John in Oly, WA

You could've been British. Aren't Marshall amps made in England?

Nice job on the pattern. I too like how it fits the profile.

You can use sodium silicate as a binder for making sand cores, but you need to either bake it or gas it with CO2 to get it to harden. Google "making sand cores".

Ah! A good ol' fashioned tar and feathering. LOL I'll bring the tar. Do I need a pitchfork or torch? But seriously, what do I know? I'm just asking questions as they come up. Looking forward to making some progress on this build this weekend. I think I have all the parts and pieces. We'll see how good I am at videoing the process. (roll eyes)

And in looking at the fans I bought, the case is pretty thin halfway between corners where the fan duct diameter nearly contacts the outside case dimension, so the margin for error is slim. When drawing up the profile of this funnel piece, the I.D. of the 3/4" pipe mixing tube is .82". You said the maximum ratio of fan opening to mixing tube I.D. should be no greater than 3:1. So .82" x 3 is 2.46" which is 62mm, so I'm designing this funnel based on 60mm fans for a 3/4" burner because a little smaller is better than a bit too big. And another question that I should have asked some time ago - what size forge would be appropriate for this 3/4" burner we're building? The typical 20 lb. propane tank type? Or would a 1/2" vortex burner be better fitted to the 20 lb. propane tank with 2" of kaowool and 1/2" of kastolite 30?

So if a 70mm fan is the best size for a 3/4" burner, not all 70mm fans have the same diameter opening? Or is the outside dimension of the case 70mm and the actual fan blade diameter can vary?

Nice sculpture Aus! Does cassowary taste good? Must not, since it's still there. So the deer and elk and bear etc. in North America are the bad tasting animals? That's why they're still here, cuz our ancestors didn't want to eat them?

I can make the flange thicker. Probably make the funnel a little longer too. I was hoping to match the "ideal" fan, size and cfm, to the funnel so it's as easy as possible to spec out the exact fan and then just bolt it up, cut a stick of 3/4" schedule 40 pipe to the right length and fire away without having to do any machining or modifying. Then get wild and stick one of Frosty's NARBs to the end of it and have a real Rocket 88, or Rocket 23 or Rocket (however many nozzlettes are in the thing).

The idea would be to have one piece casting that the fan could attach to at the large end, had a reinforced raised area on the outside for the gas inlet tube hole and a coupling cylindrical shape with set screws the mixing tube would fit into. Something very basic, simple to attach everything to, roughly like this: Goes without saying, of course. The first casting would probably happen at a casting group meeting.

When you see the signs of him getting tired, I'd suggest that's a good time to take a break, sit down and let him talk about what he's accomplished, what he thinks about moving metal, swinging a hammer, the fire, how it all went for him. Might help him review and retain the info.

Well, you're definitely at the right place to find info about everything related to blacksmithing. Read up on it, ask questions, and post your progress.

It looks good lukerec. Are you going to use it to forge things?

I'll have to talk to you about funnel shapes and lengths before jumping in to making a mold pattern.

Classes from a reputable instructor would be the first step toward a safe casting experience. So many details to learn - one left out or goes wrong can seriously damage a person.

Cool! Thanks Das! I tried the copy and paste the URL, but all I saw was... well, the URL. Didn't think to figure it'd turn into the picture thing when submitted. The @ thing is great too. Learn something new every day. The more I learn, the more I realize I don't know. If I keep this up, by the time I get to retirement, I'm gonna be downright ignorant.

Just be sure to squeeze the sheets out over the quench tank to reclaim some of that oil! LOL

Das - (I know very little about how forums work) How do you post other threads in your replies, like the two above? I was wishing I knew how just a minute ago. Heck, how do you post the @ someoneinparticular in your posts?

His point is good, just like the "collection of improvised anvils" sticky thread in this same topic, that there are useful alternatives to having an actual anvil, but his example, while being an "object" is definitely not the typical "anvil shape". AndrewB - What did you pick up at the local milling shop for an anvil? Pics! Would love to see what you ended up with.

A rap tomahawk - is that the kind you bend around in a U shape to form the handle eye and forge weld the two ends together for the blade? The answer is still no, you need a bit more heat than a weed burner can produce, and a neutral to slightly reducing flame atmosphere, which you could probably get in a brick pile forge, but not with that kind of burner.

The position of the MIG tip was a detail I wasn't remembering. I'm waiting for the stainless tube I ordered for the nozzle spacer to arrive, then I should have all the pieces to start this video build. Then I was thinking it would be fun to make a mold pattern for a funnel with the precise dimensions to fit 3/4" stainless schedule 40 pipe and the diameter of the fan at the other end and the flanges to attach both and cast it in aluminum. It'd save all this mucking about with concentric reducers and SSTs that have to be modified and messed with to make work. Then I'd just have to muck about and mess with casting. LOL

Hope you're feeling better Frosty and you have a quick and complete return to good health.

Well, I'll have an idea how to build one at the end of this process, but for expert I'd need to understand the theory behind it all. We'll see. At any rate, my understanding before I start cutting pieces - 3:1 maximum ratio between fan opening diameter on the funnel and mixing tube diameter, 14:1 ratio between the length and the inside diameter of the mixing tube, and nozzle minimum length = I.D. of the mixing tube + 1/4" + 3/4". And don't permanently attach mixing tube to funnel, so they can be separated for tuning and cleaning.

I have .030" and .025", .035", .040", .045". Oh, I'll be asking you a lot of questions Mikey, I'm sure. You're the expert, I'm just trying to follow along. One thing that will come up is how far in to position the MIG tip in the funnel.

I'll see what I can do, but it wouldn't be a "how to" video. More like a "how I'm figuring out how I do". I have some 'round about, unorthodox ways of constructing things sometimes.

I'll pick up some of the La-Co flux. I think I have some tin/silver solder around. Then I'll be needing capillary tube. I'll start cutting and fitting pieces this weekend and see how far I get. Should be fun!