Firebrick For Silver Soldering

[tel]

It depends to a large degree on the origin of the brick. For many years fireplaces here have been lined with common red bricks with little or no ill effects. It is, or was, unheard of to use fire brick for this application.

Also the 'poor man's hot water bottle comes to mind - a brick heated in the open fire, wrapped in a sugar bag (when they were made of jute) and popped into the bed to keep yer toes warm.

While I have accrued a fair collection of odd fire bricks, including some made from castable refractory, I have pressed the odd common into service for small items, again with no deleterious result. Bricks, let us remember, are a clay based product kiln fired, so there should not be a problem.

 

[Artie]

I agree with Tel... back to my first point, what I was trying to say (poorly) is that we sometimes 'over complicate' simple processes/issues.... I lean towards the KISS principle.....

 

[GWRdriver]

Do house brick explode when used for silver soldering?

No. At least not in my very long experience. My small hearth was thrown together years ago and inlcudes a sprinkling of common brick in amongst proper fire brick. It is important to say that it's entirely in the dry so any moisture the common brick might contain is limited to what they might absorb from the day's humidity. The only thing I notice is they will sweat a bit on the surface if flame is applied directly to the brick surfaces, but then in silver soldering boilers I rarely apply the flame directly on the brick. But having said that, not all common brick are created equal so it has to be said that your mileage may vary. In any case I plan a larger hearth before long and I will use only firebrick in that one.

Another product I have used is called simply lightweight refractory brick. This stuff is from what I can gather a "foamed" ceramic and it weights a fraction of fired clay brick. It's a very light cream color, almost white, and is quite soft. It can be sawed and filed, almost like wood, and is available in a range of refraction from about 2700Kelvin to 4000Kelvin. I found mine, samples so far, at a boiler and furnace supply house. It's one drawback that I can see (but have not experienced) is that it is soft and brittle and would probably be susceptable to wear and breakage from having things dropped on or scooted around the hearth while being soldered.

PS - OK I just found my particulars . . . .

As above, the material is called a "light weight refractory" in brick form and is used for furnace and firebox linings. It's made in temperature grades from about 1600F to 3200F which corresponds to its porosity. The following are products made by Thermal Ceramics Inc. which should be available at refractory-foundry-boiler-heating suppliers.

# Density Service Temp
K-20 29 lb/F³ 2000°
K-23 31 lb/F³ 2300
K-25 42 lb/F³ 2500
K-26 48 lb/F³ 2600
K-28 51 lb/F³ 2800
K-30 51 lb/F³ 2900
K-3000 58 lb/F³ 3350
(There was a K-24 but it's no longer made.)

This material is a porous ceramic solid, the ceramic equivalent of sintered metal, and can be easily cut with a bare hacksaw blade. It's also sandable and carvable but it's also quite brittle and somewhat fragile.

 

[itowbig]

hummm interesting

 

[alanganes]

I just bought a bunch of "split firebrick" (that is what brick masons call them, I asked at the supply place) to reline my wood stove. They are 4.5" X 9" and 1.25" thick. They cost me $1.17 each from a local (I'm in NE Mass., USA) masonry supply place. They cost nearly 4 times that at the local hardware store. They were pretty pricey at the stove place as well. These are the hard dense refractory type, not the softer porous insulating type.

Of course I got a few "spares" to have in the shop for precisely the use you are considering.

I've used red bricks and floor tiles, too. I've also had them spit hot sharp shards in my face. No injuries, but still no fun. For a bit over a buck each, why bother with that sort of thing?