Heat Shrink Sleeving a Decoder

[RDS]

I would prefer the Hornby Decoders that I have fitted into my loco's, to be Heat Shrink Sleeved to avoid any possibility of shorting.

I have read that they should not be covered with insulation tape but that seems to imply that Heat Shrink Sleeving

 

is OK.

Any comments, anyone?

[Augustus Caesar]

Heat shrink sleaving is OK to use. The only caveat is that not too much heat be applied when shrinking. Apart from that there isn't an issue except if you need to remove it later for some obscure reason like rewiring or whatever. Once the sleeve is shrunk

 

you will know when to stop applying heat anyway.

 

Insulation tape may also be fine if used correctly. I have in the past put the original tubing over the decoder and then covered that with insulating tape just because I wanted the job done quickly and

 

had no means then of shrinking the tubing.

 

In no way do you want the sticky side of the insulating tape touching the chips as eventually the 'glue' turns very gooey and will be very messy and almost impossible to remove from the decoder. You could always

 

put two sides of the tape together (sticky sides that is) and then cover the decoder and hold it in place with a third strip of the same. As long as you check it all every couple of years you will be fine. Checking is simply to keep a rule over the goo seeping

 

through the edges of the tape over time. I have worked with this stuff for years and different makes have better glues which take longer to break down.

 

Just my humble opinion and I have no doubt others will say the same or different. As usual it is

 

down to personal choice but I always say your own judgement and common sense is a good rule to use and follow with sound advice added for good measure.

 

Hope this helps and doesn't cause too much of a debate... :-)

[Fishmanoz]

Trouble with covering decoders is overheating. Shrunk heatshrink is in intimate contact with the components in the decoder and heat transmission is pretty good, so it doesn't lead to overheating. I wouldn't be too sure about loose heatshrink especially

 

then covered with insulation tape.

[Flashbang]

Hi

No need to shrink down the tubing Hornby supply. If you must use tubing then simply place the decoder inside the tubing and place the whole lot securely inside the loco. The tubing being unshrunk will allow some air to circulate over the decoder.

A

 

lot of heat shrink tubbing is able to transmit heat, so allowing some cooling to take place even when shrunk down. Some manufacturers pre wrap their decoders in a special heat shrink tubing.

Avoid PVC tape. It doesn't pass heat easily and once warmed the

 

glue will form a nice sticky mess and the tape can also start to come undone!

[Graskie]

In the past I have fitted several Hornby DCC ready locos with, not only a chip, but then using the (rubber or plastic?) tube sleeves supplied. This tubing can sometimes prevent tidy insertion of the sleeved chip inside smaller locos, so for them I have

 

cut the sleeves down in width, securing their join with a bit of tape, but still leaving a bit of breathing space. Anyone else had to do this?

[2e0dtoeric]

If space is tight, before fitting the chip, put a smear of silicon bath sealant over the chassis below where the chip will go, making sure any bumps of solder are underneath, and not protruding, and let it cure. This is an electrical insulator, but will

 

not prevent heat radiation. If you change your mind, later, it will peel off again with a bit of a fiddle. It goes without saying that you don't get it into the chip socket!

[Fishmanoz]

Graskie, I've found there is enough heatshrink tubing supplied to cover 2 decoders, so I cut it in half and use for 2. Slide it over the decoder then shrink it using a hair dryer. When you've done that, it comes down to the same size as the decoder so

 

there is no space problem and no need to cut and join the tubing.

[Augustus Caesar]

I usually do what Graskie has done but do have a conscience when adding the so called sticky tape. I do become very careful when adding it in that I use very little. It simply to make the join where I have cut the original tubing to size or where I think

 

the decoder may slip out of the sleeving during operation.

 

I don't think enough heat is generated to do much harm to the decoder if it is covered with shrunken tubing anyway. You would have to be running your locos for hours and at over the top speeds.

 

While a loco is stationary it shouldn't be getting that much heat to the chip although it is in idling mode if you like.

 

Using bath sealant is a new one on me 2e0dtoeric! I have visions now of folk fitting their decoders and then trying to fix the chip

 

in a place so it doesn't move around much then having to slap a dollop of this sealant in place and the chip being stuck down or stood in it to help it 'stand'. OK... that's just me being stupid. But I see where you are coming from. Would I use it myself?

 

I dunno is the easy answer.

 

As Fish says cutting the tubing in half and then shrinking it gives decent coverage and obviously allow you to cover two chips with one piece of tubing. However, are you covering a 4 function chip this way Fish or the larger

 

22 type? I suspect the former as the tubing may not be big enough? I've got both types but have never measured that out.

[RDS]

I do not recall ever getting any heat shrink tubing with my decoders.

[Fishmanoz]

Mine came with DCC ready locos, and enough for 2.

 

All you have to make sure of is that the decoder board can't short on anything. If the decoder ends up mounted in a plastic smoke box for instance, there will be no need to cover it. Similar in

 

the 2-Bil where it ends up in the driver cab with very little metal around. I think I covered one bare joint with some liquid insulation goo and left the decoder bare.

[Graskie]

It doesn't come with individual decoders, RDS, but in the box with most Hornby DCC ready locos, from my experience.

 

Incidentally I must profess a certain degree of ignorance here. I didn't realise they were heat shrink sleeves and thus have never

 

thought of shrinking them. A hairdryer has been mentioned but would a blow lamp be any good?

[Fishmanoz]

Likely to singe your eyebrows Graskie.

[RDS]

@Graskie

If you have a decoder that has already blown and a heat shrink tube you no longer need, then try the blow lamp.

Otherwise, best stick to the Hair Dryer!

[pidder]

Just wonder, if the sleeves Hornby supply are heat shrink, why do Hornby not fit them and shrink them themselves?

[81F]

This will probably make every throw their hands up in horror but I have regularly used insulation tape around my decoders. My basis for doing this is from Step 10 from the Standard 0-4-0 Decoder Installation Guide which says "... It is important to protect

 

the decoder by wrapping the PCB with insulating tape..."

 

see https://www.hornby.com/hornby-dcc/decoder-installation-guides/standard-0-4-0-decoder-installation-guide/ on this site.

 

To date I don't think I have had any trouble except with one of

 

the early chips (the sort that could only be programmed up to 59). After a few years the loco just shot off, stopped and registered a short. On carrying out the "post-mortem"/fitting a new chip I found the tape had gone very hard and looked as if it had melted.

 

However, I do not know if this was as a result of overheating, a short or just a component malfunction.

 

I do however take care to only use one layer except for the minimum of overlaps. Alternatively I have insulated the area in which the chip sits using

 

the tape but this can be tricky if you have a confined space.

[81F]

This will probably make every throw their hands up in horror but I have regularly used insulation tape around my decoders. My basis for doing this is from Step 10 from the Standard 0-4-0 Decoder Installation Guide which says "... It is important to protect

 

the decoder by wrapping the PCB with insulating tape..."

 

see https://www.hornby.com/hornby-dcc/decoder-installation-guides/standard-0-4-0-decoder-installation-guide/ on this site.

 

To date I don't think I have had any trouble except with one of

 

the early chips (the sort that could only be programmed up to 59). After a few years the loco just shot off, stopped and registered a short. On carrying out the "post-mortem"/fitting a new chip I found the tape had gone very hard and looked as if it had melted.

 

However, I do not know if this was as a result of overheating, a short or just a component malfunction.

 

I do however take care to only use one layer except for the minimum of overlaps. Alternatively I have insulated the area in which the chip sits using

 

the tape but this can be tricky if you have a confined space.

[Graskie]

I wondered that as well, pidder. Can anyone confirm one way or the other? I just thought you had to leave a bit of space to allow for possible overheating of the decoder.

[Fishmanoz]

Consider I've done it 81F. And there are plenty of instructions around saying don't.

 

And yes, it would be good if Hornby covered their decoders like some other brands.

[Augustus Caesar]

Fishmanoz is correct... the decoders come on their own in the box and the tubing is supplied with ALL DCC ready locos. At least, it should be. Some boxes are pilfered in a Hornby stockist in our area and the tubing plus the fittings, and occasionally buffers,

 

are pinched.

 

So, check the insides of the box before purchase. Mail order items should not have been opened and therefore should contain the tubing at ALL times. If it is not there it is legally up to the seller to ensure it is there upon packaging

 

if the box is not already sealed by their supplier (Hornby themselves usually). So you could ask them to supply it free of charge and postal costs which they then claim back from Hornby if not originally included. The latter will be very rare.

 

I've

 

twice bought a loco from my local stockist to find tubing not supplied but they have given it from another box and they then contact their rep to have it supplied for that one now missing it.

 

I do believe some sellers have their own stocks of this tubing

 

for different decoders. Correct me if I am wrong someone...

[RDS]

Thank you for all your answers.

I guess it does confirm why I have never had a sleeve because I have bought either DCC fitted or I have modified older loco's myself, after buying just the decoder on its own.

If the sleeves are supplied with DCC ready

 

loco's I don't understand why they are not supplied when you buy a decoder separately though.

[Augustus Caesar]

The obvious thought would be to include the tubing with the decoder would it not? There will be an obvious reason for the decoder to not have the tubing supplied... but we would need to ask Hornby that one. Any volunteers? :-)

 

As for using a blow

 

torch to shrink the tubing, great idea... but would it not be better to fry the tubing? After all, it goes with the chip!!! ;-)

 

Wish I'd been there to see the loco whizz off with smoke pouring out from an overheating decoder... but apparently it 'fizzled'

 

out to a stop... my day job's safe folks!

[2e0dtoeric]

The well-known web auction site has heat-shrink tubing in all sizes and colours, for a pound or two, you can get an assorted bag, or individual lengths (usually 100cm) and just snip off how much you need for any particular job.

[Gener8]

I would prefer the Hornby Decoders that I have fitted into my loco's, to be Heat Shrink Sleeved to avoid any possibility of shorting.

I have read that they should not be covered with insulation tape but that seems to imply that Heat Shrink Sleeving

 

is OK.

Any comments, anyone?

Hi

Saw this review and had to reply, there are varying types of shrinkfit sleaving around, probably the best one possible is a "pvc layflat heat shrink sleave" where you can apply the heat from approx 8 inches away and immediately it shrinks away.

Hope it helps you guys

[RDS]

@Gener8

Welcome to the Forum.

Since I raised this thread over 2 years ago, I have been successfully Heatshrinking my Decoders (carefully) with a Hot Air Gun, normally used for Paint Stripping.  I do EMPHASISE the CAREFULLY though and only apply the heat for as short a time as possible!

I would not use the 'glue lined' Heatshrink though.

[96RAF]

I have been using standard Maplin heat shrink tubing on my decoders since year dot, although I only shrink the ends with a soldering iron shank enough to trap the decoder but still allow some air round the leccy bits.

No failures to date.