Advice needed regarding silver soldering brass

[ejparrott]

You could do it either way, but personally I'd do it as you've got it, then put the hole in afterwards, but probably not that full size, depending on what goes through it of course.

I would silver solder with Easyflo 2, or it's equivalent, not braze.

[Deleted]

Hi Steve

I guess you can do either in regards to removing the middle section but if you do I'd leave more than just a small witness and then machine after, personally i'd probably cut the hole after but there may be reasons not too that i'm not aware off not being fully up to speed on the design. I would do the whole lot in one go using clamps/clips to hold everything in it's correct position. It looks like some parts have been riveted already so only need to concentrate on keeping the rest square to the base. I would mix a strong flux, coat all the parts before clamping together and then cut up lengths of silver solder placed along the joints on the inside. You then have two options for heating, either from underneath with the job sitting on bricks or you could also heat from the side as the flux and solder is protected from the heat being inside the box. If you do heat from underneath you may still need to do a little around the outside for the upright corner joints.
1 mm silver solder should do the job nicely...

If I've forgotten anything I'm sure others will fill in the gaps or suggest their own method....'many ways to skin a cat' as they say....

regards

Pete

[Roger]

Hi Steve,
Is there any positive registration of the parts? The one thing I've learned the hard way is that things move if they aren't held together. That device that Ed used with a weighted lever would go the trick if there's nothing to hold it in the right place.

[uuu]

If you run out of confidence, you'll have to come to the Pump House!

[cupalloys]

Hi Steve.

Some good advice being given here. Use preforms, apply alloy internally and heat externally. A word of caution.

Clamping tends to remove any joint gap. No joint gap = no capillary flow = no/poor joint

Get yourself into a comfort zone by understanding what you have to do and why when it comes to silver soldering. It really is straightforward when you understand that.

Go to www.cupalloys.co.uk/best-practice/

Put paper into your printer and run yourself a handy guide!

Keith

PS Easiflo2 is no longer available. Use 455 - a low temperature cadmium free alloy

[jma1009]

hi Steve,

Stepney's smokebox saddle is a silver soldered fabrication much like your own.

silver solder is the way to go - brazing with brass wire is not suitable for brass components!

the joints arent critical unlike a boiler, but wilf's advice to pop over to Godshill is very good advice. the beer in The Griffin isnt too bad afterwards (is that where you still go, wilf?)

i dont think removing the brass 'in the middle' will make any difference to the silver soldering job. there isnt a great mass of metal you will be removing afterwards, and leaving it there till after the joints are done will act as a heat sink. i would add a few pins to locate the base to the curved top so they wont move - one pin in each corner of the curved top just inside the angle. i would leave the assembly in the orientation shown in your pic and apply the heat underneath the curved top section with a bit of wandering of the flame, and apply the silver solder from inside the base. in fact you could add strips of silver solder inside the base before heating up and when fluxing.

cheers,
julian

[4fbuilder]

Hi folks,

A simple way to maintain a joint gap is to pop a few light centre pops along the line of the joint, simples! I'm not totally in favour of clamping, I see no good reason having to use more heat to warm up clamps, it's better to put a few screws in, in a strategic positions.

Regards

Bob

[springcrocus]

Where do I start? Thank you all, gentlemen, for your guidance in this.

Ed, Pete, I was thinking along the same lines as you both but, maybe, for slightly defferent reasons. I was contemplating setting it up like a kitchen cooker hood and heating from below with the solder above exactly as Pete described and using the mass of the saddle to conduct the heat. What I wasn't sure of was whether this mass is an advantage or not. The saddle support is riveted but the saddle will rest on top (with help).

Roger, yes it would need holding down and the gubbins that Ed showed us earlier would be ideal.

Wilf, I will be along to the pumphouse sometime and will, with some trepidation, welcome the tuition that you and John will be able to give to this gullible fool who thinks he can build a steam engine....

Keith, very much enjoyed chatting to you at the Midlands MEX and, as we talked about, I don't really know what I have here. However, John kindly demonstrated using both the silver solder and the flux and I know they work together. Also, there is definitely a gap for the solder to fill - my filing is not quite good enough to preclude capilliary action!

Julian, thanks for the comment regarding old-fashioned brazing, I always felt that brass-wire was really only for mild steel but wasn't sure. As for the follow-on, it has been quite a while since I ventured into either The Griffin (or The Essex) but I'm sure that many a problem has been solved in one of those establishments. Unfortunately, I find that the capacity of the storage tank is such that wine is favoured over beer nowadays and feel a little foolish holding my arrows in one hand and a glass of wine in the other so, therefore, tend to avoid such places nowadays. Locating pins will also be acted upon, thanks.

Bob, as mentioned above, I have a joint gap but mainly because I can't file acurately enough! I do like your hint about centre-popping to lift things a little, though.

If anybody has posted advice while I have been typing this, sorry for excluding you, as a one-fingered typist it takes me ages to prepare a post.

Tomorrow I will attempt to join the parts and it will be written up in the diary (good or bad) in a couple of weeks time. If I fail, it will be because I didn't listen properly to the advice I was given.

Kind regards, Steve



 

[digger]

If I were doing that soldering job, I would make sure everything was in correct alignment then cut eight small pieces of silver solder, then after mixing up some flux paste with water to a creme consistancy would put a dab on each of the four corners top and bottom, then with tweezers place eight pieces of silver solder, then with the whole thing placed on a fire brick hearth would gently waft a propane torch over the assembly, very carefully raising the temperature till the solder flashed into the joints, once this occured the item would be pickled and cleaned up. And further silversolder added if necessary using the same proceedure along the sides and end plates of the saddle, pickle again then the saddle should be strong enough to grip in a vice and mill the center out on the milling machine..

Digger

[jma1009]

hi drifter,

eight small pieces of silver solder added with tweezers?

ok you said add further silver solder but your description sounded like a further reheat for this, unless ive misread this. why not add strips of silver solder inside the saddle along all the joints to start with?

most poor silver soldering in my experience is due to being far too mean with the silver solder (and flux)

cheers,
julian

[springcrocus]

Digger, Julian, your comments are most opportune. I haven't yet soldered this together because I was unsure how much silver solder to use. The material is 14swg / 2.0mm / 0.080" thick CZ121 brass and I have 1mm dia solder available. Should I cut full-length pieces to lay along the inner joints or is this amount too wasteful?

I appreciate that this is not easy to judge unless you have the components in your hand and, hopefully, once I've gained some experience I will be able to use the correct amount each time. But it is expensive stuff to just throw around so some guidance would be gratefully received.

I definitely want to achieve the join in a single heating and would not want to add solder and reheat.

Steve

[ejparrott]

I've got a variety of sizes of 455 from CUP, for 2mm material I would use some of my 2mm (IIRC) cut about an inch long in the corners, then when heating I would stand by with a length of 1.5 or 2mm to add as required. I don't believe in adding huge quantities before heating, just smaller 'indicator' pieces, and then add more as the joint or filleting require.

[Roger]

If you lay Silver Solder on the joints, it's even more important not to heat the joint directly. I did it that way for the gussets I made and it worked a treat. Creamy flux can be used to cover all of the strips and that holds them in place as long as you are patient when drying out the flux in first heating.

[Deleted]

Steve, I would cut to full length, in fact i would cut over length and bend the ends so that they are going up the corner joints too, stop short of reaching the top edge. If I was doing this I would probably use 1 mm as the joint is hidden from view so any excess won't be seen and you ensure a good strong joint. I make a lot of use of 0.7 and 0.5mm wire for parts where the joint is visible but for this a larger silver solder will do and give you a nice fillet around the inner joints. Use plenty of flux to keep the silver solder in place and have a length of it to hand for any areas where the cut lengths haven't flowed along the entire joint , I doubt that you'll need it but best to be prepared, you don't want to reheat the job if you can help it. I also use old tweezers to re-position any silver solder that moves during heating.

regards

Pete

[digger]

My reasoning is the first soldering holds the pieces in position, then because of the eutectic effect (more heat required to undo previously soldered joint) the second soldering completes the process, Julian yes I agree it could be done in one heat, this is just another way.

Digger

[jackrae]

Soft steel wire as used by florists is quite good for 'tieing' parts together for soldering. You friendly local florist may provide you with some