HojPoj

Gotta say, I'm diggin' how your chisels are being stored/organized! Could you show a closeup of the one mounted to the left side of the bench? (looks like aluminum)

Looking at your bricks, is there a reason the ceiling brick has a groove cut in the middle of it? In thinking about the propensity for the bricks to develop cracks in use, you've essentially created a stress riser that guarantees you're going to get a crack there. If there's something 'hugging' everything together that I'm not seeing, then you're likely ok. If the top brick isn't being pre-loaded then when it cracks through it may just fall into the middle of the forge.

As it'll be fairly broad spectrum infratred lightbeing generated in the forge, it's a matter of what part of the IR youre looking to block. Polycarbonate (standard safety glasses) already block the farther end of the spectrum since they absorb in that band. Regular glasses reflect in the mid to long IR as well. Just by wearing something over your eyes you're already significantly cutting the amount of energy going into your eyeballs. The near to short IR range is invisible to us, but corresponds to over three times the visible spectrum. So if we make some (inaccurate) assumptions you're getting 3x the radiated energy you can see. All of the above isn't considering the spectral absorption bands of the materials in question or the gases present in the atmosphere. I would have to go back and check some references to say what the situation really is. Also, energy from a POINT source is a 1/r^2 term. Meaning energy drops of pretty fast the further you are away. A couple feet difference from the mouth of a forge will reduce it some, but may require looking longer than if you can be closer and see more quickly. Unless you're doing this for many hours every day, you'll be fine wearing standard safety glasses... just don't stare into the fire.

Given the time of year, this evening my family just went and attended a quick demo where we made 'candy cane' ornaments for the Christmas tree. 1/4 inch stock, twist along the length, bend the hook at the end, and quench. Tie a ribbon on it to dress it up, et voila! 15 minute project.

Sodium silicate is a completely different thing than colloidal/fumed silica. While it does rigidize the fibers, it does so through curing (like a glue, just requires CO2)... and at high temperatures can break down or act as a flux (eating away at your fibers). Fumed silica rigidizes the fibers by vitrifying the microscopic silica and causing it to bind the fibers together (like brazing). That's why the recommended procedure is to apply rigidizer and fire each layer as they're applied.

Just throw in with the rigidizer discussion, since I've just been recently making sure stuff I ordered should work: Be careful when ordering fumed silica, as many sellers on ebay don't specify the exact product name which can clue you into whether it's hydrophilic or hydrophobic. Of the more commonly available varieties Aerosil 200 is a hydrophilic fumed silica. In fact, if there's a letter before the number for Aerosil products (ex: Aerosil R 200) then it is one of their hydrophobic varieties (like what gets used for floatants for fly fishing). Didn't dig far enough to see if Cab-O-Sil had any such conventions.

Could you post a photo of your forge? If the openings are restricted or not large enough then that's a very real possibility. Are you dialing the pressure down to the bare minimum before turning the gas back on?

Or as I've better heard it described: "English is a language that lurks in dark alleys, mugs other languages and rifles through their pockets for spare vocabulary."

Man, those wheels must've been pushing the boundaries of that Unimat! Did you mill the slot in the table, or use something else to cut that out? What sort of motor is driving it? Regardless, looks nice!

It should conceivably work so long as you can safely handle getting the crucible in and out of the furnace. Typically copper gets run with a glassy cap or crushed charcoal to keep the oxygen off during melting. Not done any melts beyond aluminum, m'self, so I'd advise reading up on the techniques to run cuprous alloys over at AlloyAvenue.

If the VFD is rated for, the use of properly rated Braking Resistors can help reduce the stopping time. Without braking resistors you're somewhat limited in how quickly the motor can be stopped without back EMF frying the VFD.

Ausfire, that looks pretty spiffy! First thing that came to mind, though, was "Man, if those scrolls were BIGGER then it'd almost be like a cross hilt on a sword!"

Looking good! I really appreciate the effort you've taken in documenting this.

While Stainless isn't a stellar heat transfer medium, it's still better than the refractory. You may run into some issues with pre-ignition in the holes as the forge temperatures slowly creep up the tubes. I know Frosty has mentioned the problem on more than one occasion with the NARBs, particularly when turned down a little too far.

Thanks ThomasPowers, that was an interesting read!

I've got one that looks similar in construction, but roughly 2 inch wide flat profile. Been meaning to ask about it here as well.

Depending on the diameter and length of the rods, they can also be hollowed out and used as a thermocouple sheath either for submersion in molten metal, or just as protection in a forge. In the as-is condition, stir rods for melts, or electrodes for a lot of things (though electrolytic rust removal is a prime candidate on this forum).

John, what brand SLA printer did you get?

If they found their way home with your neighbor, then chances are they've lived their useful life in their intended application and aren't economical to reshape/sharpen. Just get em hot, there's a good chance they're brazed on. If they don't loosen up past a red heat, then there may be a stem that goes into the steel... which will probably be a lot tougher to remove. Generally scrap gets better prices when separated from other 'stuff' that's clinging to it.

Carbide doesn't forge. He would remove it so the steel its attached to would be used. Unless he has a really heavy duty application that could use that carbide, it can be scrapped for a decent price.

Or at the very least, think cone mandrels and swage blocks!

Huh, most of the scythe peening anvils I've seen look like a bottom fuller. Learn something new everyday.

Graphite blocks are pretty good conductors, so yes, it'll be a heat-sink. Wish I could access that much of it, though, would make great molds for casting.

Unless you know how deep the hardfacing was put on, you run a high risk of machining through the hardened section straight into the soft stuff. Personally I'd leave as is, unless I had the resources to resurface it (either the materials/equipment/knowledge, or access to a anvil repair workshop). The same could be said with trying to clean up the face, you might've removed a fair amount whatever hardened material was left. Unless the pits are causing a serious detriment to the surface finish of your work or the variance in the face is seriously affecting your ability to work the steel, just use it as-is.

True, unless the ball valve you select is oversized for the application, at which point the point of first flow creates enough orifice to exceed the desired gas flow (or rather, the difference between a little and a lot of flow is only a couple degrees of rotation). If using a ball valve for control of the idler circuit, I'd advise erring on the small side to ensure the ability to actually have a flow rate that's less than what's going to the full-flow branch of the circuit.