I bought it about a year ago and received it today. It looks like a late 40's model and has had a Coleman burner cap modification. I would like to rectify the burner modification but I am not sure if I should try it as is first or not. I will post the after photos once it's cleaned up which may take a while.
You're right about the time frame. Interesting burner modification. I look forward to seeing your progress. Be careful with the mixing tube (J tube), as you can't get spares anymore.
So I decided to get busy with the lantern today. Got it cleaned up, cut off the Coleman burner tube and fitted a brass ceramic burner holder using one of the locknuts to hold it in place. I replaced the loop on the generator as well as the old one was solidly clogged with carbon and was cracked under the repair. I now have three different versions of the Optimus 300.
Thank you. Brazing brass is not too easy but can be done. I practiced on a piece of scrap brass from the replacement and the old Optimus loop to get the flame right. It scared me as the brass and brazing rod melting points are not far apart.
@Fireexit1 Well, yes. There’s many an example here on CPL and CCS. The issue is the ratio of brass to silver: what is the melting point of your braze rod, to the operating temperature of your repair. I’ve not had a braze melt in operation. Tony
The silver-rich brazing alloys usually have melting temperatures that are lower than the usual brasses. The right fluxes also play important roles. I've brazed similar vaporizers with an oxy-acetylene torch. I find that using an oxidizing flame works better on brasses due to the tendency of the zinc to vaporize and burn off. Whatever it is, I think practice is still the most important factor to get it right.
@Andrew T Well done on the modifications and repair. The lantern is running as it should. Thank you for sharing. Cheers
