Joining flexitrack

[EnGee]

I am aware that solding track joints is not reccommended and I understand that metal needs to expand when it warms up so the track needs to move slightly. However what I don't understand is how can the track move when it is securely nailed to the base board and then stuck firmly to it with ballast glue.

 

If the track is fixed so it cannot move what difference does a few solder joints make!?

Is soldering joints as bad as it's made out to be, and if so, why is OK to screw the track down but not to solder the joints?

 

Does anybody know how much a yard of flexitrack would vary in length between say 5 and 35 degrees?

 

Thanks

EnGee

[jane1707819582]

Remember that the track sleepers are fixed but the rails can slide in the sleepers .so soldering the track joints together will prevent some expansion and contraction.

[Chrissaf]

And flexi-track in particular allows the rails to slide in the sleepers even more easily than fixed geometry track. If the rails didn't slide, then flexi-track wouldn't bend.

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Soldering joints is most definitely the worst thing you can do when laying track. It is not just about expansion and contraction. Soldered joints make it near impossible to undertake track replacements for maintenance or future track layout amendments and additions. Particularly on point work.

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Does anybody know how much a yard of flexi-track would vary in length between say 5 and 35 degrees?

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When I was laying my PECO flexi-track, say a radius 2 or 3 curve using a 1 yard track length. The inner rail would extend past the outer rail by up to 50mm or more.

[Howbi]

EnGee.............according to my calculations (?) if you laid a yard of track that had been cooled to 5°C, noted its length then waited till the ambient temp reached 35°C you would find the length had increased by about 0.3mm ( one third mm). But it is more likely that you would lay the track when the ambient temp was about 18°C so the likely expansion would be negligable, maybe 0.1mm. ..........HB

[walkingthedog]

Take my word for it, it bends. I had a length of flexi, on my old loft layout, between two firmly fixed points and on a very hot day it distorted more than a inch each side of the centreline. 

[new lad on block]

Hi,EnGee, The quick answer is,taking into account the varibles you quoted, i.e. the length you quoted, the temperature range you quoted, but taking the metal as cupro-nickle, is 36.0097 inches. increase of 0.0097 inches.

Not much, but some layouts are quite large, so if the the length was 36 metres not inches answer would be 36.0097 metres.

Now for the maths, most materials have a fixed coefficient of linear exspansion. This value varies from material to material.  Nickle-silver.The two main metals the track is made from are copper and nickle.The coefficient is 9.0. My answer is based on  9.0.

You must take into account what temperature you install your track, the temp. range you quoted was 5 to 35 C.

Metals shrink when they get cold, as well as expand when they get hot.So if you installed the track at 20 C. the size differenence would be half of that quoted.

I googled  'Linear thermal exspansion - online calculator' and got the answer.

 

[EnGee]

OK, so looks like soldering is out! Thanks for all your replies, I still find it hard to believe that about 10 thou per yard can cause so much damge - but quite happy to believe people who have had experience of this!

 

Unfortunately this still leaves me with my original problem. When laying the flexitrack I can get the two rails lined up perfectly with the adjoining track however as soon as the flexitrack is flexed one or other of the rails will slide out of the fishplate (or at least open up a big gap) making it impossible to lay the track with sensible gaps.

 

I am obviously doing something wrong so any hints and tips about laying/joining flexitrack would be welcome.

 

Thanks

[Howbi]

The inner rail will always protrude as it is a smaller radius than the outer rail so just get some Xuron cutters and cut off the surplus to level the end with the outer rail...........HB

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[morairamike]

If you are joining flexi to fixed then lay the flexi into the fishplate on the fixed and the fixed into fish plate on the flexi. Temporarily fix the sleepers down every so many sleepers. This will keep the track in the desired position Use  strips of gorilla tape or similar and tape the rail to the sleepers to keep the rails in place. Work your way along the flexi track adusting  the curve as required and fixing the sleepers down and the rail to the sleepers. When you reach the end of the section cut off the excess from the longest rail and join to the next rail. If flexible, again continue as above, if set track just join the two. When happy remove the gorilla tape from the rails. The track should stay as placed.  

[EnGee]

morairamike - Thank you so much for your detailed description, it sounds like the Gorilla tape was the key I was missing.

I will let you know how I get on!

[morairamike]

Don't press the gorilla tape down hard just enough to tack the two together or use a packaging tape, thin strips. Makes it easier to remove.

[LCDR]

Aligning the ends of flexible track requires some care, and as has already been said the ends should be cut 'square' once the desired curve has been achieved. There are aids to curving, these are called Tracksettas, but they only come in fixed radii which may not suit your needs.

 

 On my layout I worked along from one fixed point (Often a Point or Crossing) joining the next yard of flexible to the first  and securing the track with pins and cutting the excess rail with a Dremel using a cutting disc. I drill  sleepers in the centre about every 4 to 6 inches to take the pins. The rail joiners / fishplates are made to span the joint equally, or as close as possible. The first moulded chairs at each end of each length  is cut down flush to the top of the sleeper to maintain a realistic sleeper spacing without fouling the rail joiner.

 

The hardest bit is when the circuit is about to become completed, getting it all to fit. The Dremel cuts have to be made carefully so there is not too much, or not enough rail to make the join. I found that by making the final piece a fairly short one it allows a bit of adjustment by trial and error without wasting too much track. It can also be a bit of a fiddle where crossovers and junctions beween adjacent circuits and sidings are involved. I tend to place all the pointwork down first and match the plain line to it. 

 

The trickiest bit on my layout is where the track crosses a lift out section, and the track adjacent to the joints has to be soldered to copper clad gauge O sleepers.