My next project is the restoration of an old Optimus 350 CP, shown in the picture below. This is how the lantern arrived. I unpacked it from the box and found that the fount is full of very smelly, probably decades old, kerosene. The glass somehow made it intact despite there being no protective packaging around it whatsoever. What are the chances of that? Anyway, as you can see, I have my work cut out for me with the cleaning and polishing. What is the recommended way to clean and restore the finish of this type of lantern? Oven cleaner? Citric acid solution? Just a soap & water wash followed by metal polish? Next, what would be an effective way to clean out the (probably nasty) fuel tank? Also, how can I determine the approximate age of this lantern? I can’t find any markings on the base of the fount and don’t know anything in particular about this particular model. Thanks for your interest and advice .
Once the lantern is dismantled I would wash each part in hot soapy water (not the glass though, just slightly warm soapy water for it) that will let you see if more cleaning is required. Shine a light into the tank to check it's condition and if it does need a lot of cleaning then pour some clean paraffin/kerosene into the tank and add some steel nuts and ball bearings and then give the tank the shake rattle and roll treatment and repeat the process until the paraffin comes out clean, the used paraffin does not need to be wasted, it can be poured through a filter into a clean clear bottle and then left to sit in the shed for a week, any remaining dirt will gradually settle to the bottom and then the clean paraffin can be carefully poured into a clean container. You were lucky that the glass survived and it appears to be an original glass and as far as I know your lantern is from the 1960's or 1970's.
Thanks for the tips, Jeff! That sounds similar to what I did with my recent Guardsman restoration except that I only cleaned the tank with hot soapy water. I almost satisfied myself that the fount looked good enough after that and didn’t realize how much better it could actually be following a thorough metal polishing. The soft cloth I used was absolutely blackened and filthy by the time I was done. Without knowing how similar or different the Tilley’s and Optimus’ finishes are, I don’t know what to expect from the soap & water wash and metal polish treatment on the Optimus. I guess I’ll find out soon enough since I’ll probably work this into my agenda for today… I appreciate the info on conserving good paraffin/kerosene used for cleaning. I really dislike wasting and disposing of fuel. I wonder about the old fuel already in the tank…would that still be suitable for something such as burning in a traditional storm lantern or might it foul the wick (by making it permanently smelly, etc.) if it’s super nasty?
That looks to be in fairly good condition under the dirt. There will probably still be spots in the nickel after cleaning, but that just shows some age. Be careful with the enamel cap and keep it away from acids as they can make it go dull. I have managed to remove the cap by carefully bending the tabs, but have also managed to break a tab before. The condition of the tank will be obvious once you remove the NRV. If it is clean(ish), then it will most likely only be a smell in the tank and not much crud. That should not require much cleaning. Another point to look at is the seal at the bottom of the pick-up tube. They usually need replacing, but as it does not have a quick starter it is not a critical part. To estimate the age I would need a photo of the label and the wheel to start with.
Good morning, Nils! Thank you for the advice, it’s much appreciated. Below are pictures of the label and wheel.
The lantern is now completely disassembled with the exception of the lower part of the vapouriser, which doesn’t want to loosen its death grip on the fount. Is the usual solution to mount it in a vice and use the fount as leverage? I recall doing something similar with a Tilley burner once… Bye-bye burner .
Whoa Nelly, on closer inspection, does it look like someone’s done a home welding job on this or is this characteristic of the craftsmanship of these things? Any cause for concern? The lower part of the vapouriser threads into the inside of the hex nut on the top of the fount, correct? So I don’t suppose the dodgy welding should prevent me from removing it, or…
The nut is soldered onto the tank, and then a lead washer makes the seal from the vaporiser to the nut. It may be that someone tried soldering the nut without removing the vaporiser and partly melted the lead washer ?
I was afraid of that. Anything to do with this other than chuck it or try cleaning it up and using as is? Everything else looks totally serviceable to me. I’d guess sourcing another fount and lower vapouriser would cost me even more than I’ve already invested in this contraption.
Bearing in mind i am looking at a photo if it is so then you could heat it to remove it, then resolder the nut in place. But I would also wait to hear others experiences before jumping in.
OK, I’d be willing to try that if there’s a good chance it could work. I’ll wait and see if anyone else might second that idea and perhaps give some pointers. I do have a propane torch but, mind you, I don’t often blowtorch things. I’m more of a bicycle mechanic type . In the meantime, what would be the best way to clean/polish up the frame and/or fount? Would oven cleaner or a citric acid bath be more effective? Would either of those damage the label?
Any acid will damage the enamel cap. It will also remove the paint etc from the aluminium "label". I took them off before soaking the rest in citrc acid solution. The tabs that hold the cap in place can break so it is your choice. I would avoid taking it off personally - I did mine because the thing had been dropped and I needed to straighten out the cap. The label is soft aluminium so should come off with gentle straigtening of the tabs at either end. Smaller torches are helpful. The plating is nickel not speculum so should be a little harder.
I am thinking of just setting the hood in a pan of citric acid solution up to the level just below the top cap. If I take care to lift it straight up out of the bath and rinse it with running water I don’t suppose any harm would be done. I wouldn’t remove the top cap anyway as I’m not concerned about a few millimetres of nickel plating not being treated up high where you can’t see it anyway. I’m afraid I don’t understand what you mean about smaller torches being useful. Should I expect to need either light or heat (which did you mean?) to remove the aluminium label?
Ah - smaller propane torch. You need enough heat to get things hot/melt solder, and quickly before the heat spreads to where you do not want it, but small enough so you do not burn off the nickel all around it. Good idea on the pan of solution ! Although looking at the picture I would go with soapy water first
First off, dating the lamp. From the parts on it, it is not possible to get closer than from the late 1960s to the middle of the 1970s. The 350 model was discontinued in the middle of the 1970s. Removing the lower vapouriser. As already mentioned, it should just unscrew from the nut. You can try putting it in a vice but the vapouriser is not central, so it will give on off center force. I would just use a well fitting spanner on the flats of the vapouriser. As for the solder around the nut. It is not unheard of that there has been a leak in this area that has been repaired by extra solder. Some people are much better at this than others. I would just re-flow the solder and tidy it up a bit. It's inside the collar of the lamp so not seen.
Hello Jaska, for old fuel I use the filter method which I described in my previous post, it may need to sit for longer than the fresher fuel though, but once it looks clear I carefully pour it through a filter into a clean bottle, but the dirt settles in the fuel at the very bottom of the bottle and obviously I do not pour that into the fresh bottle, the dirty fuel can be used to start a bonfire and it's okay for cleaning paint brushes, I tend to use the filtered old fuel in the Tilley heater which I use in the shed and I also use it in my blowlamp.
A huge thank you to Nils and Jeff for helpful advice and information on this lantern! The project is still ongoing and I'm about to give the lower vapouriser removal another crack. I do have a nice 15" Facom adjustable wrench, so plenty of torque is available. The problem is trying to hold the fount securely enough to get things going. If it's necessary to apply heat, the torch I have is a Kemper 1217C. Does this look appropriate for the task? If so, is the idea to direct the flame only at the lower vapouriser? Please assume that I have zero experience using torches for things like this. I've gotten through my whole life with normal hand, power, and pneumatic tools . Another issue I have is understanding how to remove the check valve down at the end of the pump tube. I think I've seen this done with a long slotted screwdriver on Petromax lanterns but when I tried to peek down the tube it looked like I would need a strange-shaped socket of some kind. I tried to use my Hipólito 250 pump to see if I could pressurise the fount (the pump leather for the Optimus is perished) but it just blows back. If I remove this, will it also necessarily involve replacing a lead washer afterwards? Sorry for all the newbie questions. I really do appreciate any help I can get and love having the opportunity to learn something new every day!
Strap wrenches are useful for hanging onto fonts, but use carefully. Others have made tools to remove the NRV. A bar with a slot in it. Much of this is already on this site - you just have to search for it and you normally will find many solutions.
To undo the lower vapouriser, the best method is to have someone to help you. Have them hold the tank flat on the bench so you can then apply the necessary force to the spanner. Don't rest the side of the tank on anything hard as you risk denting it. As mentioned, there are many posts about making a tool to remove the NRV. Basically a rod with a 5mm wide slot in the end. Make sure the edges are sharp and the sides parallel to avoid any slipping on the NRV. Yes you will need a new lead washer for the NRV and a new seal for inside it. It is possible that this NRV uses the moulded rubber seal which is not replaceable. The fettlebox have a replacement with a brass cup and seal that works well.
OK, things are coming along now . My wife has a grip I never knew she had. Together we managed to get the lower vapouriser out with no damage. The part is currently enjoying a citric acid spa treatment. In the meantime I've given the frame a very thorough scrubbing with a nylon bristle brush in hot soapy water. What a robust frame I have to say! To get it looking better, I'm tempted to douse it in oven cleaner and seal it in a plastic bag for 15 minutes as demonstrated in this video: I've searched this forum for "oven cleaner" and not really found any testimonials for or against such a practice, so I thought I'd ask here. Has anyone actually tried this? Would I be risking damaging an otherwise good frame? I can't say I'm pleased with the result of dipping the fount in a citric acid bath, so I'm holding off on doing that with the frame. I really have no idea how long to leave nickel plated pieces in that sort of solution anyway.
I use this - brush on - wash off very quickly. Do not get it on enamel, brass or skin. Harpic 10x maxpower: https://www.is.fi/asuminen/art-2000007794390.html also good for cleaning motorcycle exhaust pipes - oh and yes - toilets..
I’ll give the Harpic a try. €2.95 at the local Citimarket—can’t beat that if it works. If it doesn’t I guess it’ll just be money down the toilet .
I brushed on the Harpic and rinsed it off right away. I’d say the effect was quite minimal. I then dipped the frame in my citric acid bath for about 10-15 seconds and then dunked it in soapy water and gave it another scrub. It looks slightly better now but I still don’t know how long is reasonable for the citric acid solution bath or if it would get better or worse with more treatment. Are we talking seconds or minutes? And, last question for today: How is the bail removed from the frame? I want to soda blast and paint the bail.
I make up a citric acid bath with about a level tablespoon of citric acid crystals to a liter of boiling water. I then let parts soak for 10 minutes. Checking regularly to turn and see if the bare brass parts are starting to turn pinkish. Then a good bath in dishwashing liquid with 0000 grade steel wool. The retaining nuts for the handle are held in place by the ends of the threaded studs being punched in the end. They can be forced off by using pliers to unscrew with a suitable soft material to avoid damage to the nuts. I use a soft aluminium but leather is also good.
Nils, another MASSIVE thank you!! The frame looks basically like new! I decided to drop the fount in for a ten-minute treatment now hoping for similar success. I had already finished cleaning all the other bits but now I’ve taken the steel wool to the vapouriser parts and they, too, look amazing now with the colour restored.
Hmm - maybe it is not as strong in Finland ? anyway you went back to the citric acid solution by far the best all rounder in my book
I guess I was lucky to find an original Optimus tool set from a local shop for just a few bucks. It includes a special socket built onto a long shaft with a T-handle for removing and installing the NRV. If that turns out to be the case, is it also an option to just drop in Petromax’s #10 and #83?
Yes it is but now you have the correct tool to remove / install the original NRV there's no need to waste money on Petromax #10, just use a replacement seal from Fettlebox as suggested by @Nils Stephenson, it looks like #17 on this page Petromax Spares Price List
OK. I already have a new Petromax #17. The reason I asked about it now is because I wanted to be prepared for the possibility of having a non-serviceable NRV. I won’t know what I’ve got until my new Optimus service tools arrive. Fettlebox is completely offline for two weeks, by the way, so I can’t even view the parts that have been recommended.
