Protecting external turnout decoders

[Airbuspilot]

Hi

I am using ZIMO external (weather proof) decoders with LGB motors. The decoder is very small with thin wires attached, simply left free to the elements the wires would most probably break, it needs some sort of weather protection.



The decoder comes in a small plastic box which could presumably act as a top cover if glued to the motor housing but I am sure there has to be a better solution.

Suggestions welcome.

Robin

 

[Paul M]

Hi

I am using ZIMO external (weather proof) decoders with LGB motors. The decoder is very small with thin wires attached, simply left free to the elements the wires would most probably break, it needs some sort of weather protection.

View attachment 292699

The decoder comes in a small plastic box which could presumably act as a top cover if glued to the motor housing but I am sure there has to be a better solution.

Suggestions welcome.

Robin

Perhaps some heat shrink over the wires may help

 

[Greg Elmassian]

Actually, you don't want to trap water in the heat shrink if it was to go over all wires.

I'd think of potting it in something, and keeping the wires splayed so the potting material seals around each individual wire.

In the sun, the wires will probably at least fade, any way to have a small box affixed to the end of the turnout motor, pot the decoder in it, and minimize the exposure of the wires?

Greg

 

[Airbuspilot]

The idea to use shrink tubes on individual wires is good, I will give that idea a try. I think I can use the small box which comes with the decoder as protection, it will be a green house in the sun here so probably under the motor to keep it cool.

 

[phils2um]

I'd be tempted to attach heavier gauge wires near the decoder and include some sort of strain relief such as the suggested epoxy potting to toughen it up for use outdoors.

 

[Airbuspilot]

I’m not sure what you mean by epoxy potting? Two part epoxy glue is commonly available but is this some sort of paste / putty like material?

 

[phils2um]

Get a small container that will act as a mould for the decoder and whatever length of lead you want "potted". Partially fill with mixed epoxy. Put the decoder and lead length you want to protect in, then fill to cover with the remaining epoxy. You may need to hit it with a hair-blower/heat gun to help dislodge air bubbles. You can use standard two part epoxies but best results are achieved with a more runny mix like the polyester resin epoxy used for fiberglass. You should probably practice once on something else before committing your decoder. Should you not want the container as part of the final assembly line it with waxed paper or spray it with mould release if you have it. You might even try a cooking spray like PAM. There are special epoxies made specifically for this purpose but you need not go to that extreme.

 

[Airbuspilot]

OK, thanks for that I will give it a try

 

[JimmyB]

Get a small container that will act as a mould for the decoder and whatever length of lead you want "potted". Partially fill with mixed epoxy. Put the decoder and lead length you want to protect in, then fill to cover with the remaining epoxy. You may need to hit it with a hair-blower/heat gun to help dislodge air bubbles. You can use standard two part epoxies but best results are achieved with a more runny mix like the polyester resin epoxy used for fiberglass. You should probably practice once on something else before committing your decoder. Should you not want the container as part of the final assembly line it with waxed paper or spray it with mould release if you have it. You might even try a cooking spray like PAM. There are special epoxies made specifically for this purpose but you need not go to that extreme.

As mentioned in the "Resin Casting" thread, a good source (in the UK is:

Polyurethane Casting Resin - mbfg.co.uk

The best liquid plastic supplies from MB Fibreglass. We can deliver to any part of the UK

www.mbfg.co.uk

 

[Airbuspilot]

ThanksJimmy, I live in Cyprus and with new regs delivery from UK is painful. I should be able to find an equivalent here, if not Amazon Germany.
Robin

 

[PhilP]

Search for "conformal coating"..

A spray 'rubber-like' compound which will cover and seal electronic assemblies..
The beauty, is with a little effort, it can be cut/peeled off, if you need to get at things in the future..

If you pot something, the heat stays inside, and it is "for life"..

PhilP

 

[The Shed]

 

[Airbuspilot]

Available from Amazon Germany, thanks
Robin

 

[LGeoB]

I remember seeing my dad use wax to pot an audio amplifier in an Eddystone box. When he had to repair it, he put it on the stove to melt the wax to get the circuit out!

Geoff

 

[trammayo]

I remember seeing my dad use wax to pot an audio amplifier in an Eddystone box. When he had to repair it, he put it on the stove to melt the wax to get the circuit out!

Geoff

Had to google that!

 

[ACD134]

I have some similar sized decoders, (not Zimo) and they actually fit within the spare space of the point motor. They are outside all year in the UK and have been for 12 years without problems.

 

[Dan]

I cut off the terminals in the EPL unit and the Zimo 820D decoder (already waterproof) fits inside very nicely.

 

[Airbuspilot]

I took the motor apart and decided it wasn’t possible, there are two slots under but just too small.
I will take it apart again and look at your idea which would be a perfect solution.
thanks
Robin

 

[Airbuspilot]

You are correct, it fits perfectly.
Do you have a clever solution for soldering the motor wires to the decoder wires? Presumably the small pins under the connectors have to come out with the block.
Robin

 

[Gizzy]

You are correct, it fits perfectly.
Do you have a clever solution for soldering the motor wires to the decoder wires? Presumably the small pins under the connectors have to come out with the block.
Robin

You can de-solder the terminal block and use the holes and 'lands' (as the tinned copper etch is known). Solder your wires directly.

Although I've not tried this with a decoder, I have removed rusted up terminal blocks from LGB motors and hard wired a suitable lead in place.

I've then filled the any external holes with Dow Corning black mastic which I get from work which helps with weather proofing.

The idea of using a small decoder such as the Zimo in the space vacated by the terminal block is inspired....