The Evolution of a Winter Stove – Part 3

[Billy Ray]

> " I also use best practices to maintain a 'warm' canister before I start "
> tell me what you mean specifically by that.

See Bob's reply.

And here I though you guys were into something I didn't know… throwing around them fancy terms like 'best practices'… gee…

Billy

[James Marco]

I think the tempertures needed could be reached with simply looping a piece of stainless tubing over the flame. Then we need to supply a dufferent jet, since the raw WG vapour wiold differ in density. I would guess that the valve would be OK. As far as initially feeding the fuel, some sort of pump would be needed. I belive that it starts adding a LOT of weight. The only thing that would survive, intact, would be the valve.

Yeah, it could be done. Feasability seems do dictate otherwise, though. Such a hacked up combination would undobtedly be approching the weight of the Simmerlite (~8oz.) It would likely suffer the same problems with simmering.

[Roger Caffin]

The purist would use Inconel; the pragmatist would use brass. Yep, some preheat tubes are brass. But a stove does not get as much use as a steam angine boiler.

Cheers
PS: YOU try machining Inconel. It's a nickel alloy.

[USA Duane Hall]

I noticed on this stove that it has some tiny screws in the plastic that is part of the piece that attaches to a canister. One stove had that part come off, the new owner had some issues getting it attached to the canister, maybe user error. He may have found a tiny screw driver to see if it could be screwed back on. A lot of plastic on the stove I noticed also at the GGG. Still in beta stage correct?
Duane

[Roger Caffin]

Hi Duane

Yes, still in beta test, but that means I am looking for what can go wrong, not for any major design changes. As I have shipped over 60 stoves now, with only a few problems reported and all fixed, I am fairly happy with the design.

Plastic: yes, good stuff. NO intentions AT ALL of changing the plastic to metal. That wouldn't work, for a start.

The tiny screws: yes, they are small. Yes, you need a small Philips head screw driver to handle them, IF you intend to disassemble the connector. Such screw drivers come in little kits for a few dollars. Other stoves also have tiny screws. The ones on watches are even smaller!

The 'Main Ring' on the connector which is held in place by two screws. Yes, this can come off, but it should only do so AFTER the screws have been removed. If it is ripped off accidentally the screw holes will be damaged. Gently, gently with the rotating Spider is the message. If this has happened to anyone (or to their stove), please contact me. I will help to fix the problem. There are ways.

Cheers

[Hikin’ Jim]

As reported on the GGG photo thread, I had a bit of trouble getting a "Caffin stove" (is there a better name?) to work with PowerMax Canisters. It may have just been a time thing; I had very little time to experiment before the stove's owner needed to leave. I hooked it up to a threaded canister first, then a Camping Gaz canister. Took me a bit to figure out exactly how things went (I didn't have the benefit of instructions), leaving me little time to experiment with PowerMax. I did give it a good number of tries though.

There has been the suggestion that perhaps the canister I used was "not quite right", and I was asked if I might take some photos, which I have.

The top canister (marked with a "2") is the one I believe I used at the GGG. The second canister is shown for comparison. More on that in the second photo.

Here are our two canisters again, this time showing the connectors. The canister on the left is the one I used at the GGG.

It's possible that the connector on the canister on the left does not protrude as much as the canister on the right. The canister on the left is stamped with a manufacturing date from 2003. The canister on the right is stamped with a canister date from 2004.

HJ
Adventures in Stoving
Hikin Jim's Blog

[Roger Caffin]

Hi Jim

Odd, very odd. I would expect both of those canisters to work just fine.

Do you still have access to that stove, or does the owner have some Powermax canisters? I would like to ask for some photos of the stove in some VERY simple tests.

Could you get the owner to email me direct? Yeah, this is a beta test, but it should work OK. I WANT to know what the problem is!
[email protected]

Cheers

[Hikin’ Jim]

Unfortunately, EJ, the owner of the stove, lives about 7 hours drive north of me. Now, I've very curious as to why I wasn't getting gas flow. The canister did work both before and after when I hooked it up to a Coleman Xtreme, so I know the canister was in working order.

I believe you and EJ have been in contact previously, yes? Perhaps he can run those tests for you. I believe he has some Powermax canisters.

HJ
Adventures In Stoving
Hikin' Jim's Blog

[Roger Caffin]

Hi Jim

OK, EJ and I will sort it out.
Such canisters work for me when tested over a number of stoves. May have been a 'learning' problem. Even so, I want to know about it.

Cheers

[Billy Ray]

"I haven't noticed any compromise. The only time I experienced flaring was when the Caffin stove and canister were at -25F and I immediately inverted the canister after lighting, before placing the pot on the stove. (Producing and evaluating flaring was the point of that test, documented earlier in this thread.) By the time I reached out and grabbed the pot and brushed the snow off, there wasn't enough flaring to stop me from putting it on the stove with my bare hand, and it settled down quickly after that"

Douglas,
I wish I could say the same. I've had lots of flaring.. From 20F to -15F..
and in some cases it doesn't go away until I turn the canister back upright.

wondering if you pre-warmed the canister and/or the heat shunt?

Billy

[Roger Caffin]

Hi Billy

> I've had lots of flaring.. From 20F to -15F.
In that case maybe you should bend the heat shunt a little bit towards the flame. Maybe just 2 mm movement at the top. This will get heat down to the stove body a bit faster. I do mention in the Instructions that you may need to do a litte tuning on your stove.

Cheers

[Billy Ray]

Hi Roger,
Yes, I had already bent the heat shunt to the point that it's a bit hard to get the one pot holder past it… so don't think I can bend it further.

Yes, I understand about the 'tuning'.
In addition to that this is my first inverted canister stove so there is a learning curve.

I'm actually wondering if maybe you put the tissue filter in there an maybe it is getting saturated with liquid fuel and thus inhibiting the flame (very weak after/during flaring).
I may open it up an see what if any filter in in there. If it's tissue, then I may try your filter recommendation.

I believe I am using quality canister fuel… Snow Peak and JetBoil… so I am assuming that clogging is not the issue.

billy

[Billy Ray]

Hi Roger,
so… pulled the jet… there was a little very light oily substance on the top of the jet… no light visible though it… got a hand lens and it is obvious that the jet is clogged… stuff so small it is hard to see, but looks like very very fine, gray metal shavings maybe… just packed in the jet hole… very few on the outside top of the jet so it must have been passing some..

that would explain the weak flame this morning when cold with lower pressure in the canister… and maybe at warmer room temp it may explain the very strong flame in that maybe the pressure coming from the canister at room temp was enough to blow those extremely find particles through the jet?

So my next question is WHERE do I find a copper wire small enough to clean the jet?
AND… do I have to know for sure that the wire is smaller than the 0.28mm jet hole before I go trying to push it through??? Any possibility that a copper wire will damage the jet hole?

Other things that concern me now:
If there are shavings (or whatever it is) inside the jet, there are likely shavings inside the jet holder, the fuel tube, and the spider connector. How do I clean all that???

AND where do these shavings come from???? The manufacturing process of the stove? Or the canister??? I'd like to avoid having this happen again… especially if I'm camped out in winter :(

thanks,
Billy

[Billy Ray]

oh, and there was no tissue filter or any other filter..

billy

[Douglas Frick]

>wondering if you pre-warmed the canister and/or the heat shunt?

No, as I detailed in my post, both canister and stove were at ambient temperature.

But from your subsequent posts, it seems you may have isolated the problem (I hope). I'm sure Roger will follow up with a comment about the clog, but I thought I'd add that I made a canister-gas jet cleaner from a single strand of copper wire from an old twisted-pair Ethernet cable (not telephone station cable; that's too thick). I doubt such a fine copper wire would hurt the jet, because it's smaller than the jet, and softer than the jet material. Roger specifically cautions against steel needles because they're too big, and probably harder.

I used that wire on my Coleman Xtreme. Not sure what got into its jet, but it sure ran a lot better once I cleaned it out.

[Billy Ray]

Hi Doug,
well, I've had the stove apart.. jet was clogged.
I managed to find a very small copper wire for the task.

Also, there was no filter. So I made one on Roger's suggestion out of coffee filter paper.
Stove runs better now, but only ran it for a minute.

Will try again tomorrow morning in the cold.

Billy

[Roger Caffin]

> I believe I am using quality canister fuel… Snow Peak and JetBoil…
There is some suspicion about the Jetboil canisters. They may be rebadged Chinese. The Chinese ones I tested were AWFUL: instant blockage. Does the label have specs for the fuel percentages? Yes, the label may be significant.

Oily stuff on top of the jet? That's out of the canister fuel. I've seen it before. It collects all sorts of gunge. It suggests a Chinese canister. You should also clean the needle valve tip in that case.

> [filter] getting saturated with liquid fuel and thus inhibiting the flame
Very doubtful if we are talking about butane and propane. Liquids from dirty fuel might do this, but I suspect not.

The dirt at the jet? Not sure whether it is actual dirt from the canister or fine aluminium swarf from the stove body. The latter may have come from the jet socket – unfortunately.

Filter paper: seems to be working well for quite a few people. Thus beta testing.

Cheers

[Billy Ray]

"instant blockage. Does the label have specs for the fuel percentages? Yes, the label may be significant."

No percentages on the JebBoil canister.

The 'oil at the top of the jet' was clear, very and very think and it did not look dirty. I even though it might be some of the silicone greese…

Needle Valve was clean…

Using a hand lens at least some of the stuff blocking the jet appeared to be very find silver colored flakes… could be aluminum from the thread cutting?
But there was also darker stuff that look more like dirt…

I guess it could be both canister contamination and from the thread cutting…

Any idea what the safest canister fuel is for being clean? The local REI sells MSR, JetBoil and SnowPeak… those are my choices.

Billy

[Adam Kilpatrick]

Just caught up on this article and thread. Really impressed Roger. If I was planning a lot of Tassie trips in the next few years (no, baby(s), I'm grounded) or snow trips soon I'd jump on one, but you should sell your beta's to those who can test in the cold for you.

Have you considered what your next stove project will be? It would be cool to see you apply yourself to the super efficiency equation for above freezing stoves. Overall system weight efficiency, I mean. Personally though I love the convenience and efficiency of upright canister stoves, I'm torn by the use of canisters and the whole partial canister issue. On long trips (eg cycle touring Europe) its not much of a problem, but for trips of just a few days where I might need less than half a canister, it screws with my head. So I think I'll personally stick to alcohol for now.

[Billy Ray]

Adam,
regarding the 'partial canister issue'
I weight my canisters. The weight before and after a trip divided by the number of days gives you a good idea of how many ounces or grams of fuel you need per day.
That will tell you how many days any of your partially used canisters will be good for.
It's not perfect, but allows one to use up at least some of the partial canister fuel.

Billy

[Jerry Adams]

+1 to Billy

I sometimes have a number of partial canisters of various weights to choose from which can be a nuisance

I do some car camping so I eventually get all the partials used

If I do a lot of trips that use a little more than half a canister it's more of a problem. For me that's 5 nights, and I've done several 5 night trips recently, but eventually all the partials will get used.

[Roger Caffin]

Oh, the oil on the jet is liely to look clean. It is just a much higher hydrocarbon from unrefined gas.

> Using a hand lens at least some of the stuff blocking the jet appeared to be very
> find silver colored flakes… could be aluminum from the thread cutting?
> But there was also darker stuff that look more like dirt…
Yeah, I would say a bit of both.

> Any idea what the safest canister fuel is for being clean?
Depends on what is available. Have a close look at the canister for the 'Made in XXX' mark. Most of them do have this. If the canister says where it is made (Korea, France, anywhere but China) then it is probably OK. If it says China or does not say, I would be suspicious.

Interesting note: the Powermax canisters do not say where they are made, but they ARE clean.

Cheers

[Billy Ray]

Roger… all my canisters say Made in Korea.

So it would seem that the blockage was from not enough cleaning of the stove on your end before shipping.

In any event I have not had another blockage since pulling it apart and cleaning the jet… (and using the same canisters)…. yet.

I did try your suggested coffee filter paper as a filter. But I don't think it works very well. Looked at it after using the coffee filter circle for a while and it looks to me like the pressure of the fuel entering at one side of the jet socket just pushes past the edge of the coffee filter paper circle.

What was wrong with the toilet paper filter anyway? Why did you suggest go go away from that?

Billy

[Roger Caffin]

Hi Billy

Sorry – I was away.

> What was wrong with the toilet paper filter anyway?
I found that if one used a shade too much TP and poked it in the hole a little to enthusiastically, it could wad up and partly block the jet. That is, the TP became as bad as a small bit of 'stuff' for blocking the jet. The disk of filter paper does not do that.

If the filter paper looks as thought he fuel is bypassing it, try a very slightly larger diameter of filter paper. All I can say is that it has been working fine for me.

Cheers

[Roger Caffin]

Hi All

Herewith an update on progress with completing the latest batch of stoves. To explain
why: I still have some unfilled orders from enthusiastic beta-testers who have paid up front some time ago despite being told that there would be a delay due to my CNC machine dying and having to be rebuilt. My thanks to those people for their long-suffering patience.

I started to rebuild all the electronics on the the CNC, but a series of domestic
problems slowed me down. Our grey water dispersion system died (we live on a farm) and had to be rebuilt; a storm took the roof off our chook shed so it had to be rebuilt; our elderly LandCruiser suffered a pulley failure and there were NO spare parts left in Australia (we got the original pulley manufacturer in Japan to make one to the original specs), plus a few other small delays. Murphy strikes! But all of these have been solved. Hopefully, not too many more will happen.

The electronics for the CNC have now been completely rebuilt from scratch and have been tested. There were a few hiccups along the way as might be expected, but nothing
serious. As far as I can see it is now running again and I will soon be finishing off
the next batch of stoves. I HOPE!

To recapitulate: so far I have shipped
batch 1: 10 stoves with FMS-116T burners (all gone)
batch 2: 27 stoves with FMS-300T burners
batch 3: 22 stoves with FMS-300T burners
batch 5: 9 stoves with FMS-300T burners
batch 6: 8 stoves with FMS-300T burners to the 6th annual GGG
I still have some FMS-300T burners for the next batch, but my stock of them is fast
running down.

Cheers

[Author]

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