Heat Blocking Paste

N

Natlek

Joined
Jun 9, 2015
Messages
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I did not notice that there was topic on this subject in this part of the forum . I think that this is good to know and usable in knife making .........................I use this paste in my no knife related work many time and it works ! Well , I can t find video that is not commercial and if it is no go , mods. can delete ...............

 
I have it, but almost never use it. I am not comfortable with it as being reliable for knife work, and certainly not for fine jewelry work.

It blocks a flame from touching the surface covered, but won't stop heat from moving through the metal. That works fine for protecting thin places in a ring while welding a new shank on. However, anything under the paste and still in contact with the mounting, like a delicate stone, may still be ruined by heat from the hot metal.

If used to protect a HTed blade while doing some brazing on the tang, I would expect some of the heat to still run down into the blade and affect the temper. It protects the surface from the flame, but doesn't have enough thermal mass in my opinion.

I prefer placing the blade in a larger heat sink (more thermal mass). like between two metal plates, in water, or wrapped in a wet towel.
 
Notice the guy didn't hold the steel in his hand! I can guarantee it wasn't at room temperature.
Advertising like this makes me want to never buy the product.
We used wet asbestos to do the same thing Stacy spoke of in the jewelry business.
 
I've got a bottle of it, but I've never used it. Can't comment how it works.
I've always used a wet rag and a spring clamp for brazing tangs and the like.
 
Aluminium blocks work just fine. When i need to anneal a hardened tang, i have the blade clamped in a vice with two aluminium blocks clamped at the lower part of the ricasso. Color change due to the heat barely even reaches the aluminium plates and the blade is just barely hand-able afterwards. It takes a long time before the aluminium blocks heat up to the point where it will start to have an effect on the blade.
 
Bill, your post brings back fond memories of my 5 gallon barrel of powdered asbestos. It was mixed with water to make heat shields for jewelry and other brazing work and also mixed with a cement to make refractory patches and cover joints on steam piping. We also used asbestos paper and asbestos roll soldering pads. I eventually got rid of it along with my old asbestos iron smelters suit and a 4X6 foot asbestos welding blanket. They had a free hazardous materials drop off day and I double bagged the lot and took them down. I kept one asbestos glove and have it on the grinding room wall ( in a heavy plastic bag) as a souvenir. The days when asbestos was in every shop are now replaced with closing an entire building and calling the haz-mat teams when someone detects a few ppm of asbestos particles in an air sample.

Heck, I used to go rock hounding for kyanite and other crystals at an old asbestos mine.
 
Stacy E. Apelt - Bladesmith said:
It blocks a flame from touching the surface covered, but won't stop heat from moving through the metal.
If used to protect a HTed blade while doing some brazing on the tang, I would expect some of the heat to still run down into the blade and affect the temper. It protects the surface from the flame, but doesn't have enough thermal mass in my opinion.
Click to expand...
Stacy , it works . I use this thing many ,many years.........When I weld something with paint on for example , I have no burn paint very close to welding spot with this paste .Ask some gunsmith about this , they use this stuff often .....
I Will do some test and measurement of temp this Spring............in my neighborhood I have SKF distributor and they have some expensive gun for temp measurement I can borrow....
 
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I was a steam engineer in my real life. LOTS of asbestos!
 
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