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Copydex, How Much Dare You Dilute?


Ray Von
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50/50 is just about right as long as it's a fairly new bottle. I opened a year-old bottle a couple of months ago and it was thicker than I expected and had gained a brownish tinge. It worked fine as a ballast glue, however, but seemed to need a bit more like 60/40 water/glue.

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10 minutes ago, Mick Bonwick said:

50/50 is just about right as long as it's a fairly new bottle. I opened a year-old bottle a couple of months ago and it was thicker than I expected and had gained a brownish tinge. It worked fine as a ballast glue, however, but seemed to need a bit more like 60/40 water/glue.

Brand new and hopefully used this week, mixed with play sand....

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I can't comment on the dilution, but  possibly certain types of carpet adhesive is a suitable and cheaper alternative, if you run out of copydex. See  

at various points on this linked page. (can certainly remember my dad sticking down carpet tiles with a glue that smelt similar to, but much stronger than, copydex) 

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I've just finished ballasting a big section of my layout using tinted sand fixed down with Copydex. I've been using a mix that's about one part Copydex to three parts water with a good dollop of Fairy liquid added and all seems to be firmly stuck down. I've used 4mm thick, black yoga matt material between the mdf  base and the track. I mist the track with a screenwash/water mix from a perfume atomiser then apply the dilute  glue with a pipette. The Fairy liquid is essential to get the mix to flow easily.

 

1166225050_vib4.jpg.616438efea4d6c99627d0f04b73be542.jpg

 

Here's the early stages showing my test section in the middle and work in progress at either end.

 

 

 

 

 

 

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38 minutes ago, nickwood said:

What are the pros and cons of using Copydex over the more usual (and probably cheaper) diluted PVA mix?

 It's my first time using Copydex, I've always used PVA before - just wanted to check out it's apparent sound muffling qualities.... Keep you posted.

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1 hour ago, nickwood said:

What are the pros and cons of using Copydex over the more usual (and probably cheaper) diluted PVA mix?

 

When it sets it has a rubbery texture to it, supposedly better sound muffling as  Ray Von above mentioned.

If you need to uplift any track it's fairly easy to do without damage when it has been fixed with Copydex. PVA sets like concrete.

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'The Works' sell a cheaper alternative. 'Hobbycraft' used to (it's where I bought mine), but I can't find it on their website. (usual disclaimer).

 

https://www.theworks.co.uk/search?q=fabric+adhesive&search-button=&lang=en_GB

 

I dilute until it runs freely and will flow into the ballast by capillary action. Besides noise reduction, a slightly flexible track base helps road holding and current pickup.

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16 hours ago, nickwood said:

What are the pros and cons of using Copydex over the more usual (and probably cheaper) diluted PVA mix?

Dependent on your sensitivity to the curious pong, you may need more ventilation and shorter working sessions to tolerate it.

 

The reduced transmission of track vibrations to the supporting substrate is noticeable, especially if a compliant material such as the yoga mat mentioned above is used, as it won't make this rigid as dilute PVA can easily do. Materials choices and combinations, and the matter of making the track base area as small as possible are all significant factors to be considered in reducing coupling of track vibration to the supporting substrate.  Basically we want inefficiency in this process for which 'rubbery' is useful.

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17 hours ago, nickwood said:

What are the pros and cons of using Copydex over the more usual (and probably cheaper) diluted PVA mix?

 

Biggest con is the smell.

Biggest pro is the ease with which you can correct errors.

 

If I was you I'd stick with PVA.

But I'm not!

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It's very important when adding adhesive to ballast to counteract the surface tension of the liquid. If you don't do this then adding a drop will unavoidably drag the surrounding ballast into a ball. I did this belt-and-braces style by first applying a fairly heavy mist of 50/50 water and isopropyl alcohol from a little spray bottle off ebay ( about £1 each), then adding 70/30 water/copydex from a dropper from very close up, a drop at a time. Sometimes it still would mysteriously want to ball so I dropped onto the edge or a sleeper and let capillary action suck it in. An occasional ball should not be tampered with immediately as you'll only make things worse, but when it's gone off a bit and before it sets you can poke it back, and a torch shone across will reveal any highs and lows which you will be able to press into shape. Any mess on the sleepers is easily rubbed off the next day. I don't think the proportions are critical as long as it's "watery". The next day I would run my finger over it and if any patches were not well stuck then another drop of glue fixed it.

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5 hours ago, Mick Bonwick said:

 

Biggest con is the smell.

Biggest pro is the ease with which you can correct errors.

 

If I was you I'd stick with PVA.

But I'm not!

 

Thanks for the replies, all very informative.

I'm naturally suspicious of alternatives to tried and trusted methods. I once  ballasted some track with Johnson's Klear to see how that performed after hearing it's virtues extolled on RMWeb and it was a disaster, the stuff just would not set. You could remove the ballast with a slight touch of the finger.

Because my layout is portable I need things that are glued down to stay stuck, no matter how many knocks they get. I will stick to ballasting with diluted PVA as I've never experienced a problem with it.

 

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I use Copydex in tubes, rather than the plastic bottles.  The brushes built into the lids of the plastic bottles never reach the bottom of the bottles, so there is a lot of wastage, and as the level drops the increasing amount of air that replaces it makes the remaining glue go manky, as mentioned by Mick Bonwick above.  The tubes make it much easier to control how much you use and there is little wastage and no contamination by air.

The downside is that while most supermarkets, Wilko's etc all seem to sell the bottles of Copydex, the tubes seem to only be available on line, so if you run out at a crucial point it takes more than simply nipping down the shops to get yourself up and running again.

And as for Copydex v PVA.  No contest!  Copydex every time!

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18 minutes ago, mike morley said:

I use Copydex in tubes, rather than the plastic bottles.  The brushes built into the lids of the plastic bottles never reach the bottom of the bottles, so there is a lot of wastage, and as the level drops the increasing amount of air that replaces it makes the remaining glue go manky, as mentioned by Mick Bonwick above.  The tubes make it much easier to control how much you use and there is little wastage and no contamination by air.

The downside is that while most supermarkets, Wilko's etc all seem to sell the bottles of Copydex, the tubes seem to only be available on line, so if you run out at a crucial point it takes more than simply nipping down the shops to get yourself up and running again.

And as for Copydex v PVA.  No contest!  Copydex every time!

They had 

tubes of it in Hobbycraft yesterday. 

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Question, if I may.

Should it be necessary in the future to lift track which has been ballasted using a Copydex solution, will simply spraying with warm water do the job as in PVA ballasted track? If not, which removal process would be recommended?

 

 

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Although the track is stuck down and won't fall off if you upturn the boards, it can be removed without any soaking with anything. It has a lot of grip, does Copydex, but exerting pressure can unstick it. I have used a steel rule pushed under the sleepers and twisted slightly to remove track and points, when making mistakes on my layout, without damage. It's almost as if I knew I'd get it wrong somehere.

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Yes indeed.  A very annoying, silly problem,  I bought a 500ml of Copydex and soon found out that the brush didn't reach the liquid without tilting the bottle, which is really awkward to do if you are tack laying and haven't got three hands.  I bought a smaller 125ml bottle - the brush is the same size as in the 500ml bottle- but now nearly reaches the bottom of the bottle.  I've been topping up the small bottle from the larger one.  Otherwise, Copydex is great - sticks well and mistakes can easily be remedied with a sharp knife or my wife's kitchen stainless steel spatula.

Peterfgf

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On 23/09/2020 at 11:18, 34theletterbetweenB&D said:

Dependent on your sensitivity to the curious pong, you may need more ventilation and shorter working sessions to tolerate it.

 

The reduced transmission of track vibrations to the supporting substrate is noticeable, especially if a compliant material such as the yoga mat mentioned above is used, as it won't make this rigid as dilute PVA can easily do. Materials choices and combinations, and the matter of making the track base area as small as possible are all significant factors to be considered in reducing coupling of track vibration to the supporting substrate.  Basically we want inefficiency in this process for which 'rubbery' is useful.

I found some 3mm thick EPDM adhesive-backed foam which does the job very well at Rubberstock.com.  Good stuff and good service at:

https://www.rubberstock.com/cellular-rubber/epdm-cellular-rubber-sheets/foam-rubber-epdm-grey-with-adhesive-3mm-width-100cm_13560.html?channable=003dde69640032383131303030332d477265792d53495a455f504c414345484f4c44455283&sqr=Foam rubber EPDM grey with adhesive 3mm (width 100cm)&

Peterfgf

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On 23/09/2020 at 11:43, Mick Bonwick said:

 

Biggest con is the smell.

Biggest pro is the ease with which you can correct errors.

 

If I was you I'd stick with PVA.

But I'm not!

 

It has some other advantages over PVA too:

It can be cut with a sharp knife. This makes board joins a lot less visible than with PVA, which chips away.

Any excess can be peeled away which, as mentioned above, is good for correcting errors.

It dries with a very slight brown hue. (Brake dust is brown). PVA gives some types of ballast a rather strange looking green hue. This is fine if you want to weather it heavily, but not very helpful for lightly weathered areas.

If the board takes a knock, its flexibility allows it to hold together. Ballast fixed with PVA flakes away.

It dries faster than PVA.

 

It does have disadvantages from PVA though:

It is more expensive.

If you need to drill a small hole for something, it can wrap around the drill bit.

 

I would always recommend trying any new method on a small test piece before potentially ruining a layout.

 

Having used it, the only reasons I think that people still use PVA for ballast is because it is cheap & more widely available. Its resin properties make it dreadful for this purpose.

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copydex does degrade faster in a. lot of conditions some model railways are subject to (strong light and or heat) you might want to read this thread before deciding on the mass use of copydex

 

I can confirm some of the findings a 12" to the foot locomotive bulkheads use copydex to hold banding in place over the gaps of the insulation, and it doesn't last too long in direct sun. or around the heaters.

 

 

 

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