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MYOG: SUL Remote Inverted Canister Winter Stove Version 7


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Home Forums Campfire Editor’s Roundtable MYOG: SUL Remote Inverted Canister Winter Stove Version 7

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  • #3814712
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    Hi Jim

    Not at all!
    You made me think. I don’t have to use a cyanoacrylate after all: a silicone adhesive works just as well. The idea if a slightly roughened surface was brilliant.

    The key point here is that the adhesive does not have to fully anchor the PFA tube in the inner sleeve. The SS braid and the crimps provide all the strength needed. The silicone just helps keep the tube where I want it. And there is an added benefit of using a gap-filling adhesive here: it serves as a backup to the Viton O-ring.

    We advance, 4 sides of a triangle at a time.

    Cheers

    #3814718
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    More progress report

    Then I ‘burn test’ each stove to make sure every one works. Well, unexpected trouble when I did that. They ‘worked’ but with quite limited power, and not in just one stove but in the several I tested. Not at all what you want in the mountains when you are trying to melt snow into water. What had gone wrong?

    Checking back through previous models, I found that the bore in the stove body into which the Heat Exchanger fitted, had shrunk. It used to be 3.3 mm, but this had been reduced to 3.2 mm This is for a HX rod nominally 3.0 mm OD. Surely a clearance all around of 0.1 mm over ~5 mm should be OK? Well, possibly so, but the 3.0 mm OD for the rod was not what I had in practice. Oops.

    So I bored out the hole in a stove body to 3.3 mm, inserted the HX rod, and retested. The stove roared.

    The saga continues.
    Cheers

    #3814975
    Gary W
    BPL Member

    @gawilliamson

    Locale: Santa Cruz County

    Roger, how do I get in line to buy a V7?

    My shop consists of a screwdriver, a crescent wrench and a hammer…….so I won’t be building my own inverted canister stove any time soon……..

    #3814986
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    Hi Gary

    Email me: [email protected]
    All will be revealed. :)

    Cheers

    #3815041
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    AAAaarrrggghhh

    I think I mentioned in the article that I test each stove, first with 100 psi pressure from my compressor with the whole system under water, then a ‘burn’ test on the bench to make sure it works properly.

    So I was pressure testing, and two stoves failed. Odd, very odd.
    The failures were at the place where the hose goes into the canister connector: a stream of bubbles. I stripped the joints down, cleaned them, reassembled them, and retested. They still failed. But all the rest passed.

    OK, back to the lab for forensics. The hose is 2.0 – 2.05 mm OD. Check. The 6x2x2 O-rings have a 2.0 mm cross section (CS), so the OD outside the O-rings should be 6.0 mm. In the failures, the OD was less, to the point of just not sealing in the 5.6 mm bore. Huh?

    Eventually I had to carefully measure the cross-section of the O-rings involved. How very odd: the failures seemed to be about 1.8 mm CS. Um … Oh. An imperial sized O-ring can have a CS of 1.78 mm. More measurement, and it seems as though the vendor has allowed some BS005 O-rings to get into the metric 6x2x2 bin. They are very similar, at least in appearance.

    That meant I had to strip every completed stove down and check the hose O-rings. Two more bodgie ones found. They were replaced with some (measured) 6x2x2 O-rings. The previous failures were also fixed.

    Back to testing.

    Cheers

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