Solder masking

[N10]

I'm finding that I spend too much time cleaning off the tinning and solder from my project brass models. I have tried Plumbers black and correction fluid but had little success, has anyone any suggestions what I could try. The large easy access areas are fine to clean, but on some of the difficult to access areas it's a bit of a pain.

Thanks

[Bucoops]

Do you have a Resistance Soldering Unit (RSU)? They're a bit pricey but the amount of solder you use is tiny so cleaning up is much reduced.

[Bucoops]

These panels were all soldered in using my RSU and there's be no cleaning up afterwards (the marks you can see are where I cleaned the brass before applying the solder cream).

 

[brossard]

You might get neater solder joints if you cut tiny amounts off the roll, pick them up with iron and apply them.  I've been doing that for years and find it pretty effective.  There'll still be clean up needed but there should be less.

 

John

[N10]

14 hours ago, Bucoops said:

Do you have a Resistance Soldering Unit (RSU)? They're a bit pricey but the amount of solder you use is tiny so cleaning up is much reduced.

Hi I use a temperature controlled set, which works fine, but it's those difficult to access areas I fine a pain.

[Torper]

I use Carrs Green Lable flux for most jobs together with a 70 watt iron - I don't know what sort of iron you have but hopefully it won't be less than 40 watts.  Ideally, you don't put the solder on the iron and then convey the loaded iron to the work, although sometimes you have to do that.  Much better is to use a small paint brush to apply some liquid flux to the area to be soldered, then snip off a small bit of solder wire (almost certainly smaller than you think you'll need) and using tweezers place that onto the area you want to solder.  Then apply a hot iron to the work.  Aided by the flux, the solder should almost at once flow into the joint and you can then remove the iron.  If it doesn't, then you may have insufficient flux, or your iron may not be hot enough or it may have lost some of its heat when applied to the work, which is why you need a reasonably powerful iron.  You'll be surprised by how far just a very small bit of solder wire will go - use too much and you'll be left with excess to clean off.  With this method you won't really use much more solder than you would with an RSU.

 

I do have an RSU which I use for certain tasks for which it is excellent, but it is really a back-up and not a substitution for a conventional iron.

 

DT

[N10]

6 hours ago, Torper said:

I use Carrs Green Lable flux for most jobs together with a 70 watt iron - I don't know what sort of iron you have but hopefully it won't be less than 40 watts.  Ideally, you don't put the solder on the iron and then convey the loaded iron to the work, although sometimes you have to do that.  Much better is to use a small paint brush to apply some liquid flux to the area to be soldered, then snip off a small bit of solder wire (almost certainly smaller than you think you'll need) and using tweezers place that onto the area you want to solder.  Then apply a hot iron to the work.  Aided by the flux, the solder should almost at once flow into the joint and you can then remove the iron.  If it doesn't, then you may have insufficient flux, or your iron may not be hot enough or it may have lost some of its heat when applied to the work, which is why you need a reasonably powerful iron.  You'll be surprised by how far just a very small bit of solder wire will go - use too much and you'll be left with excess to clean off.  With this method you won't really use much more solder than you would with an RSU.

 

I do have an RSU which I use for certain tasks for which it is excellent, but it is really a back-up and not a substitution for a conventional iron.

 

DT

Thanks for the tips, will try them on my next project. Regards

[adriank]

If you are concerned about stopping the spread of solder, I find Vaseline very effective. I use brass wire droppers soldered to the switch blades as a means of operating my points. The top of the dropper extends under the stock rail to stop the blade rising and there is a high risk of soldering the whole lot solid. I put a tiny amount of DCC Concepts Sapphire flux paste where I want the solder to be and a smear of Vaseline where I don't. The Vaseline can go right up to the flux paste. Unlike liquid flux, the paste tends to stay where put. When a small amount of solder on the tip of a hot iron is applied, neither paste nor solder encroach on the Vaseline-covered area. The Sapphire flux is excellent but corrosive and the joint needs to be washed - easily done with a cotton tip soaked in water.

 

Adrian

[Jol Wilkinson]

From some years of experience I have found that a liquid flux brushed into the joint and a good free flow solder, with a 50W AntexTCU works well. Having plenty of heat at the right temperature ensures that the solder flows into the joint, so you have only to use just enough. I use London Road Models 145 solder and "Phosflux".

 

For any excess of solder, I have several special scrapers made  by the late John Hayes from old hacksaw blades - they are the blue ones  in the photo. They are great for removing excess solder  from right angle joints.

 

[heavymetalwagons]

just been reading the 2mm association book about track making and they use "solder balls"(insert own joke) they range from 0.2mm to 0.65mm and seem useful (just ordered some)

can see a problem with them pinging off into the carpet !! may have squeese them with pliers so they don't roll around and are better for picking up with tweezers .

as mentioned above if you can flux the parts first, place the solder then use the iron 

Or even if you have one or two balls on the work bench and then pick them up with the iron and apply to the job at least there's not massive amount to clean off

I have made wagon door bangers (1mm wide x 4mm long) with 0.3 wire as bolts !! there real fun to make !

 the best bit is trying to hold everything and still have a hand free for the iron !!

the amount of posts about soldering issues ,I would have thought some one would have done a "dummies" guide to soldering on here, instead of issues/fixes all in separate posts (would be reading it my self as still learning) 

[Steven B]

How are you applying the solder?

 

By cutting wire solder into short lengths I find that there's not much to clean up when combined with flux and plenty of heat.

 

If you do want to try masking, then get some kapton tape. It's heat proof and solder won't stick to it.

 

Steven B.

[N10]

I have no problem soldering , I may say I am quite good at it even soldering small white metal parts. I can always get a good strong bond between the parts. All I want to do is to stop the tinning running into those difficult to get corners. 

[Jol Wilkinson]

14 hours ago, N10 said:

I have no problem soldering , I may say I am quite good at it even soldering small white metal parts. I can always get a good strong bond between the parts. All I want to do is to stop the tinning running into those difficult to get corners. 

 

The recommendations about using a small amount of solder could be the answer. It has been suggested that you can use solder pellets or cut off small pieces of solder "wire". If you can pre-tin the edges of the part(s) you are assembling, that may help with applying a smaller amount of solder.

 

Perhaps using solder paint, cream or paste may be better. Eileens Emporium do a 188 deg. solder paste/paint. Phoenix Precision list the Carrs 138 deg. solder cream but at a horrendous price.

[N10]

On 01/12/2021 at 11:05, Jol Wilkinson said:

 

The recommendations about using a small amount of solder could be the answer. It has been suggested that you can use solder pellets or cut off small pieces of solder "wire". If you can pre-tin the edges of the part(s) you are assembling, that may help with applying a smaller amount of solder.

 

Perhaps using solder paint, cream or paste may be better. Eileens Emporium do a 188 deg. solder paste/paint. Phoenix Precision list the Carrs 138 deg. solder cream but at a horrendous price.

I always tin the brass/ white metal, it's the spread of tinning can be an issue in the confined spaces. As a plumbing apprentice in the 1960s I had to wipe lead joints on lead pipes and lead covered electrical cables, we used plumber's black but its a bit to course for model building.

[Barclay]

I haven't tried it but I'm sure I read somewhere that a soft pencil (B grade) rubbed onto the area in question will prevent solder spreading. 

[KingEdwardII]

On 01/12/2021 at 11:05, Jol Wilkinson said:

using solder paint, cream or paste may be better

Yes, I use the solder paste - you literally paint it on to the locations you want to tin and/or solder. It has flux included, so you don't need anything else. 

 

Yours, Mike.