Apr 11, 2011 at 3:45 pm #1272078
This is my first attempt at reporting a MYOG item. Sorry for the crappy photos, but I think they'll work OK. This MYOG is reported to honor Roger Caffin, another SP stove lover. He'll absolutely cringe when he sees what I've done here.
Here's a photo of the setup, with a SP 600 pot in place.
First off, if there's no wind, there's no need for this stove screen. But as a breeze kicks up, any stove's efficiency drops off dramatically. With this screen setup, I've been able to protect the stove flame from the wind, while allowing sufficient flow of air to the burner. The key element is to protect the stove burner from underneath, in addition to the screen that surrounds the sides of the pot. The two screen components are shown below.
Screen assembly mounted on stove:
Top view. Note the minimal, but adequate ventilation from underneath. The bottom disk rests at the base of the burner head, 2" above the canister, held in place by the slots that engage the stove pot support arms.
The side screen is fastened together by means of a titanium rod that connects the ends of the screen together. Hopefully this photo shows that well enough. When disassembled, the screen and bottom piece slide nicely into the SP 600, leaving plenty of room for the stove and other small widgets.
DANGER! UNDER NO CIRCUMSTANCE WILL THE USER ALLOW THE CANISTER TO BECOME HOT TO THE TOUCH! (If you do, and live, Roger C. will thump you hard).
I keep the canister well below even a warmish temperature, by only using the most minimal flame setting on the stove. Just a little bit higher than the setting at which the stove will not continue to stay lit. In the case of the SP Giga stove, this is about 1/8th of a turn of the control knob from the OFF position. If I turn the knob even a half turn, the canister will begin to warm up appreciably. I monitor the canister constantly, to assure that there aren't any variances in the flame output.
In the event that I run out of canister fuel, the screen will function with other fuels. In the photo below, you will see a pair of titanium rods that have been inserted into the holes on the screen to act as a pot support. While the holes don't happen to be located at the optimal height for using an Esbit tab, it still works OK in a pinch. Next to the screen is a support triangle that works quite well for both Esbit and a wedding tin stove.
OK, so here comes the fun part–the increase in the stove's efficiency by employing this screen arrangement. I waited for a moderately breezy night to do my testing. Nothing too serious, maybe 5-15 MPH. Using a new canister, 2 cups of 45*F water repeatedly consumed 0.20 oz. of fuel. I then did a few 2 cup boils using a 5-year old Jet Boil stove at its lowest functional setting (maybe 1/8th of a turn from the OFF position). Each of the Jet Boil runs consumed .25 oz. of fuel. So, while the Jet Boil reached boiling much, much faster than my SP setup (4-5 minutes vs. 7-9 minutes) the Jet Boil actually used more fuel to reach boiling. By the way, I tested the SP stove without using the screen, and 2 different boils each consumed 0.4 oz. in those breezes. So the screen works. My Jet Boil setup, minus fuel, weighs 15.0 oz. The SP stove/pot/lid/screen arrangement is 7.9 oz. So, for me, saving 7 oz. and 0.05 oz./burn, as well as having a much more wind-resistant stove, makes me a very happy guy (not that I'd consider hauling a Jet Boil in the first place!).Apr 11, 2011 at 4:01 pm #1723308
You might state what materials you used for the windscreen and for the heat reflector. Also, you might state what the weight is for the windscreen and for the heat reflector.
–B.G.–Apr 11, 2011 at 4:15 pm #1723320
Good call, Bob. My bad. The material is .005" CP-2 titanium foil purchased from Ti Goat. Together, both pieces weigh 0.7 oz. My prototype version of this setup was made of .003" 6Al-4V titanium, and it weighed just 0.4 oz. But it isn't as tall as this one, the bottom plate doesn't fit as snugly to block the wind from below, and the 6/4 material is more brittle than CP-2.Apr 11, 2011 at 5:26 pm #1723358
I would think that 0.005 foil is better if it is weight-bearing, but yours isn't, so the 0.003 foil should be adequate. Of course, when you are getting down to 0.4 versus 0.7 ounces, it doesn't matter too much.
In MSR parlance, the main vertical piece is the wind screen, and the round bottom piece is called the heat reflector. About 90% of its function is reflecting the burner heat back up, which makes it more efficient. It does block a little wind that may be sneaking around underneath, and it blocks excess heat from toasting the fuel canister. MSR makes those things out of aluminum foil, but it is nowhere near that light.
–B.G.–Apr 11, 2011 at 6:20 pm #1723384
"I would think that 0.005 foil is better if it is weight-bearing, but yours isn't"
Actually, Bob, it will be weight-bearing when in the Esbit/alcohol mode.
"About 90% of its function is reflecting the burner heat back up"
I think that the reflector is paramount here in keeping wind from messing with the flame. It certainly does reflect heat back up to the pot, and the titanium screen helps hold the heat close to the pot–I think that's why this all works as well as it does. But make no mistake, a hot titanium reflector can certainly warm up the canister 2" away. Actually, that quality came in handy a week ago when we were snow camping at +20*F. I found that by turning up the stove's output a little, I was able to create enough downward heat flow to keep the canister happily efficient.
Thanks for your input, Bob. For some reason, I just knew you would be one of the first to chime in. I didn't know that you'd be the only one, however. Must not be many SP Giga users out there, or else my idea doesn't appeal. I'm certain that Roger will hit me upside the head fairly soon anyway. No matter, as I'm off to another earth shaking project now.Apr 11, 2011 at 6:30 pm #1723388
If your rig is only weight-bearing from the middle holes down, then you could substitute the lighter foil for the top half and leave the heavier foil for the bottom half.
And then, you could fashion a heat vent in the reflector. For those cold mornings, you could open the heat vent to keep the fuel warm. Then close it for hot days to prevent overheating the fuel.
But, I don't know if you want to gild the lily.
I don't use Snow Peak stoves, but most of them are about the same.
–B.G.–Apr 11, 2011 at 6:57 pm #1723399
There are plenty of other SP Giga users out there but in my case I'm running a much larger pan for water for three people. In my case I worked on a windscreen clipped to my pan and didn't get into the reflector stuff. Roger chimed in about canister heat issues. Give it time. The other thing is for some of us the Giga is a summertime stove , not a winter stove so consider whether your set up is way too hot for Summer?Apr 12, 2011 at 3:37 am #1723510
@rcaffinLocale: Wollemi & Kosciusko NPs, Europe
Cute! And neat.
Comment: I think the flame normally picks up extra air as it travels up to the pot, although with a Snow Peak GT100 (aka GigaPower) it may not need very much. What this means is that you need to ensure a little air ventilation at the bottom, for that extra bleed of air. Although I can see plenty of air holes at the bottom in the fourth photo, so maybe you could ignore that.
I am a little puzzled as to why the canister heats up when you have anything more than a very low setting. I don't get that problem with a bare stove. A bit strange.
> (If you do, and live, Roger C. will thump you hard).
Not a chance. I will just be standing well clear! :-)
CheersApr 12, 2011 at 4:41 am #1723515
@jamesdmarcoLocale: Finger Lakes
"Comment: I think the flame normally picks up extra air as it travels up to the pot, although with a Snow Peak GT100 (aka GigaPower) it may not need very much. What this means is that you need to ensure a little air ventilation at the bottom, for that extra bleed of air. Although I can see plenty of air holes at the bottom in the fourth photo, so maybe you could ignore that.
I am a little puzzled as to why the canister heats up when you have anything more than a very low setting. I don't get that problem with a bare stove. A bit strange."
Yeah, I am guessing there is just not enough air ventilation,hence the additional heat on the burner head being conducted down to the canister.Apr 12, 2011 at 5:11 am #1723521
I'm not convinced of the wisdom of the 'floor' to this windscreen; are you not partially blocking the air supply to the burner?
Wind blowing across a burner generally blows horizontally, so the main protection required is from the sidewall. I'm not sure that the floor provides much improvement to the wind protection.
Easy to test this, of course: just leave the floor out next time you use the stove…
It would save a few precious grammes, too ;-)
There's an argument that the floor acts as a reflector, preventing the canister from getting hot, but removing it is likely to improve the chimney effect, pulling air over the canister. Again, easy to check.
I'd also go for a slot & tab closure mechanism, as it's simple to make & use, and doesn't require a locking pin (that can get lost). One slot and tab at each end of the screen; upper tab faces out, lower tab faces in. Tabs formed just once, and slide into place in their mating slots.Apr 12, 2011 at 8:16 am #1723558
@bigjerrLocale: high country
very nice , and the heat getting down to the canister is a concern .I made one very similar to your design last year out of soft alum. trying to get the max amount of boils (16 once ) from a canister.if not on low , heat would build under the bottom and get a bit warm @ top of canister,not sure why ,could be radiant heat from the bottom or not enough air getting to the burner thus causing heat to travel down the shaft to the canister ? but on a very low setting (as mentioned ) Id get 15-19 16once boils out of a large can in the home/Patio testing but on trail that would drop due to excess wind and flame going out ….Jerry PS because of the heat build up it would be tough to recommend to any oneApr 12, 2011 at 9:56 am #1723594
Thanks for your comments, guys. It is appreciated.
I think James has it correct. The canister warms up from being just 2" from the reflector. Since there is minimal air flow within the confines of the reflector/screen, and since titanium is a poor conductor of heat, things can get pretty warm inside that somewhat closed environment. This helps with boiling the water efficiently, of course. But if things get too hot, some of that heat will radiate downward from the reflector to the canister. My design somewhat prevents a dangerous scenerio from occuring. The stove cannot be turned up very high due to the limited intake of air to feed the flame–the stove just sputters from lack of enough oxygen. If I know I will need a more robust flame, I don't use the reflector. This allows for plenty of air to reach the burner from underneath, but it also allows strong winds to affect the stove's efficiency. So, it's a trade-off.
Again, thanks for your informed comments and opinions.Apr 12, 2011 at 2:01 pm #1723690
@rgmccollLocale: East Tennessee
what did you use for the handles and pot lid?Apr 12, 2011 at 5:38 pm #1723773
Rick, I used silicone tubing to insulate the handles.Apr 13, 2011 at 5:41 am #1723930
@rgmccollLocale: East Tennessee
I thought that might be the answer. Did a short google for it but came up short.
I have tried several materials but nothing has worked. Those look good.
Thx in advance.Apr 15, 2011 at 7:41 pm #1725106
@carspideyLocale: san fernando valley
I was planning on fashioning somethig of that sort from soft aluminum and see how it worked.
I was just thinking of adding just a screen around the pot – 700 ml bcApr 17, 2011 at 8:10 pm #1725879
@redleaderLocale: Luxury-Light Luke on the Llano Azul
I made this one from a Snow Peak Ti bowl. It works fine. I'm on the road and don't have the weight, but it's pretty light.
Snow Peak Ti Bowl windscreen for Giga Power stove.Apr 18, 2011 at 6:42 pm #1726336
I tried making an oven out of pie tins on my SP every thing was above the flame control knob but i had the same results the canister was hot which made little sence to me cause there is a sheild between the stove and canister and it was to bad cause it cooked a great pizza with less fuel than boiling two cups of waterApr 18, 2011 at 7:29 pm #1726367
@dwambaughLocale: Pacific Northwest
I wonder if the canister gets hot from heat transferring down the neck of the stove rather than the radiant heat? With no windscreen in place, there is a lot of air available to cool the neck of the stove. It has to be getting pretty hot around that burner!
The old Gaz stoves had an accessory wind screen that was a shallow pan– tall enough to cover the burner and the pot stand and just reach the bottom of the pot. Maybe an inch tall or less?Apr 18, 2011 at 9:44 pm #1726418
@redleaderLocale: Luxury-Light Luke on the Llano Azul
"The old Gaz stoves had an accessory wind screen that was a shallow pan– tall enough to cover the burner and the pot stand and just reach the bottom of the pot. Maybe an inch tall or less?"
Snow Peak makes one like that. Don't work worth a pile of rooster p00p.Apr 19, 2011 at 6:35 am #1726492
As I read the various comments, I've been playing around with different variations of my setup. I find that by removing the reflector and employing a full flame, the canister can heat up fairly quickly, wind or no wind. There's not a lot of room between the pot and the screen for a rapid chimney effect, so that much of the heat tends to radiate downward as it bounces off the bottom of the pot. The reflector mitigates this to a great degree, but only if the stove is not turned up very high. But the minimal amount of space between the pot and screen/reflector is, in my opinion, the reason for the efficiency of the setup–nearly all of the heat that is generated is utilized to boil the water. I am certain that relacing the titanium components with aluminum would result in a lower efficiency, since aluminum would conduct much of the heat away from the pot. Titanium is such a poor conductor, that the heat gets rather trapped between the pot and the screen/reflector.
I've appreciated all of your comments–thanks.Apr 19, 2011 at 6:46 am #1726496
@retiredjerryLocale: Oregon and Washington
As you pointed out somewhere above, as long as the canister isn't hot to the touch you're okay, according to Roger
If it gets cold, you can take advantage of this. Canisters don't work so well especially below freezing. If you get some heat from the flame then this won't be a problem.Apr 19, 2011 at 8:13 am #1726535
>>> Canisters don't work so well especially below freezing. If you get some heat from the flame then this won't be a problem.
The problem with this is that it relies on positive feedback. If its cold and the canister is less than 1/3 full, the flame won't produce enough heat to warm the canister to boost the flame…
You will need to pre-heat the canister first to get it going, then the flame might produce enough heat to compensate for evaporative cooling of the canister.Apr 19, 2011 at 8:26 am #1726541
@retiredjerryLocale: Oregon and Washington
"You will need to pre-heat the canister first to get it going, then the flame might produce enough heat to compensate for evaporative cooling of the canister."
The problem with pre-heating is that as soon as you turn it on, evaporative cooling quickly cools it and it stops working.
Heat from flame will solve that problem.Dec 8, 2011 at 12:27 am #1809961
@5150broncoLocale: Bay Area, Ca.
This is a great thread. Very helpful so good to get this up so people can comment.
I am going to order some stuff from Tigoat and make something work. Not really a fan of aluminum foil. Seems to be that Ti is a better use for this application since it does not conduct heat well and keeps it trapped.
I will see whats up with the spacing from the reflector to can and see if the can heats up or maybe making it 3 inches space instead.
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