Need help please with Silver Soldering steel

[jimsshop1]

I am trying to silver solder a 1"x 1"x 1/8" thick square piece of crs to another piece of steel I think is 4140. It also is 1/8" thick but a tube. I have the same radius on the small piece to fit the curve of the tube. I am using Harris silver bearing Stay Brite solder and flux which has a melt point of 430 degrees. I have cleaned, wire brushed and used alcohol as a prep and preheated before using the flux as per instructions but cant get the solder to flow out on the pieces and even stick at all to the tube. The solder just rolls off. I have even tried to do the tinning process an the small part but the solder only flows on to part of it. Obviously I am not getting the parts clean enough but I thought the flux was to clean any remaining contamination. I know there are members on here who silver solder all the time so am hoping for some help. I never have this problem with brass or copper. Also please don't suggest brazing as I don't have the oxy/ace set up to do that. Thanks in advance for any help.

Jim in Pa

 

[kwoodhands]

I am trying to silver solder a 1"x 1"x 1/8" thick square piece of crs to another piece of steel I think is 4140. It also is 1/8" thick but a tube. I have the same radius on the small piece to fit the curve of the tube. I am using Harris silver bearing Stay Brite solder and flux which has a melt point of 430 degrees. I have cleaned, wire brushed and used alcohol as a prep and preheated before using the flux as per instructions but cant get the solder to flow out on the pieces and even stick at all to the tube. The solder just rolls off. I have even tried to do the tinning process an the small part but the solder only flows on to part of it. Obviously I am not getting the parts clean enough but I thought the flux was to clean any remaining contamination. I know there are members on here who silver solder all the time so am hoping for some help. I never have this problem with brass or copper. Also please don't suggest brazing as I don't have the oxy/ace set up to do that. Thanks in advance for any help.

Jim in Pa

Jim, I use SRA solder and flux. I have two different types, one for copper, brass and bronze. The other for steel and other ferros metals.
They look the same, white borax type of flux. I don't know if your flux is similar to SRA products. The flux will help to keep the parts from oxidizing. Try pickling the parts with a mild acid. I use ordinary vinegar, some use a citric acid type. Both are safe to use though they take longer to brighten the parts.
I believe your problem stems from not pickling the parts.
After about 3 hours ,probably less ,remove the parts. If they look bright then wash the parts with plain water. Then heat the parts a bit , flux the parts and add small pieces of solder around the parts. I have trouble using long lengths of solder so I cut it to about 1/8" / 3/16" long. Then place it around the parts and cover it with flux. After the soldering is complete and cools down to 200/300° place the parts in the pickle for an hour. Wash the pickle off. This will get the remaining flux off , this is necessary to stop corrosion.
Try the pickle and use your flux, I think you will be happy with the results.

mike

 

[goldstar31]

This really has been discussed only hours ago.
My guess is a case of wrong preparation and lack of heat.
Initially, I would clean everything but before fluxing, I would ''B or 2B' pencil around the flat plate to give just a neat rim of solder around the tube and I'd do the same for the tube.

Then I would put WET flux around the parts to be solders. I wouldn't be unduly fussy about the type of flux but I would put a ring of silver solder closely around the part of the tube to receive the solder. Then I would put a 'cap' over the tube to limit the heat going elsewhere.

THEN, I would circle the flux with the torch slowly until the flux bubbled, getting rid of the water and get the flux to turn into a glassy state. Then I would blow the heat unto almost red and the silver solder should wick to complete the join.

All this time, the heat source should be circled.

Note-- this is the way that artillery shells were soldered!

Me, and I may be different , wouldn't bother and would stick the two bits together with my little cheap Mig- in say 4 places and do much as stated.

I could be wrong but from what has been said- the faults are not melting the flux properly to hold the unmelted silver solder wire and - the lack of lots of heat

N

 

[jimsshop1]

Jim, I use SRA solder and flux. I have two different types, one for copper, brass and bronze. The other for steel and other ferros metals.
They look the same, white borax type of flux. I don't know if your flux is similar to SRA products. The flux will help to keep the parts from oxidizing. Try pickling the parts with a mild acid. I use ordinary vinegar, some use a citric acid type. Both are safe to use though they take longer to brighten the parts.
I believe your problem stems from not pickling the parts.
After about 3 hours ,probably less ,remove the parts. If they look bright then wash the parts with plain water. Then heat the parts a bit , flux the parts and add small pieces of solder around the parts. I have trouble using long lengths of solder so I cut it to about 1/8" / 3/16" long. Then place it around the parts and cover it with flux. After the soldering is complete and cools down to 200/300° place the parts in the pickle for an hour. Wash the pickle off. This will get the remaining flux off , this is necessary to stop corrosion.
Try the pickle and use your flux, I think you will be happy with the results.

mike

Mike,

I think you may have solved my problem, PICKLING!. I have soldered copper and brass to make boilers in the past and always pickled but I did not think it was necessary with steel. The thought did come to me though, I just did not try it since I got so frustrated I just gave up for the day. You know how you try so hard to do something you know is so simple it's stupid you cant get it?. Well, its 6am so I will get back to this project again in a couple hours after a few sweets and some coffee.

Thank you, I will get back on here after while and let you know if I was successful.

Jim

 

[goldstar31]

If it's pickle, you can use vinegar or citric acid but really dilute sulphuric is the thing. Get it from the battery acid people but observe the cautions for such corrosive stuff.

'Do as you outta, add the acid to the wattah'

Mind you, I'm an old hand with double distinctions in City and Guilds and was a Certified Welder as a - manure student and seem to have little need of such things.

My late wife was probably better and could silver solder with a mouth held blow torch and could do stainless with ordinary borax.
She would flick the unused flux off with a finger nail. She was a dab hand at centrifugal casting with gold which she re-cycled from the teeth that she extracted. No great thing- compared to maxilla facial surgery!

N

 

[jimsshop1]

 

[WOB]

Jim, you are probably overheating the solder and underheatng the workpiece Staybrite solder and flux works perfectly well on steel. I have soldered small pieces like yours with a hot air gun that could only each 800 deg. Wire brushing and then degreasing ( alcohol is very poor grease/oil solvent, use brake cleaner or acetone) should do the trick. Coat the joint area with flux and heat the steel pieces gently. Lay down the solder into the liquid flux. As the steel reaches the solder's melting point, the solder should flow out readily and wick into the joint. Done.

WOB

 

[mcostello]

Hey Goldstar, better reread Your last post. Jokes are looming and getting hard to stiffle.

 

[jimsshop1]

Manure, didn't know they taught that?

 

[jimsshop1]

Jim, you are probably overheating the solder and underheatng the workpiece Staybrite solder and flux works perfectly well on steel. I have soldered small pieces like yours with a hot air gun that could only each 800 deg. Wire brushing and then degreasing ( alcohol is very poor grease/oil solvent, use brake cleaner or acetone) should do the trick. Coat the joint area with flux and heat the steel pieces gently. Lay down the solder into the liquid flux. As the steel reaches the solder's melting point, the solder should flow out readily and wick into the joint. Done.

WOB

Thanks, I do think I'm over heating them.

 

[goldstar31]

We also did Latin at college and this is what I can remember of those days

Caesar ad sum iam forte
Brutus état erat
Caesar sic in omnibus
Brutus sic in at

 

[Peter_A_Lawrence]

Jim, the tin solder you are using, with 430-F mp, is hard to find a flux to use with, the typical tin/lead solder mp is around 360-F, which is why I agree with all those before me that said you're probably over-heating. But, while they called it "silver solder" this is misleading, it has only 2~4% silver, and is only marginally stronger than tin/lead solder, are you sure you don't need the strength of real "silver solder", which is also misleading since it might better be called "silver brazing", but whose joints are almost as strong as the steel you are using.

 

[jimsshop1]

Got it done. Cleaned with Acetate used the flux that came WITH the solder kit. Cut and made a solder ring under the part. Used a very weak spring clamp on the part. Heated very slowly under the tube and watched the solder melt while the clamp compressed the part down. I knew I was using too much heat. Thanks WOB for the help.

Peter, I do not need the strength of true Silver Solder and knew that what I am using is only 4% silver and that the flux was correct but thank you for the advice.

Goldstar, I meant no offense and I don't know Latin so please carry on and humor yourself!

 

[goldstar31]

Gotcha! I'm an old fart and suddenly remembered my chemistry days at school.

The flux- as near as I can recall- is not a borax based flux but what was called 'killed spirits of salts' which in today's parlance is nothing more than zinc pellets dissolved in hydrochloric or muriatic acid- until it stops giving off free hydrogen.

So putting two and two together this is the possibly the sort of flux used for joining zinc coated steel sheets'

Cheers, Jim

Dead simple but it may be Greek to some

 

[jimsshop1]

Gotcha! I'm an old fart and suddenly remembered my chemistry days at school.

The flux- as near as I can recall- is not a borax based flux but what was called 'killed spirits of salts' which in today's parlance is nothing more than zinc pellets dissolved in hydrochloric or muriatic acid- until it stops giving off free hydrogen.

So putting two and two together this is the possibly the sort of flux used for joining zinc coated steel sheets'

Cheers, Jim

Dead simple but it may be Greek to some

I'm a 71 year old fart also so I've seen a thing or two. Some simple things don't come back too easy but I can remember the 60s so well, the best years of my life. Wish I could go back!

 

[davidyat]

Being self taught, when I was working on my Meyers Hot Air engine, the plans said to "silver solder" a stainless steel round plate to the bottom of an iron tube. Well the conventional solder just rolled off. I took the plans to the welding supply and asked what I was doing wrong. When they found out I was using low silver solder, they suggested a high silver count solder. 3 rods, 18 inches long, $10 a stick, yikes!! Well, heating up the joint, the high count solder flowed like butter and the joint was great. I thing they said it was something like 55% silver. I don't care what it costs if it works like I want it to.

 

[goldstar31]

I'm a 71 year old fart also so I've seen a thing or two. Some simple things don't come back too easy but I can remember the 60s so well, the best years of my life. Wish I could go back!

Today is the my last day as a 87 year old. Going back? Marriage was the best thing but there were terrible hardships as well.
'Engineering', and chemistry and languages are merely sidelines. I worked and studied so bloody hard that I was able to retire at 55.
As my son rudely put it- 'Dad, you've been retired longer than you ever worked'.

Tomorrow, I'm still working. I have a Finance and General Purposes Committee for perhaps the World's Largest Charity. I sit on four of these. I'm trying to give back what people did for me. Playing about with tools? That's only a way to keep dementia at bay whilst I try to do something more useful to others.

This is Life not the Dress Rehearsal

Norm

 

[jimsshop1]

Well, Happy 88th Birthday to you Sir!! Thank you for telling me a "little" bit about your past. Since I have not been on here as long as some others that know you better I did not realize you were that "up in years" so to speak. You have my respect for keeping yourself going and still trying to help people. One of the things my parents taught me at a young age was always help people in need, it doesn't matter if the need is great or small, someone will always appreciate what you do for them. And never expect return favors. My working career lasted 36 years and with the same company but I have kept on working and helping others when I can. I always say, "one of these days I'm going to take a "vacation" but I never do. Some days I feel sorry for or Mad I guess at myself because I have severe Rheumatoid Arthritis and can't do the things I used to be able to do and some days I just do very little, nothing I can do about it. Any way, I hope you have a very pleasant birthday surrounded by some wonderful people that you are happy to be with.

Respectfully,

Jim

 

[goldstar31]

Thank you. I'm sort of OK or better than OK for my age.
My little hairdresser, a friend since she swept up hair at 16 has acute ~Rheumatic Arthritis now. It's a terrible complaint.

I've got a buckled old pal with even worse and I'm down to buy him 'several' Chardonnay's and the rest of my aged and quite delightfully decrepit - and quite wonderful friends, the usual double whiskies.

So cheers to what the future holds- for us all

Norm