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Plastic chairs and MEK. Very poor bond.


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All the chairs on these are glued using Butanone.

P1010010.JPG.f00622488bb5095980b48eab181ba9ae.JPG

When I first started using this method, I had my doubts and experimented by glueing some chairs on spare ply strip, threading a rail through and then trying to break the joint.

 

The jaws of the chairs broke before the joint between the sleeper and the chair.

 

I really can't understand it when a technique works perfectly well for some people but not for others.

 

I use a few rivetted sleepers for strength at baseboard joints and then add cosmetic half chairs.

 

I glue the sleepers down, paint them (Precision Sleeper Grime in this case) and then glue the chairs on with a good brushful of Butanone to allow it to "flash" around and into the join.

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38 minutes ago, t-b-g said:

I really can't understand it when a technique works perfectly well for some people but not for others.

 

Sometimes it's because you are describing something you did 10 years ago, or using parts you have had in stock for years. You can't assume that similar products obtained fresh now will be the same.

 

For example, it's well-known that some currently available bullhead rail no longer fits Exactoscale chairs properly, causing the base to bend significantly:

 

bent_chair.jpg.4744976247c5851b5fa09ef4b8ce6d77.jpg

Sorry about poor image quality, copied from Scalefour web site.

 

If the chair base is not flat, with pure solvent you will be gluing only along the outer ends, and it will come away very easily. It needs a cement-type adhesive with some gap-filling ability, such as the Polypipe stuff.

 

A possible solution, after threading the chairs onto the rail, is to run a soldering iron along the rail to soften the chair, and press the rail and chair down onto a flat surface as it cools. It's tricky to get the temperature just right to avoid damaging the chair or pushing the rail through the chair base.

 

cheers,

 

Martin.

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MEK and Butanone are exactly the same chemical, but with a different name. Let's get that straight. CH₃CCH₂CH₃.

I have a fat bottle of MEK here. Its Butanone. 

Manufacturers however may have slightly different formulations. Just like petrol isn't just petrol. It can vary a great deal. That's why I asked for someone who had apparently found a winning formula. 

 

So, I have a bottle of MEK here that bonds plastic chairs to ply sleepers very poorly.

You can push it side to side, and it won't budge. You can thread some rail through it, and pull the rail upwards, and it won't budge. But....twist it or put your fingernail at the side and lift? Pop, it's off. No good. 

So. Can anyone suggest a chemical that bonds exactoscale chairs to EM gauge society ply sleepers such that I cant just flick them off with a fingernail? 

This is why I said it's the 'Emperors new clothes.' there may be people out there who have track that seems fixed, but it isnt, and nobody dare check.. because when they find its ready to fall to bits, they'd have a load of work up in smoke. I want track that is rigid and durable, for many years. 

This stuff isnt cheap, but the way I see it at the moment, plastic to wood bonding the way we want it for our hobby, is deeply flawed, and nobody is calling it out. The only good bond is superglue. And that can be brittle.

There isnt a good proven 'system' of plastic chairs and wood sleepers out there at the moment.

I would be tempted to give up and go back to using 2.5mm rivets and solder, but guess what? the EMGS doesn't have those rivets in stock! And they haven't had them in stock for ages (Amongst other things). The dreaded 'Read More' button....

Frustrated. 

 

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3 hours ago, martin_wynne said:

 

Sometimes it's because you are describing something you did 10 years ago, or using parts you have had in stock for years. You can't assume that similar products obtained fresh now will be the same.

 

For example, it's well-known that some currently available bullhead rail no longer fits Exactoscale chairs properly, causing the base to bend significantly:

 

bent_chair.jpg.4744976247c5851b5fa09ef4b8ce6d77.jpg

Sorry about poor image quality, copied from Scalefour web site.

 

If the chair base is not flat, with pure solvent you will be gluing only along the outer ends, and it will come away very easily. It needs a cement-type adhesive with some gap-filling ability, such as the Polypipe stuff.

 

A possible solution, after threading the chairs onto the rail, is to run a soldering iron along the rail to soften the chair, and press the rail and chair down onto a flat surface as it cools. It's tricky to get the temperature just right to avoid damaging the chair or pushing the rail through the chair base.

 

cheers,

 

Martin.

 

The track above was made about a year ago from components bought for the task, so things must have changed significantly in the last year for a new problem to have arisen.

 

I have obtained rail from several different places over the years and there are clear differences between batches, even batches from the same place. Some have a deeper web and a squarer top to the edges of the rail. Some have a thicker web in the centre, which you only really notice when you are filing blades and crossing nose Vs.

 

Some, like the example in the photo you posted, don't look as if the web at the base is the same thickness on both sides.

 

I must have been lucky as I haven't found any that distort the chairs like the example you have shown. The idea of putting a soldering iron on the rail to melt it into the chairs isn't one I would be keen on trying. I wouldn't fancy my chances of keeping it flat. 

 

None of this has very much to do with the original query which was about problems sticking the plastic to the sleepers. The answer to that is simple. Butanone!

3 hours ago, Haggerleases said:

Tony, what make of butanone are you using? 

Mine was from Wizard Models bought in the days when you could pick up such things at shows (probably bought at Doncaster show last year). Due to problems sending such items by mail order I don't think they supply it any more.

 

But yes, Butanone is Butanone and the brand shouldn't matter. Slater's MEK or MEKPAK was, I was told once, originally Methyl Ethyl Ketone hence the name but apparently the formula was changed some time ago to something less aggressive which is fine for polystyrene but no good on some other plastics including ABS. 

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9 minutes ago, Haggerleases said:

MEK and Butanone are exactly the same chemical, but with a different name. Let's get that straight. CH₃CCH₂CH₃.

I have a fat bottle of MEK here. Its Butanone. 

Manufacturers however may have slightly different formulations. Just like petrol isn't just petrol. It can vary a great deal. That's why I asked for someone who had apparently found a winning formula. 

 

So, I have a bottle of MEK here that bonds plastic chairs to ply sleepers very poorly.

You can push it side to side, and it won't budge. You can thread some rail through it, and pull the rail upwards, and it won't budge. But....twist it or put your fingernail at the side and lift? Pop, it's off. No good. 

So. Can anyone suggest a chemical that bonds exactoscale chairs to EM gauge society ply sleepers such that I cant just flick them off with a fingernail? 

This is why I said it's the 'Emperors new clothes.' there may be people out there who have track that seems fixed, but it isnt, and nobody dare check.. because when they find its ready to fall to bits, they'd have a load of work up in smoke. I want track that is rigid and durable, for many years. 

This stuff isnt cheap, but the way I see it at the moment, plastic to wood bonding the way we want it for our hobby, is deeply flawed, and nobody is calling it out. The only good bond is superglue. And that can be brittle.

There isnt a good proven 'system' of plastic chairs and wood sleepers out there at the moment.

I would be tempted to give up and go back to using 2.5mm rivets and solder, but guess what? the EMGS doesn't have those rivets in stock! And they haven't had them in stock for ages (Amongst other things). The dreaded 'Read More' button....

Frustrated. 

 

 

If I want to lift chairs, the only way I can do it without wrecking them is to slide the edge of a scalpel or single edged razor blade between the chair and the sleeper. When I started out, I tried getting chairs off with a fingernail. It could be done with a huge amount of force.

 

Having said that, I only did those tests when the materials became available and I haven't repeated it in recent times. I might have a go tomorrow.

 

I do have a couple of layouts built this way that date back to when such things first came out and K & L predated C & L and have had no problems.

 

I had always thought that MEK/Butanone was the same thing and that if it was being sold as that then it should have the same properties as other MEK/Butanone products from other places. If there are differences, (perhaps some diluted/thinned to make it weaker but to fill more little brown bottles from a big bottle?) then that may explain some of the problems. 

 

 

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On 16/07/2021 at 03:51, martin_wynne said:

@Haggerleases

 

If you are not in a hurry, and have access to 3D printing (yourself, or friends, or a club maybe), there is a new track-building process in the offing which I'm calling 3D Plug Track. No glue, no solder, no gauges, the chairs are a press fit in the timbers. The timbers can be 3D printed, or could be laser-cut from plywood:

 

cheers,

 

Martin.

 

This sounds like platelayers' paradise Martin! It would solve many of the difficulties and save most of the time in making your own track. I look forward to further developments.

 

Adrian

Edited by adriank
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6 hours ago, Haggerleases said:

MEK and Butanone are exactly the same chemical, but with a different name. Let's get that straight. CH₃CCH₂CH₃.

I have a fat bottle of MEK here. Its Butanone. 

Manufacturers however may have slightly different formulations. Just like petrol isn't just petrol. It can vary a great deal. That's why I asked for someone who had apparently found a winning formula. 

 

So, I have a bottle of MEK here that bonds plastic chairs to ply sleepers very poorly.

 

Most chemicals are available in at least two grades. 100% pure Laboratory Grade, and a lesser/cheaper Commercial/Industrial grade. For example, ordinary commercial Meths is only 70% alcohol. I don't know about Butanone/Mek, but as it's a widely used industrial solvent in paints and adhesives I imagine the same applies. 100% pure Butanone is likely to be a much better solvent for ABS polymer than lesser grades.

 

But that's not the main problem. Which is that Butanone does not dissolve raw plywood. The way to fix ABS to plywood is:

 

1. dissolve some chair sprues in Butanone until you have a thin gloopy mess. Or buy it ready glooped in adhesive cements such as Polypipe.

 

2. apply it to the plywood underneath the chair positions so that it penetrates the wood grain.

 

3. leave it to dry/evaporate.

 

4. you now have some ABS polymer embedded in the wood grain, and chairs can be attached to it with fresh Butanone.

 

This was the method recommended by Exactoscale when they first introduced their injection-moulded chairs.

 

Martin.

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My understanding was that the Butanone softened the plastic on the base of the chairs enough to allow it to envelop some of the fibres of the ply. When I have removed chairs with a scalpel blade, there is always a small brown rectangle left behind on the sleeper. This would seem to indicate that some of the plastic had gone into the surface of the ply.

 

It is a laborious enough process as it is and if I had to go to every sleeper to individually prepare them to accept chairs, I wouldn't bother. I did build one point using 40thou black plastic sheet sleepers individually cut and then sanded to give a dummy grain effect to see if it was an option but it was no easier than just sticking the chairs to the ply, so I have used that ever since.

 

The only problems I have are when a rail is really short and is only held by a small number of chairs, as can happen with some complex point formations, or with slide chairs where a rail might not sit tight against the jaw on the outside. I secure the rails to the chairs with a tiny spot of superglue or epoxy in those situations.

 

There is a degree of strength in having multiple chairs on a rail. If you have 30 chairs all glued down with a rail through them, trying to put a twisting action onto a single chair is very difficult as the rail prevents it. One chair on its own doesn't have that benefit.

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10 hours ago, Haggerleases said:

MEK and Butanone are exactly the same chemical, but with a different name. Let's get that straight. CH₃CCH₂CH₃.

I have a fat bottle of MEK here. Its Butanone. 

Manufacturers however may have slightly different formulations. Just like petrol isn't just petrol. It can vary a great deal. That's why I asked for someone who had apparently found a winning formula. 

 

So, I have a bottle of MEK here that bonds plastic chairs to ply sleepers very poorly.

You can push it side to side, and it won't budge. You can thread some rail through it, and pull the rail upwards, and it won't budge. But....twist it or put your fingernail at the side and lift? Pop, it's off. No good. 

So. Can anyone suggest a chemical that bonds exactoscale chairs to EM gauge society ply sleepers such that I cant just flick them off with a fingernail? 

This is why I said it's the 'Emperors new clothes.' there may be people out there who have track that seems fixed, but it isnt, and nobody dare check.. because when they find its ready to fall to bits, they'd have a load of work up in smoke. I want track that is rigid and durable, for many years. 

This stuff isnt cheap, but the way I see it at the moment, plastic to wood bonding the way we want it for our hobby, is deeply flawed, and nobody is calling it out. The only good bond is superglue. And that can be brittle.

There isnt a good proven 'system' of plastic chairs and wood sleepers out there at the moment.

I would be tempted to give up and go back to using 2.5mm rivets and solder, but guess what? the EMGS doesn't have those rivets in stock! And they haven't had them in stock for ages (Amongst other things). The dreaded 'Read More' button....

Frustrated. 

 

 

The simple answer is Butanone, not MEK.

 

MEK used to be exactly the same as Butanone, however some years ago the formula was altered and MEK became MEK-PAK, what you now buy in the model trade is not the same.

 

With plastic chairs bonding to ply timbers, neither solvent will give a permeant bond. Sliding a scalpel under a chair will release the chair (a feature many like as it allows alterations to be made). The strength of the bond does not come from individual joints but the whole as a group.

 

Martin has given you one piece of advice, otherwise use a good quality industrial strength super glue or polymer glue. I use a product made by Ever Build "industrial grade superglue GP" The chair breaks before the bond

 

I now suggest to those who ask what products to use, to use plastic timbers, if well painted no one will notice the difference, thin timbers if used must be stuck firm to the track bed. All new 00, EM and P4 flexible track bases are/will be available using thick plastic or 3D bases, like it or not this is what the majority of the buying public want and the trade is moving across to it. C&L plan to discontinue their whole range of thin track based flexitrack over time.

 

You are very wrong in thinking everyone wants ply timbers, quite the opposite. Thick plastic timbers has been very popular for years, the latest products use 3D printing. Ply and rivet track construction is now a very niche market, and for the reasons given the use of ply timbers and sleepers is far less popular now.

 

The EMGS decided to use thick bases with their new flexi track and RTR turnouts, and are made in plastic with, they also supply Finetrax 3D printed kits which has the same thickness base. 

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Tony, the problem I have is I'm not getting that lovely little rectangle of plastic left behind on the ply when I ping it off. There's virtually nothing left behind.

 

All, its early days for me, I'm just experimenting, I have one of the British Finescale EM points, and very nice it is too, also a few lengths of EMGS flexi track, I'm pretty much trying every technique to find one that suits. I've soldered to rivets, soldered to copperclad, glued to plastic, etc etc, but I can't get away from the look of stained ply sleepers. They look amazing.

I was quite impressed with the look of the DCC concepts brass chairs, but what on earth sort of chair is that?! 

I wasn't that bothered about track at first, as it was all about the locos and carriages etc, but the more you know, the more you notice! Damn stuff is a hobby in itself! 

 

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Posted (edited)
1 hour ago, Haggerleases said:

was quite impressed with the look of the DCC concepts brass chairs, but what on earth sort of chair is that?!

@Haggerleases

 

It's a bridge chair. Either L1 (48 lb) or M1 (43 lb) size*. For plain track they are used only on waybeams -- on bridges, ash pits, turntables, etc. :

 

lichfield1_1990_1280x800.jpg.87a7bd3fc982f5a3aa1b97cc7c331285.jpg

 

Also used within pointwork where there is no space for a standard chair.

 

The L1 is too wide to fit on a standard 10" sleeper. The M1 just fits, but the screw fixings would be too close to the edge.

 

p.s. DCC Concepts also do a mysterious 6-bolt fishplate.

 

*has anyone measured them?

 

Martin.

Edited by martin_wynne
p.s. added
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Why would they produce that as a chair for plain track? What an odd decision? Unless it's just a beefy generic chair that looks like a bridge chair? Or casting other chairs in brass was difficult? 

It's a head scratcher for sure. 

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1 minute ago, Haggerleases said:

Why would they produce that as a chair for plain track? What an odd decision? Unless it's just a beefy generic chair that looks like a bridge chair? Or casting other chairs in brass was difficult? 

It's a head scratcher for sure. 

 

After the 6-bolt fishplate, we expected nothing less. :)

 

Martin.

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2 hours ago, Haggerleases said:

Tony, the problem I have is I'm not getting that lovely little rectangle of plastic left behind on the ply when I ping it off. There's virtually nothing left behind.

 

All, its early days for me, I'm just experimenting, I have one of the British Finescale EM points, and very nice it is too, also a few lengths of EMGS flexi track, I'm pretty much trying every technique to find one that suits. I've soldered to rivets, soldered to copperclad, glued to plastic, etc etc, but I can't get away from the look of stained ply sleepers. They look amazing.

I was quite impressed with the look of the DCC concepts brass chairs, but what on earth sort of chair is that?! 

I wasn't that bothered about track at first, as it was all about the locos and carriages etc, but the more you know, the more you notice! Damn stuff is a hobby in itself! 

 

 

I would suggest that you get hold of a chair in your fingers, slop on some of your Butanone and after a second or too (but don't leave it any longer than that or it will evaporate off)  tap it with your finger to see if any plastic has melted with the solvent.

 

If it has and the Butanone is melting the plastic even just a little bit, then there is a chance that you are just not putting enough solvent on. It evaporates very quickly and if you just put a tiny spot on with a small brush, then it may be vanishing into thin air before it gets chance to do anything. I let a good brush load flash between the base of the chair and the sleeper then gently press the chair down while the plastic is still soft.

 

When building track, I don't use my usual small brush for assembling plastic kits etc. I use one a bit bigger, which holds more solvent.

 

If the plastic isn't melted at all, then the solvent you are using isn't up to the job and the stuff you are using is either too diluted or somebody has flogged you something else labelled as Butanone.

 

I hope that helps.

 

Tony

Edited by t-b-g
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I have used the Butanone supplied by Hobby Holidays which, as I've stated above, works very well with C&L chairs.  Are Exactoscale chairs made from a different material, however slight, that might affect 'sticking' performance with Butanone?

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4 hours ago, 5050 said:

I have used the Butanone supplied by Hobby Holidays which, as I've stated above, works very well with C&L chairs.  Are Exactoscale chairs made from a different material, however slight, that might affect 'sticking' performance with Butanone?

 

Exactoscale chairs work fine

 

Firstly as Tony said flood the joint with solvent, also lifting a chair and re-sticking it makes for a stronger bond

 

Secondly its the OP's expectation rather than the performance, as there will never be a permeant bond between ply and plastic

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Superglue does it, it bonds the plastic like hell to the wood, but it's very unforgiving, in terms of time and placement. It's long term strength is also suspect.

What I'm saying is butanone isn't neccasarily the wonderful fixing method it's made out to be, and the various producers of chairs etc are not promoting a complete system. They're selling a product and relying on the end user to spend a small fortune on a whole shelf full of very nasty chemicals to find something that works. Not really acceptable in this age of caring for the environment. If you're selling a plastic chair in 2021 you need to specify how to fix it easily and cheaply to the various options available, with the least environmental impact possible. 

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12 minutes ago, Haggerleases said:

If you're selling a plastic chair in 2021 you need to specify how to fix it easily and cheaply to the various options available, with the least environmental impact possible. 

@Haggerleases

 

Hi,

 

The intention is that you use the plastic timbers with plastic chairs.

 

The chairs are not designed or intended for plywood timbers -- that's entirely up to the user.

 

cheers,

 

Martin.

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33 minutes ago, Haggerleases said:

Superglue does it, it bonds the plastic like hell to the wood, but it's very unforgiving, in terms of time and placement. It's long term strength is also suspect.

What I'm saying is butanone isn't neccasarily the wonderful fixing method it's made out to be, and the various producers of chairs etc are not promoting a complete system. They're selling a product and relying on the end user to spend a small fortune on a whole shelf full of very nasty chemicals to find something that works. Not really acceptable in this age of caring for the environment. If you're selling a plastic chair in 2021 you need to specify how to fix it easily and cheaply to the various options available, with the least environmental impact possible. 

 

I get the distinct impression that you wish the plastic chair / plywood sleeper method of track-building to be something that it never was.

 

Plywood sleepers were intended for rivet / cast cosmetic chair construction; plastic sleepers were intended to be paired with plastic sleepers.

 

More than a few modellers find that plywood sleepers combined with plastic chairs will produce perfectly acceptable track - though perhaps not with the degree of robustness that you demand.

 

Yer pays yer money and yer takes yer choice - don't have a tantrum if the real world fails to match up to your expectations!

 

CJI.

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43 minutes ago, Haggerleases said:

Superglue does it, it bonds the plastic like hell to the wood, but it's very unforgiving, in terms of time and placement. It's long term strength is also suspect.

What I'm saying is butanone isn't neccasarily the wonderful fixing method it's made out to be, and the various producers of chairs etc are not promoting a complete system. They're selling a product and relying on the end user to spend a small fortune on a whole shelf full of very nasty chemicals to find something that works. Not really acceptable in this age of caring for the environment. If you're selling a plastic chair in 2021 you need to specify how to fix it easily and cheaply to the various options available, with the least environmental impact possible. 

 

I get the distinct impression that you wish the plastic chair / plywood sleeper method of track-building to be something that it never was.

 

Plywood sleepers were intended for rivet / cast cosmetic chair construction; plastic sleepers were intended to be paired with plastic sleepers.

 

More than a few modellers find that plywood sleepers combined with plastic chairs will produce perfectly acceptable track - though perhaps not with the degree of robustness that you demand.

 

Yer pays yer money and yer takes yer choice - don't have a tantrum if the real world fails to match up to your expectations!

 

CJI.

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11 hours ago, Haggerleases said:

Superglue does it, it bonds the plastic like hell to the wood, but it's very unforgiving, in terms of time and placement. It's long term strength is also suspect.

What I'm saying is butanone isn't neccasarily the wonderful fixing method it's made out to be, and the various producers of chairs etc are not promoting a complete system. They're selling a product and relying on the end user to spend a small fortune on a whole shelf full of very nasty chemicals to find something that works. Not really acceptable in this age of caring for the environment. If you're selling a plastic chair in 2021 you need to specify how to fix it easily and cheaply to the various options available, with the least environmental impact possible. 


Don’t blame the makers. This is I feel my fault, because as Martin says they were/are intended for use with plastic sleepers. It was just that when I did that review I mentioned previously all I received were some chairs and a few plastic sleepers. Not really enough to do much with. As I was then using the white metal ones on ply sleepers, which were the only type available to people at that time, I thought I’d just give it a try, the plastic onto the ply, using the plastic glue I had to hand, which happened to be Slaters Mek-Pak. 
 

When it worked okay I included it to show what was possible. Pointwork using a few rivets under the crossing and at the divergence for electrical connections. The producers were of course hoping to sell loads of plastic sleepers alongside the plastic flexible track. But the plastic-on-ply seemed to gain favour with quite a few who also found it worked for them.

 

My apologies.

 

Izzy

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