Mini gas burner

[Blogwitch]

DT,

I am no expert by any means, it is just that I have a full understanding of the mechanics of the process, so if I follow the rules I have learned, things turn out well and as expected.

That coating is just a normal occurance with a citric pickle. It is a chemical reaction, and you will also find that any ferrous parts will get a copper coating as well.
It very easily cleans off, and I will show how I do it in my next post. Most of it should wipe off with a cloth while it is still wet with pickle.

You seem to have got your silver soldering fairly well under control now, and as you proceed further, you will find things start to get a very lot easier. Getting the heat into the right position is one of the main criteria, and that can only come from experience.

Bogs

 

[Blogwitch]

To carry on from where I left off on yesterdays post.

Straight out of the pickle and dried off. Most of the copper coating has been wiped off, except for where the flux had been at work, that is where there is an etched surface, so it will be embedded in a little. But more of that later, first off, I have a couple of machining jobs to do on them.

Using a 1.8MM drill (tapping for 8BA) I drilled down thru the previously tapped hole in the jet holder, into the needle chamber. If you didn't realise, without that new hole, the gas couldn't get to the jet.

Hole from above.

The tapped hole was then extended right thru.
That is all the machining done on this part now, so it is finished except for cleaning it up.

On the pigtail is a BRASS wire brush, this isn't as harsh as a steel one, so it won't wear away any of the material, just give the whole surface a good scrubbing. But as you can see, it gives a lovely brushed sheen, IMHO, much nicer on a job like this, rather than a high polish. Also notice the nice silver soldered fillets, no excess solder to be removed at all.
These only took about a minute each to get to this stage.

When using rotary wire brushes you have to be very careful with your safety routine, especially glasses. Razor sharp needles get thrown out in all directions at a very high velocity.

Another thing to remember is that you need to turn the brush around very regularly, because just by the action of holding the part against the bristles, it bends them backwards, and they lose their efficiency to clean very quickly. I turned mine around after doing each individual part.

All nice and clean, showing that nice soft sheen.

Built up, ready for the next piece, which I didn't have time to do today.
You can see the difference in finish between the two parts. They will all be matched up with regards to surface finish at the very end.

I'll see if I can get a bit more done tomorrow.


Bogs

 

[Deanofid]

They look very nice, John. Good tip about turning the brass wire wheel. Funny, the things a guy never thinks about.

Dean

 

[Blogwitch]

That's the advantage of using a pigtail Dean, it takes only seconds to flip the wheel around, I do the same with my buffing wheels as well. They last a lot longer and you always have an efficient surface to work with.

But I am always very wary of using wire brushes.

I was in the workshop at work many years ago when one of the machinists starting running around shouting his head off. He had been using a wire brush in an electric hand drill, and a piece had come off and embedded itself right on the middle of his eyeball, he wasn't wearing glasses.
Luckily the first aider in there soon had things under control, three people took him to the local hospital, the driver, another holding his arms down, and the first aider holding his eyelids open and dripping emergency eyewash continuously onto his eyeball. That first aider saved the chaps sight in that eye that day.
At the hospital, supposedly they used a large magnet to remove the spike, and in a couple of weeks, his eye was back to normal. He was very lucky indeed. If he had rubbed his eye with his hands, the eyeball could easily have been permanently damaged.

I occasionally get the odd piece embedded into my bare skin, that isn't very nice either.

In the UK, the cheapest place to get brass pigtail mounted wire brushes is here. The wooden hub can easily be drilled out a little so that it fits your machine.

http://www.proopsbrothers.com/acatalog/Online_Catalogue_Polishing_42.html

Safe buffing.


Bogs

 

[doubletop]

A brass wire brush is the trick then. I assume its a pure brass brush and not a brass coated steel wire brush. I ask that because I picked up a cheap set of brass coated brushes recently and I'm sure that error could easily be made and a nice job messed up

And Proops; that takes me back a bit We'd spend hours rummaging through their place for a bargain in their place in the Tottenham Court Road. Just looked them up........

Way back in 1946 members of the Proops family opened a shop on Tottenham Court Road, close to the major London shopping district.
They traded in War Surplus items as well as many other clearance or job lot lines.

The principal products were medical equipment and 'technical' items from aircraft such as instrumentation and electrical components.
The shop also traded in radio spares, surplus engineering and woodworking tools.

Many of our customers (now youthfully middle aged!) remember being taken to the Tottenham Court Road shop as small boys by their fathers and uncles. Some even confess that the experience sparked their interest in all things mechanical

 

[Blogwitch]

DT,

I've been using Proops for more years than I care to remember. They still attend most model engineering shows. Digging your way to the front is the usual problem. They still use the old system of giving you a plastic box to use as you work your way around the massive stand, dropping all the cheapo bits in, and tallying up when you think you have got everything you want. Then as you are leaving, you notice something else you fancy. :wall:

They do have some real tat, but things like their cheapo stainless dental probes and wax carvers I find perfect for silver soldering work. They are also about the only ones now selling the mixed packs of Whiston's steel, 10KG for 15 squid. Rather expensive for the mainstream machinist, but perfect for the average chappie in his workshop who wants the odd bit of steel now and again.

I can root thru their site for ages, ordering those little bargains and normally ungettable bits.

At one of the shows, I remember buying 100 squids worth of metric taps. They must have got a job lot somewhere and they were real top quality, every main size from 2mm to 12mm, 50 pence each. I am still using some of them nowadays, and everyone at work got a set as well.

They are pure brass wire wheels BTW, and do a wonderful job. Their pigtails, soaps and buffing mops are a bargain as well, if you want to use one end of your offhand as a buffing machine.


Bogs

 

[doubletop]

BogS

My experience with Proops was in the radio/electronics field as my background is electronics, and now IT. I thought they'd long gone but I see they have been bought out and now trade from Leicester or there abouts. They probably couldn't afford the rent in Tottenham Court Road these days, funded by low end second hand goods.

anyway we're way off topic here. So back we go......... By way of an experiment I tried out one of my "brass" brushes tonight. They make a right mess!!! so a proper brass wire brush is the order of the day

regards

DT

 

[xo18thfa]

I've tried to find it, have you drilled the jets yet?

 

[Blogwitch]

Bob,

I haven't got to the jets yet, but after I have made the air control sleeve, that is the next job to be done.

The problem is that I have to make a sensitive drilling attachment for my lathe to drill out the small main bore in the jets, and also a holder for turning the jets to length and holding them whilst drilling the main bore, only then can I actually drill the jetting holes in the other end, and that will require a jig making to align everything on the high speed drill so the holes are true and centrally located.

One thing leads to another, if the job is to be done correctly. Also, because this job might turn out to be a continuous little job for me, everything needs to be made to last.
For making a one off, you can usually cobble something together to get the job done, but for making multiple parts, I would never go that way.

Bogs

 

[NickG]

Bogs, thanks for the updates, lots of good tips in there. Will be getting a brass wire brush, nasty story about the accident but worthwhile sharing.

Good tip on the thread undercuts for small diameters too.

Thanks,

Nick

 

[Blogwitch]

Sorry this post has stalled yet again, but more pressing matters are being dealt with.

But it shouldn't really matter as this is being written as a reference article than a build one, so time doesn't come into it.

Glad you liked a couple of the tips Nick, and hoped you enjoyed the cramped lifestyle of my shop with three of us in there. As I have always said, I like to be able to have everything within easy reach. What I never mentioned is that you can almost do it without moving.

I forgot to give you one of those scraping tools, but I will send you one when the burner is eventually ready.

Bogs

 

[NickG]

Bogs,

It was a pleasure to meet you and be shown your shop and some of your work. I wish I'd really spent the time up front to sort my workshop out like yours.

Thanks, very much appreciated. Enjoying this thread and don't worry about stalling, my poppin has been going since the end of January and there is really no end in sight at the moment if I'm honest. If you feel you have to do something it's not a hobby any more in my opinion so just go at your own pace and do bits and pieces when you feel like it and time permits.

I forgot to ask, I prefer your brushed surface finish on the valve work etc also, but is there anything you can put on it or brush it with to preserve that finish? I usually just sort of polish my stuff with oil to attempt to preserve the finish but for the finish you require would that make it too shiny? For my aluminium I used paraffin or white spirit which gave a more satin type of finish.

Nick

 

[Blogwitch]

Nick,

I have mentioned this over a few years now.

I did some experiments with a piece of brass that I had engine turned. I tried all sorts of laquer coats to keep the shine but only one ever shone thru (excuse the pun), and I still check it every so often, and it still hasn't deteriorated one tiny amount.

Many years ago, I bought a couple of tins of fixing laquer that is used to apply over wax rub down letters that I used to use on my model boats, to stop them lifting off the surfaces they are applied to. The coat goes on super thin when sprayed from a distance and there is no sheen that is physically detectable, it just seems not to be there. I think mine was a satin sheen, but I can't check it out at the moment as it is buried in deep storage at the back end of my shop. This is the stuff

http://www.artistmaterial.co.uk/acatalog/Letraset_Fixatives.html

and another with different ranges

http://www.wheatsheafsales.co.uk/acatalog/Fixatives.html

I must get around to spraying one of my engines over when it has been repolished, only then could I give a definite result.

But I do treat my engines with a spray and polish with 'Mr Sheen', and that definitely keeps them spick and span a lot longer than normal. I wouldn't try either of these things on a 'heated' engine though, as I am sure it would just burn to a brown chocolate type of surface.

John

 

[NickG]

Bogs,

Thanks for the info, it's cheap enough that stuff too. My engines usually look ok when I've first finished them but once built most of them are too fiddley to start polishing unless you take them back to bits.

Nick

 

[Blogwitch]

Nick,

I managed to check my two tins this morning, and they are both gloss.

John

 

[metalmuncher]

Hi Bogs


I'm new to this site have been lurking, been watching what you're doing and have bought the plans to make a burner. I'm a member of another site to do with toy engines like mamods and and found a post for a cheap gas tank and burner. Its on ebay in Germany at less than half price of anything you can buy in the U.K.

http://cgi.ebay.de/Tank-Brenner-5...Bausätze?hash=item1c08135cbb


I purchased one and it arrived this morning very good quailty and runs my stirling engine ok. Got to be worth a punt just for the tank at £20.00 including postage. I didn't want to take anything away from your build just thought members would like to be made aware of whats out there. Metalmuncher.

 

[Blogwitch]

Unfortunately MM, it seems that link is no longer available.

I have no problems at all about people showing their fixes and sundries, it all adds to the mix, as long as it doesn't take over the post.

Personally, without seeing it, I can't imagine a refillable gas tank for that price being built to the exacting standards required by UK legislation and insurance cover.

You do have the necessary third party insurance cover, don't you? If you don't, I would recommend a 5 million squid third party, as that is what most local councils are demanding for public liability now.

It isn't the cost of building the tank that is the problem, but the cost of the special filler and discharge control valves, which should be specifically for gas control, not steam (that pair would normally cost at least 20 squid by themselves), and the time taken to carry out the necessary high pressure testing of the tank.

If it didn't come with the relevent documentation certifying conformity, it is illegal for you to operate it in a public place (see insurance cover above), and that means in your own home if anyone else is in the building or grounds. They don't mind you hurting yourself, but if it means someone else might get injured (including your family members), they take a very dim view of it, and the book would fly if they got wind of it.

But each to his own I suppose, if you want to take the risk.

Now a little about this post, it hasn't stalled, but been put onto the back burner while a major building project (for me) on the back of my house is brought to stage where it is weatherproof, while this good weather we are having holds out. A couple more days and I should be ready to get back into the shop and continue on this deep insight post.

Bogs

 

[metalmuncher]

Hi Bogs Sorry the link didn't work, just so you know what i was talking about heres a picture hope it works.

 

[Blogwitch]

MM,

That is basically just a stripped down commercial 'cooks' mini blowtorch with a small extension tube fitted, not a proper rechargeable gas tank in the sense of the word when referring to steam raising gas tanks and burners.

http://www.cookware-online.co.uk/sh...hen-craft-black-cook-s-b-256802.html?shopping

As far as I can remember when I was experimenting with those blowtorches, they don't have an actual jet in the burner nozzle, but a tiny ceramic porous disc that clogged very easily when run on the wrong type of gas. I think they are designed to run on a pure butane, which is the gas used for cigarette lighter refills, not the normal butane/propane mix as used in plumbers gas torches and most steam raising burners, which runs decidedly hotter.
I found the only way to successfully clean the diffuser disc (about 2 - 3mm diameter) was to reverse it in its mount and hope the gas pressure would blow away the debris. That worked about 50% of the time. I gave up on them after a couple got clogged up and couldn't be cleaned out.

Good luck.

Bogs

 

[xo18thfa]

Just happened to find this very interesting way to make jets for mini gas burners. This is very do-able. I think we engine builders should hang around the clock and camera makers a little more.

http://www.deansphotographica.com/machining/projects/burner/burner.html