# Firebrick For Silver Soldering



## Troutsqueezer (Nov 2, 2009)

Question: I was wondering if common red brick would suffice for making a simple hearth for those times when I am using a propane torch for silver soldering. I may use it with a MAPP torch for some brazing as well. 

I'm not sure where to find official, high temp fire brick around these parts. I know there are reflective and absorption properties that may come into play for this but to what degree is a mystery to me.  

-trout


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## mklotz (Nov 2, 2009)

Don't do it!

The water trapped in stuff like concrete and bricks can turn to steam when heated and spall off nasty, high velocity, sharp bits of shrapnel. DAMHIKT.

Fireplace brick and the like should be available at places that cater to home renovators.


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## georgeseal (Nov 2, 2009)

As Marv said DON"T do it


Tractor Supply has them ever wenter in a large box and are sold as each.

I pick up a couple each time I go buy bird seed

They are used to reline heaters


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## Troutsqueezer (Nov 2, 2009)

That sounds pretty definitive. I love it when the answers are as plain as the shrapnel in my eye... Thanks guys. I'll check those out.

I'm still kinda new here, what is "DAMHIKT"? Or should I ask?  I can guess: Do All Machining Hobbyist's Insist on Killing Themselves?  

-T


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## mklotz (Nov 2, 2009)

Don't Ask Me How I Know This/That.

If you run into other acronyms that puzzle you, you can decode them with the acronym finder...

http://www.acronymfinder.com/


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## shred (Nov 2, 2009)

I found firebrick (get 'splits' if you can; they're half as thick and much more manageable) at a brick-and-masonry supply store. If anybody constructs anything with a fireplace, there's such a store around somewhere.

If that doesn't work, and you're in anything close to an artsy area, check out pottery-supply stores.


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## Deanofid (Nov 2, 2009)

Also check any place that sells wood burning stoves. They line 'em with fire brick.


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## tmuir (Nov 3, 2009)

For small work I use a fire proof tile that I got for free from a pottery place that used them to line their kilm. The one I got for free had a chip in the corner. No good for them but perfect for me.
I've got 4 big firebricks to use for bigger items and they are realy HEAVY, also they cost me $15 each, hence why I only got 4. 

I've got a system now where I work on one item and plan what I want to do 6 months in advance and stat ordering material, tools now.
The idea is hopefully by the time I'm ready to start I have everything already.
It hasn't worked yet as I still constantly find I forgot to order something. :


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## Troutsqueezer (Nov 3, 2009)

>they cost me $15 each

oh ya, that's what I'm trying to avoid too. For that much money I can order a few more toys tools from LMS.

>The idea is hopefully by the time I'm ready to start I have everything already.

I keep telling myself this is only a hobby, take it slow, take it easy and take it as it comes. If I don't have what I need at hand, side step to something else for awhile. Still, I count the days each time I order something and the wife is starting to resent having to watch for the UPS man every week. *club* 

Thanks for all the good ideas. Maybe I'll try a brick and masonry supplier first, I know there's one around here. If not maybe the wood burning stove place although I've bought stuff for my stove there before and there came this giant sucking sound from my wallet. 

-T


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## rickharris (Nov 3, 2009)

Here in the UK any builders merchant will sell firebricks = about £3.50 each around $5.70

Information from Travis Perkins http://www.trademate.co.uk/products/productextra.asp?ProductCode=855782&M=I&Bounceback=/products/advsearchresults.asp?Words=firebrick:Type=allwords:Filter=


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## Artie (Nov 3, 2009)

Ceramic pavers are suitable and can be found at your tile centre, you only want a few so the cost will be minimal, I use them for resting the crucible on while I get ready to pour (and thats bloody hot). I dont use concrete or house bricks for this application though (never tried, and dont want to....).

Rob


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## max corrigan (Nov 3, 2009)

Troutsqueezer  said:
			
		

> Question: I was wondering if common red brick would suffice for making a simple hearth for those times when I am using a propane torch for silver soldering. I may use it with a MAPP torch for some brazing as well.
> 
> I'm not sure where to find official, high temp fire brick around these parts. I know there are reflective and absorption properties that may come into play for this but to what degree is a mystery to me.
> 
> -trout


Trout you can use Thermal Blocks easily obtainable from builders merchants or DIY stores can be cut to any size with a carpenters saw and very light and cheap and as others have said don't use bricks even bricks from an old furnace as i used once are deadly chips fly of them like bullets
Max.......


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## doc1955 (Nov 3, 2009)

georgeseal  said:
			
		

> As Marv said DON"T do it
> 
> 
> Tractor Supply has them ever wenter in a large box and are sold as each.
> ...



Thanks for the tip I didn't know Tractor Supply sold them. I will take note next time I visit them and pick up some I need to replace some broken ones in my welding table.


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## applescotty (Nov 3, 2009)

Also, note that there are two types of firebrick. There's the heavy kind, and the light kind. Perhaps they each have their own name, but it seems to me that they're referred to both as firebrick. The heavy stuff is what you want. It's more durable. It doesn't insulate as well (which is what the light kind is for), but for our uses, you won't be putting enough heat into it for that to matter.

Scott


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## Troutsqueezer (Nov 3, 2009)

I've got a lot of left over ceramic kitchen tiles from re-doing my counter tops. Would those work? These are a half inch thick.


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## firebird (Nov 3, 2009)

Hi

Towards the bottom of this page you will see how I made mine. 

http://www.homemodelenginemachinist.com/index.php?topic=2092.45

Cheers

Rich


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## itowbig (Nov 3, 2009)

ok i just got to find out why red brick wont work cause its made by fire and water and ive never seen it explode or any thing like that . i was in mexico for a while and while there i saw them making red brick its stacked very high and a big fire lit under it all. also why then is a fire place made of such red brick and it gets wet all the time from rain ect. 
i would assume that if the red brick was stored in doors then it would have no water content. 
not being argutive just want to know why it works for one fire and not the other . also when i was a welder i had a large table that the top was iron plate and the top filled with red brick for when i was cutting steal with a torch.
so i assumed that it (the red brick was ok to use)


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## Artie (Nov 3, 2009)

Itobig, the discussion regarding moisture content and explosive spalling in the building industry goes on. The last paper I read indicates that there is no real evidence for OR against the moisture theory. Who's right who's wrong..I have no idea really. Personally I have my theory and its more to do with very localised heat (and therefore localised expansion) on a very brittle and inflexible medium.

To test whether house bricks is suitable get your oxy or propane torch out and play it on the brick (wearing suitable portective gear of course..), you will soon know.

I dont know exactly how a brick will react, I know concrete will react quite violently......

Incidentally, the build up of a fire brick kiln for job heating purposes is generally used for heating larger objects to quite high temps..like preheating a cast iron cylinder head prior to welding...

Does anyone here think its really necessary for the very small items this site is concerned with? Ive never used such for small silver soldering or bronzing... 

Just my thoughts... for what its worth... (mostly not much.... :)


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## Troutsqueezer (Nov 4, 2009)

firebird, I like that setup. It also gives me an excuse to fire up my welder.


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## Steam4ian (Nov 4, 2009)

G'day

Do house brick explode when used for silver soldering?

Limekiln dry house bricks may not explode. Equally wet fire bricks will explode (well most likely).

Part of the problem is how the material in the brick deals with differential expansion, fire brick can handle heat differences better. Clay Tiles will not be very good in this aspect. 

Concrete will spall under heat because it is a hydrated compound which breaks down under heat releasing water as steam.

Fire brick can be obtained from pottery supply stores, barbeque service stores, potbelly stove service stores and more recently the places that sell outdoor ovens.

You can even get castable refractory which works well. Made some fire bricks for a brick arch on a full size steam loco; they were OK for a number of years.

Regards
Ian


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## tel (Nov 4, 2009)

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.


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## Artie (Nov 4, 2009)

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.....


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## GWRdriver (Nov 4, 2009)

Steam4ian  said:
			
		

> 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.


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## itowbig (Nov 4, 2009)

hummm interesting


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## alanganes (Nov 6, 2009)

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?


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