Member postings for Keith Hale

There are two grades of 316. There is the common or garden variety and there is 316L. The L denotes a lower carbon content.

What makes stainless steel "stainless" is the chromium content of the steel. If the steel is heated to between about 250 - 530 degC. (casting, welding etc) for any length of time, the chromium combines with the carbon to form chromium carbide. This depletes local areas of the protective chromium and the steel rusts! (Sensitization)

316L contains the lower carbon content. As such it sensitizes the steel to a lesser extent and the corrosion resistant quality of the steel is not compromised.

316 is fine for general use (cutlery etc) but for more aggressive marine applications it's 316L.

But be prepared to pay more for it!

This is not a case of defective materials, it's probably a misunderstanding between customer and supplier.

Keith

PS if you want to create rust spots on stainless steel knives, braze the blade to the handle with a low silver content (cheaper) alloy and use oxy-acetylene. Seldom fails!

Edited By Keith Hale on 04/07/2022 11:58:04

Hi Phil,

If the problem is as you say"the burner is too big" why not use a smaller and more controllable flame?

Do you need 43kw?

Turn the regulator down from 4 bar to 2 bar the to reduce the gas consumption and heat output down to 23kw.

Alternatively buy a smaller burner eg 2941. That will give you 7kw at 2 bar rising to 14 kw at 4 bar.

Either way you will achieve more controlled heating and that means better quality of joint. You will find that you are also more comfortable. Remember that you are brazing and that requires controlled heating for the best results. It is not all about blasting heat at something. Leave that approach to the folks painting lines on the road!

Keith

Hi Stephen.

Sievert will give you the best options for heating. These options are enhanced by using a variable regulator which allows you to to increase the amount of gas being burnt and increases the amount of heat generated.

This only applies to the 2000 series which is designed to run at 2 to 4 bar. The 2941 will generate between 7 and 14 KW of heat and is a good starting point.

If you want less heat, consider the 3000 series. The. 3941 burner that delivers about 3 KW with a more focused flame.

Heating is the most skilful part of a very simple process. If you want any more information on heating techniques then let me direct you to my book available from CuP Alloys or send me a pm.

Best wishes

Keith

Hi Nick,

Sievert every time until propane heating does not fit your needs. This is likely really when you might want a more defined flame.

The mapp or map torch is ideal for a plumber. It has a slightly higher flame temperature but may not deliver enough heat because it is not burning sufficient gas.

Heating is probably the biggest cause of brazing (silver soldering) problems usually resulting in poor joints.

Look beyond the headline price. You could be heading for higher costs later.

Why not discuss your requirements with someone who appreciates and understand what you want to achieve? Try CuP Alloys.

Why ask a storeman in a plumbers shed? Alternatively read my book. Either way, you will understand enough to buy any pre-loved equipment.

But buy sievert.

Keith

As I recall, "an engineer told me before he died" is the first line to a song simply called "The Engineer's Song"

It features twice on an album released 1965(?) Rugby Songs Vol 2 by the Jock Strapp Ensemble on Surprise Records ILP 1012.

Looking at it now brings back a lot of memories.

Would I play it again - yes

Dare I - no!

Edited By Keith Hale on 24/02/2022 12:32:09

10 gm salt/litre

Keith 

Sorry can't convert that to the number of lemons!

Depends on size, moisture content, soil, Brexit, covid, number of lorry drivers and.......

Edited By Keith Hale on 25/11/2021 19:39:46

Hiya Mark,

The key to successful silver soldering is capillary flow of the alloy into and through the joint.

So determine what you need to do.

Why you have to do it.

How to do it.

Then do it.

This knowledge will also enable you to evaluate any "advice" offered and further enhance your prospects of success.

Best wishes

Keith

Deleted - duplication!

Keith

Edited By Keith Hale on 19/11/2021 09:23:59

Hi Baz

Thank you.

When ordering from CuP, talk to Glen/Shaun, tell them your daughter's name and request a signed copy. Over 600 copies have been sold, but only a handful have been signed!

I'll add a little more information relating specifically to jewellery making.

If you have bought it already, message me with the information and I will respond accordingly.

Best wishes

Keith

Hi all,

The demo by Helen at the Midlands exhibition was carried out using an oxy-propane kit from CuP Alloys not BOC

She did the work, I did the commentary.

Keith

Quite probably!

I saw them being used in an Indonesian silversmith's workshop.

Bloody frightening!!!

But the workmanship was incredible.

Keith

I am told that Hermes have asked if they can help with the fuel shortage.

So far they have lost 35,000 gallons, 2 tankers couldn't find the petrol station and one took a picture of the station and drove off claiming that there was no answer!

There are no reports of problems affecting model engineers using petrol fuelled blowlamps. Yet!

Keith

Edited By Keith Hale on 10/10/2021 11:08:36

Hi Steve

10gm of citric acid crystals per litre of water.

Regards

Keith

Edited By Keith Hale on 09/10/2021 14:51:45

Hi Jon,

This post baffles me!

Why would you want to make joints at 1000°C , probably using a fine hot flame (oxy acetylene?) when you can be using simpler equipment and making your joints at a considerably lower temperature.

You would also be able to use more readily available filler metal with an intrinsic value of approximately 50% of fine silver. What's not to like?

Are you simply looking for a cheaper method of making your joints?

Can you get fine silver fuse wire from say your local DIY shed? Don't try to explain what you are trying to do 😀

Find a supplier to the amateur silversmith for the rods and wire. However they tend to restrict themselves to standard or sterling silver and not fine silver. Don't expect their overheads relating to distribution to be any different!

Then follow Dave's advice.

Regards

Keith

Hi Chas,

45T is not anything "special" but it will do the job you require.

Joint gap details and a method of attaining them are in the message.

Torch should be suitable but check in your book for the best way to heat the components to produce the strongest joint.

Regards

Keith

Another posting with unknown provenance.

52 years in the brazing/silver soldering brazing business, I have not come across a "special silver solder for stainless steel". I have come across alloys that are suitable for ferritic stainless steel in certain conditions.

What I have come across are common silver solders being used correctly and universally on austenitic stainless steel in a wider range of conditions.

Austenitic stainless steel is non-magnetic.

In my experience, "special silver solders" are often of unknown composition, at a premium price from red and yellow boxes. Is yours the one with the pink coating? Cheaper to buy the bare rod and flux!

Before buying it, ask yourself, "Do I really know what I'm buying?"

Any problems that Chas may have are extremely unlikely to be anything to do with the alloy being used.My earlier posting illustrated!

You pay your money and take your choice.

Keith

Edited By Keith Hale on 30/09/2021 20:40:37

Hi all,

When I can appreciate what Chas is doing, why, how and with what, then I can offer sound practical advice to resolve the difficulties. In the meantime, I don't want to add to the confusion by introducing facts that are at variance with ill founded opinion.

I am confident that the answer is in my book.

It's not bedtime reading, but it's a good source of information to achieve good, strong brazed joints.

The usual disclaimer does not apply. 😃

Keith

Hi Chas,

See personal message.

Let's not complicate things unnecessarily.

Keith.

Hi Matt

See personal message.

Keith

Hi Mike,

Pleased to hear of your success.

A triumph for the argument of how when using the right materials correctly in a simple process you achieve what others consider impossible.

You have a good, strong, neat joint requiring no dressing for an aesthetically pleasing result.

You have demonstrated just why the brazing process has been around for 5,000 years

Well done. I salute you.

Keith