I ran into another problem on my 123R clone labeled Champion (original post here Removing the SRV on a Taiwanese Svea 123R clone?). The third time I used it (with a borrowed fuel cap) I saw flame coming out the adjustment shaft. I took it apart and found this split. How it passed a dunk test I do not know, I think the heat cycling made it worse. Anyway, at this point I combined it with some parts from a partial Pak-Cook 235 I had to make one working stove. That being said, if I want to repair this, what material would I use? I am guessing that it gets hot enough that solder would not work. We use 15% silver brazing rod (Sil-Fos) at work to assemble copper tubing but the liquidus point for that is pretty close to the melting point of brass. Any repair would require re-threading and such so this is mainly an academic question. Thanks.
Others will have ideas for sure, but I'd grind out the crack to some extent to give a v-groove and fill it with 55% ag filler rod.
You’re referring to this area? The channel I see looks like it’s a casting flaw (there’s no practical reason for it) but I guess you’re seeing a crack along the line of it? Right. So the whole component could end up as a puddle. @Blackdog has rightly suggested a lower melting point silbraze rod that will fill the ‘channel’ and the crack (a shallow ‘V’ cut along it as he’s said). 55% silver rod provides a filler that’s got a much higher melting point than the temperature that component reaches when the stove’s in use but nowhere near the melting point of the underlying brass. The combination of the casting flaw and the force imposed on it by the compression of the graphite packing might well be the cause of the crack. I guess you fear that molten silbraze will seep through. Unlikely with a crack and the ‘lining’ of graphite deposited on the threads is likely to act as a barrier besides.
Double up your dunk test. Be sure there is a actually a crack and that the flame was not from the gland packing.
I will pull out the parts & look again. In real life (rather than the photo) it sure appeared to be a crack but I agree in the picture it does not. Won't be the first time I should have put on my glasses and didn't.
So as a follow up to this, I had stripped this stove down to bare parts and used a few to fix a partial Taiwanese 123R-clone stove I found. Based on the input above, I am reassembling the original Champion parts and I ordered new seals & packing. The graphite rings I got for the flame adjustment shaft seem to be too long, I cannot get the packing nut started to compress it around the shaft. Any reason why I shouldn't just cut it down slightly? This is my first experience with either the R version or the clones, I didn't have this problem with my non-R 123's (different graphite ring supplier too). Thanks.
I can't help regards the packing, I've only ever wound my own from strip, but interested if you established if there was a crack or not?
I think not, bot that's what I am trying to accomplish by putting it back together & re-dunk testing it.
Cutting a little off the packing should be OK, but keep the offcut as it can be added later after the first piece of packing has compressed.
I finally managed to get it put together without cutting it. And after some fiddling, it passed a dunk test. I plan to use it to make breakfast & coffee the next couple days, and we will see if it leaks.
Well, it made 4 rounds of coffee, 2 pots of oatmeal, and a cup of hot chocolate so I am going to assume the crack was just my poor eye sight combined with casting marks and worn out grphaite packing. The shaft is still rather hard to turn but I assume it will get looser with use. I still like my Swedish Svea non-R 123 better, but this one certainly works.
