Originally Posted by Zeke (Post 10568862)

He was here yesterday. Phone no. in his avatar.

Originally Posted by Zeke (Post 10568245)

I'd like to see the ratio of ingredients by volume for the resins, steel particles and other fillers. I think you are correct about the binding aspect but I'd fall short of calling JB "steel."

This may be of interest as no "steel" or even AL particles are mentioned:

What is in JB Weld?
Bisphenol-A-(epichlorohydrin)
The resin in J-B Weld epoxy is bisphenol-A (yep, that BPA) combined with garlicky-smelling epichlorohydrin. Chemically, the molecule is a chain with little carbon-and-oxygen triangles, called epoxide rings, on the ends. That’s where the sticky action happens.

Crystalline Silica
Basically quartz. It’s added to the resin for body and viscosity, without which the goop would be too fluid to adhere and set properly—more like J-B Melt.

Carbon Black
The name says it all. Made up of sooty bits often produced by burning hydrocarbons, it gives the resin its inky color.

Calcium CarbonateA cheap filler, found in both the resin and the hardener. Like the silica, it gives the product more volume while decreasing the cost per ounce.

Tetraethylene*pentamine
This is the curing agent. It contains amine groups that break open the epoxide rings so their carbons can hook up with the amine’s nitrogen. One TEPA molecule can lock onto four epoxy resin chains, and the other ends of those chains can bond to other TEPA molecules. All that cross-linking forms a super-strong network structure—a thermoset polymer. When it hardens, J-B Weld can withstand forces of nearly 2 tons per square inch and temperatures up to 550 degrees Fahrenheit.

DMP-30
The curing agent on its own is kind of lackadaisical at opening the rings, so epoxies often use accelerators like this one. DMP-30 is short for 2,4,6-tris(dimethylaminomethyl)phenol. It has a reactive hydroxyl group (–OH) hanging off the side that helps rip those epoxide rings open like Christmas presents.

Benzyl Alcohol
This colorless liquid modifies viscosity and acts as a solvent to help the curing agent disperse during mixing. Like DMP-30, benzyl alcohol also has a hydroxyl group that can trigger curing, so it’s put in the hardener tube.

Titanium Dioxide
This stuff adds more body to the mix, and it turns the curing agent a color-coded white. Mix with the black resin and you get that famous gray.

Barium Sulfate
More filler. BaSO4 is radiopaque, which is why they make you swallow it to x-ray your innards. Pro tip: Do not attempt this with J-B Weld.

Source: https://www.wired.com/2016/08/whats-inside-industrial-epoxy-bpa-somethin-garlicky/

Originally Posted by A930Rocket (Post 10568825)

Is there a way to make JB Weld darker by adding something?

Originally Posted by Zeke (Post 10569353)

If you look at the ingredients, I would thing some more carbon black would not compromise the compound. You could grind up some BBQ bricketts and screen the powder but I'd be somewhat concerned about the additives like the binder. You could do the same with real charcoal I suppose. However, there are black pigments available. I have some that dissolve in water which I then add to alcohol so it becomes soluble in shellac. IDK if that would mix properly with BPA but the raw powder likely would.

https://images-na.ssl-images-amazon....IL._SY550_.jpg

10 bucks. Your local art supply will have this too.