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I wonder if you could just spread some solder paste (stuff used for assembling PC boards with SMD devices) on the joint areas, carefully place all the hoods on the target (which sill be placed on some sort of ceramic or glass panel, the stick it in the oven to solder them all at once.
My only concern with the solder paste is if too much is applied, its definitely going to get everywhere on the face or make the board not seat properly. I used a precise air operated nozzle to dispense and reflow boards at work but I feel like most modelers wouldn't have such tools available to them. We'll see how it goes once the first samples are in, it wouldn't be too bad to glue the hoods as well.
I'm really worried that an average modeler will have a very difficult and frustrating experience trying to not only bend the hoods to a specific curvature but then glue or solder those fairly precisely to the signal head. I not everybody is really adept in precise miniature assembly.I also think that if solder paste in the oven doesn't work, soldering one at a time is a recipe for disaster. Even using minuscule amounts of epoxy or CA glue might also result in real sloppy assembly. Then, as far as the glue goes, how robust will those glue joints will be for those times operators, or someone cleaning the track accidentally bump the signal?Lost-wax brass casting for the signal head with integrated hoods would be the best solution. 3-D printed head would also work (as it has been shown recently), but it will be a bit out-of-scale (too thick). Speaking of thickness, the PC board also looks a bit thick.Not trying to rain on your parade - just pointing things that migth not be optimal
On my scratch-built D-Type Darth Vader signal heads, the easy way to solder the hoods to the signal target is to lightly tin the inside of the back edge of the hood before it's bent to shape, which usually also tins the back edge. Use a 2B pencil to draw a line about 1/32" from the back edge, flux and tin. The solder won't cross the pencil line and Supersafe #30 flux gel applied with a micro-brush allows the solder to flow freely and evenly in that small 1/32" space between the pencil line and the back edge of the hood.I now use my 200W American Beauty resistance soldering station to put mine together to both hold and heat my parts, but I still tin with an iron. If I were to design and etch a fret of D-type signal head parts, I would have three locator holes etched in the target, and three pins on the back edge of the hood that will register through the locator holes. These pins would not be tinned and a couple of smooth hemostats clamped on the back would keep the hood tight against the front of the target while flux and solder are applied with a hot, clean iron.Upon further thought, these pins could also be engineered to be locators for the PCB I assume is being designed for the LED's, and when bent after inserting through matching holes in the PCB...would hold the PCB firmly in place and possibly act as both locators and standoffs for any detailing metal parts that might be applied to the backside of the PCB.These locator pins would also allow the clean use of CA to assemble the target/PCB/light housing, so the "average" modeler wouldn't have to bother with the highly technical aspects of slobbering...soldering. I also have some ideas how to make better ladders rather than the typical etched POS ladders, and maybe both simplified (typical/POS) ladders could be used for the "average" modeler, and ladders that must be assembled (sides & rungs) for the more detail-oriented modeler could be included on the same fret.I use hard stainless hypodermic tubing for the masts on D-Type Darth Vader signal heads which aren't mounted on cantilever signal bridges. These are the correct diameter for signal masts on the UP that I measured with a coat of paint (.036" or 5.75 N-scale inches) and because the tubing walls are much thinner than brass tubing, the hole is the same size (maybe even a bit larger) than those in much larger outer-diameter brass tubing. Soldering SS is not a problem using the proper flux (Superior Supersafe gel #78) and 96/4 Tin/Silver solder. The thin walls of everything getting soldered together (platforms, ladders, targets, etc.) will make soldering brass or NS to SS a cinch.Bending the hoods is easy...just bend them around a proper sized drill bit and adjust their angle and squareness by applying a bit of pressure with your fingers. Test fit, and adjust...simple...even for an "average modeler".Truthfully, even without any locator holes, I find assembling and soldering the hoods to the target to be one of the least problematic tasks when building N-scale signal heads out of .003" brass. The odd-sized attachment/adjuster fixture under the light housing on the back is the hard partCheerio!Bob Gilmore
Those are all great examples and useful tips, but Bob, you keep forgetting one very important thing: There are probably less than one in 10,000 of your caliber modelers out there You are s far ahead of "average modeler" that even what you are imagining to be an average modeler would be way above average. And I'm not just stating this to butter you up - it is the honest to goodness truth!To me, if someone is hoping to produce a viable product in a kit form which sells in large quantities (large by the N-scale consumer world standard), it really needs to be easy to assemble.I also still prefer using thin-wall brass tubing. No special flux, no special solder. No matter how you look at it, soldering brass will always be easier than soldering stainless steel.
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Topic: CPL Signal Project (Read 5275 times)
