Know where I can buy firebrick for Propane brazing?

[tycoonman]

It's commonly know that Propane alone won't get hot enough to successfully braze with. It would need to be mixed with additional Oxygen.

I've compared the numbers, and technically Propane alone would be hot enough to melt brazing rods (as they are made mostly of brass). The issues, however, is heat transfer, and simply too much heat is lost in the air.

Anyhow, I read and article that said that if you propane braze on firebricks (or better yet, make a little firebrick cave, then it will melt the brazing rods and heat the metal (steel in my case) enough.

Firebricks don't absorb hear like most items, and obviously mud bricks, so that otherwise lost heat is retained. They are used to line ceramics kilns.

SO, I think it's worth a try, and they can't be that expensive. I've touched 'em before and they're extremely light. They feel almost like foam... or lava rock.

Does anybody know were I can buy a few of these things? Preferably locally.


Article: http://www.carbideprocessors.com/pag...h-propane.html

[bob1961]

i would guess at any fire place shop or the big box home stores....using safety-silv i have used propane to braze with........bob

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[hotwheels000]

I would have to disagree with the statement about propane not being hot enough.... From first hand experience, I have brazed many a brakeline/hydrolic line tubers/bumpers/sliders etc... with just propane. Solid stock becomes a bit tricky but can still be done with just propane depending on the thickness of the material.

I use 1/16th brass filler rod and a powdered flux. Mapp gas will get a bit hotter for you and is redily avail at most hardware stores (yellow bottle). The only time I use my oxy/acet set up is for a more controlled heat in a smaller area since the micro torch has a finer flame pattern, or larger solid stock areas.

One problem you may encounter with propane when working with sheet stock is if the heat is applied to long it will "carbonize" the area so to speak. Meaning the material will become contaminated with the carbon in the steel and getting the brass to adhere may be tricky.(it will develop a black flacky type substance on the surface) Preheat or consentrate the heat on the thicher material to prevent to sheet stock from doing this. This can happen with any heat source if the heat is applied for to long in any one area.

All that said, I use a kiln brick when I am brazing on the table to prevent any fire hazard.It is not necasarry to accomplish the braze as most of my building is freehand and suspended in the aair via a vise or helping hands.

Hope that helps

Edit: I just glanced at the article and it touches on my comments in the 3rd paragraph. 1/8th solid flat stock is pushing the limits. I wouldnt see a use for that in our r/c builds much and as stated above, for tubing and the little stuff we use making these rigs....Propane alone is fine.

[tycoonman]

Oh, thank you very much! I've actually really revealed to hear that.

These are the rods I've seen at The Home Depot: 1/8 in. Flux-Coated Brazing Rods (3-Pack)-KH515 at The Home Depot

Next time I'm around I'll pick them up and try it out... also see if they have firebricks. I don't know of any local fireplace store.

[JKMotorsports]

I agree with hotwheels, but I know I buy my firebrick at Rona or Homedepot for my woodstove in my shop.

[tycoonman]

Originally Posted by JKMotorsports

I agree with hotwheels, but I know I buy my firebrick at Rona or Homedepot for my woodstove in my shop.

How much are they at Home Depot?

[WICKEDWOLFRC]

ever make it to SLC? we're gonna have 100± pallets pretty soon that will be going to scrap I'll be getting enough to build a firepit/oven

[DwaneO]

Originally Posted by WICKEDWOLFRC

ever make it to SLC? we're gonna have 100± pallets pretty soon that will be going to scrap I'll be getting enough to build a firepit/oven

Pallets of firebricks...or just pallets ? I need more info please.

Dwane

[DwaneO]

I guarantee propane gets hot enough, the fire brick is a good idea , just not real practical for our application. If you can get your parts in the "brick cave" has the OP said , you would be fine.....but not that easy.
Mapp gas gets a bit hotter and works fine , just preheat your rod and your work piece a bit.

( not my picture, borrowed from a search )


On sort la lame, et on teste avec l'aimant by poildortie, on Flickr

[bob1961]

i use a piece of alum plate 3/8" thick that i can clamp stuff to hold where i need it........bob

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[BigSki]

You never got an answer about the price, I know that locally I can get firebrick that is the size of a 'regular' red brick for about $5 each. The firebricks are available in different sizes. I get mine at a Ace/Courtland Hardware store.

[tycoonman]

Yikes, that's a lot for one brick. I think I'll skip that unless I have to.

Even then, I would like to get an arc welder... brazing will just a cheap experiment so I don't want to invest too much into it.

[WICKEDWOLFRC]

Originally Posted by DwaneO

Pallets of firebricks...or just pallets ? I need more info please.

Dwane

pallets of firebrick all differant sizes and shapes. When we'vescrapped it before it sells for a buck a brick. It was going to e used for our furnace at our smelter but was left outside so now it can't be used.

[JKMotorsports]

Ya, five - six bucks a brick.

[tycoonman]

Just got the torch head and fired a piece of 1/8" steel to a red glow. It took a while, but it worked just find. The Propane-air torch should be just perfect for my current needs. Hope to get started brazing the trailer frame together soon!

[dmgriff266]

the oxy / map torch from home depot with silver solder is the way to go. small easy to work with fine tip heat. and silver solder flows like water if done right. no fluf to clean up and files and shapes easy

just my 2 cents

[tycoonman]

Picked up the brazing rods today. Heated up the steel to a nice red glow, and could never heat the rods to melt... or even glow. I was very patient and heated for a looong time.

Oxygen-Propane torch is $60 from McMaster, but that plus the cost of fuel would cost just as much as a flux or arc welder.

[Trail rate this]

Can pavers be used for your application? They are really cheap and can be found anywhere. I used pavers when I built my fire pit and haven't had one problem yet.

[tycoonman]

Regular bricks absorb heat and can explode, so it would be scary to use them with too much heat.

Anyway, I bought a welder the other day and am really loving it. Nice step up for JB Weld!

Working on a 1:10 scale trailer frame right now.