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Plastic chairs and MEK. Very poor bond.


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Hi all.

I'm attempting to attach 4mm scale Exactoscale 4 bolt plastic chairs to EMGS ply sleepers with MEK, and having failed with that, now latterly plastic weld. Same result. Bond seems OK when you try to move the chair laterally, but try to flick it off with a nail and it comes straight up, with virtually no trace of plastic remaining in the wood. A very poor bond. Super glue holds chairs very well to the wood sleepers, but gives little time to adjust. 

I have serious doubts about plastic to wood Bonding. I've tried opening the grain of the ply with sandpaper too. It would probably hold, but it's nowhere near as durable as I'd 

like it. At this moment I'm close to going back to society track, which is unfortunately bog standard 3 bolt, and no good for pre-grouping. Wrong chairs, wrong sleeper lengths.

I tried soldered/ riveted track, but it looked exactly what it was. Many blobs of solder. great for days gone by, but surely it must be possible to thoroughly bond a bit of plastic to some wood by now? Is MEK the Emperors new clothes? 

Perhaps riveted track and purely cosmetic chairs is the way forward? At least then I'm not relying on a very dubious bond? 

Penny for your thoughts? 

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6 minutes ago, Haggerleases said:

Hi all.

I'm attempting to attach 4mm scale Exactoscale 4 bolt plastic chairs to EMGS ply sleepers with MEK, and having failed with that, now latterly plastic weld. Same result. Bond seems OK when you try to move the chair laterally, but try to flick it off with a nail and it comes straight up, with virtually no trace of plastic remaining in the wood. A very poor bond. Super glue holds chairs very well to the wood sleepers, but gives little time to adjust. 

I have serious doubts about plastic to wood Bonding. I've tried opening the grain of the ply with sandpaper too. It would probably hold, but it's nowhere near as durable as I'd 

like it. At this moment I'm close to going back to society track, which is unfortunately bog standard 3 bolt, and no good for pre-grouping. Wrong chairs, wrong sleeper lengths.

I tried soldered/ riveted track, but it looked exactly what it was. Many blobs of solder. great for days gone by, but surely it must be possible to thoroughly bond a bit of plastic to some wood by now? Is MEK the Emperors new clothes? 

Perhaps riveted track and purely cosmetic chairs is the way forward? At least then I'm not relying on a very dubious bond? 

Penny for your thoughts? 

 

As I understand it, the plastic / wood bond relies upon the solvent softening the plastic enough for it to flow and penetrate the fibres of the wood.

 

This is not a true bond; no component of the plastic chemically bonds with any component of the wood.

 

As such, any adhesion will be tenuous; track construction using this method can only rely on numerous questionable joints combining to provide an acceptable degree of mechanical strength.

 

What is essential is the use of a solvent that chemically breaks down the plastic to allow it to flow into the wood fibres - this will be dictated by the type of plastic used.

 

CJI.

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You need something with butanone in it, anything else isn't aggressive enough to dissolve the plastic (ABS ?) that the chairs are made from. MEK doesn't have proper MEK in it anymore, I suspect it's not strong enough now. 

 

There at least 2 products called Plastic Weld as well, one (JB) is an epoxy which won't melt anything and the other (EMA) I can't find a datasheet for. 

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Agreed.

 

I have build quite a few yards of Exacto on Ply.

 

Butanone is the thing. Buy it on eBay in 1lt or 500ml plastic cans. Well worth it. As you empty the container, squeeze the air out.

 

https://www.ebay.co.uk/itm/265043775505?hash=item3db5d71011:g:SZYAAOSwn55a6BAu

 

The great thing is, if you go wrong, slip a scaple blade between sleeper and chair and it will pop off allowing re-alignment.

Dave.

 

Edited by dasatcopthorne
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Years ago "MEK" was Methyl Ethyl Ketone.  This is the same chemical as Butanone and as dasatcopthorne correctly says, this is the only thing which will do the job. 

Plastic Weld is dichloromethane. The stuff sold as MEK these days is not Methyl Ethyl Ketone - I believe it too might be dichloromethane.  Neither of these will work - though they may give the impression that they do - temporarily. 

 

How do I know? I built much of my plastic / ply track using Plastic Weld and all worked well, until in the middle of an exhibition there was a very embarassing plain track derailment...  One of the team had to be dispatched to buy a bottle of butanone sharpish ...

 

Best Wisjes,

Howard

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On a similar problem. I'm looking for something to stick C&L chairs to new Peco bullhead to fix check rails on a curve.

Tried Plastic weld and Superglue without success.  Found a glue which sets with shining a light (supplied with the glue) after application.  Worked for a while but a few trains round the layout broke the bond in places.

Anything else I could try please ?

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I built all my 0 gauge turnouts on wooden timbers using Peco chairs.  I used MEK but I bought it at a hardware store (perhaps the hobby stuff is toned down).  Haven't had any issues.  You really do need to flood the joint because MEK evaporates quickly.  Apply weight as well.

 

John

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I have built points using this glue https://www.amazon.com/Tamiya-87038-Extra-Thin-Cement/dp/B000BMYWYC/ref=mp_s_a_1_1?dchild=1&keywords=tamiya+extra+thin+cement&qid=1626297134&sprefix=tamiya+extra&sr=8-1 it seems to work ok. Capillary action means that the cement gets between the chairs and the plywood. Holding the chair I place under pressure from a screwdriver does the trick

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I have been making track using plastic chairs (K&/C&L) on ply sleepers since I reviewed the 'new' chairs when they first appeared for the now defunct magazine Your Model Railway way back in the 1980's - I forget exactly when now. Not just in 4mm/P4 but also in recent years in O gauge and 2mm 2FS. All of this has been done using Slaters MEK of whatever mix it has been at the time. Sometimes it is neccesary to apply a couple of loaded brushfuls of the stuff to get the odd chair to stick fully, but I have never had an issue with chairs not staying stuck down. I do run my finger over the rail to press the chairs fully down onto the sleepers after doing a short length. The plastic generally keys into the surface grain a bit. Indeed over time I find it gets harder to slide a scalpel under the chair to lift it away from the sleeper should you wish to make any changes/adjustments. 

 

I don't know if the Exactoscale chairs are a different plastic compostion since I have never used them. This might be the problem. My current 4mm/P4 plank is now around 8 years old and the track is as rock solid as it was when first laid using this method. I would agree some care is needed until the completed track is laid and painted -  I have never build track in-situ straight onto a baseboard, but none has ever fallen apart either.

 

The problem with using a stronger glue such as butonone or Plasticweld is that they can damage/melt the surface of the chair mouldings with over-application. Being a bit milder MEK doesn't, even with multiple applications.

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Thanks so much chaps for your replies. I do appreciate your effort. 

Martin, I had thought of pre-treating the ply with some sort of glue before using the MEK, so your suggestion fits my way of thinking. At the moment the shear strength is very good, but torsional is very poor indeed. My armory of nasty chemicals is rapidly expanding. I hope I have a use for it all once I find something that will really stick these damn chairs! (And yes in moments of teeth grinding anguish I've even considered tiny screws..)  My goodness does good old Peco code 100 look tempting.. But something tells me the end result of this hand built experiment will be worth the painful trial and error. 

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Handmade turnout building can be "teeth grinding" and there's a lot to know, notably the "set".  I find it satisfying to make my own.  I had a fair few disasters along the way mind.  Most of mine are actually built on Peco footprints, so nothing special, although I did do a single slip, which was a challenge.  However, 0 gauge turnouts are pretty dear so there's a big cost saving, provided you make your own crossings and blades.

 

John

Edited by brossard
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Methyl Ethyl Ketone is another name for butanone

3 hours ago, martin_wynne said:

Exactoscale recommended treating plywood sleepers with Polypipe cement before sticking their chairs to them. Let it dry, then stick chairs with solvent (butanone).

 

Polypipe solvent C250 is 50%-100% butanone, so it should be a good substitute for the pure stuff.

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Frankly I've given up on using plastic chairs with plywood sleepers. Riveted track looks fine to me especially when the rail is painted and the track viewed from the side. I did try cutting plastic chairs in half and sticking them on for cosmetic effect but quickly decided that life is simply too short! What happened to the white-metal half chairs that used to be available?

 

Adrian

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4 hours ago, dpgibbons said:

Polypipe solvent C250 is 50%-100% butanone, so it should be a good substitute for the pure stuff.

 

I believe it is a cement rather than a pure solvent, i.e. it has some ABS or other filler dissolved in it. Which becomes embedded in the plywood has it dries. To which the chairs can then be bonded.

 

You could make your own by dissolving the chair sprues in butanone. Follow safety advice if you are sloshing solvent about.

 

cheers,

 

Martin.

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Have you pre-stained the timbers if so with what ?

 

I have an old tin of Colron wood stain spirit based, which I thin 50/50, works a treat and no issue with sticking chairs with Butanone. However be careful with wood dye, as some contain wax, you will never stick anything to it

 

You may well find the plastic used over the years has changed, but as said use Butanone and decent quality ply timbers.

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Very chuffed (see what I did there) with your responses guys. Very helpful. I will report back with my findings  when I find a method that works well. 

I wonder if rubbing thinned balsa cement into the sleepers would help? I have plenty of duco which I build my freeflight model aircraft with. I've ordered some of that polypipe stuff in the meantime, will give it a whirl. 

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Adriank, I got on well with ply and rivet, and I may well come back to it! Cast chairs would be great. Rev. Denny and many other great modellers used soldered track with great success so I'd be in good company. 

I think my poor results with plastic chairs are making me determined to find a solution to my current problem though.

I'm writing down my results with different combinations so I guess it's now science! 

 

I wonder if ABS is recyclable? There seems a lot of sprue for the amount of chairs attached to it. 

I will have to look into it. I hate waste. 

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44 minutes ago, Haggerleases said:

Cast chairs would be great.

@Haggerleases

 

Hi,

 

You wouldn't say that if you had ever tried filing and fitting them!

 

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:

 

bibo_sockets_daylight1-jpg.1587

 

bibo_sockets_daylight_grey1-jpg.1588

 

Some initial experimental stuff should be available in Templot in the next few days.

 

More info: https://www.rmweb.co.uk/community/index.php?/topic/155917-3d-printing-chairs-and-sleepers-for-bullhead-track/&do=findComment&comment=4500290

 

cheers,

 

Martin.

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1 hour ago, Haggerleases said:

 

I think my poor results with plastic chairs are making me determined to find a solution to my current problem though.

I'm writing down my results with different combinations so I guess it's now science! 

 

Haggerleases

 

Like all things if you follow the manufacturers instructions things work better

 

The system with both C&L and Exactoscale was designed by Len Newman, the message was always the same especially for sticking plastic chairs to ply timbers. Use Butanone as the present day formula of MEK does not work. You will also find that it works better with good quality ply timbers and sleepers. If you paint the timbers/sleepers use plastic ones rather than ply, the bond is far superior. Care must be taken with thin plastic timbers, simply because as the solvent dry's it contracts, potentially curling the timbers unless they are well stuck down. This is the reason why Exactoscale's plastic timbers are 1.6mm thick

 

As for sticking half chairs to riveted track ? I believe you are asking for trouble (I have had experience with a P4 exhibition layout in the past which used this method). anyway with so many good quality modern glues about, a permeant bond can easily be achieved. However the rivet method makes using Exactoscale's special chairs for turnout and crossing construction quite difficult

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1 hour ago, Haggerleases said:

Cast chairs would be great. Rev. Denny and many other great modellers used soldered track with great success so I'd be in good company. 

 

Soldered track is a different animal to using cast whitemetal chairs. Or am I not reading this right?

 

If you think using plastic chairs a fag then I would sugest you forget about using cast chairs. Before Len Newman started making the plastic ones I built a small P4 layout using the Scalefour cast chairs. These were cast whole, with the intention you cut them in half to place around rivetted track. Thinking that the way to the mad house and being lazy anyway I thought I would just use them functionally following the lead of Ian Pusey who was doing the same in S gauge with whitemeatal chairs onto ply sleepers.

 

So they were glued onto the ply sleepers using Evostick - not sure what Ian used. This was you will realise a very slow process. A day to allow each rail section to glue off properly, so the correct gauge would be achieved when the opposite one was laid - the chairs held the rail at the cant angle as per the plastic ones rather than upright as with soldered/ply&rivet, so gauging is very important so as not to end up with gauge narrowing.

 

But the results were reasonable and stood the test of time re durability. Here's a bit of the layout.

 

1640956910_RMweb03.jpg.c23d820a1f643b6b6e955d2ad3569e6b.jpg

 

I'm not sure if they are still available. I still have a small box of them, but using them in preference to the current plastic ones? No way.

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Most sources say MEK and butanone are two names for the same thing. How odd. 

 

Liking the look of that system Martin. I have Templot and found it very easy to use and it made perfect sense to me from the off. Perhaps my being Autistic helped? I found it a real pleasure to use and really intuitive. 

Perhaps another reason was I defenestrated Windows many years ago, and with using some of the more obscure flavours of Linux (I like to be able to  tinker) im used to doing things a little differently.

I'll watch the development of this with interest. 

 

Day off today so off up to my rather warm modelling room to play with chairs and various glues..

 

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On 14/07/2021 at 22:01, martin_wynne said:

Exactoscale recommended treating plywood sleepers with Polypipe cement before sticking their chairs to them. Let it dry, then stick chairs with solvent (butanone).

 

polypipe.jpg.98861b3f431a9deac63d84f67649e2cf.jpg

 

https://www.builderdepot.co.uk/250ml-polypipe-solvent-cement-tin-sc250

 

Martin.

 

When I started on ply sleepers and plastic chairs, I used the Polypipe stuff. It worked very well but I soon found that plain Butanone was just good enough.

 

Especially when you can pop off the odd sleeper to re-position it.

 

Dave.

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Butanone for me on several layouts, can't ever remember any problems getting chairs to stay attached.  Sleepers are either S4 Society or EM Society ones.  For points I use a combination of rivets in 'strategic' positions and plastic chairs elsewhere.

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