Optimus 300 Pressure Gauge

Can anyone tell me, is the 300's pressure gauge window glass or plastic and has anyone got a spare and also its seal, i will post a wanted add too, thanks.

 

If it's the same as the Petromax then it should be plastic

 

Ok thanks, my 1550 has a plastic window but i'm not sure on ages or different materials used etc.

 

There have been a couple of variations over the years, so it could either be glass or plastic. A picture would help.

 

@Nils Stephenson

This is the offending article, i expect it probably won't be that easy to replace but hopefully someone will come up with something.

 

@MG, that's actually the fuel level gauge but it looks as if the workings are missing. There should be an arm pivoted on the underside of the plate with slot, the arm extends into the tank and should have a cork on the end which will obviously raise the arm according to the level of fuel, the part of the arm which protrudes through the slot is bent over 90 degrees thus providing a visible indication of fuel level. The original window would have been glass.

Henry.

 

@Henry Plews

Hi Henry, thanks for that, its not the greatest of pictures but it looks like all the workings are there, i didn't check until now, i just thought it was a pressure gauge but can now see the cork on the end of the arm etc, it is sitting a bit high considering there is no fuel in it so more investigations are needed, i don't suppose you'd know where i could get a replacement glass and a new washer from do you?

 

@MG, I honestly can't remember if mine needed a new seal or not, if it did, I would have made one myself. No idea where you'd get a glass from or what thickness it would be, don't forget, it will be subject to whatever pressure you put in the tank.
I'll dig-out my 1550 tomorrow, take some measurements and let you know my findings.

Henry.

 

@Henry Plews

That would be great, thanks Henry, its on my 300, it did have a seal which was rock hard but i can't seem to find it now, yes i guess the glass would need to be a couple of mm thick to stand the pressure? i wonder if anyone on here could cut such a sized piece being so small, have you got your own hollow punches etc to make seals, i haven't invested in any as yet.

 

Hi Mark, The glass will be the same size. Yes, I have a set of imperial punches but they don't always match exactly metric sizes, so I should really get a metric set as well.

Henry.

 

@Henry Plews

Hi Henry,
I don't know if all 1550's have the same sized window but mine is larger than the 300's for sure, if not that clear, the 1550's window is sat over the 300's in the first picture,
I will need to buy both metric and imperial punch sets then, i read its best to punch material on a hardwood base and using lubrication (soapy water) really helps in stopping the punches from dragging on softer materials,
Although expensive the American Mayhew punches look good, can cut both the external and internal sizes at the same time and some adverts also state they can be used for lead as well.

 

If you can find a suitable piece of plate glass (about 2.5mm thick) (maybe a laboratory microscope slide?) you can cut it to size under water in a basin using an ordinary side cutters or kitchen scissors. Then just sand the edge on wet sandpaper until it is a good fit. If you cut or nibble it under water it will not crack or shatter. Wear gloves, though.
The seals are 1mm viton and about 3mm wide between inner and outer edge.

 

The original glass for these level gauges is 1.6mm thick and 20mm in diameter. You need a washer on both sides of the glass when installed. The rubber is 1mm thick and you need 20mm OD and 15mm ID. Not long back I got some new glasses from Fogas, so maybe they still have them.

I have tried this but it didn't work, Maybe it only works with certain types of glass? I tried with a microscope slide.

 

It works on Youtube I think the trick may be to just nibble around the edges until it is close to size and round. The water is supposed to act like shock absorber.

 

Thanks gents, now i have the measurements i can get someone to make me some washers, i will check out Fogas first to see if they have one and how much inc post it will be, if not i'll see if i can find some appropriate glass and have a go at making one myself.

 

@Nils Stephenson

I can't find anything on Fogas's website but thanks for all the dimensions it is much appreciated.

 

@phaedrus42

Nearly but still looking,

100Pcs Circular Round Microscope Slide Coverslip Cover Glass Diameter 18mm FEH | eBay

100Pcs Circular Round Microscope Slide Coverslip Cover Glass Diameter 25mm UK | eBay

So far 1-1.2 mm is the thickest i've found so probably best to try and get near to the original thickness i guess.

 

You should be able to get a mineral glass watch crystal for that pretty cheaply. If you're in the UK the Cousins has 20mm 1.5mm for 75p plus postage and VAT.

 

@DaveN

Thanks, any idea how i decipher their catalogue, i'm just looking through but its only giving me watch manufacturers and model numbers etc.

 

1.50mm, Cousins

Should get you to 1.5mm round mineral glass.

 

That's excellent, thanks Dave.

 

@MG I should have have logged on here before I started dismantling and measuring. No matter, your question has been answered. Although the rubber washers on my example make a good seal, they are somewhat misshapen which meant a little guesswork with the sizes, so thanks to all who provided accurate measurements.



Henry.

 

@DaveN

I've bought three just in case, what a bargain if they do the job, thank you.

@Henry Plews

As always, thank you so much for your efforts, they are much appreciated, have you got any spare rubber seals of the correct size lying around that you would be willing to part with, obviously all costs covered?

 

One of those happy cross-overs of interests. I'm much more familiar with pulling a watch to bits than a lamp...

 

Well i know a little about lamps and next to nothing about watches but yes in this case a very happy cross over of interests indeed!

 

@MG I'll put a couple of home made ones in the post, they're not super symmetrical but are "fit for purpose".
Costs? Put whatever you like in the charity box of your choice.

Henry.

 

That watch glass looks great, I might have to get some myself. The ones at Fogas can be found here. They are SEK 35, so quite a bit more expensive.

 

@Henry Plews

Henry you are a star, thank you.

@Nils Stephenson

That's not too bad a price though, i thought they would be quite a bit more than that plus i expect the postage would be a little dearer,
Yes the watch glass looks great and there are also so many different sizes to choose from which is very handy, its only my first 300 but i thought i'd best buy a few glasses in case any more comes along!

 

Any update on the watch glass? It would be interesting to know if it works.

 

I have used glasses from the old type of ceramic fuse holders we used to have here. They are still present in many applications, and houses that hasn't been upgraded to more modern circuit-breakers.

Below is one I grabbed just to show.
The glass is 19.5-20 mm, and the thickness on this one is 1.3 mm, so they fit right in, and I don't think the slightly thinner glass is an issue. If you're worried, you can always use two.
I also bet there are variations in thickness depending on manufacturer. I think I will explore this at work tomorrow, because there these are abundant.

These glasses has worked a treat for me.