Roll-up stove

[John Nausieda]

Count me in as interested. Can't a standard punch press handle this since it is so thin? I imagine it would wear faster than one punching steel or aluminum but I'd look into it first . And you should ask Roger Caffin what he thinks would work. I'd still take those photos down . Good luck.

[Rob Bouchard]

Not sure what number I am but count me in as well if you make these up. It's just so dang pretty….

[Michael Schwartz]

Bravo! Count me in too. M

[. Callahan]

I'd be more than happy to buy at least one of these stoves, more than happy to pay in advance to help defray your set up costs too.

Please protect your design because YOU created this gem and it, along with your ingenuity and skill certainly merits protection, as well as recognition!

[Chris Benson]

+1 on Seth's mention of steampunk. Has a bit of that design aesthetic to me.

Add me as another potential customer if you're considering the production. Regardless of what you do, I agree, you should take a bit of time to protect the design.

Really nice work!

[tyler marlow]

You may want to contact Steve Evans of Suluk 46 about water cutting.

On his site he has a list of the services he provides and I know he has done some water cutting with his titanium snow stakes…you can probably work something out.

If anything you could have someone else make them and just get a % as the creator.

Or you may want to stay out of the production side of it and just enjoy tinkering without all of us gear obsessed cretins bothering you :)

[Jared Dilg]

Colin, this is really cool!

I'd echo what John Nausieda said and suggest you hold your designs tight. I had only learned about 3 weeks ago of Devin Montgomery's kettle project. Though not on the market for one, I'm really rooting for him to succeed! It's very cool to see a grad student bootstrap a project like that and take it to market. I'd love to see you get some recognition for your design.

Again, really sweet!

[Backpack Jack]

Count me in for at least one if you build them.

[Chris Hanson]

Not sure if you'd need the services of a laser/engraver but I have one. You could put your name, logo, etc on it. Works great on anodized aluminum but the mark would disappear from any place that get hot enough to "color" it…

[Chris Chatman]

Count me as another interested buyer!

[Roger Caffin]

> Can't a standard punch press handle this since it is so thin?
Punching really thin but hard sheet metal is actually a right pain. The tolerances on the punch and die have to be much tighter, which makes them rather expensive.

If you are making hundreds, consider laser or water jet cutting.
If you are making a small number, buy a carbide scribe (not a steel one) and some industrial/production quality tin snips. Not your local hardware store.
Then make up a template out of 2 mm aluminium sheet and mark the bits out one by one. Cut them out with the tin snips.
Ah, but the slots … HARDER! Steel sheet templates, clamp on both sides, drill and Dremel.

If you are mad keen, make up a solid steel template, stack 20 layers of Ti foil together, bolt down really firmly and CNC with a carbide cutter. The cheap Chinese carbide won't hack it: you need German or Swedish carbide (HRC55+). (He speaks with experience …)

Photos – too late. Once published, that's it.

Cheers

[Richard Brownkatz]

"…work of art is the only way to describe."

+1

"You definitely need to patent."

+1

Count me as another interested buyer!

+1

"…more than happy to pay in advance to help defray your set up costs too."

+1

Genius. Absolute genius.

[Eugene Smith]

Very sharp.

[Rob Wolfenden]

Awesome job!!!!

[Derek Goffin]

Very pretty and in this case therefore right.
Get Steve to give advice on water cutting.
Tiny quibbles but I guess assembly with all those slots on the top top and bottom disks is a bit awkward and a bit of distortion and it would get worse. The top disk at least doesn't carry any weight it just gets knocked, would less slots still keep it in shape? or even just the main 3 slots? Can you assemble the bottom and lock it then assemble the top? If the top disk is too fragile without the slots could it be pressed/formed into a stiffer shape?

[Colin Krusor]

Thanks again for all of the feedback. I wasn't prepared, I guess, for so enthusiastic a response. In light of the arguments many of you have made for intellectual property protection and small-scale production, I have reconsidered my intitial position a bit.

I sent in a provisional application for a utility patent this morning (which is limited in legal fortitude in that it does not include a detailed report on prior patents, but establishes a first claim to a described "novelty"), and this entitles me to one year of protection in which to complete and submit the more rigorous full patent application (with all of the substantial associated fees). The provisional patent application is essentially like buying an option. It creates a paper trail and guarantees that I have first dibs on obtaining a full patent for one year.

Also, I found a Sketchup plugin that will allow me to export .skp files as .dxf CAD files, which would be required for laser-cutting. I've contacted several laser-cutting shops here in the Central Valley and in the Bay Area (CA), and I'll try to compute per-unit materials costs (including cutting) some time this week.

However, I'm not promising anything. I'd rather not take any money beforehand, and, at this point, I'm not committing to any delivery date or update schedule. My principal obligation is graduate school, and this project will have to take a backseat to that. I appreciate all of the interest in this stove, and I'll do my best to find a way to produce a batch that I can distribute to the readers of this forum, but it may be a slow-moving project.

Also, I'd like to mention some of the shortcomings of this design before anyone vows to obtain one. I'm really pleased with how it turned out, on the whole, but I just want everyone to be familiar with the imperfections.

Assembly isn't confusing or complicated, but it is a little tedious, especially the first few times one tries it. Once you're accustomed to it, it's not difficult. It can be slow going with cold fingers, though. It's like setting up a tiny model of a tent.

Also, as I mentioned in an earlier post, the 15-3-3-3 alloy foil becomes brittle after the beta transition, and can crack at the edges. The pictured prototype has a small crack. This isn't likely to affect the function, but you might find it unsightly, and it creates a new sharp edge. There may not be a way to remedy this.

Lastly, the screen is a store-bought stainless steel screen, in a circular stainless steel frame. The frame is just pressed onto the edges of the wire, and, over time, some of the wires will inevitably slip out, I think. So, keep in mind that the screen might need occasional replacement.

As long as the limitations are clear, I'm interested in hearing design feedback. Does everyone who expressed an interest see nothing about the first version that could be improved? Any ideas about the aforementioned shortcomings? I'm personally interested in trying 0.003" CP4 foil, but I won't be using it on versions that I might hypothetically distribute, because I'm afraid the thinner and softer foil might warp or bulge when red-hot. I plan to replace the ceramic-fiber twine on the door with a wire, for durability, and I plan to shorten the "crook" part of the tent stakes and enlarge the triangle in the pot stand (to make the stakes more functional as stakes). Any other ideas? What would you like to see if you were to receive one, hypothetically?

Derek, I think the top ring could have fewer tabs, and the upper part of the foil could have fewer slots. The main three might be enough. I doubt that it will be possible, with a good fit, to insert the top ring during assembly with the bottom ring already "locked in", even with a reduced number of tabs/slots. This would require a looser fit, which, for stability, I'd rather avoid. It has to be assembled bottom-ring first with the body tabs in the slots, then the screen, then the top ring, then cinching up, then the pot stand.

[Henk Smees]

Hi Colin,

This ain’t fair. It’s only a few weeks ago that I received (from Steve Evans) a few feet of his 0.003” ti sheet. I THOUGHT I had some good ideas about turning this into an UL multi-fuel stove and was only waiting for a few packages of JB-Weld (can’t buy this here in Spain and they’re in the mail) to start working on same and now you’re “throwing soot in the food” (the old Dutch saying “roet in het eten gooien” means you’re spoiling the fun) with this absolutely stunning design of a roll-up wood stove. Now I HAVE to go back to the design-table and start all over again. I HATE you – just kidding :).

I’m really impressed with your stove and can only say that I fully agree with what all the others have said before. I’d be one of your prospective buyers if it wouldn’t be for the fact that I already bought the ti-sheet, so now I have to turn this into SOMETHING (even tough it won’t -not even remotely- be as nice as yours). Whatever comes out, I’ll have to live with it.

[John Nausieda]

Good move on the patent. I'm wondering one thing right off the top of my head: What is the largest pot relatively full of water that the stove can handle without tipping over? Width? Must that pot be without a handle unless it is a removable handle since the stove is more or less symmetric? Another issue. Many people at BPL us pop-can alcohol stoves. Is there anyway one would fit down in the stoves bottom for alternate use? And I notice all of those air-holes punched all the way through. I'm wondering if some could be left mostly punched though as on some Anti-gravity gear windscreens so you can close some up in the face of a strong wind. Many Asian stores sell stainless steel sink traps . Most are very cheap and could be recycled at the end of their service life.

[Colin Krusor]

John,

I'm not familiar with the Anti-gravity gear windscreens. They have metal tabs that can be bent toward or away from a hole to allow more or less air to pass through? I think flex fatigue would eventually cause flexible tabs to break off with titanium.

One of the objectives I had in mind when I made this stove was improved reliability with damp fuel. I found that the air holes help it to burn hotter and more vigorously, which aids in keeping it going when the fuel you're adding is damp. This also requires more tending and feeding of the fire, and it makes the design somewhat sensitive to wind. This approach is the opposite of a Caldera Cone, which burns more slowly and has excellent performance in wind but can sputter out if the fuel is damp because air throughput is small.

I don't know how this stove would fare with heavy pots. The footprint is a 4.5" diameter circle, so it should be pretty stable, but I haven't tested it with anything more than a full Firelite 900.

I haven't tried an alcohol stove inside yet, but esbit tabs work well. In fact, the screen at the bottom already has a bump in the middle, and I was thinking about giving this bump a flat top to accommodate esbit tabs or alcohol stoves.

[John Nausieda]

Absent bendable tabs for windscreen holes I would then just use aluminum foil over the holes in the case of severe winds or constant winds from one side etc. The pot size is something I consider to be very important . In my case I'm usually traveling with my wife and daughter so that pot size is about right for us. For larger groups some might want to see a scaled up stove but it's also possible that you would just bring two stoves. The Esbit option seems ideal to me for back up , but the alcohol option would really help in those situations where wood fires are technically prohibited.

[Jim Pemrick]

A US patent gives you the right to exclude others from making, using or selling your invention (in the US) for a period of 20 years from the date of filing. Of course, you can license your patent to others for a fee.

A provisional patent application only locks in your date of invention and gives you priority over later filed inventions that may be similar. In itself, it does not give you the right to stop others from making, using or selling your invention, only an issued US patent can do that.

You must file a regular utility (non-provisional) patent application within one year from the date of filing the provisional application. It typically takes the USPTO (US Patent & Trademark Office) about 2-3 years to send you out a first office action. So you are looking at 3-4 years until the application issues into a patent if it is found novel.

The wording of a patent application is critical and many pro se inventors (inventors that write and prosecute their own applications) end up with patents that have very limited if no commercial value.

If you are serious, I would recommend hiring a professional (e.g., a registered patent attorney or patent agent) at some point. If anyone offers to market your invention for a fee, run away as fast as you can. If you see ads on TV or in magazines, do not use them.

Please PM me if you have any additional questions regarding the patent application process.

[Colin Krusor]

Thanks for the information and advice, Jim.

[Ben Egan]

That's a great stove. And a great idea.

I was wondering where you got the titanium? The titanium foil as well as the center pieces.

And how it was cut? The holes and the center pieces.

Thanks,

Ben

[Derek Goffin]

Hi Colin,
If you change the top pot triangle so you can use straight pegs and drop it over the heads so they cannot move apart and it can only lift off not slide sideways, and put the pegs not inside but outside the foil body through the 6 main outer tabs it would trap the foil. Then the cinching tabs would not be needed or at least would not be so important. Your door would have to go over the pegs somehow.
A preheated secondary air supply with a second half height outer foil cylinder in lighter foil should be possible to add for some sectors of the market, also I suppose an insulated foil base to stop scorching for the ultimate LNT.

[Steven Evans]

That looks great! Very cool and good for you for thinking outside of the box. I really think there is some potential for something like that.

Laser cutting is the way to go for the thin titanium. I have cut my 0.003" ti foil with the waterjet but it doesn't leave a very nice finish. I wouldn't say it is "bad" but just not clean.

Here a picture of the squeezebox I cut for Kevin a while back. He may have some better pictures but you can see the rippling.

And just to get the mind churning, if you used the 0.003" stuff, you could weld it into a permanent cylinder and it would still roll up tight. Sort of like a version of the Titanium Flexible Windscreen available on my website. Just thinking out loud.

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