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Author Topic: How to Silver Solder  (Read 6729 times)

Martin13

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How to Silver Solder
« on: March 25, 2008, 11:09:53 am »

Hi All,

I need to make three Brass "P" brackets for my prop shafts. The outer shaft will be 8mm OD running three 50mm three blade props.
At this stage I believe only silver soldering will be the only thing that will have structural strength on the "P" brackets.

Can anyone please give some instructions on "How To" Silver Solder and equipment needed  O0

Thanks a heap

Martin from Down Under
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boatmadman

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Re: How to Silver Solder
« Reply #1 on: March 25, 2008, 12:21:04 pm »

Most importantly is clean the components first. I use wire wool.

Position the components to be soldered, I place them on a brick with another behind - helps keep the heat where you want it.

Then, make up some silver solder flux paste, apply to the components in the area to be soldered.

I then use an ordinary blow torch, heat the components taking care not to allow them to move. When the flux has bubbled off, gently touch the components with the silver solder rod, if they are hot enough, the ss will flow into the joint, if it dont, heat some more and keep on trying until it flows. Once the ss has got in there remove the ss rod and heat and allow to cool. Clean with meths then wire wool.

Experiment first - you will soon get the hang of it, its quite easy once you get the knack.

Good luck

Ian
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FullLeatherJacket

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Re: How to Silver Solder
« Reply #2 on: March 25, 2008, 12:29:29 pm »

Ian
What constitutes the flux paste? I seem to remember using Borax for the job, but my memory dims with over-use of my remaining brain cells.
FLJ
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Re: How to Silver Solder
« Reply #3 on: March 25, 2008, 12:33:27 pm »

Martin13,

Call down to your local engineering or hardware shop and ask them for silver solder rods, over here the usually come pre fluxed.............


Roy
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boatmadman

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John W E

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Re: How to Silver Solder
« Reply #5 on: March 25, 2008, 02:45:08 pm »

Good Doy Martin doon under :)

I have included a little scribble of a jig I made up to hold 'A' frames and 'P' brackets whilst silver soldering and soft soldering.   It was made out of a couple of pieces of 6mm thick mild steel; clamped to form a step and with two bolts and the clamp bar.

The bolt that holds your bush must be the same diameter as your prop shaft (to keep it central) that is why there are 3 sizes 4, 6 and 8 bolts.   I found after making this jig it saves a lot of heartache of trying to hold pieces together whilst soldering.   

The only thing else I can add is, if you are going to make yourself a soldering hearth from bricks Make sure they are fire bricks.    Normal household bricks tend to crack and explode when you put any heat on them, along with concrete.   

The other thing is, the temperatures (pieces should be a dull red) and the way I was taught to silver solder was firstly clean the joint you are going to solder using wire wool.  Keeping it clean without touching your fingers on it - because the grease from your fingers play havoc with the flux.  If you have the flux which is mixed with water to form a paste, the paste must be a 'thickish' consistency - so if you make peaks out of it, they stand - or if you are using the powdered flux you warm the end of the silver solder up first - dip it into the flux and then apply it to the joint along with the silver solder rod.

Hope this helps.

aye
John e
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Re: How to Silver Solder
« Reply #6 on: March 25, 2008, 04:00:19 pm »

Hi Martin
Just to add to Johns post.
If you are using the flux which you mix with water, add a drop of washing up liquid to it, this will help it to adhere evenly with no gaps.
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bogstandard

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Re: How to Silver Solder
« Reply #7 on: March 25, 2008, 04:55:23 pm »

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Martin13

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Re: How to Silver Solder
« Reply #8 on: March 26, 2008, 07:40:43 am »

This might help a bit to understanding the basics

http://www.pollymodelengineering.co.uk/global/technical-notes/basic-silver-soldering.asp

John


Thanks John,

That site was very informative and thanks to the rest of the troop on your suggestions.

I currently work part-time in a hardware store (timber area) and today purchased some Flux Cored Silver Solder (98% Tin - 2% Silver) along with a hand held Propane Blow Torch at Staff Discount Rates.

Apparently the Silver Solder has a melting temp of 430 Degrees F. Do you think that the blow torch will produce sufficient heat to melt the solder ? Also, the composition of the solder - is that right?

Martin Down Under - Isn't life great - it's finally raining :D :D
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bogstandard

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Re: How to Silver Solder
« Reply #9 on: March 26, 2008, 08:17:57 am »

That is a hard version of soft solder, and your blowtorch will melt that with ease, in fact hold it away a bit as it just might be too much and 'cook' the flux.

I have a few firends in Oz, and they always have to have easyflo wire and tenacity 4a flux shipped from the UK.

I usually send people to Blackgates Engineering, or the site I posted.

John
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Martin13

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Re: How to Silver Solder
« Reply #10 on: March 26, 2008, 09:54:19 am »

That is a hard version of soft solder, and your blowtorch will melt that with ease, in fact hold it away a bit as it just might be too much and 'cook' the flux.

John

Do you ever have the feeling that you are going backwards rather than forwards :'( :'( :'(

Ideally, what should the composition of silver Solder be for my little project ??

Martin Doon Under
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Re: How to Silver Solder
« Reply #11 on: March 26, 2008, 09:59:55 pm »

If you see a gas fire at the tip, grab the ceramic plates out of the back of it - I've used some for brazing hearths for years. Some are ribbed on on side - the grooves are useful for holding round bits.
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hopeitfloats

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Re: How to Silver Solder
« Reply #12 on: March 28, 2008, 08:47:15 am »

generally the higher the silver level the hotter temp. it takes to melt. i have done a lot of silver soldering but to be honest i dont know what the composition of the solder is. (** hangs head in shame**) my supplier knows what i use and just sells me more when i need it.  i mainly use it for model work and the odd repair of various machinery for friends.
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Captain Povey

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Re: How to Silver Solder
« Reply #13 on: March 28, 2008, 12:27:49 pm »

Hi all, www.cupalloys.com website is worth a visit. It contains lots of ifo on all the different alloys, fluxes etc and has a section especially for modellers. Cheers Graham
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Re: How to Silver Solder
« Reply #14 on: March 28, 2008, 10:56:26 pm »

I have been reading this post with interest and although i have not done much brass/copper soldering before i would like to try .
I have a pencil blow torch and one that uses one of those disposable cylinders and some silver solder that i used once to join some brass wire together ,when i did it i used flux that i have in a tin but it is the jell/paste type ,with the green lid (will get the name in the morning ) is this sutable for silver soldering or do i have to get some propper stuff .
daz
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Martin13

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Re: How to Silver Solder
« Reply #15 on: March 28, 2008, 11:23:48 pm »

Hi all, www.cupalloys.com website is worth a visit. It contains lots of ifo on all the different alloys, fluxes etc and has a section especially for modellers. Cheers Graham

Graham, thankyou very much Sir.  O0 O0 O0
I had a good look at the site - brilliant with loads of info. I should be able to find everything I need here. Hope to email the company and see if they will send product to Australia.

Also, the "P" brackets - does anybody know the correct marine terminology ?

Martin Down Under
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andygh

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Re: How to Silver Solder
« Reply #16 on: March 29, 2008, 04:14:05 am »

Quote
That site was very informative and thanks to the rest of the troop on your suggestions.

Hey wait a minute, it's a troop of monkeys isn't it?  >>:-(  {-)  {-)
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Martin [Admin]

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Re: How to Silver Solder
« Reply #17 on: April 02, 2008, 08:04:31 pm »

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Martin13

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Re: How to Silver Solder
« Reply #18 on: June 22, 2008, 12:02:23 am »

Can anyone tell me the difference between Silver Soldering and Brazing (excluding the rods of course).

Is Brazing structurally stronger than Silver solder ???

I have seen a setup using a small torch with an LPG bottle and have been told that this equipment is ideal for both - not to mention a lot cheaper than Oxy/Acet

Martin doon under
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Bunkerbarge

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Re: How to Silver Solder
« Reply #19 on: June 22, 2008, 12:55:23 am »

Hi all, www.cupalloys.com website is worth a visit. It contains lots of ifo on all the different alloys, fluxes etc and has a section especially for modellers. Cheers Graham

Graham, thankyou very much Sir.  O0 O0 O0
I had a good look at the site - brilliant with loads of info. I should be able to find everything I need here. Hope to email the company and see if they will send product to Australia.

Also, the "P" brackets - does anybody know the correct marine terminology ?

Martin Down Under


The correct Marine Terminoligy is....."P" Brackets!!
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Martin [Admin]

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Re: How to Silver Solder
« Reply #20 on: June 23, 2008, 12:08:59 pm »

What next up, in strength, from soldering, ie, electronic "soft" soldering please?
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John W E

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Re: How to Silver Solder
« Reply #21 on: June 23, 2008, 12:28:55 pm »

Hi ya there one and All

Martin13 I hope this answers your PM  O0

If we start off 'soft solder' the lead tin mix or its not lead now because of new Regulations.  This is, to my knowledge, the softest and weakest of all solder joints.  Then we have silver solder - which requires a lot more heat than soft solder - normally with some form of Gas torch - this can normally solder the majority of metals apart from aluminium and I cant remember the other one  :P

Then there is brazing; which is a lot more stronger than the last previous mentioned.   But, it does require a slightly more heat.  Then, I suppose we could go to the next form which would be oxy acetylene where we use a mild steel welding rod and the two metals to be joined are actually melted whereas the above, we do not melt the metals to join we only use the solder as a bonding agent.

We could then go to electric welding; where the 2 metals are yet again melted together with a filler rod; but, this time we use electricity instead of a gas - then we could go to mig & tig welding - yet another form of electric welding.

Finally we could go to 'friction' welding where the 2 components are brought together - one is revolving at a very high speed, the other is held stationary and they are forced together generating immense heat and literally bonding to one another.    British Rail used to use this method for bonding the axles to the wheels of trains - and there is one last form of bonding metals together and it is what the blacksmiths of old use to use and what can still be done - this is where the two pieces of metal are heated up 'white hot' in a forge, brought together and then hammered and this is a form of friction welding.  O0

Aye
john e
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Captain Povey

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Re: How to Silver Solder
« Reply #22 on: June 23, 2008, 02:10:43 pm »

Hi All, Just to add one more to the list there is also Ultrasonic welding. Especially useful for plastic parts but it requires some very  expensive equipment as the 'horn' has to be 'tuned' to the parts in the application. Cheers Graham.
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merlin

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Re: How to Silver Solder
« Reply #23 on: June 24, 2008, 02:05:52 am »

Hi! Martin  Just to add a bit more info silver solder comes in several grades from relatively low temps, Exta Easy-flo to Easy-flo hard so that you dont unsolder the first bit as you add to a complex structure Obviously the harder the solder the higher the heat reqd [ for easy butane for hard propane ] brazing requires at least propane for lower temp grades for higher temp grades Mapp gas or similar if anything over fine wire is used or you could use for model work an oxy-propane rig which will give similar temps to oxy-acetelyne for model purposes but not if you use it on your car!.  If you want to solder aluminium butane torch will do but you will need a special solder [ Cup-Alloy again] but the technique is closer to welding than soldering as both the metal and the solder fuse together during the process. Futher to above the only metals you cant SOLDER!  are cast iron and maziak or as I call it Mickey mouse metal as far as I know but i wouldnt think you would want to use either in a model boat. Flux can be obtained wherever you get your solder Easy-flo is merely the most famous brand name, there are lots of makes. 
Whatever you do keep your work spotless and after soldering pickle the work in any weak acid, vinegar etc (trade use is 10% sulphuric in water.GET ADVICE BEFORE ATTEMPTING to use ) Or just boil in plain water to remove flux

Technically for you purists out there what iis known as silver soldering should really be called hard soldering, because in the silver trade silver soldering, does not include hard alloy solders as above.
.
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tonyH

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Re: How to Silver Solder
« Reply #24 on: July 05, 2008, 01:03:29 pm »

I may have missed the answer to this somewhere else but, just in case.....

With silver soldering, I understood that the workpiece(s) are often heated to a point when they are being tempered and can soften.

I noticed on the Project 1710 (Submarines) topic that he hard-soldered the blades into the prop boss. Would this be rigid enough or is there a simple method of re-hardening the brass.

Any ideas please?

Tony
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