Scalefour Forum

Moving to passenger stock, a job I have dreaded is fitting drop lights. How does one go about this without covering everything in solder yet still getting the things equal, especially side to side?

Because I wanted to keep the front as clean as possible, I naturally thought of soldering from the back. This has it's problems, not least getting the droplight in the right place. After some hit and miss (mostly 'miss') attempts and then scribing lines on the back of the side, I thought there had to be a better way, so I stopped and talked it over with a few people at the South Hants show in Portsmouth yesterday.

The main conclusion was that I would have to solder from the front. How does one do this cleanly?

This is what I have come up with. I would appreciate thoughts from you out there.

1. I cleaned the back of the side with one of those very useful abrasive foam sticks - such useful tools - and applied a small (and I do mean 'small') dab of solder at each corner of the aperture. Too much solder will flood the front of the droplight and make an unsightly fillet. In the photograph, the aperture is 6.5 x 9.5mm. The dabs sometimes had points so I lightly filed them flat.


2. I laid a droplight on to a piece of thin MDF, a second piece is there to support the coach side. The drop lights for this kit have a shelf at the bottom on which to rest the glazing which is why they are on the side of the block. There is nothing special about the blocks - I just had them handy.


3. I laid the side, face up, over the droplight and held it down using two blocks of moulding rubber. This material is a very poor conductor of heat which makes it very useful in protecting fingers from hot soldering irons. I put a small drop of flux (I use phosphoric acid) in each corner and used an RSU to do the soldering. If you leave the current on a bit longer you might see the solder, if it comes through to the front, flash along the join and recede into it. If you take the current off too soon, you get a noticeable fillet which I would feel necessary to take off.


4. From the back, you can see the 4 points of solder at the corners. The droplight is firmly held and you need no more solder.


5. On the front, you can see what I hope you will agree is a neat(ish) job. You can also see where the RSU was applied but this rubs off. In this case I used a fibre brush which I know some people dislike.


6. Finally, after cleaning and a scrub with Cillit Bang (I have run out of Shiny Sinks).

David.....looks nice and tidy. I hate the fibre brushes and have stopped using them....the fibres always followed me and Jen to bed!!!! Never admitted to her what was the cause of the irritation......
Rob

Very tidy, David. I will try this next I have the job to do. I too don't like fibreglass brushes, so have stopped using them in favour of a Garriflex block in almost all cases. Lots of the block turns to dust but it is much nicer than fibreglass splinters.

Philip

Little bits of bluetack on the front, in the middle of the sides. Tack solder on the back, top and bottom. Check the front view. Remove bluetack. Can then seam up on the back if you want, but really, there's not much point because there's no need for a strong joint.

I have tried using bluetack, not in this context though, and found that if it gets hot it sticks like **** and more difficult to remove. Perhaps I have got it too hot and need to be quicker with the iron.

I cannot disagree with people about the fibreglass brushes though I find a good wash (of the kit) gets rid of the bits. I have not used the Garriflex blocks (note: get one at Warley this weekend); those foam sanding sticks are my favourite. I shall stock up with them again at Warley from ModellingToolsUK

Garriflex blocks come in different grades and are a large version of a track cleaning block, such as the ones the EMGS and Double 0 gauge Association sell. One of their useful attributes is that they can be sliced up into various shapes to clean out corners etc.

Philip

David,

very neat work and looks good in the unpainted state.

The difficulty will be keeping that separate look when you paint them. Might a better solution be to paint and add the droplights later using a small blob of non runny adhesive in each corner. The Hypo Cement sold by Wizard, Hobby Holidays and others would suit.

Jol

Jol Wilkinson wrote:David,

very neat work and looks good in the unpainted state.

The difficulty will be keeping that separate look when you paint them. Might a better solution be to paint and add the droplights later using a small blob of non runny adhesive in each corner. The Hypo Cement sold by Wizard, Hobby Holidays and others would suit.

Agree that looks neatly done. I use marking tape applied to the front to hold the drop light in the right place and tack one corner. Remove tape check position and then tack the other corners and run the full length of the sides if you wish. Any solder that forms a miniscus on the visible side is easy enough to scrape out. I'm happy with the glass fiber brush to polish up the result, but then I wash my hands before retiring to bed. No complaints from the wife so far.

If you do glue them in as David suggests, you need to be able to get in side the body later, when somebody has picked the coach up by the sides and pushed one in. I always have removable roofs anyway even after soldering them in. To keep the separation between droplight and coach side, (drop lights are often modeled not quite deeply enough recessed) a strip of shim brass along the edge of the droplight does the trick.

RobM wrote:David.....looks nice and tidy. I hate the fibre brushes and have stopped using them....the fibres always followed me and Jen to bed!!!! Never admitted to her what was the cause of the irritation......
Rob

That's one of the funniest posts I've read for ages!

One thing I hate is repositioning after tack-soldering, although sometimes there's little alternative (and with glue if you get it wrong it's more difficult to adjust).

I haven't tried this, but how about scribing a line on the inside up to which you can position the light, then solder?

How about making up a a square jig, like a small, flat engineer's square? Clamp it to the inside of the side, push the drop-light into the angle, check positioning and adjust the jig as necessary. Then solder from the back along the two exposed sides of the drop-light.

I tried the scribing method but hit a snag when I found that the drop lights were not all exactly the same size! The sides varied in width, granted by hundredths of a millimetre, but with so little to play with side to side, if the droplight is a tad out it shows. It has to look right, square with equal widths down each side, which I concluded could only be done by eye from the front.

Back to the 'quick tack but don't melt the bluetack', David?

David B wrote:I tried the scribing method but hit a snag when I found that the drop lights were not all exactly the same size!

That's what you get with antediluvian kits. Another reason why maturing cabinets are a BAD THING(™). I also notices that this carriage has no provision for door hinges, which if done well give a location for one side of the drop lights.