View Full Version : removal of lacquer from homemade caldera cone
BirdBrain
03-22-2013, 10:35
I am building a 2 piece caldera cone out of aluminum flashing that fits in my Kmart grease pot. I am not quite done. I was about to punch the vent holes, but I have discovered a new obstacle. Aluminum flashing has a lacquer on it to keep it from oxidizing. This lacquer shows up as a brown heat stain when heated. It is also toxic when heated.
My question is how do you remove this stuff without buffing it and making it thinner?
I am happy to answer question of construction methods as well.
20578
BirdBrain
03-22-2013, 11:07
Acetone should work
Is this the voice of experience? I will buy some if you say it will work. I was tempted to bake it in an old barbeque grill and burn it off. That way it would be evenly discolored.
Hot Flash
03-22-2013, 11:14
I would say acetone as well. It's not expensive, but if you don't want to buy a whole quart, then just pick up a small bottle of fingernail polish remover instead.
I would say acetone as well. It's not expensive, but if you don't want to buy a whole quart, then just pick up a small bottle of fingernail polish remover instead.
Make sure it has Acetone. Much of the nail polish remover is non-acetone.
I have used flashing for different windscreens... No problem with some light steel wool and some elbow grease.
Fur Queue
03-22-2013, 12:48
Very nice BB...will you make me one? :)
I let my alky stove burn it off. It doesn't take long and it's not like your burning your stove indoors. Plenty of ventilation outside. It's probably no more toxic than methanol.
rocketsocks
03-22-2013, 14:19
Bird Brain, nice job! really clean looking, like the keyed joinery...maybe try some scotch brite or the like.
BirdBrain
03-22-2013, 14:30
Bought a 4 oz bottle of acetone at Wallyworld. I have access to good buffing tools and the like. I don't want to go the abrasive route. The stuff is already thin enough. Not making any extras. I have been in construction and acquiring mode since last September. I still have a lot of studying and building to do before my walk and I am running out of time. Next, I will be making a pot grabber for the grease pot that will weigh about 1/2 an oz. Perhaps I will post that item when it is done.
Odd Man Out
03-22-2013, 14:38
How are you calculating the needed area for the air holes (both intake and exhaust)? I believe that is a rather critical parameter and dependent on the kind of stove used, but I don't quite understand that variable yet.
BirdBrain
03-22-2013, 14:44
How are you calculating the needed area for the air holes (both intake and exhaust)? I believe that is a rather critical parameter and dependent on the kind of stove used, but I don't quite understand that variable yet.
I am doing it very crudely. I have looked at numerous designs and have decided to start with 1 row of 1/2" holes at the top and 1/2 row of 1/2" holes on the bottom. This is likely not enough. I am taking the haircut approach: You can take more off, but can't put it back on. If the stove is starved, I will add more holes or try another stove.
rocketsocks
03-22-2013, 15:23
Don't forget laminar air flow and asymmetrical resonance with regard to volcanic short steaming, wouldnt wanna... Snuff it out!
Another Kevin
03-22-2013, 15:35
I never tried flashing aluminum for the purpose. For my most recent trips I've been using a windscreen/chimney made out of a foil cookie sheet from the dollar store. I put a double row of holes around the bottom, below the level of the stove jets, with an office paper punch. I didn't put holes at the top, I just don't try to make it fit tightly to the pot. About a half inch air gap all the way around seems to let it burn well and channels the heat around the pot quite nicely.
It doesn't look as nice as yours, but I've cooked some tasty meals with the arrangement.
Odd Man Out
03-22-2013, 23:12
Don't forget laminar air flow and asymmetrical resonance with regard to volcanic short steaming, wouldnt wanna... Snuff it out!
I give up. I know what laminar flow is, but "asymmetrical resonance with regard to volcanic short steaming"?
BirdBrain
03-23-2013, 00:05
I never tried flashing aluminum for the purpose. For my most recent trips I've been using a windscreen/chimney made out of a foil cookie sheet from the dollar store. I put a double row of holes around the bottom, below the level of the stove jets, with an office paper punch. I didn't put holes at the top, I just don't try to make it fit tightly to the pot. About a half inch air gap all the way around seems to let it burn well and channels the heat around the pot quite nicely.
It doesn't look as nice as yours, but I've cooked some tasty meals with the arrangement.
Like I told Storm, I like to try things the hard way 1st. Going out to try it right now.
BirdBrain
03-23-2013, 00:59
Well, 1st test can only be described as a complete failure. With no screen I was able to boil 3 cups of water with 1.5 oz of fuel and keep boiling for 5 minutes. With cone, was not able to get past 192 F before fuel was gone. Before I do anything more I am making a super cat and getting some foil cookie sheet from the dollar store.
Train Wreck
03-23-2013, 01:43
Well, 1st test can only be described as a complete failure. With no screen I was able to boil 3 cups of water with 1.5 oz of fuel and keep boiling for 5 minutes. With cone, was not able to get past 192 F before fuel was gone. Before I do anything more I am making a super cat and getting some foil cookie sheet from the dollar store.
get a JetBoil :bse
BirdBrain
03-23-2013, 01:58
get a JetBoil :bse
Buy something already made? Where is the fun in that?
Train Wreck
03-23-2013, 02:19
Buy something already made? Where is the fun in that?
I'm eating, you're still heating :p
rocketsocks
03-23-2013, 02:21
I'm eating, you're still heating :pAh man....baby that's cold
rocketsocks
03-23-2013, 02:22
I feel a haiku coming on
I am doing it very crudely. I have looked at numerous designs and have decided to start with 1 row of 1/2" holes at the top and 1/2 row of 1/2" holes on the bottom. This is likely not enough. I am taking the haircut approach: You can take more off, but can't put it back on. If the stove is starved, I will add more holes or try another stove.
I made my cone 5 years ago and kept cutting on it until it worked. It's not pretty anymore but it works good. I ended up slotting from the top to get enough air flow to keep the pot hot.
Wise Old Owl
03-23-2013, 05:59
Well, 1st test can only be described as a complete failure. With no screen I was able to boil 3 cups of water with 1.5 oz of fuel and keep boiling for 5 minutes. With cone, was not able to get past 192 F before fuel was gone. Before I do anything more I am making a super cat and getting some foil cookie sheet from the dollar store.
Well you were up late last night - from your picture - you dont have the air slots at the top and bottom. distance from stove to kettle and keeping the heat close to the kettle must move air to work. The vents are important. Also my home made flashing has melted from time to time... Removing the lacquer, is not important, if you have a lid on your pot - the lacquer fumes won't get in there.
BirdBrain
03-23-2013, 06:31
Thank you for the advice guys. For those that might be trying this too, this is what I found.
Acetone does work for removing the lacquer, but it takes forever. I ended up buffing the lacquer off which warped the metal.
I drilled a row of 1/2 holes on top (17) and half of bottom (10). Flames sought the bottom holes using a side burning stove.
I ended up having some success by just using the bottom half and setting the pot on the stove.
If I try this again, I will not remove lacquer, will have a wider base, twice the holes, and/or chimney stove.
BirdBrain
03-23-2013, 06:32
I'm eating, you're still heating :p
Ah man....baby that's cold
I am feeling the love. My friends follow me everywhere.
Wise Old Owl
03-23-2013, 07:12
BB my take on the whole thing about alcohol stoves is that if heat is centered on the bottom of a wide pot and there is enough air, the cone isn't that important. Any wind screen will do.
I am not a fan of a cat stove or models with side jets, after making several stoves.
If you are really bothered by the lacquer. Have you considered getting a buff wheel for a drill and put a pad of 000 steel wool in-between?
kayak karl
03-23-2013, 07:32
don't know if this will help on hole placement. consider a heat-gun to remove lacquer. too much heat will warp.
20606
BB, I've been playing with fire for a long time and have had a lot of fun making backpacking stoves. The caldera cone system is really neat when you get all the variables to work together. I think that the best lesson I have learned is that if the stove or fuel container like a cat can gets too hot then the fuel will boil away too quickly. The trick is to keep the stove itself cool and only just hot enough to vaporize the fuel efficiently. The question then is whether to have fewer air holes to resrtict the oxygen and keep the burn small or to have more holes to keep the can cool?? Life is full of tradeoffs! Have fun.
BirdBrain
03-23-2013, 20:54
don't know if this will help on hole placement. consider a heat-gun to remove lacquer. too much heat will warp.
20606
Thank you KK. This further confirms what I have been seeing. The holes distribution is counter intuitive in my mind. I thought I would need more holes on the bottom. In reality, I need many more holes at the top. My setup had 17 1/2" holes on top and 10 1/2" holes on bottom. With that distribution the flames sought the holes on the bottom. i did not expect that.
As to the lacquer, I believe Rasty has the best solution for removal. Acetone works, but very slowly. I buffed mine with as good of equipment as you will find. Even though I was gentle, the material got thinner and warped.
As to my stove, it takes too long to prime and is a side jet stove. I am finding chimney stove instructions hard to find on YouTube. WOO, you say you have made several stoves and are not a fan of the Cat or side jet ones. Can you point me to a good chimney design that I can build?
BirdBrain
03-24-2013, 13:59
don't know if this will help on hole placement. consider a heat-gun to remove lacquer. too much heat will warp.
20606
Thank you again KK. Using the picture you supplied and with a bit of geometry and trig, I was able to able to calculate the proper angle of slope and transpose this to my pot's needs.
I will also try removing lacquer from a test piece using a heat-gun. I suspect the best method would be to soak the parts in acetone in a long shallow pan.