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SGT Rock
2011-06-18, 09:41
Hey y'all.

I've been playing with some titanium foil to make a windscreen. The idea is to make a windscreen that could be used as a wood stove for back-up if you need to stretch fuel. The screen I am using is 0.003" thick wich is VERY light, so by itself it doesn't hold up the weight of a full pot. As an alcohol stove windscreen it is outstanding.

To add some extra strength in a few spots I've laminated it with a couple of extra strips of titanium in four places using JB Weld as the bonding agent. It stands up fine with a full pot if I also use something like tent stakes to distribute the weight a little. The problem is both times I have tried a test run with wood, at some point the JB Weld fails and the lamination points fall apart. Looks like the JB Weld had burned off.

Also, FWIW, I have taken an Imusa 10 and an Imusa 12 mug and cut the aluminum handles off and replaced them with titanium scraps from old stove manufacturing. Apparently they either don't get as hot or are not exposed to as much flame - not sure which. But they are are holding up just fine to all this testing. This has dropped their weight about 8 grams and 10 grams respectfully, plus you can usually just lift them off by the handle since the titanium doesn't transfer heat like the aluminum ones did. I added some titanium foil lids made from scrap left overs from making the windscreens at 4 grams each.

So any ideas as to what sort of "glue" might hold up under higher heat than JB Weld?

Hog On Ice
2011-06-18, 10:26
have you considered pop riveting the strips onto the foil?

SGT Rock
2011-06-18, 10:49
I have, but it seems like you would add so much weight in pop-rivets that it would be more efficient to make a stand for wood fire that you just wrap the screen around. I'd also probably have to order some more Ti foil since I would have to re-engineer some of the main parts to accommodate holes and material large enough to pop-rivet. These strips are only about 1/4" wide.

SGT Rock
2011-06-18, 10:53
Anyone have any experience with Permatex ultra copper?

http://www.permatex.com/products/automotive/automotive_gasketing/gasket_makers/auto_permatex_ultra_copper_maximum_temperature_rtv _silicone_gasket_maker.htm

I've used the red permatex but it is very watery coming out, seems like it would be terrible to try and do what I am doing with it.

mudhead
2011-06-18, 10:54
Must be some fool in a shop at the complex you work at that has Tig finesse.

SGT Rock
2011-06-18, 10:57
Or this stuff:

http://www.oreillyauto.com/site/c/detail/VCH0/00160.oap?pt=N0073

Spec sheet says it has a heat resistance up to 1,000F with intermittent needs up to 1,500F.

SGT Rock
2011-06-18, 10:58
Must be some fool in a shop at the complex you work at that has Tig finesse.

Probably, but some guy got fired for taking a $20 drill bit. I'd hate to see what they would do for fabricating on government time with their stuff.

Hog On Ice
2011-06-18, 11:02
not too sure about tig welding that thin of ti but possibly spot resistance welding could be used

mudhead
2011-06-18, 11:06
Probably, but some guy got fired for taking a $20 drill bit. I'd hate to see what they would do for fabricating on government time with their stuff.

The bit I can understand. Never thought about the shop time. Probably call in the FBI.

Bet one of those types has stuff at home. Old guy. Likes to frig in the garage.

Might know enough metallurgy that he/she could tell you what you need 1/2 drop of...

SGT Rock
2011-06-18, 11:12
not too sure about tig welding that thin of ti but possibly spot resistance welding could be used

Yes, I think if I was going to weld it, that would be what would have to be used with something this thin.

Skidsteer
2011-06-18, 14:50
have you considered pop riveting the strips onto the foil?


I have, but it seems like you would add so much weight in pop-rivets that it would be more efficient to make a stand for wood fire that you just wrap the screen around. I'd also probably have to order some more Ti foil since I would have to re-engineer some of the main parts to accommodate holes and material large enough to pop-rivet. These strips are only about 1/4" wide.

Harbor Freight has a small grommet plier set (http://www.harborfreight.com/grommet-pliers-with-100-grommets-66707.html) that would probably work on such small material.

I use it on foil and flashing with no problems. Probably have to weigh 15-20 of them to make a gram. Haven't tried it over a wood fire though.

http://www.harborfreight.com/media/catalog/product/cache/1/image/370x/9df78eab33525d08d6e5fb8d27136e95/i/m/image_1899.jpg

I would love to find some truly high heat epoxy too.

Rock, where did you get titanium foil so thin?

Hog On Ice
2011-06-18, 15:19
another thought that I had was to notch the ends of the strips then lock in place using a tab from the foil - here I don't know how this would work with ti foil - this is sort of what I showed you with that beer can windscreen where instead of strip I tab locked the z folded joints between the beer cans

JAK
2011-06-18, 16:51
My first thought was silver solder, so I googled "soldering titanium" and things seem to point to optical labs for soldering titanium glasses. So maybe check with a local optical lab that does repairs on titanium frames, or see where you can get the stuff.

The way silver solder works is you want the two surfaces to be super flat, and then you heat them up and the solder has to melt and wick in so it is as thin as possible, which makes for a stronger and tougher joint. When working with thin sheet and tubing it might be harder to do, but with trial and error I think you would get there if you had the right solder to work with. You could probably use any metal or metal alloy that had a low enough melting point to be able to melt with a small butane torch, and a high enough melting point to not melt or weaken too much when in use. You might also design it in such a way as to keep the joints away from the hottest points, maybe near some air inlets.

You might try tin or pewter, which a a tin alloy. Not sure of melting points. Also, maybe try mixing some powdered metal in with the jbweld, maybe copper powder, not sure. Model railroaders might have a solution also. Some of those guys work with small metal parts. I would start with optical labs that repair titanium frames though. Jewelers also. I think they use silver solder in the form of very thin silver foil. Its really a brazing process, also called hard soldering.

JAK
2011-06-18, 16:54
I like this idea by Hog On Ice.


another thought that I had was to notch the ends of the strips then lock in place using a tab from the foil - here I don't know how this would work with ti foil - this is sort of what I showed you with that beer can windscreen where instead of strip I tab locked the z folded joints between the beer cans

Another thing to try might be that shiny aluminum muffler tape. It might be useful in holding Hog On Ice's Z-Folds together between the tabs. Also, you can make small tubes with it maybe. Also cheaper stuff to mock up designs with until you are ready to use your titanium sheet.

Wondering what your overall design is like. I was just thinking, the re-enforced areas should also be where your holes might be for whatever rods you stick through to support the pot. Tent pegs are a bit of overkill for this unless you have them anyway, and don't cook when they are in use. I have found thin skewers to work well, as the distance from the wind screen to the pot is not that great. I thin piano wire might work. Hobby shops carry it as control rods for model airplanes and such. Snare wire is a bit sketchy, but works for hanging but not like a beam if you know what I mean.

The thin skewers might slice through your titanium sheet, but if reinforced there anyway, which is ideally where you would transmit the load anyway, it should be strong enough to take that bearing force even over such a small diameter piano wire skewer. It would be nice if the 2 or 3 skewers could also be used for something else but not sure what. Skewers maybe, once the pot is off the stove. You can make little circle loops on one end as handles. You might also find skewers already like this. I think they are for fondue, not for shishkabobs.

You might play around with them for your vertical load reinforcement also, but you would need to keep them from skewering too far into the ground. The titanium windscreen might take care of that. Not sure how it would all come apart and go together. The other thing I have tried in the past was somehow welding three tubes directly onto your pot, so that 3 skewers or tent pegs can slide in as legs. They can also provide the exact gap spacing you want for your wind screen, and somehow the skewers can skewer there way from the pot tubes, weaving there way through the wind screen, and into the ground, and still give you your gap somehow. I think the air gap area should be the same as your total air inlet area, but not sure what it should be. 1/4" maybe. The air inlet hole should be one or two or three big holes though, rather than many small holes, for less resistance. I like one hole which can be aimed into the wind. The air resistance of the air gap around the pot doesn't really hurt because the resistance helps heat transfer. You can google Reynolds Analogy. Play with the air gap to get it right though.

I am not sure the wind screen should be conical. I think cyclindrical is better as long as you get the stability you need. Conical might provide for a bigger fire though and some radiant heat transfer to the sides of the pot, which might help if it is a tall and skinny pot like a Jolt can or whatever. You would get less convective heat transfer in the sides, but more radiant heat transfer to the sides. Probably doesn't matter. The practical consideration might be to have big enough combustion chamber at the bottom to hold the wood you are burning without the whole thing becoming too tall and tippy, so that is where a conical design probably is better. Fun stuff.

Do you put the fire directly on the ground, or maybe a titanium foil ground pad. Useful if the ground is damp. For snow you need something more insulating as well as fireproof and waterproof. In winter I usually do something like tinfoil over some sticks or branches. Everything needs to be scaled up a bit in winter also as you know. Summer is a fun time to try making stuff smaller.

SGT Rock
2011-06-18, 19:24
Harbor Freight has a small grommet plier set (http://www.harborfreight.com/grommet-pliers-with-100-grommets-66707.html) that would probably work on such small material.

I use it on foil and flashing with no problems. Probably have to weigh 15-20 of them to make a gram. Haven't tried it over a wood fire though.
http://www.harborfreight.com/media/catalog/product/cache/1/image/370x/9df78eab33525d08d6e5fb8d27136e95/i/m/image_1899.jpg

I would love to find some truly high heat epoxy too.
That might work. Right now I am trying the Permatex ultra copper. I tried the exhaust sealer and that was a total flop.




Rock, where did you get titanium foil so thin?
Here: http://www.ecrater.com/p/8288611/titanium-foil-sheet-long-1000mm

atraildreamer
2011-06-18, 19:47
Electric spot weld? Maybe at an auto body shop?

Skidsteer
2011-06-18, 19:47
http://www.ecrater.com/p/8288611/titanium-foil-sheet-long-1000mm[/url]

Perfect. Thanks.

JAK
2011-06-18, 20:15
Some metal foil tapes can handle 600F, which might be enough to reinforce the titanium sheet from the outside. You can make tubes with it from more rigidity. I think the adhesive cures with temperature, to a point, so it becomes a permament bond, at least until it fails, but you can stick and unstick it some until you fire it up. You can layer it and stuff. Also good for mocking up designs.

http://www.3m.com/product/Docs/Metal-Foil-Tapes-PDF.html

Skidsteer
2011-06-18, 20:27
Some metal foil tapes can handle 600F, which might be enough to reinforce the titanium sheet from the outside. You can make tubes with it from more rigidity. I think the adhesive cures with temperature, to a point, so it becomes a permament bond, at least until it fails, but you can stick and unstick it some until you fire it up. You can layer it and stuff. Also good for mocking up designs.

http://www.3m.com/product/Docs/Metal-Foil-Tapes-PDF.html

JB Weld can handle close to that much heat intermittently.

The problem is that a wood fire gets quite a bit hotter than that. Foil tape curls and melts long before JB Weld fails in my experience.

Skidsteer
2011-06-18, 20:31
Electric spot weld? Maybe at an auto body shop?

That would work. Zelph has one.

I'm not spending a couple hundred bucks on one however. If we all lived close to each other, it would be easy to go in together to buy one and just pass it around.

Hog On Ice
2011-06-18, 20:31
what about stitching in place with some wire?

Skidsteer
2011-06-18, 20:33
what about stitching in place with some wire?

Or staple it. I've done that before and it works very well.

Hog On Ice
2011-06-18, 20:34
yes - that's a good idea Skids

JAK
2011-06-18, 20:39
Good to know about the foil. Still useful for mockups maybe.
I like the wiring and stapling ideas.

I would if piano wire skewers alone could provide the weight bearing, threaded in and out of the wind screen for stability. Still not sure how the pot is to be supported by the wind screen. More skewers?

Rock's Titanium Sheet: 0.003" thick

Hobby shop aluminum and brass tubing...
http://www.hobbyplace.com/materials/metal.php
0.014" thick and outside diameters from 1/16" up in 1/32" increments

So maybe better to make tubes out of Rock's Titanium sheet, and use that for weight bearing.
Stronger, lighter, wicked fire resistance.

Not sure how best to hold the tubes together. Maybe cut hoops out of the 0.014" brass tubing, 1/4" or 3/8" or 1/2" diameter maybe, depending on how small you can roll up that thin titanium sheet. You might have to go around twice for it to hold up, but it would still be only 0.006" wall. Still wonder if piano wire skewers might be light and stiff enough. 0.006" x 3/8" diameter titanium tube would be about the same weight as a 0.016" diameter steel piano wire. The titanium tube would be stiffer, but if the piano wire was stiff enough it would certainly be more durable. 0.016" would be too bendy though, I think. Depends on what you would be doing with it maybe. Getting into hardware cloth territory.

Sorry just thinking out loud.

JAK
2011-06-18, 21:28
Is it better to support the pot from the bottom or from the rim?

JAK
2011-06-18, 21:41
What about simply going around twice with the Titanium sheet, or would that be too heavy? Maybe with some "quilting" wire or staples to keep them integrated so you end up with more than twice the stiffness, rigidity, or whatever you want to call it. You would also gain some extra insulation if you did it right. Maybe accordion corrugate it somehow, for even more insulation and rigidity?

Skidsteer
2011-06-18, 21:46
Is it better to support the pot from the bottom or from the rim?

Immaterial. Like asking if it's better to left-click or hit Enter. Not enough data.

JAK
2011-06-18, 22:13
Immaterial. Like asking if it's better to left-click or hit Enter. Not enough data.I suppose it depends on the dimensions of the pot.

What sort of distance from ground is best for small wood fires? Half the diameter of the pot? Full diameter of the pot? I think you need more initially, and less as you get some good coals going. So maybe multiple positions if supporting the pot with the wind screen, so initially its on top, and then 1/4 down, then finally 1/2 way down maybe. You might mess around with a light weight baffle also, or partial baffle, like a choke ring, to increase combustion temperatures. Useful when water is initially cold especially with a relatively large diameter pot.

I used a small stainless bowl last trip, but with oil not wood. Interesting shape. Fit well on Rock's Ion stand.

SGT Rock
2011-06-19, 11:16
The Permatex Copper stuff failed miserably. I've ordered the grommet kit off Harbor Freight. What size hole do you need to make for a grommet in this kit?

Skidsteer
2011-06-19, 11:19
the permatex copper stuff failed miserably. I've ordered the grommet kit off harbor freight. What size hole do you need to make for a grommet in this kit?

3/16" iirc.

SGT Rock
2011-06-19, 11:24
Sounds good. If you get some of that ti, don't use a HF hole punch on it, it really messes the stuff up. A normal paper hole puncher does a much nicer job.

I think I am going to modify my design a little. Instead of trying to add layers of .003" ti to get up to about .009", I am going to use some scraps of .016" I have around here to make four stiffening points on the screen. So the screen will be about 8gr for about a 3"x16.5" screen with about 4-6gr of ti stiffeners added for the back-up wood burning function.

SGT Rock
2011-06-19, 13:12
Maybe I'm over thinking this....

I was just sitting here thinking about this design, and I think I may have just had an epiphany.

The windscreen is currently 8 grams with nothing else added or attached. So I am trying to figure out how to make it support a pot that will weigh about 1.5 pounds with water and food in it. Then it hits me that the windscreen does fine holding in the fire without burning up, the hard part is getting it to hold up the pot without burning up. SO what if I came up with some separate method of holding the pot up for the fire. Maybe something simple like taking 6 each 4" stakes and sticking them 1" into the ground 2" each so that the tops are all level and at the right diameter so that they sit under the pot. Maybe even add some sort of cross parts to that for structure. This isn't something I would ever use on a table anyway, it is made to sit on the ground.

I can get aluminum arrow shafts that weigh at about 3grams each for 6" lengths. So the minimum the "stand" would weigh is 12 grams without needing any fancy bonding system to make it work on the ti stand. Add to that I could make a Ti foil base that has holes pre made into them with the correct positioning for the stakes. I With this system you wouldn't have to worry too much about leveling it since you could push the stakes in however far is needed based on slope.

I wonder if carbon fiber would weigh less and also work?

SGT Rock
2011-06-19, 13:55
I posted a concept video:
http://www.youtube.com/watch?v=DZoh-atngvI

DZoh-atngvI

Hog On Ice
2011-06-19, 13:59
carbon fiber stakes would probably burn in a wood fire - or at least the epoxy that holds the fibers together

btw - good luck finding someplace that you can get a bunch of stakes into the ground without hitting rocks and also is a good place to have a fire (ie no duff) - might work for a sand bar but where else?

SGT Rock
2011-06-19, 14:00
My yard LOL.

Lugnut
2011-06-19, 15:28
Rock, I just googled 'gram weenie' and it has your picture! :aetsch:

SGT Rock
2011-06-19, 15:53
I hope it is up to date

SGT Rock
2011-06-19, 19:00
Just got done playing with it:

http://www.youtube.com/watch?v=RPaYO3VR80Q

RPaYO3VR80Q

I made 4 titanium V stakes. 3 of them are smaller ones at 7 grams each, and one is also my potty trowel at 12 grams. So 33 grams of stakes which replace about 16 grams of stakes I would normally have carried (my 4 gram aluminum ones) - 17 total grams added to use the screen as a back up wood stove. Not bad.

I was already planning on adding the big ti stake for a potty trowel anyway so maybe I can call it just adding 9 grams.

Weary
2011-06-23, 13:42
Once you guys solve Rock's pot stand problem, ponder how I might permanently repair a Revereware stainless steel, copper bottomed, pot. I found it on the trail years ago and have used it at home since. Well until it developed a tiny hole on the bottom. I've patched it with a lead-free solder, several times, but the leak aways returns after a few uses. We have a lot of smaller pots and larger pots, but this one is a perfect size for the two of us, when kids show up unexpectedly, expecting a meal.

Hog On Ice
2011-06-23, 14:18
well here's an idea but its nothing I have ever done not being so sentimentally attached to a pot but anyways ...

get a stainless steel "plug", drill out the spot where the hole is to match the plug and then press the plug into the hole and optionally do some blazing on the copper side to help support the plug

realistically what I would do is measure the pot, go to the net and search for a pot of the same size and buy it, throw out the old pot

Crikey
2011-06-23, 14:47
Man, I was doing a ton of this stuff a while back.

Then after the fire trucks left, my mom took my matches away. :aetsch:

Seriously, good stuff, Rock. I wish I had time to experiment like you do!

sheepdog
2011-06-23, 17:37
Man, I was doing a ton of this stuff a while back.

Then after the fire trucks left, my mom took my matches away. :aetsch:

Seriously, good stuff, Rock. I wish I had time to experiment like you do!

Once it took a while for my left eyebrow to grow back.:albertein

mudhead
2011-06-23, 20:29
Once you guys solve Rock's pot stand problem, ponder how I might permanently repair a Revereware stainless steel, copper bottomed, pot. I found it on the trail years ago and have used it at home since. Well until it developed a tiny hole on the bottom. I've patched it with a lead-free solder, several times, but the leak aways returns after a few uses. We have a lot of smaller pots and larger pots, but this one is a perfect size for the two of us, when kids show up unexpectedly, expecting a meal.

Revereware outlet store in Kittery. What size is it? Should say on the bottom. Unless it is so worn, you can only see the head and not the "1.3Quart" or what ever.

Weary
2011-06-23, 23:48
Revereware outlet store in Kittery. What size is it? Should say on the bottom. Unless it is so worn, you can only see the head and not the "1.3Quart" or what ever.
Thanks. The pot is stuffed away someplace at the moment. But I'll find it and let Kittery know.

Skidsteer
2011-07-22, 21:25
Rock, where did you get titanium foil so thin?


Here: http://www.ecrater.com/p/8288611/titanium-foil-sheet-long-1000mm


Perfect. Thanks.

That stuff was just the ticket.

I had designed a cone style windscreen to form-fit my generic Ziploc container and used oven liner to fabricate it. Problem was that the tolerances were so close and dialed in the stupid thing would start to melt after about ten burns. I made one from flashing, which solved the problem, but was heavier than I liked. Here's how the new one made from titanium foil turned out:

http://i222.photobucket.com/albums/dd238/acsskidsteer/New%20titanium%20windscreen/th_IMG_1256.jpg (http://s222.photobucket.com/albums/dd238/acsskidsteer/New%20titanium%20windscreen/?action=view&current=IMG_1256.jpg) http://i222.photobucket.com/albums/dd238/acsskidsteer/New%20titanium%20windscreen/th_IMG_1257.jpg (http://s222.photobucket.com/albums/dd238/acsskidsteer/New%20titanium%20windscreen/?action=view&current=IMG_1257.jpg) http://i222.photobucket.com/albums/dd238/acsskidsteer/New%20titanium%20windscreen/th_IMG_1258.jpg (http://s222.photobucket.com/albums/dd238/acsskidsteer/New%20titanium%20windscreen/?action=view&current=IMG_1258.jpg) http://i222.photobucket.com/albums/dd238/acsskidsteer/New%20titanium%20windscreen/th_IMG_1259.jpg (http://s222.photobucket.com/albums/dd238/acsskidsteer/New%20titanium%20windscreen/?action=view&current=IMG_1259.jpg) http://i222.photobucket.com/albums/dd238/acsskidsteer/New%20titanium%20windscreen/th_IMG_1261.jpg (http://s222.photobucket.com/albums/dd238/acsskidsteer/New%20titanium%20windscreen/?action=view&current=IMG_1261.jpg)

SGT Rock
2011-07-24, 15:42
Very nice. :D