9x4.5x2.5 brick, and I only need to cut a few.

Which is the better way to go, or is there a better way (that DOES NOT involve buying more brick and paying for shipment?)

I would not use the electric with water as it could shock you . The air grinder may work but you must check to see that it does not exceed the maximum speed of the saw blade., If that is the case, youi may be able to reduce the speed by lowering the air pressure. You can get a saw blade to fit a hack saw frame that will work wet and it should not take you too long to cut a few of them.

Wet or dry will depend on the saw blade.

You may be farther ahead to rent a tile saw for an hour or so, it takes maybe 45 secs to split a fire brick with a tile saw.

Sometimes it isn't worth the hassle to kluge something together when a good alternative is available.

Frosty

Check local farm supply stores that carry those pellet stoves and such, they have the 1 inch fire bricks in boxes of 6 or 8 very reasonable.

I have used a brick hammer for regular bricks, I am not sure if fire bricks are much different than regular bricks.

Order half thickness bricks from Larry Zoeller... Just Google with his name to get the site url.

I tried to cut a few with a brick hammer and it didn't go to well.You can get a good cut if your just trying to make a half brick, but I don't know about doing it the length of the brick.
Check your blade and see if it's a dry blade.If it is ,you should have everything you need.Dad has one of those blades and it works good,and yes you need a mask because they make alot of dust.

What 48 willys said.

If you have a 4 inch grinder there dry blades for them meant for tile, or that's what i use them for. I would would imagine you could use them on brick, just don't rush it. Oh, and not just the mask, safety glasses too.

Mount your 7" blade in a portable table saw. Then make light cuts 3/16 at a time flip the brick and cut from both sides. You'll be though the brick fairly quickly and wont burn up your blade.

I just built a new forge, a brick side draft. I used my normal chop saw, and bought a brick rated blade (about $15 vs the $20 I pay for a package of the 14 inch diameter metal blades.) to cut them. while I did all the cuts dry, I kept a 5 gal bucket of water at my side to dunk them and keep the brick cool, as the heat build up will crack or chatter them.

Worked well. I cut 80 fire brick and a small percentage of the 1000 regular brick with it, I wore out about 3/4 the blade, its till usable. PLus I had the stability and safety of the chop saw that I would not have had with a hand saw.

Appreciate all the great replies/advice.

I'll experiment around a bit and see how that goes. Buying 1/2-thickness brick would be great, but I want to do this today and not a week from now, and (unfortunately) there is no farm-supply store nearby that sells brick for pellet-stoves either.

I do have a chop-saw/abrasive-cut-off, and I thought about trying that too. In any event, I'll take my time and go slowly with it. If I can't make it work, I'll be forced to wait and buy them, but maybe I'll get lucky and it'll work.

Thanks Again.