My version of SandyC's 3" vertical boiler

[steamboatmodel]

Gerald,

There are five pages in the PDF file, you are only looking at the first page. :

I would suggest you try to scroll down. ;D

Bogs

Right you are, I had looked at the first drawing and it had in the title block sheets 1 of 1. I then missed that there were 5 pages of the PDFs. Thanks Bogs.
Regards,
Gerald.

 

[doubletop]

I went out today to start the silver soldering of the boile components.

Water Gauge alignment jig following Firebirds design

All the parts out of the pickle and dried off

Graphiting on the threads of the jig so they don’t get soldered in inadvertently

All the components fluxed and assembled ready for soldering

First attempt was with the flue tube but it resulted in poor flow of solder around the joints. I've done plenty of plubing joints so my expectaion of soldering is apply the heat and when it is right the solder flashes round the joint giving a nice clean finish. That wasn't happening so I gave up on that that threw it back in the pickle ready to clean it up and start again. I was using 620degree C solder.

I then attempted to the three bushes in the top plate. Again the solder wouldn’t flow and then disaster. I had plenty of flow as one of the bushes melted!

The melted bush

I can only assume that I had too much heat ??? and I hadn’t enough flux on the spelter, and maybe the joint.

So back to the drawing board make a new bush and try to salvage the end plate by drilling out the collapsed bush. Otherwise a new end plate is required.

A bit disheartened; but that’s why we are here, to learn, so a few disasters are to be expected.

 

[bearcar1]

Oh my , what type of heat source are you using ???

BC1
Jim

 

[doubletop]

I was using my Sievert torch on LPG. I have three burners for it and when the middle sized one didn't work I went for the big one

Which was probably a bit too much heat !

I can only assume ist a flux issue. I was using Sivaloy #1 flux and Easyflow 620C solder

 

[Blogwitch]

DT,

It looks like you have two major problems, one is the technique, the other is material.

The golden rule with silver soldering is that you must try to keep the heat source away from the jointing material (silver solder and flux) as much as you can, and use conducted heat to melt the flux and solder by sneaking up on it.

Because of where you are in the world means that you don't have access to what I class as the best silver soldering flux there is, Tenacity #5.

http://www.axminster.co.uk/product-Johnson-Matthey-Tenacity-5-Silver-Brazing-Flux-23460.htm

What can happen, and it looks like it has happened to yourself, the flux has been exhausted before the solder has had time to flow. Tenacity #5 doesn't suffer from that fault, as it is designed for silver soldering stainless steel, so keeps on working well after other fluxes have given up.

I would send you some for doing your job, but customs officers have great suspicion of little bags with white powder in them. But if you want to take the chance, if you PM me with your full name and address, I will get a little bag (enough to do your job) sent to you.

Bogs

 

[doubletop]

Bogs

Thanks for the offer. Before we incur the wrath of the customs people or get accused of shipping hazardous substance by air (if it is). Or if it has to come by surface mail it will take 9 weeks as it bobs around on various oceans on its way here. So I'll check around in NZ first. There's a lot of stainless work done here, probably as a result of the diary and wine industries. If it can be made out of stainless somebody is doing it.

If I fail I'll get back to you.

Thanks again

 

[firebird]

Hi Doubletop

That's a shame but don't get disheartened, it definitely takes practice. Did you see my hydraulic pump build, I melted that!!! Everything John says above goes. If you look at my small steam engine build you will see I use silver solder wire. A ring of wire placed around the part in the flux and build the heat up till the solder flows around. That works well for me. Have a go with some scrap copper and brass before you try the boiler again.

Cheers

Rich

 

[Blogwitch]

DT,

If you do change your mind, I have sent this flux to a few people in various parts of the world, and haven't had any trouble. It would most probably be with you in a week, but if you want to try your own way then that is fine.

I would just like to query something on your build. Are your bushes made from brass? The reason I ask is that all your bushes should be made of bronze.

The reason being, at the temperatures your boiler will be working at, zinc will leech out of brass bushes and they will very quickly go porous. The same goes for stay rods in a horizontal boiler, they must also be of bronze, not brass. Coupled with the fact that if you are buying your fittings from a reputable dealer, they will be bronze based. If you then screw them into brass bushes, a galvanic action sets up, coupled with the de-zincing, very quickly the threads in the brass bushes will reduce to nothing and you then run the risk of the fittings being blown out of the boiler when under pressure.

I had this happen to me with a commercially made boiler, luckily, I spotted it weeping, and when the fitting was removed, there was very little left of the threads. I had to make all new bushings and rebuild the boiler, which I still have in the back of my shop, and have had no further troubles with it.

If they are bronze, then fine.

I thought I had better mention it because when a boiler build like yours is ever shown, a lot of people want to build one as well, and they might not know about the brass/bronze bushing situation.

Bogs

 

[doubletop]

Firebird/Bogs thanks again for your encouragement.

I had a look at the Tenacity spec and saw it had a tem range of 600-900 so thought this may be a good substitute so have some being delivered overnight. I'll do some practice pieces before the real job. I've got plenty of scrap parts now to try it out.with

Easy-flo Flux Paste a brazing flux suitable for use with silver brazing filler metals. It has a working range of 575-825C and can be used with silver brazing filler metals melting below 775C. Easy-flo Flux Paste exhibits better life at temperature and greater overheat resistance than many other flux pastes. Easy-flo Flux paste has a low melt viscosity and as such performs well when pasted onto vertical surfaces, and can be useful when brazing stainless steel. The molten viscosity of Easy-flo Flux Paste is such that it holds on vertical surfaces. It is therefore particularly useful when brazing joints in positions where other fluxes may have a tendency to run away from the joint.

Bogs; you are right pointing out the use of brass and I am probably using brass. That's what I had and I hadn't intended for this boiler to be used for much it was to be just a stepping stone to bigger and better things. Therefore I didn't see the de-zincification as a major issue. However, I hadn't realised that the electrolytic action between the bronze fittings and brass was an issue. So I'd better think again. I don't want this sitting on a shelf looking pretty and some years, to later fire it up to have all the fittings come flying out. Not good.

So I had already made the decision to remake all the messed up parts and the end plate is now re-done and back in the pickle

I also took the opportunity to make the flange larger so the plate sits outside the barrel slightly. I didn’t like the look of the top and barrel end being flush, to drawing, it was odd.

I hope to get hold off more stock by the weekend so I can remake all my bushes; the flux is on its way so hopefully I can be back on track by the end of the weekend.

One thing I do want to try to achieve is good clean soldered joints. I may have to end up resorting to Firebirds solder rings approach but I don’t want to. I come from an electronics/ electrical eng background and a perfect soldered joint is a thing of beauty. I’ve also done a bit of plumbing in my time and joints with globs of solder, however small, were a failure to me. I know that a good sound joint can be made when it isn’t even apparent that any solder has been used. Get it right and the slightest touch with the solder and it rings around the joint and is done. Hopefully that’s what can be achieved.

I’ll let you know how I go. if I’m not successful I’ll be back to take up the offer of the Tenacity export to NZ.

 

[doubletop]

While on the subject of bronze bushes; maybe you can help with identifying this. When I made my wobbler on my first attempt at the cylinder I grabbed two bits of stock and machined them up and soldered them together. You can see that they are both different materials. The plate is definitely brass, is the cylinder bronze? If it is I already have some and can start the new bushes straight away

I eventually cocked this up to; so the final cylinder ended up being in brass.

 

[Blogwitch]

DT,

It is very difficult to tell with the heat sheen on them. The darker one could just be caused by it not reaching the same temp as the flat plate.

When you come to checking between bronze and brass there are a couple of easy (but not infallible) checks. All because the brass/bronze alloys can run into each other and there are most probably hundreds of different recipes for each alloy, depending what properties are required from the final product.

Normally bronze will have a slightly redder hue than brass. The drill test is usually a good one. When brass is drilled or machined, the swarf normally comes off as either fine dust or very sharp needles, whereas bronze will tend to come off as a curl.

As a note, my problem with the purchased boiler was partially accelerated by myself, I had wrongly stored the vertical boiler with some water in it over the winter period, and the bottom site glass fitting was the one affected and showed imminent signs of failure. But on redoing all the other fittings, they were also showing signs of corrosion and de-zincing as well, so it would have happened sooner or later anyway. I do know that a few of the 'toy' brass boilers suffer from the same fate of de-zincing. A brass boiler made by Wilesco that I owned, ended up with areas on the central flue that were heavily perforated and tissue paper thin. That was consigned to the dustbin. So it is a well known problem in certain circles.

Bogs

 

[firebird]

Hi DT

Bronze will often have a dark spiral around the bar like this,

Cheers

Rich

 

[doubletop]

Thanks Firebird it looks like I may have some bronze then. There appears to be some remants of markings on this bar. I can now remake my bushes over the weekend. A set of indexable tipped lathe tools are on its way to me so I'll have some new toys to play with to make them.

 

[SBWHART]

DT

Another thing you have to watch out for is that you're not using Aluminum Bronze as it just wont solder, bin there got the scrap, one way to tell ally bronze is with a strong magnet for some strange reason ally bronze is magnetic.

Hope this helps

Stew

 

[doubletop]

Fortunately Stew it wasn't ally Bronze

OK I’m back with an update on progress. I made a new end plate and a complete set of bushes out of the material that could be bronze, going on Firebirds spiral stripe identification.

End plate and central flue have now been successfully silver soldered but not without further issues.

I gave it a generous amount of solder on the water cross tubes as there is no way to get back into then to fix any leaks once the boiler is completed. The joints can’t be seen anyway.

Eventually a degree of success with getting all the bushes installed but it wasn’t as clean and tidy as I would have liked. A few globs of solder here and there.

I’ve now moved on to the bottom end plate and now had about 4 attempts to get it soldered up. Once it fails its back into the pickle for an hour, quick clean with one of those green kitchen scoring pads (nothing drastic) rinse and a generous application of flux. (I now have some Easyflow paste).

You’ll see I have tried Firebirds “ring of solder” technique hoping that the whole thing would heat up and flow nicely into the joint without any problems. No such luck, hence the 4 attempts.

LESSON LEARNED – Don’t get your silver solder mixed up. I had had some Easyflow 620degC but in amongst it was some 840degC, no wonder the brass bushes melted before the solder when I tried to blast it with my biggest burner. I am heading towards throwing away all my silver solder and buying new so I know what I have.

I’m persevering with getting this thing soldered up, but I've had better success. But that's why I am doing this, to learn.

In the meantime, while all the pickling was going on, I used the time to make myself a safety valve based on a combination of the drawings from Firebird and BogS posted on Firebirds thread “A small boiler”

That's it for now...

 

[Maryak]

Dtop,

To help me with identifying which solder I pick up, I put a small piece of masking tape on one end and write the silver % in texta. The side benefit is it stops you grabbing the hot end, (ask me how I know :).

Great job on the boiler by the way. :bow:

Hope it helps.

Best Regards
Bob

 

[ianjkirby]

Hi DT,

As no-one else has mentioned the following, I will pass them on fyi, and anyone else interested.

Most silver solder comes with a colour-coded tip (at one end only!) for different grades (eg, light blue is 245, or 45% silver content). Provided you are always careful to use the non-painted end first, it will always remain to identify the grade.

Secondly, may I suggest you carefully check your flux compatibility. It often happens that some different grades of silver solder use different fluxes, and if you have the wrong flux, NOTHING will make a good joint. Always test on a small piece of scrap before attacking good material.

Regards, Ian.

 

[tel]

Further to which .....

put a short 'U' bend in the colour coded end of the rod,

a: Stops you grabbing the hot end
b: Preserves the colour coding
c. Lets you hang the stick on a convenient nail.

Pretty much standard practice.

 

[mklotz]

I'm betting my cynical mind has already puzzled out the answer to this question, but...

Is there any consistency in the color coding from one manufacturer to another?

If so, is there a chart detailing the code?

 

[doubletop]

Maryak , ianjkirby and mklotz; Thanks for the useful tips, helpful to everybody.

I have the masking tape labels but there's a bit of a story with my workshop. All my contents belonged to my father and when he couldn't see well enough to continue working on his projects we called in Crown Movers and they shipped the contents lock stock and barrel to me New Zealand. It's been in storage for a while and last year I finally built somewhere to house it all. I had some time and started work on my projects literally 7 weeks ago, with no previous experience to speak of. Firebird convinced me to post my progress, so here I am.

Anyway on the subject of silver solder; with all the contents I had a bag of labeled up rods some bound into bundles and some labels just dried and shriveled up in the bottom of the bag. I had thought I had worked out what was what, but apparently not.

On the flux I have EasyFlow SS 620degC and have obtained Easyflow flux paste so I should be good there.

Anyway for the avoidance of any doubt of what I may have I'm going to re-stock so I can then only blame the operator and not the materials.