Still flogging the CinderCone #chimenea and fire tools. Holler if you want to get your mitts on one.
“Portal,” from CAD model to finished sculpture. Last photo by my friend and Real Photographer, Jafe Parsons.
So. Close. Wind today is NOT helping. Stitch welds on the seams are next, and there's enough wind in the Corona Carport Studio to mess with my argon. Aaargh! On?
Now that I’ve figured out how to correct the issues that presented themselves in V1, it’s time to implement the changes. That means generating new patterns for the laser and having the improved design cut. I also went with slightly thicker material — 11 gauge instead of 12 — to provide a touch more rigidity. Let the games begin!
The updated upper faces. Here you can see the threshold below the door, and the updated trio of fastener holes in the bottom of each face. ^
Voila! The laser-cut metal in all its glory. ^
The bottom plate and fire basin faces. ^
The 3D model of the new & improved anchoring bracket… ^
… and its real-world counterpart. ^
To insure a proper fit, I bolt the brackets into the fire basin and tack them together while there. Here, you can see how the ring of brackets pins the grill in place. ^
Once tack welded, the brackets are removed, clamped securely flat, and the final welds added. Oh - about that work surface: I was massively frustrated with how my fixturing and clamping setup worked on the prototype, so I broke down and bought a fancy German fabrication table. I really only spend money on things that make making better. ^
That’s the first half of the assembly for version 2. I’m really pleased at how the design is working out, and the new welding table not only makes things easier, but insures that the quality of my parts is top notch.
With the welding and sanding and bolting all finished up, it’s time to test this thing out. My dear friends Bruce and Cyndi volunteered their beautiful property on the lake for a test site, and, once a day with cooperative weather materialized, it was time.
What an amazing evening! Couldn’t have been happier with how the CinderCone performed — and the visual effect of the cut-out pattern when combined with the dancing flames was nothing short of spectacular. We stoked the flames MUCH more than required to have a nice fire in order to stress-test the design. Glad we did, as it revealed some structural shortcomings that would need to be addressed before offering these up for sale.
Metal may seem like a solid, stable material — one that you can rely on to hold its shape and remain true to itself under stress. In reality, it is subject to all kinds of movement when subjected to heat. These thermal stresses need to be countered to maintain the integrity of the object.
The aftermath of our stress test showed that the outer “shell” of the design handled these forces well — but the grill itself, directly in contact with the source of heat, needed some shoring up. Any welder can tell you that one only need curtail expansion and contraction throughout the heating cycle to minimize warping. The grill was allowed too much freedom in this design, and the forces went to work on it. I needed to do some redesigning, but thought I’d try to retrofit the V1.0 CinderCone before tackling V2.0.
Adding ribs that radiate outward from the center of the grill to add stiffness. Notice the bonus colors provided by the fire!
The brackets not only attach the upper section to the fire basin, but they also serve to pin the edges of the grill in place. I fabricated longer brackets to spread this pinning action along the entire edge.
A phalanx of new brackets ready to be installed. You’ll notice that there are only five; the side with the door doesn’t get one, and that proves to be problematic.
After a second test fire, you can see just how much force gets applied to the grill, and why the design for the opening is not going to work.</>So, although the overall design was a success, there are some structural details that need improving. Another sticking point was removal of the ash that accumulates beneath the grill. I’d thought that removing the top section and grill would be easy enough to access this area, but adding the longer brackets and their additional fasteners made that too big a hassle. This thing needs an ash clean-out door.
On to CinderCone Version 2!
Now that the design and layout work is complete, and the laser has done its thing, the real work begins. Or the FUN, depending on your feelings about welding and sanding metal. The interesting thing about my process is just how much of the fit-up and fixturing is simplified by the earlier CAD work — there’s very little guesswork or problem solving left at this point. Photos below tells the story of assembling the first CinderCone prototype.
Cleaning and preparing the raw laser cut parts. ^
A closer look at the warped hexagonal pattern. ^
Welding the attachment nuts into the brackets. ^
The bracket parts have hex cutouts to accept the nuts. Simplifies positioning. ^
A Quarter for Your Brackets - These brackets will hold the top section to the bottom fire basin.^
These hexagonal standoffs accept the leveling feet. ^
Attaching the legs to the base plate. Pretty colors. ^
All the legs attached to the bottom plate. ^
Finishing up the fire basin and adding the brackets. ^
Upper section welded up and bolted to the fire basin.
The Hard Part - Adding the “eyebrow” above the main door; bending metal of this thickness is never easy. ^
How many clamps can you fit in there, dude?
Eyebrow on and grill in place. Just a few final details. ^
Pulling the warpage out of the grill and adding some ribs to prevent it in the future. This ridiculous "fixture" was the straw that broke my bank account: ordered a new Siegmund workstation from @tricktools to end this foolishness. So excite!
I've been slowed down with the cold and a nice dose of the flu, but I am still plugging away on Interwoven.
Working on the tenth module.
I’m still — slowly — making progress on the Interwoven piece.
The modules are beginning to weave together.
The cutouts where the main body meets the base.
Still working on Interwoven and making good, albeit slow, progress. We had a nice cold snap where the temps dropped down near 0°. Makes the interior of my nice all-concrete shop feel like a meat locker, only colder.
Flipping it over for easier access.
Clamping and using Clecos (temporary rivets) to hold things in place.
Pulling the seam together. Nice Depth of Field!
That’s a LOT of rivets.
More progress on the assembly. Starting to feel like this just might work!
Now that I've bent some tabs, the actual assembly can start. First steps are to figure out which part goes where; I've employed a letter-plus-number system cut right into the metal to try to simplify this process. Seems to be working OK, but ascertaining "front" and "back" on a form without them is somewhat problematic. It's just a matter of playing "who's your neighbor" and keeping track of those relationships. I divided the form up into 13 "modules" consisting of the sheetmetal surrounding each hole. Beyond planning, the actual assembly is aided by the use of these little doodads called "Clecos," which are spring-loaded temporary rivets that hold things in position until actual rivets can be added. Pneumatic riveter for the win. (I "love" "using" "quotes," apparently.)
Laying it all out. Using printouts from my 3D model, I’m trying to figure out who goes where.
Rivets. Lots of rivets. Over 1500.
Clecos. Clecos are temporary rivets that hold things in place until you can use a real one.
First. The first half-module is done. This just might work.
More Clecos. This is looking pretty cool.
One and a half. Look at that caveman go.
Once the virtual model is finalized and I have all the surfaces flattened and laid out, the files are sent off to Wesco Laser to be cut from 14 (main body) and 7 (base) gauge 304 stainless steel. Now I get to try to turn this:
Into a piece of public art.
Oh, and remember those tabs I talked about? Here they are, ready to be bent and employed to hold the whole works together.