Optimus No 9

Optimus were obviously out to produce a revolutionary design, as light as possible for the more extreme sports, and just a bit too light. They must have tested it in production and manufacturing, this was standard practice, possibly they did just not account for the cyclic fatigue loading in use? It just seems such an enormous error for a company with three decades of experience when they launched the No.9.

Although obviously any liquid fuel stove needs to be treated with care and respect, a tank failure on a paraffin stove would be nowhere near as dangerous as a petrol equivalent, it would be a case of a puddle of paraffin which may or may not ignite with a sooty yellow flame, rather than a fireball. The real danger would be letting it sit in a puddle of burning fuel until it heats to explosion point, but even in that worse case situation there would be plenty of warning to take action or run.

Regards your last point, sadly Optimus did not date code their stoves, and so far no overall or individual model production figures have come to light. We only have overall figures for Primus.

The only real guide to numbers is how few there are catalogued on here, and how often they turn up for sale. There will be more around not on here, and yet to come out of the woodwork, but likely very few. I image many were scrapped on tank failure, but how many again we'll probably never know.

 

It was marketed as usable with paraffin or petrol.

 

@presscall Thanks for putting me right, I was forgetting these were dual fuel! To be honest, they don't occupy my thoughts very often, based on likelihood of ownership! A failure on petrol would be a lot more dangerous. Best to stick with paraffin if you intend to make it a regular 'user.'......

 

Today I thought I would carry on with the No 9 refurb.
Clam shells were the first to get some fettling, I had a few dents to tap out and generally clean them up, unfortunately at some time in its life it looks as though someone has decided to use a screwdriver or something similar to prise open the stove, why they didn’t just press the button beats me, anyway I decided not to take a file to the edges it as it would of just made things worse, sometimes it’s best to leave imperfections and life long patina alone as it is all part of the history.

The nickel plating has started to flake off the bottom heat shield and main bracket that the burner mounts onto and also connects the clam shells to the fuel tank.
I managed to get most of the carbon build up off the burner assembly and then started reassembling.

Next job is to spend some time on the primer pump, new cup washer and cap rubbers needed, any advise on where to source these would be very helpful ? as I’m only really looking on eBay, I have all the measurements.

My thoughts so far on these stoves are.
I agree Optimus designers were well ahead of there time on the design of the No9 but unfortunately it is full of faults in almost every area, so in my opinion it was never going to be a practical stove to take along on camping trips in a back pack, in its present form they are to fiddly to use, no where near strong enough and liable to blow you to pieces if you use it, that’s not a good way to end your camping trip.

Like already suggested, perhaps if it wasn’t for ww2 getting in the way then perhaps it may have had all the imperfections rectified and would of made a lovely futuristic stove, but we’ll never know now.

My end goal is still to make a cup of tea, if I succeed and survive without a big bang and lots of flames, i think i will just add it to my own collection of collectibles, as for regular use, I think not.
One thing I think we can all agree on, it is a lovely stove in more ways than one.

 

I applaud your thoughtful reflections as you methodically explore your stove. You’re wise just to aim for a brew as your goal and retire it. It may well have escaped stress cracking for now but the nature of the phenomenon is for cracks to propagate cyclically - pressurise/depressurise/repeat.

You mention some plating loss. I appreciate what you say about ‘life long patina’ but nickel plating at home is straightforward and pepping up some parts with a top-up of nickel plate is legitimate restoration I think and not excessive.

Excellent work and very well presented. Thank you for taking the trouble to document it.

 

@presscall Thank you for planting the seed in my head regarding re-plating the nickel, I will now look into having a go at this, it’s something I’ve not done before, but it looks easy enough and I have just about everything needed to do it already.
After my cup of tea (if it doesn’t blow up) i will have a go, I also plan on fabricating a new replacement end cap to make it as complete as possible,

Would you know if the tools that are stored inside the clam shells are still available ? I’m sure Optimus would of used tools that were already available as I can’t see the stove needing any unusual tools.

Thank you for taking the time to read my post and your interest in my refurbishment.
Joe

 

I have decided that as this stove is a little bit special i have decided to give it the extra special attention it deserves, @presscall suggested that it would be worthy of renewing the nickel plating on the bottom heat shield and mounting, I have had a look on YouTube and i am surprised how straight forward and easy it is, I shall also be asking for the return of my ultrasonic cleaner from a friend so I can and make a better job of removing the rest of the carbon deposits from the burner.
I have now managed to source and order a replacement leather cub and rubber seals for the pump and ordered some nickel.
I’ll add another post with photos once I get the platting rig up and running.

 

Quick little update and a few photos.
While I’m waiting for the nickel to arrive I thought I might as well start getting bits prepped ready, so I stripped it down again and started on the shield that sits under the burner, I first removed all of the remaining nickel coating using a rotary wire brush and a little one on the dremel to get into the hard to reach places.
Then it was time to start polishing with the mop, unfortunately because over the years some of the nickel costing has flaked/worn off the dreaded tin worm had set in on these areas, I managed to polish out all the marks left from the wire brush but the rusted areas were becoming a problem as the metal is very thin and the rust has eaten itself quite deep, so I had no choice but to stop where I have because it is getting dangerously thin, if you’ve done metal polish you’ll know what I mean, so I’m not completely satisfied with the result but it’s the best I can do without risking destroying it. as long as I get it 100% spotlessly clean it should plate ok, yes I know it will show where the rust had been, but you can only do the best you can with what you have, I suppose i could of made another plate, but then it’s not original.
What would you do ?

 

Hello,

I can be wrong, but I guess John’s suggestion to restore the nichel plating was referred mainly to the body of the stove.

I don’t think that the burner bottom plate was nichel plated originally, probably those parts were galvanized.

Personally, I am never for the “restore to new” choice, but that’s personal. As you experienced, trying to achieve perfection implies some aggressive methods on the original material… wire brushing or sand blasting are always non return operations which remove some of the original material forever.

After the first cleaning and manual polish the stove was already in a very good state, showing its age… I personally like to stop myself at that point.

In any case, I think you should try to save as much as possible of the original… replacing parts that are honestly in a good and acceptable shape I think is absolutely to avoid.

Go ahead to the flame shot, that’s what is really important

Nicola

 

In short, I highly doubt that the burner bottom plate was originally plated and polished to mirror level… so restoration should also take in consideration the original aspect of the stove. For those parts a dull galvanized grey is what should have been in origin.

Nicola

 

Hi Nicola
Thank you for your reply, the parts in question were definitely originally nickel plated and not galvanised, the polishing that you see here is needed in the process of plating, once the nickel plate has been applied it will be a dull shade of grey, like you see on the bracket that is next to the shield in one of the photos, nickel plating only becomes shiny if it is polished.
I fully understand what you mean about leaving it as it was, that was in fact something i was going to do, but as it is a special stove I do agree that re-plating is quite acceptable in restoration.
The flame shot that you seek to see is on its way in due corse.

 

Hi, you’re welcome… yes I understand that the extra polishing was the preparation for the plating.

By the look of what I have seen on photos I thought it was galvanized steel and nichel plated brass, you have the stove in hand so surely you know what it was better than me I know that the nichel is not shiny after the plating so that’s fine anyway as protection for the steel and the final look should be ok.

Nicola

 

I'd have left well alone too, especially with such a sought after stove, but each to their own. Replating with zinc rather than nickel would bring less attention to the re-plating over a pitted surface.

Edited after seeing the above- agree non-polished nickel would be a good bet.

 

I have given this more thought at I must now prove to myself that it was in fact nickel plate and not galvanised, I have checked my precious metal testing kit and it doesn’t contain the fluid needed for testing nickel only gold silver and platinum, it is extremely important to me that I get it correct so I have just ordered the necessary kit to test for nickel, I can then test the bracket as it’s still as it was, I’m at a point where I can re-plate it either way, nickel or galvanised.
Can anyone else comment on this subject please, with there views.

 

Ahah you’re doing your job very seriously and we all appreciate your approach, that test would be very interesting and thanks to take the chance to do it.

In general, galvanization, is a more expensive process and adds a thicker layer of protection than nickel plating. In my opinion a better option for steel… while for brass the nickel plating is the perfect choice.

Let’s see what they have chosen at Optimus

 

That’s not what I’ve found. In the case of my initial nickel plating experiment I had the objects plating too long, minutes rather than a minute at most. The result was indeed dull/grey …




… but acquired a lustre on polishing.




Latest project to be plated, a lighting torch for lanterns, was shiny straight out of the electrolyte after maybe a minute of plating, moved about in the electrolyte as the cathode (-ve pole).







John

 

@presscall amazing plating! You’re mastering also this skill!

Nicola

 

Quick update
I’ve just ordered some pure zinc anodes, so after the results from testing i will have the option of re-plating nickel or galvanised.
I will report back with the results once the test kit arrives.

 

@Nicola Francesco Elia
Hi Nicola!

Like most things, it’s possible to improve with practice.

An early lesson was that as I’d expected the electolyte expires, easily identified when an object is removed from the plating bath and the nickel rubs off. Fresh electrolyte and the plating makes a robust bond. Moving the object around, or alternatively passing the nickel anode over it on a ‘line of sight’ basis, gives the best coverage and a shiny (not dull) surface straight out of the electrolyte. 6-volts works well for plating. 12-volts is better to make electrolyte (nickel cathode and anodes).

 

Thanks John for sharing your experience, that’s something I will try soon or later… very useful skill to acquire.