HojPoj

Are you considering posting your designs to Thingiverse? Printing the parts for casting had been on my list for awhile, particularly for a NARB, just haven't gotten to experiment with the holes and sizes. For the interface to the mixing tube, are the intakes using threading, or just slipping over the pipe section?

...and what material?

I've made a furnace out of a 20lb propane tank, and it only needs a 3/4 Reil burner to do Aluminum. That said, I believe 4" was the recommended outlet diameter for that size furnace. May want to double check on AlloyAvenue (look for the .pdf book by user Anon).

JLP, this was an excellent video. Thank you so much for taking the time to document the build and showing how it's used!

I've mucked with those knobs, they're only rated for a few psi. When you try to get the forge hot it *will* leak as the higher pressure will be needed.

Mighty spiffy! Hard to tell from the angle presented, are they hollow ground, or some other profile? Just a personal thing, but I'm not sure I'd like the emblem being raised so prominently on the handle. Looks good, just cant imagine it'd be particularly comfortable when using these blades the way they're meant to be.

Yes, it really shines in pattern-making for casting pieces. Though it's also handy for making templates and jigs for repeat work (primarily for machining or grinding ops, not compatible with hot metal). While there are sites like thingiverse.com that have all sorts of things that other people have made and shared with the world, to make 3D printing useful for YOU requires learning some sort of 3D construction software (I'm reluctant to use the CAD label, as Sketchup is adequate for many tasks, but isn't what I'd call CAD software). Also, pretty much every consumer-grade 3D printer (which are now very affordable) will require a lot of fiddling, trial, and lots of error to get things dialed in to the point where it does what you want. Even some of the more expensive printers still don't do a perfect job without some tweaks.

Word of caution, front yard wouldn't be far enough away from danger if the acetylene tank blows- They've been known to level houses.

BartW, I would think that electronics potting compounds are non corrosive, but good luck getting your stuff out of it.

Funny, I do the same for the house since the rest of the occupants aren't motivated otherwise. Sounds like a great event, those folks are lucky to have you near!

If I come across a source of them, I’ll let folks know. Since they’re standing that command up in Texas, I guess it means there’ll be more than just Huntsville on my list of work trip destinations.

JHCC, what do you do to pulverize the dehydrated borax?

Sadly the autocorrect seemed to do a proofreading after my initial corrections. You just happened to catch the mistakes between my initial submittal and subsequent corrections

I had debated whether or not to post that here since that is what my organization will be falling under in the next few months. Guess you took care of it for me!

Argon doesn't have the leakage/migration issues of helium. Only brought up helium because it was part of Paul's response.

His gas solution has a few flaws, diffusion over the longer storage timelines is still going to allow the constituents of air to work their way in. And inert though it may be, Helium is one of the hardest elemental gases to contain... it readily migrates through a lot materials. Back when I was a co-op at a nuclear power plant we used it to check the seals of a few bits of piping that penetrated into the containment silos. Had to use a giant roll of refrigerant tubing as a supply line since the unavoidable leakage from the tank and regulator fittings was enough to trip the mass spectrometer we used to detect leaks in the equipment. Anything other than metal lines had too much through wall leakage to be usable. From my time learning about the operation of lighter than air vehicles (a different weird work experience) they have the same problem with helium migration through the envelope (which for the zeppelin we got hands-on with, used mylar as the material if I recall correctly).

Is there a utilization plan for the remnants of the data point?

The smart alec answer is "It cut metal before, didnt it?" It's a likely 'yes'... with caveats. Plane taking off now, gotta go!

You might want to consider trying certain types of mortar that don't shrink or even expand slightly when curing to be sure the fill doesn't pull away from the sides.

Shrink wrap wouldn't cut the mustard for that sort of application, you'd need a hermetically sealed enclosure. A large heat-sealing bag might work, but the reality is that handling things would most likely damage the plastic. If the anvil's on a smooth, nonporous base, you could put a giant bell jar over it and draw a vaccum in the resultant chamber (with dessicants present, too). Safe from environmental ravages, and still on display!

Is that a commentary on the people attending the event? Nice openers! I've got some similar fodder that I'd like to give the same treatment.

If efficiency is one of the things you want from your forge, then more insulation is always better. Keeping the cracks from opening up and creating gaps is all you need to mitigate. The fracture planes are rough enough that if you keep the cracked bricks physically held together then there shouldn't be any real loss in insulation effectiveness. You keep using the phrase 'heat making its way through', do you mean the outer part of the forge actually getting hot? The heat energy will find its way out one way or another, it's just a matter of the paths and transfer mechanisms available. What's the longest you've actually run this small unit? Once it reaches steady-state operation (probably 45 minutes or more) you'll have a good idea of whether the conduction through the walls is the primary heat transfer mechanism or radiation/convection are what's causing more of your heat losses. The outer metal skin should really only be there to keep the insulating stuff from spilling out (much like skin does with our guts). It's not supporting a significant load, so no real reason to make it really thick.

The third one looks like it'd be nice utility knife in the kitchen. Nice work! (Though I do share Frosty's concern for the rest)

All of them, of course! You forgot good looking, by the way.

Unless you're piling combustibles on the forge after shutdown I don't see much in the way of safety issues. If the concern is the burner getting too hot from chimney effect, then pull it out or cover the ports to slow the movement of hot gases. As far as the shell goes, unless you're using it to support a lot of externally mounted stuff then thicker isn't necessarily better (unless weight if the forge is a metric for success).