Fast Tracks

Rob,

A light solder, barely (but completely) covering both metals, is actually stronger than one with a big glob. Copper pressure vessels will fail quickly with over soldered joints. Key is a good clean joints, properly fluxed, and thin solder joint. For our modeling purposes, this has a big aesthetic value as well. Heat both metals equally, when the tinning on the iron has 'whetted', apply your joint solder sparingly. Pre-tinning the PC tie also is usually enough solder when heat is applied to both parts equally and a good flux has been applied.

Using a wick braid should pick up the excess without debonding the good joint. True, too much heat application does allow the joint to brake away and re-solder, but use a cooler iron or temperature control to wick excess blobs. The iron is on the wick, just as the excess solder flows into the braid, pull it away. This does take some practice, but it's lot's easier with a temperature control. Just don't let the heat go all the way into the good joint parts.

-ed-

_________________
-ed mccamey-
COSLAR RR - http://www.coslar.us/
NMRA Standards and Conformance Department
PROTO & FINE Scale Coordinator
I estimate I have about 5 pounds of coupler springs somewhere in the vicinity of my workbench.

I realize this is turning into a soldering discussion, but...

Ed, do you care to elaborate a little more on how you pre-tin the PCB tie? I'm working in N scale and I've developed a technique where I flux the joint, then I touch the iron to the solder and get a little bit on the tip, then I go in and solder the joint. If everything works out well, the solder flows from the tip to the joint, once heated, and the joint is finished. I'm just wondering if your technique is any better/strong/faster?

Cheers, Brent

Brent,

I do HO (actually P87). I flux, heat, and tin a thin solder on the PC tie even before gluing or installing the PC tie. When I lay in the rail, it has a clean base. I place a thin small drop of liquid flux at the rail base and tinned PC tie. Heat, and it bonds very rapidly, leaves or has almost no solder - no excess - just right and nice strong joint. I will occassionly have to add just a bit of extra solder. Key is a fine thin solder tinning.

-ed-

_________________
-ed mccamey-
COSLAR RR - http://www.coslar.us/
NMRA Standards and Conformance Department
PROTO & FINE Scale Coordinator
I estimate I have about 5 pounds of coupler springs somewhere in the vicinity of my workbench.

So do you pre-tin the ties where the rails sit, or just to the side of them? My thought was, if you have a thin layer of solder on the tie where the rail sits, it would be impossible to get a uniform thickness of solder, and therefore wouldn't get the rail to sit at a consistent height.

Just my thought and I could have it all wrong.

_________________
Now waiting for a better currency exchange rate before I order.

When the heat is applied, the rail will (under some pressure) settle down on the PC tie just fine. I tin the PC tie along where the rail base sits. Seldom have to add any additional solder as long as I use the flux properly. Makes a nice clean solder joint without excess solder.

-ed-

_________________
-ed mccamey-
COSLAR RR - http://www.coslar.us/
NMRA Standards and Conformance Department
PROTO & FINE Scale Coordinator
I estimate I have about 5 pounds of coupler springs somewhere in the vicinity of my workbench.

I was actually thinking of using some sort of clamp to hold the rail and ties into the assembly to make sure everything was held in place properly. Your reply now means I will definitely be doing this. Just need to work out what type of clamp to use. Have you any thoughts on what brand would be easier to use?

With pre-tinning the ties, is the solder under the rail enough to form a solid mechanical connection, or is more solder needed on the sides of the rail to keep it in place?

_________________
Now waiting for a better currency exchange rate before I order.

I just use a weights along the rails when soldering. Most cases the tinning is enough solder, but I have the solder wire ready and can place some additional extra. It's all about some experience in making the joint. I've not found the solder joints to have to handle any real stress. My points are always hinged and I use a variety of switch machines - but always a slow motion type (some stall , others are screw driven). My stock rails are not subjected to hard shocks of solenoid throws.

-ed-

_________________
-ed mccamey-
COSLAR RR - http://www.coslar.us/
NMRA Standards and Conformance Department
PROTO & FINE Scale Coordinator
I estimate I have about 5 pounds of coupler springs somewhere in the vicinity of my workbench.

Thanks for the tip about the switch machines. I was thinking of using the Peco switches if they could be adapted, simply because I can get then very cheap here in Melbourne. But if they're not really suitable, then I will use slow motion switches instead.

_________________
Now waiting for a better currency exchange rate before I order.

With the slow motion switches, is there really much difference between stall and screw driven types? Also, is there much difference between brands? I'm more interested in long term reliable operation than anything.

_________________
Now waiting for a better currency exchange rate before I order.

Yes, the stall motor provides constant tension and has a very modest amperage draw in the stall position. Actually has more draw when moving and changing directions. Very reliable and at least with the Tortoise brand (most favored and excellent) there is also the extra sets of 2 each SPDT contacts. Linkage is a direct spring wire to the throwbar. I use the Tortoise unit.

Screw motor machines have electrical contacts that remove the power at the end of the throw. When in operation they draw more amperage than the stall motor type, but draw no current when stopped. They rely on an indirect linkage mechanical spring wire for the continuious tension. There are several makes, and some have extra signal contacts, others don't, and with some it's an option. These are reliable, but require an indirect linkage, and also are a bit less expensive. I use the Scale Shops unit, with the optional spare contacts.

-ed-

_________________
-ed mccamey-
COSLAR RR - http://www.coslar.us/
NMRA Standards and Conformance Department
PROTO & FINE Scale Coordinator
I estimate I have about 5 pounds of coupler springs somewhere in the vicinity of my workbench.

So apart from the current draw at stall and the extra cost, it seems that you would prefer the Tortoise brand over others then?

_________________
Now waiting for a better currency exchange rate before I order.

Yes. For me; the Tortoise are reliable, with some practice - easy to install, provide the extra contacts flexibility, and effective for all commercial as well as handlaid track. You will want to use a larger activation wire of 0.032" rather than the wimpy one provided. Using a 2 amp, 9 volt power supply, you get good switch activation timing and can handle several dozen (excess of 60 units) without problems.

-ed-

_________________
-ed mccamey-
COSLAR RR - http://www.coslar.us/
NMRA Standards and Conformance Department
PROTO & FINE Scale Coordinator
I estimate I have about 5 pounds of coupler springs somewhere in the vicinity of my workbench.

I've just started using my first FastTracks assembly fixture, and what I've found is handy for keeping the rail down in place is easily at hand... the point form fixture. Its a nice, flat, hefty chunkasteel. Just something to think about... Mind you, all I've done so far is a little soldering practice and build a single frog, so my experience is quite limited.

I have no doubt the point form fixture tool would work, but I would prefer something softer than the aluminium assembly jig, so there would be no chance of scratching or otherwise damaging it if it happened to be accidentally bumped by the family cat etc.

_________________
Now waiting for a better currency exchange rate before I order.