Have you only tried soldering nickel silver so far? And have you de-greased the material? I wonder if you'd get the same result with brass.

What are you using for a return plate? Could it be conducting the heat away from the work too efficiently?

Paul.

I've only tried nickel silver so far and have cleaned the material with a scratch brush.

For a return plate I've got a terminal ring screwed to a 4mm thick gauge plate with a 5mm bolt. I thought that could be a problem so tried the trick with cooking foil as a thin metal layer that's not so good at heat conduction on top of something insulating (an offcut of hardboard in my case). I can burn the parts and the tinfoil. I could try some brass, but nickel silver is favoured in 2mm by most kits (including my own that I just got back from the etchers). I prefer soldering n/s with a normal iron.

Rich,

It might be worth cleaning the nickel silver with a sanding stick or a fine file - I sometimes find that the scratch brush isn't brutal enough when cleaning etches, especially if there is some sort of coating on the etch.

Other than that, I don't know what to suggest!

Andy

Hope you manage to solve your mystery soldering problems - unfortunately I don't have any RSU experience so don't have any suggestions for you.

I am intrigued to know what etches you are developing, as I will probably be interested in 2mm GWR NPCS if/when they are available - siphons?

David

Rich,

 

It might be worth cleaning the nickel silver with a sanding stick or a fine file - I sometimes find that the scratch brush isn't brutal enough when cleaning etches, especially if there is some sort of coating on the etch.

 

Other than that, I don't know what to suggest!

 

Andy

It seems strange. I thought that I had pretty good results when I tried your (dad's) RSU at Railex. What voltage is it set to out of interest? I don't know if that will be any help, but maybe, just maybe?

Hope you manage to solve your mystery soldering problems

Thanks

siphons?

You win one point* All will be revealed. The test build of one of the frets reveals quite a number of areas to fix before I could even consider them suitable for general consumption. I can get them together but there are a couple of very obvious thing wrong with them so I will have to go back and do them properly.

*points are not redeemable for anything, but maybe you feel better about yourself just for a short moment.

Thank you all for your input thus far. Main entry has been updated with additional information for those helpful people to peruse. Hopefully the answer is there somewhere...

Richard,

I only ever use my RSU with the tin foil and hardboard method. Using a thick metal plate I generally find useless. I only use Carrs solder paste, which works fine for me with no flux (it has it in already).

If you are burning the tin foil then you have it on too high a setting. Some solders, especially the cheaper ones, can be rendered useless by ioverheating them, which an RSU certainly has the capability to do.

Other than that, I can only say that a lot of techniques you have learned with a nomrla iron have to unlearned with an RSU. I know with mine I have to work hot and fast to get good joints, and remember to stop your soldering by taking off the power, not by moving the iron away.

Chris

Thanks Chris.

I tried no flux first because I was certain that solder paste is solder 'bits' suspended in some kind of carrier that contained flux. I have Eileen's own 188°C solder paste. The other solder I have tried is generic 60/40 with rosin core, which I use for almost everything usually.

I had success with the RSU Andy had with him at Railex in putting together some coach bogies, but that had already been set up. I usually work hot and fast with a normal iron too (to avoid singed flesh).

May be I need to turn the thing up further and spend less time on the pedal. Do you have a measurement or value for the setting that you use on your RSU? I have a high and low current setting on the input side to choose from (this was part of the original electrical set up) and then I have 1, 1.5, 2, 2.5, 3, 4.5 voltage outputs. I haven't measured the current because I don't have the equipment to measure AC current this high at home but there is a good chance that there is some kit at work that would do it because we have projection welding equipment.

Do you have a measurement or value for the setting that you use on your RSU? I have a high and low current setting on the input side to choose from (this was part of the original electrical set up) and then I have 1, 1.5, 2, 2.5, 3, 4.5 voltage outputs. I haven't measured the current because I don't have the equipment to measure AC current this high at home but there is a good chance that there is some kit at work that would do it because we have projection welding equipment.

My RSU is from the now defunct Dean Sidings- I think the owner's brother made them in his garage. It just has a three position switch with no indication of the voltage/current. I tend to use the highest setting, except on small parts which will be simply vapourised on that setting!

Avoid any temptation to apply more and more heat if it is not working. I find that one way or another that only leads to trouble.

Have you tried normal soldering with your paste to prove it is OK? I have no experience of Eileens, the Carrs costs an arm and a leg but it is well worth the money, and lasts for years in 2mm modelling.

Perhaps you should also start with some larger pieces of metal before working on smaller detailing parts. Loads of people tell me an RSU is only useful for small detailing work but it is not so. I use my RSU for all my etched kit assembly and getting admiring comments from people like Tim Schackleton about how neat the soldering is.

Chris

I have one of your toads built with 0.3mm n/s wire stirrups for the thin footboards put together with this paste and they ultimately won't stay together when handled, but they could just be too fragile. I also built a pair of MR coke hoppers with it and they've gone a bit grey and crusty around some of the joints since they've been sat (maybe 4 years or more?) I daren't attack them to see if they will actually stay together. I really want to get to a solution so I can build the rest of these MR kits and to make it easy to finish GWR/RCH style axleboxes, as there is nothing to locate the final layers.

As an indication and example how long are you typically on the pedal to form a laminated joint in one place between 2 pieces of .010" n/s.

I would say that you should only be on the pedal for a second or two at most. If you don't get the sizzle and the smoke from the flux in that time, then you need to adjust something.

The Carrs solder cream is fantastic stuff - a fellow NEAG member told me about it. I use the 179 type, which is about half the price of the 138 stuff. As Chris says, it lasts for years and doesn't dry out because it is sealed in the syringe (unlike the paste which I find dries out quickly).

The RSU I have used is one of the Swanage Model Company units. I'll try and find out the voltage/current info (if it exists) tonight.

Andy

As an indication and example how long are you typically on the pedal to form a laminated joint in one place between 2 pieces of .010" n/s.

Almost no time at all. As soon as it fizzes I take the power off. But of course it depends on the volume of metal being soldered how long it takes.

Like Andy, I also use the Carrs 179 paste - the idea of temperature-graded soldering is a bit of a joke with an RSU as it heats up so quick. If you can buy/borrow some of this, I think this may be the solution to your problems.

So I guess usually less than 1 second.

I'm always getting sizzle and smoke!

I've got my brother to pick up some 179 solder cream for me from Antics (it was highest on the google search results), because he works at the Coventry branch. I should see him in the next couple of weeks. In the meantime I might make myself an odd shaped bit and play with some multi-core on right angle joins, rather than laminated, to try and observe what is happening better.

So I guess usually less than 1 second. I'm always getting sizzle and smoke!I've got my brother to pick up some 179 solder cream for me from Antics (it was highest on the google search results), because he works at the Coventry branch. I should see him in the next couple of weeks. In the meantime I might make myself an odd shaped bit and play with some multi-core on right angle joins, rather than laminated, to try and observe what is happening better.

One thing you should not expect an RSU to do is to create those solder fillets used to reinforce the inside of joints. I have found them to be generally quite useless in that regard.

Rich,

The instructions for the Swanage Model Co RSU don't give values for the current/voltage for the different settings - it's just done on a simple numeric scale.

Have you had to add water to the pot of paste you were using? I had to do that with an old pot of solder paste and it affected the potency of the flux.

Andy

Thanks for checking Andy, and to you also Chris for all your help. I'm going to await solder cream.