PDA

View Full Version : Pressure Gauge



electrosteam
15th Feb 2016, 07:31 PM
I have been tasked with providing a decorative/artistic steam pressure gauge of about 3 - 6 inch diameter for a pizza oven made up to look like a steam-punk street-cart.

How hard is it to make a suitable gauge ?

I already have some brass 2" tubing for a whistle, but any suggestions or offers in this direction gladly received.

John

BobL
15th Feb 2016, 07:49 PM
Do a google search for "Antique pressure gauge images" and you will get a good selection.

But why pressure. What about Temp, it would change and could even be useful to the pizza chefs.

Michael G
16th Feb 2016, 06:43 AM
Making should not be difficult but time consuming. There is an architectural salvage shop down the road a bit from me and when I looked in the other day I saw a raft of brass gauges. If you have a budget for this project I can go in and see what I can find.

Michael

electrosteam
16th Feb 2016, 09:42 AM
Bob,
Using the gauge as a temperature indicator for the oven has merits, I will run that idea via the chief artist.

I have a start on the whistle, a length of 2" brass tubing recovered from the bin at a local scrap merchant in the shape of a drainage bend for the cost of $20.
I can easily make the end caps, centre spigot and top finial, but a representation of the cast curved and tapered operating lever of a typical whistle is going to take some imagination.

I am thinking of making an open top mould in the shape and melting my brass swarf collection into it using oxy-acetylene.

Michael,
Thanks for the offer, but don't make a special trip for me.
I suspect that my budget (love job for art) would not stretch to the prices a specialist salvage shop might expect.
But, perhaps you could get a name/number/address for me so that I can give them a call ?

Thanks for the comments,
John

BobL
16th Feb 2016, 12:15 PM
You could make a very steam punk temp gauge by making a large bimetallic (brass and say stainless) strip riveted or bolted together.
Then add a lever action to move large pointer across a brass strip with calibrated marked temperatures on it .

Michael G
16th Feb 2016, 05:50 PM
I am thinking of making an open top mould in the shape and melting my brass swarf collection into it using oxy-acetylene.

You might find you boil the zinc off and cause all sorts of problems...


... perhaps you could get a name/number/address for me so that I can give them a call ?

Be a day or so away but, yes I can do that.

As a guy at work has said 'I go straight past it (a particular bakery) if I detour the right way'

Michael

electrosteam
16th Feb 2016, 09:47 PM
Michael,
Thanks for whatever you can do.

The matter of zinc boil off interests me.
I have seen examples of oldtime tradesman permanently marking tools by engraving their names/initials/mark in the surface and then melting brass into the engravings.
I was never sure of the exact process, but assumed it was relatively simple and easy to do.
If not oxy-acetylene, I wonder how the heat was applied.

John

clear out
17th Feb 2016, 07:56 AM
Here's a whistle that I picked up at the Garden Island auction a few years ago.
Klaxon from the wood shop is my fav.
They have a few large pressure gauges at the local ms wot USYD civil chucked.
H.

Michael G
17th Feb 2016, 07:54 PM
...perhaps you could get a name/number/address for me so that I can give them a call ?

Stepney Architectural Traders
78 King William St
Kent Town SA

(08) 8362 4910


With respect to boiling the zinc off, if you used gentle heat you may get away with it. I tried TIGing some brass once. While the surrounding metal sucked the heat away, it worked but as soon as it got hot - gas and white zinc oxide. Brass is cast but I think it needs reasonable control to do so properly.

Michael

electrosteam
18th Feb 2016, 11:51 AM
Thanks Michael,

I have contacted Stepney A. T. and they will send me some representative photos of a large collection that they have recently acquired.

Pricing is about $120 upwards depending on age, condition, appeal etc.

A chap I know has said that he is willing to part with a 6 inch 300 psi panel mount gauge at a price somewhat lower, so this is probably the way to go.

I have got two nice pieces of straight brass tubing out of the drainage bend and have started on the cap.

John.

Grahame Collins
18th Feb 2016, 12:25 PM
Both brazing and silver soldering processes can suffer from zinc boil-off.

The boil off is the zinc gassing off as the temperature has been allowed to rise above a temperature that sustains the specific brazing or S Solder process.

Tig temperatures being way above would be problematic,I imagine.

Not having had Tig shielding gas for a while now, I have not had the opportunity to try it.

Micheal G ,
Oxy Acetyelene is the tool of choice for brazing or silver soldering giving pin point heat control.

When brass is joined to brass the term becomes braze welding as both the parent metal and filler metal are fused.

A shape in brass that may be suitable as a look a like whistle is a water sytem tank relief valve.361033

electrosteam
18th Feb 2016, 07:57 PM
Grahame,
Thanks for the suggestion on the valve.

The intention is to make an operating lever similar to that shown on the steam whistle in the attached image, but the whistle body itself will have a square bottom and top (less work).

From the discussion by you, and Michael, zinc boil appears to be a real risk requiring an appropriate procedure.
I will be attending the Knifemakers and Blacksmiths get together next week, I may be able to get some ideas there.

361048
John

Michael G
18th Feb 2016, 09:56 PM
John, can you give some sizes for the lever? I have some brass strip around that I may be able to spare if it is big enough.

Michael

electrosteam
19th Feb 2016, 07:42 AM
Thanks Michael, but I have appropriate brass bar in stock.
I just thought it would add to the appeal if the lever had a cast finish.

The image shows the Stepney gauges, quite a collection.

361057

John.

KBs PensNmore
19th Feb 2016, 02:38 PM
Hi John,
To give the handle a cast look, what about dimpling it with a prick punch, no need for the hammer, just using the punch as a hmmer point down should give it the right effect.
Kryn

Michael G
19th Feb 2016, 05:03 PM
Or sandwich it between two pieces of say 60 grit sand paper and hammer.

Michael

Grahame Collins
19th Feb 2016, 05:27 PM
I realise from the first post that the asked for dimensions were between 3 -6", but a neat way of utilising the brass drain bend would be to use the union nut screwing down a glass lense and behind that, a small gauge to fit in the union (in the pipe). That would look very steampunk-ish I reckon.

electrosteam
22nd Feb 2016, 08:12 AM
The mates gauge turned out to be an absolutely beautiful 5" brass 800 psi that is still in original wrapping and operating perfectly - I just couldn't bring myself to abandon it tacked onto a pizza oven.

Looked around some antique shops and eventually found the attached 6" for $50.

361200

John

electrosteam
22nd Feb 2016, 08:10 PM
Some good contacts today convinced me that heating swarf in an open topped mould with a torch is a recipe for disaster.
Plan B is to cut the lever shape out of barstock and then to apply the techniques described above.

I wonder if the old tradesman tool markings were really letters shaped out of brass wire laid into grooves, then melted with a torch.

John