Member postings for Keith Hale

Rob,

1) The re-melt temperature of easi-flo2 is higher than the original.

2) Even if it melts ,Easi-flo 2 is totally compatible with 455. 455 will repair any leaks.

3) Any molten silver solder will be retained in the joint gap by capillary action (the fundamental principle behind the process). Ensure a good coverage of flux to prevent oxidation and dewetting of the alloy = another leak. Use HT5 flux.

Bob,

I suggest to anyone struggllng with Silverflo 24 as the first alloy in a step-brazing operation to simply switch to a lower melting point alloy like 438. 438 and 455 work together well.

For more information go to **LINK**

regards

Keith (Hale - no relation to Phil!)

As Rod explained, you just need more heat. His approach is spot on. Possibly use a bigger burner and insulation to keep the heat in. You may need a longer life flux like HT5

Watch the flux. When it has melted and started to flow apply the alloy. It is pointless trying to braze until the flux has melted. The joint is simply not hot enough. Do not heat the alloy. Allow it to get its' heat from the joint. Getting the alloy hot is one hing - getting the joint hot enough is another. If the joint is cold the alloy won't flow

GOLDEN RULE FOR SILVER SOLDERING/BRAZING

HEAT THE JOINT NOT THE ROD

Keith

According to the (temporary) powers that be in Brussels and their UK enforcers, it is illegal to "place cadmium bearing silver solder in the market".

Not only is it illegal to sell it, it is illegal to give it away as samples! The new larger market for cadmium free alloys has to be protected so as not to affect future sales! Existing stocks, in sheds and workshops around the country are impossible to control or police.

Whatever you do decide to do with your easiflo is a personal choice. It is not an offence for you to use it. Just be careful, sensible and responsible. Just don't shout about being prepared to trade it!

Don't blame me or CuP Alloys. We were not part of the stitch up.

Post Brexit? Who knows? There are no stocks of these alloys in Europe. Any past or future supplier is likely to want a 50 kg order to justify restarting production or, put it another way, 6000 rods 1.5mm dia x 500!

If they ever become commercially available again, CuP Alloys will tell you all - loud and clear. But, having now got used to the cadmium free alloys, do you want to change again?

Keith

It is impossible not to produce cadmium fume when using easiflo 45. The question is "how much is produced?"

An amateur model engineer generally does not use enough alloy/continuously to constitute a health problem but, to make sure that you keep yourself safe, take some simple precautions.

Ensure good flux coverage of the joint and alloy.

Braze in well ventilated conditions e.g. outdoors or well ventilated workshop.Ensure any natural draught is away from you.

Do not hold your head above the workpiece

Examine your brazing technique. Do not overheat the alloy. Apply the heat to the joint not the alloy. Melt the alloy using heat from within the joint not from the torch. Avoid oxy/gas torches. Their flames are very hot and intense. They tend to encourage the modeller to use a welding technique - not brazing.

Having made the joint remove the heat. Little is to be gained by continued heating.

Better still, switch to a cadmium free alloy. Depending on your circumstances e.g. size of component you might need to fix a larger burner to your torch to accomodate the slightly higher melting range of cadmium free alloys. They are not as fluid but stick to the basics of the bazing process- joint design. fluxing, heating you will continue to produce high quality joints.

Keith

Edited By CuP Alloys 1 on 05/01/2017 15:24:18

The stiffness of a piece of silver solder is no reflection on its'composition.

A rod directly extrudes to size is softer than one produced by spin-straightening a hard drawn wire!

1) Cut a small piece of your strip to a similar size to that you can make from your 1.0mm 55% cadmium free rod.

2) Place both pieces on a small sheet/strip of copper and apply flux paste.

3) Heat the two pieces eveny from underneath.

4) Observe when the two samples melt.

My bet is that the unknown material will melt just earlier than the known. It may even spread a little further!

My bet is that you have a 42%silver alloy with cadmium. 5 x 1 strip was commonly supplied to shipyards and the automotive industries. One way you could put down metal slowly. Turn it through 90 degrees and you had a thick rod and could put a lot down quickly

For the alloy to become so tarnished implies that it has been lying around a while. This may date it before anyone became concerned about the health risks for the model engineer of using such small amounts of silver solder.

All my other thoughts on original source etc stay with me!

Keith

The perils and dangers of baked beans has been known for years.

These were even highlighted as part of a public awareness campaign by the Serendipity Singers in 1964. Of particular concern was the effect on the sense of hearing.

Any record buying teenager of the time would have had a copy of "Beans in My Ears"! I am arranging to send a copy to HSE in order to bolster their efforts,

But fear not, I have no intention of causing further public outcry by bringing to the attention of HSE, Ministry of Agriculture, Food & Fisheries, etc the dangers of fruit highlighted in another of their hits "Peaches Grown on Lilac Trees".

Can't believe I have written this and am about to post it!

Sad or what? But it makes a change from banging on about silver solder!

Keith

Hi Alan.

You are not alone! Call us any time. Help is at hand and it is only a phone call away.

Stick to the basics, understand what you are trying to do and why.

YOU WILL BE SUCCESSFUL

Regards

Keith

Mapp Gas and Propane burning in air have very similar flame temperatures - 2010 and 1925 deg C respectively.

Mapp gas has a 40% higher flame speed which allows you to push more gas through a burner and develop more heat.

However the size of burner on a hand held canister is unlikely to be big enough to consume the amount of gas to develop Jasons' 26kw. Your hand is also going to be too close to the boiler for comfort.

I would suggest that you opt for a propane torch starter kit. It is reasonably priced and has a burner to develop that 26kw. But, equally important, it will give you all the flexibility of heating that you currently , and may in the future, require. Simply changing burners (£20ish) and altering the pressure via the regulator, will give you a heating capacity of between 0.25 and 86KW.

Fitting a longer neck tube to the handle gets your hand away from the heat.

If time allows, see this at Ally Pally.

I would not recommend the use of any oxy-gas flame, in isolation, to build a boiler. That includes the oxy-propane torch to which Malcolm refers! They are best used after first pre-heating the joint with propane. Their more precise focused flame will enable you to develop the heat pattern required to control the metal flow and ensure complete penetration of the silver solder into the joint.

Depending on the size and joint design, you may well be able to achieve what you want, from a single propane burner, by simply moving the point of attack of the burner. Your decision!

It is very difficult to achieve good overall heating of a joint with oxy-gas flames. The professionals don't do it......!

Poor heating technique is the most common cause of silver soldering difficulties and problems.

455 silver solder is ideal and will be the mainstay of the build. If you feel that you want to build the boiler using a two stage approach, use a higher temperature alloy eg 438 first and follow it up with the 455.

For more information go to **LINK**

See also **LINK**

Keith

Hi Chris.

Silver soldering will destroy the silver plating. You have two options.

Glue it on or

use soft solder.

To maintain the appearance, use an alloy that gives a good colour match on the silver plate. Ordinary tin-lead solders will produce a grey/black joint. Use a silver tin alloy, 2207, that melts at 225 deg C. It is readily available as a flux cored wire in 1m lengths. It can be posted to you ex stock for £5.39. You don't even have to leave the house!

http://www.cupalloys.co.uk/soft-solders/

What the eye can't see .................!

PS It works equally well on stainless steel.

Edited By CuP Alloys 1 on 31/10/2016 08:51:07

Edited By CuP Alloys 1 on 31/10/2016 08:54:47

Edited By CuP Alloys 1 on 31/10/2016 08:57:28

Sievert offer a wider and more versatile range than Bullfinch including cyclone burners for use in the firebox. (They don't blow out in confined spaces.) See **LINK**

For technical help/advice contact CuP on 01909 547248

Keith

As long as the joints are designed to operate in shear ie the components overlap and you get good penetration of the silver solder into the joint, you can expect a joint strength of 10 - 20,000 psi dependent on the joint gap.

The copper will fail before the joint!

It's one of the reasons you silver solder in the first place!

For more information go to http://www.cupalloys.co.uk/best-practice/

Keith

Edited By CuP Alloys 1 on 24/09/2016 08:54:35

Edited By CuP Alloys 1 on 24/09/2016 08:58:14

Edited By CuP Alloys 1 on 24/09/2016 09:00:37

As suggested by Brian use C101 and C106.. The reason is that these grades are oxygen free and are not subject to the risk of "hydrogen embrittlement"

Oxygen exists in the copper as copper oxide. If the brazing torch gets too close to the work the flame takes on reducing characterstics. The flame reduces the oxide to metal and creates steam. The exit for this steam is via the grain boundaries. The associated stress cracks the copper.

Cheaper grades of copper may also contain lead. Silver solder does not like lead. It is diissolved by the filler metal and alters ithe alloys' flow characteristics. Penetration of the filler metal may be compromised.

You pays your money and takes your choice

Keith

Hi Phil. Spot on!

Castolln always supplied good products. It will do what it says on the tin without telling you what is in the tin!

Welcome to the confusing world of Castolin and what are you actually getting when buying their silver solders.. After 47 years in this business nothing has changed!

It has not been uncommon for the same alloy to have different numbers dependent upon marketing conditions.

One of the links tells me that 1801 is cadmium free with a melting range 660 - 743 C but little else, This is more closely aligned to a 38% silver cadmium free alloy

The other tells me that it is 51% silver, 5% cadmium, 22% copper, 1% tin and 21% zinc which incidentally is nothing like the composition of easyflo 2.

Is it any good for boiler making ? Possibly.

If all the joints are being made on a small boiler using the same alloy - fine. Use it but in well ventilated areas because of the uncertainty about cadmium.

If you want to use two different alloys, ie step braze, then it falls between two stools. It is too high a temperature for the low temperature joints and too low a temperature for the high temperature joints!

If you have enough, I would suggest you scrap it and with the money buy alloy that you know and can trust. Contact John Betts Refiners Birmingham.

Keith

Hello Pero

Relax! The coefficients of copper and most common brasses are sufficiently similar as to ignore it. Set your gap up at 4 thou and you ill have no difficulties.

The differential only becomes significant with leaded free-machining brasses which expand 20% more than copper. You probably are not using these as the lead can make it a pig to braze.

As a direct result of your thread the Best Practice page on our website **LINK** is being amended to deal with this aspect. We thank you for the nudge!

As in all cases of difficulties when brazing, pick up the phone and call us. 01909 547248. Talk to us at exhibitions. There are over 100 years of brazing experience at your disposal, going back to 1969.

Understand and stick to the basic principles of the process, have confidence and you WILL be successful.

Regards

Keith

For more info on easi-flo and silver solder alloys, how to use them etc go to **LINK**

Easi-flo is no longer available within the EU. Other alternatives are.

keith

Silver soldering of cast iron is sraightforward once the surfaces are clean and free of carbon/graphite. Silver solder will not wet onto carbon. The best jigs are carbon.

Get rid of the surface carbon by using the oxidizing part of the flame. That's the bit outside the blue zone of your flame. Heat to red and hold for a couple om minutes.

Allow to cool naturally in air and then clean with a stiff wire brush. Apply a long life flux eg HT5. Reheat. When the flux melts and flows apply the alloy.

Soldering aluminium is also straightforward. Any soft solder can be used, but,as above,. success depends on getting the surfaces lean. Proprietary fluxes are readily available. Your alloy selection will be based on price (?), colour match (?) melting range (?)

For more info see "Best Brazing Practice" and "FAQ" here. **LINK**

Keith