I have an old Svea 123 that I do not have the pot stand for since it was acquired with a Sigg cook kit. Instead of buying one from A & H I thought I try and make one out of some Ti I have. Does this look as though it will be OK. As in not over heat the stove too much. This is rev 2. Rev one had less holes and i blew the cap safety valve. New caps on order
Um...you have scrap titanium laying around the shop? The thermal conductivity of brass may be quite different than titanium alloys. I looked this data up in my Metals Handbook but could not find the co-efficient of thermal conductivity of Titanium (or brass for that matter). If you have the Ti, you might also have access to the physical constants and can compare the two alloys.
Titanium does not conduct heat as well as brass. Quite a bit less, IIRC. So, if brass doesn't overheat the stove, then Ti should not overheat the stove. Ti might reduce the performance of the stove. Recall that a Svea 123 works via heat feedback. Since Ti doesn't conduct heat as well, there may be less heat conducted back to the tank. If less heat is conducted back to the tank, there will be less pressure in the tank, and the performance of the stove would be somewhat reduced. In theory. The reduction in performance may be offset by the fact that your Ti windscreen has less air flow than the stock brass windscreen (at least judging by the photo). I don't see any obvious "red flags" here, but I'd try it cautiously the first few times. Watch the flame and listen to the stove. If the flame seems excessively strong or the stove starts sounding like a runaway freight train, then back it off a bit or shut it off as needed. Just gut feeling, I think your Ti windscreen will probably work just fine. HJ
Funny Rev 1 did not have as many holes. (see photos)I Kept having to back the stove off then the cap caught fire. Turned it off at that point and blew out the cap fire. Had to go looking on the internet for a new cap, which lead me to this site. So I have not had a chance to test this one yet.
Probably blew the SRV due to collected heat rather than thermal conductivity. The real SVEA 123 windscreen has a barrier right under the burner to reflect heat upward and a large opening on the side to let heat out. The windscreen would not be able to conduct enough heat through the material itself. It would be like putting a SVEA 123 in an Optimus 80 or Primus 71 box and closing the door. sam
Eggs, did the cap catch fire in an explosive fireball sort of way or was it a more gentle flame? Sam raises an excellent point -- that on the normal windshield there's a sort of heat reflector underneath the burner that deflects some of the heat away from the tank. I'm still not sure exactly what your new windscreen (rev 2) will do and think that you'll probably have to (carefully) test it. Your first windscreen (rev 1) does look a little dangerous. Not enough ventilation I think. It looks as though a lot of heat would be trapped in the column of air inside the windscreen. HJ
No explosion just a gentle fire. I remember hearing an odd chug just prior to noticing the cap was on fire. Then it started to lose roar, I guess you could say. Will not lite at all now or if I get it hot with a few primes goes out pretty quick. I may have to try a heat shield idea. Just below the burner head I guess. Then test when my new caps come in. Not trying to make a wind screen by the way just a pot stand since the Sigg kit is too heavy but I like this stove otherwise. Oh by the way Sparky the Ti I buy is from a web site called Titaniumgoat.com. I make wind screens for my various stoves out of it so had few pieces left over
Your SRV may have blown and may need replaced. That's what it sounds like to me anyway. If you have another cap in good standing you may want to give it a try. sam
Well, the Titanium Goat site is interesting, if not a tad expensive. I make my windscreens out of aluminum gutter sheathing from Lowes. Works fine as long as you are not counting the grams although they are not much heavier than Ti screens. The Ti foil seems to be a bit thin for many applications at .005". Why, that's so thin it probably only has one side!
I have three caps on order assuming I'll mess one more up before I kill myself. I also messed up the pentagon hole (striped it) thinking it was a common heck key nut when I tried to take it apart to see what it looked like in there after I blew it.
All of the "123 style" stoves have a heat shield between the burner and the tank. This is also true for the Optimus 8R, 99, and the like. These stoves get the heat transfer for pressurizing the tank through the brass fuel line. Any additional heat coming to the tank by radiation or hot air is simply too much. IMO, you MUST add a heat shield to your titanium contraption. Yonadav
Titanium, being a lousy conductor, won't conduct or radiate heat to the outside world, the way brass does, so one would expect more heat retained inside the wind screen making its way to the tank, raising the pressure of the vapor and blowing the pressure release valve, but boiling your water faster. Maybe you could punch more holes or castellations or slots near the top of your ti shield to let more heat out around the pot. The values below are from matweb.com, a fantastic source for material properties. Best... Gary For titanium: Specific Heat Capacity 0.528 J/g-°C 0.126 BTU/lb-°F Thermal Conductivity 17.0 W/m-K118 BTU-in/hr-ft²-°F Melting Point 1650 - 1670 °C 3000 - 3040 °F For brass: Thermal Conductivity 159 W/m-K @Temperature 20.0 °C 1100 BTU-in/hr-ft²-°F @Temperature 68.0 °F Melting Point 990 - 1025 °C 1810 - 1877 °F For aluminum: Thermal Conductivity 210 W/m-K 1460 BTU-in/hr-ft²-°F Melting Point 660.37 °C 1220.7 °F
