So I'm fettling my recently cleaned up SVEA 5, trying to get it to light, following the instructions of Kerophile. Despite it holding pressure and producing a fine jet of paraffin easily when cold, once I've primed it with meths to get it hot, and pressurised it, I get basically a dribble from the jet, which at best underburns. So I took the burner off again, removed the jet, soaked the burner in hot soapy water, brushed it out, washed it some more, jetted hot tapwater through it and then used an air blower to completely dry it out inside. I'd read about pricking the nipple but have no tool to do so. I tried a sewing pin, but these are too thick, I tried the wire from the middle of a freezer bag tie - too thick. Sitting there wondering what else I had that was about as thick as a cat's whisker... it struck me - try an actual cat's whisker! Now before you ask, no animals were harmed in the making of this photo. We have two cats who regularly shed their whiskers and it didn't take much looking under the sofa to find a spare one. So... in it went. The shocking thing to me is that the thicker end of the whisker is still too thick to pass through the nipple jet.. is this about right? From this close up you can see the nipple is pretty bashed around I'll order a spare in case this is my problem. Even after all this cleaning, the jet spews cold paraffin really well, but doesn't work properly when hot. (edit: spelling)
The cats whisker was a good thought. If you have given the burner a good preheat then the burner could have a build up of carbon inside. It needs to be cleaned out.
If you have a guitar about the thinnest steel string is about right is it an E string? The edges of the depression round the orifice look pretty rough too so maybe time for a new one? Nick
There was really good flow of water / air through the burner tubes when I cleaned them. Would carbon buildup still be a problem in that case?
Light gauge high "E" guitar string (should be called wires!) will work for many stove jet orifice as a pricker.
Yes, Carbon is a good heat insulator. A build up of carbon prevents the transfer of heat to the fuel and can stop proper vaporisation of the fuel. It depends on how you cleaned the inside of the burner. Carbon is very hard and impervious to most cleaners. It can be removed by : mechanical abrasion but it's hard to get into the very top, heating the burner to dull red and quenching in cold water (causes the carbon to shatter) or heating the burner until the carbon burns whilst passing a low volume of air through the burner. I have heard that boiling the burner in a caustic soda solution will remove the carbon, but I haven't tried it.
So almost 2 weeks later, a progress update. Tonight I got it lit for the first time! I uploaded a 15 second video to youtube - seeking advice on how to make the flame go blue! There are a couple of still images linked here also. The burner assembly was clogged internally with carbon, which meant that the jet nozzle kept blocking with carbon particles every time I heated it for lighting. This caused a lack of flow and under-burn every time. I tried a number of approaches to cleaning the inner tubes of the burner, eventually boiling it for around an hour in water with a little Barkerper's Friend in it. By the end of the boil there were lots of small flakes of black carbon bubbling around the pan. I left it overnight full of carb cleaner. The flame is still not right, it's too yellow and sooty, but at least the fuel is vapourising properly and lighting in the right place. Any suggestions for next steps on adjusting to get a blue flame?
I'm still plugging away at this after a summer break. I had replaced the filler cap washer with one I made from cutting out some spare rubber I had. This presented an opportunity to learn from my mistake. This used to be a solid circle with no hole. As you can see, the paraffin had dissolved the rubber in the center, leaving only the compressed ring. This had compromised the quality of the paraffin and was probably part to blame for the yellow flame, and certainly for the constantly blocking nipple jet. I ordered the correct parts from the fettlebox. When I tipped out the old paraffin, and then rinsed several times with fresh paraffin, there was a fine silt of black rubber particles washed out of it. I filled it with fresh paraffin, it lit first try, and I finally got the sought after blue flames. Albeit with some yellow in the flame still, but a real step forward. It was simple to boil a kettle of water quite quickly and my son had the first hot cocoa this stove will have produced for probably a few decades! The kettle was a car boot find over the summer, it is the perfect size and fit for the stove! We went on to cook bacon and eggs, but had to abort due to paraffin leaking back out of the pump tube. Clearly I need to adjust the seal on the non return valve next.
I spent some further time reading kerophile and others' posts on NRVs, and suspected mine was missing a washer... testing with it under pressure, but unlit, demonstrated that the fuel was definately leaking from within the tube, not from the outer solder joint. Fortunately this was a quick one to check as I've had the NRV out a couple of times before, and had previously made a removal tool. Indeed - there was no lead washer! Now I have spare NRVs I bought a while back, and lo and behold they had lead washers fitted to them, so I wrangled one of those and used the new lead washer with my original NRV... reprimed everything, tested it and could find no evidence whatsoever of leaking. Fingers crossed, I lit it up, got it going and ramped up the pressure. Oh my days I'm happy with the result! It looks and sounds beautiful! My son and I were dancing round the workshop, and have just enjoyed more cocoa!
@Coffindodger , Well done! Your persistence paid dividends for sure, and the flame now looks perfect! By the way, the mental picture of you and your son dancing around the workshop, was hilarious, but understandably apt! Again, well done! Take care, and God Bless! Every Good Wish, Doc
