Hello! Thanks so much for getting back to me and for your comments and further testing, I really appreciate it. Sorry for taking time to respond. I am not on the forums often enough! 

What materials did we use? 

Alcohol from NZ no colour, we add a bit of water (10%?)  to burn cleaner (which works). Once I finished the current container I will try neat alcohol with the modified burners. 

Fittings - stainless steel bolt with the penny washer as per David Tyler's instructions. 

Pete did think that lifting the washer up a bit might help, yet to try it. 

Watery eyes? 

Bad, at the point of crying, while the burner is heating up. Not affecting me so much once it gets going. We noticed a strong smell at the beginning which we never noticed before. 

Conclusion -  probably go back to standard flame spreader (which we ordered from the UK - SEAMARK NUNN on eBay). After 6 years the flame spreaders are giving up the ghost! 

Awaiting further development - although once offline for a while I am not sure how I will catch up on it. 

Thanks so much for helping with this. 

Cheers - Linda & Pete 

I also did some experimenting to see if I could make the Origo burn better.  One of the observations I had was that anything you put in the flame path absorbs heat initially and depending on what I put in the path, some things seemed to continuously conduct heat away as well.  I suspect your observations can be explained by the increase of mass in the flame path causes incomplete combustion, at least while the stove is warming up.  So the stove takes longer to get going and during that period you have incomplete combustion.  Pure ethanol shouldn't cause eye irritation in this case, but there are lots of additives that do.  I've found the non-dyed ethanol fuel available for in-home non-vented fireplaces to be much better in this regard than some others.  Although, denaturing methods and laws are different the world over, so experimentation is likely required.

These stoves rely on a particularly delicate balance of forces.  As David described there is not a lot of draft and mixing in air can be a problem.  However, at the same time the heat reflected back to the canister controls the rate at which alcohol vapor is released and the temperature in the cylinder above the canister also effects how complete combustion is.  Unfortunately, changing one of these factors can have a knock-on effect on the others.  A hard nut to crack indeed.

The extra condensation makes sense to me:  there's more H2O around due to the more complete combustion.  

The eye watering - not as clear, but a perfect phenomenon for rampant speculation.  A couple questions:

I don't have Facebook - what were the modifications and what materials did Pete use to make them?  

Do your eyes remain irritated as long as the burner is going, or only for the first few minutes after it's lit?

David Porter wrote:

Just discovered this interesting thread. My two cents - I bought an Origo two burner forr a yacht I had in HK and was very happy with it for the three years or so before I sold the boat on leaving the country. Well made, and it cooked fast enough for my admittedly modest requirements.The only issue was that the flame was sometimes a bit hard to see in daylight but you got used to it. I would certainly buy another one, though I think they are pricey for what they are.

David

Hi David

This topic seems to have become subsumed in this thread.  (I would really love for someone to volunteer to go through all the various fora and reorganise them.  For example, there are a lot of topics on the General Forum, that really ought to be on the Technical Forum.)

It's good to hear your positive comments.  If you look at the thread I've just linked to, you will see that David Tyler reckons he has improved the Origo - although I think, if anything, the flame will be less visible.  This can be a problem with an alcohol cooker.  Holding a hand over the burner usually clarifies the issue!

Pricey for what they are?  Probably.  On the other hand, I don't suppose that the demand for them compares with gas cookers and the carriage and import duties were no doubt a significant part of the cost.

Annie Hill wrote:

Neil Tanner wrote:

I don't know if this link has been mentioned or if will be of any use.  It's been helpful for me since I use kerosene for cooking and heating on Sea Elf.  https://classiccampstoves.com/

Yup, I discovered it some time ago when investigating pressure alcohol stoves.  All sorts of interesting stuff.  It's amazing how many people appear to collect them rather than simply to use them!!

The folks in the group were really helpful when I had issues with my heater.  In fact one of the fellows in the UK sent me misc. stuff no charge to get the heater running properly again. 

I guess if it exists, someone's gonna collect it, some just like to look at the stuff on their shelves...others like to use 'em.  Actually, there is a section in CCS where the guys will show meals they're cooking with the their refurbished stoves......my mouth drools looking at some of the meals!