Jump to content

Plastic chairs and MEK. Very poor bond.


Recommended Posts

9 hours ago, martin_wynne said:

At that time the only plastic-based bullhead track available was SMP Scaleway.

 

 

I was greatly impressed when I saw it at first although somehow it still didn't look quite right. The latter version was a lot better. I still have some of the original stuff. I'm saving it so our kids can have the pleasure of disposing of it :D

  • Friendly/supportive 1
Link to post
Share on other sites

Oh dear. 

After my reasonable trial results the other day, I made a length of track at the weekend. Pre-loaded the sleepers with butanone, added a decent smear of 'Poly Pipe' adhesive, put the rail with the pre-threaded chairs on the sleepers after painting a little butanone on each, more butanone on the sleeper after fitting to wick its way in, weighted it down etc. Looked great. Felt quite pleased with myself. 

Left it 12 hours or so to be safe, picked it up off the template and the thing basically fell to bits in my hand. Disaster. 

I think I'm going to have to admit defeat very soon. I need my track to be way more durable than this. my EMGS bullhead rail pulls out of the chairs very easily too.. I think I may be doing something fundamentally wrong, though I can't think what.

Back to the good old soldering iron at this rate.

 

 

 

Link to post
Share on other sites

  • RMweb Gold

When using solvent on pvc waste pipe, it is recommended that one sands the surface of the areas to be joined to ensure a good joint.

 

I imagine that the same would be true of ABS chairs. Best done when still on the sprue.

 

I recall problems (many years ago) with MEK and ABS. I had built a rather complicated skew bridge. All seemed well at first but as the MEK dried out, not having bonded to the ABS, the whole thing fell apart.

Link to post
Share on other sites

  • RMweb Gold
45 minutes ago, Haggerleases said:

added a decent smear of 'Poly Pipe' adhesive, put the rail with the pre-threaded chairs on the sleepers

 

Hi,

 

Did you miss a step there? "added a decent smear of 'Poly Pipe' adhesive, waited a good hour for the Polypipe to dry, put the rail with the pre-threaded chairs on the sleepers"

 

The idea is that the Polypipe impregnates the sleeper with a plastic material. It's not going to do that if you wash it out again by flooding butanone over it while it is still wet.

 

In the original Exactoscale days, whole batches of sleepers would be Polypiped in advance, and left for days before being used. Some folks who cut their own plywood timbers would Polypipe the sheet of ply before sawing it up.

 

You can make your own Polypipe by chopping up scraps of plasticard, chair sprues, etc., and dissolving them in butanone. It might work better than real Polypipe because you can adjust the consistency by trial and error to whatever works best.

 

If it still doesn't work after all that I would begin to wonder if your "butanone" is in fact butanone? What happens if you brush it over the chair sprues? They should go instantly soft , sticky and smeary, and the brown colour should come off on your fingers.

 

cheers,

 

Martin.

Link to post
Share on other sites

Sorry I'm late to the thread. I built a lot of the track on my previous layout Morfa using C&L chairs and ply sleepers stained with a water based ink.

 

morfa 82.jpg

 

I used EMA Plastic Weld to stick the chairs to the sleepers without any need to treat the sleepers with polypipe or any other adhesive. I had no problems with the bond even though the layout room (in an old stone chapel) could get pretty arctic in winter. I couldn't ping chairs off with my finger but I could loosen the bond with a sharp craft knife which was useful when it came to making adjustments.

Link to post
Share on other sites

  • RMweb Gold
Posted (edited)
35 minutes ago, Neil said:

 

That's dichloromethane, not butanone.

 

I've been wondering whether the advice to use butanone for ABS is only good for plastic-to-plastic bonds? It has to be a very pure grade to be effective. Dichloromethane is better, but it's a very nasty chemical:

 

Toxicity

Even though DCM is the least toxic of the simple chlorohydrocarbons, it has serious health risks. Its high volatility makes it an acute inhalation hazard. It can also be absorbed through the skin. Symptoms of acute overexposure to dichloromethane via inhalation include difficulty concentrating, dizziness, fatigue, nausea, headaches, numbness, weakness, and irritation of the upper respiratory tract and eyes. More severe consequences can include suffocation, loss of consciousness, coma, and death. DCM is also metabolized by the body to carbon monoxide potentially leading to carbon monoxide poisoning. Acute exposure by inhalation has resulted in optic neuropathy and hepatitis. Prolonged skin contact can result in DCM dissolving some of the fatty tissues in skin, resulting in skin irritation or chemical burns.

 

Not to mention the utterly awful pong.

 

Don't use it to make your own Polypipe mixes.

 

Take care.

 

Martin.

Edited by martin_wynne
quote added
  • Informative/Useful 2
Link to post
Share on other sites

 

I’m sorry that things just don’t seem to be working out for you no matter what you try. I have no experience of Exactoscale chairs, but while it doesn’t seem logical I get the distinct feeling that they are the core problem somehow. That the material they are moulded from, and there can be an almost infinite number of plastic mix combinations, just won’t play nicely with the available glues you have tried. It is noticeable that most people who have stated no issues with using plastic chairs on ply sleepers whatever the liquid glue used appear to have used C&L ones.

 

As I have stated previously I have always used Slaters Mek-Pak even though the present day offering is no longer based on the chemical MEK. I have read on a thread here somewhere from Dave Hunt that this was because they found George Slater collapsed in the works one day having been overcome by the noxious fumes, and so changed the formula to something less dangerous to peoples health. I have also used both PlasticWeld and pure Butonone but they are both much more aggressive in action and can severely melt chair surfaces with over-application, bolt detail etc.

 

To further illustrate that using C&L chairs seems to cause no problems even using the current MEK-PAK here are a few shots of my current 7mm micro-minimal plank that uses – don’t laugh – plastic chairs on sleepers cut from mountboard. Again using Mek-Pak. So this is good enough to melt the chair base to allow it to adhere to almost any material.

 

959416521_RMwebTC01.jpg.e13fd8e722a544c0f8d816762d88b28c.jpg

 

1425617421_RMwebTC02.jpg.7397a2d9e70e9068abf1f810433cfef3.jpg

 

2061083925_RMwebTC03.jpg.c16d1ed76d24c7b9ff0fd84aabdb6ea7.jpg

 

You will note that as it was 7mm I used PCB strip under the crossing nose and at the divergence for electrical connections and a bit of added strength. In 4mm/P4 I have always used a few rivets in these locations. Here is my most recent P4 plank track build. Again using C&L on ply.

 

web1.jpg.a5ae12cf647ce2960c105d325b2b6597.jpg

 

web2.jpg.4cce5a991199b5f4a2f4ec17692aeff8.jpg

 

web3.jpg.5ca4d4f2984660b139e87e62cdc6a2ea.jpg

 

web4.jpg.f6af1d1af1bc3f3ecb1b536054dc8109.jpg

 

I only ever use very thin strips of d/s tape to hold the sleepers in place on a template, and it is ‘peeled’ off using turps/white spirit washed on to temporarily break the glue joint

 

1511443696_web5.jpg.8223c721830f25b11b9b2401c973cec3.jpg

 

On it’s own trackwork made in this manner is fairly fragile until laid down. Painting the rail sides and chairs to ‘lock’ them together can be done before removing from a template. It does often help.

 

It should be noted that quite a few modellers build their track straight onto the baseboard. This does overcome the issue of lifting the finished track from the template. I never have, preferring to build it on the workbench, but it’s each to their own.

 

However, once laid and finished unless a scalpel is used to break the joint between chair and sleeper I find it impossible to part them without extreme force. And the older the construction the more force seems needed. That the bond strength increases with age. A screwdriver under the rail levered up will do it, but wrecks both the rail and the chairs, which on average break in two, one half coming away but the other staying firmly anchored to the sleeper. Very rarely do chairs come away whole. If they do often they take the top ply surface with them.

 

Might I suggest that you acquired some C&L chairs to see if your experience is the same as with the Exactoscale ones. Please don't give up, the results are worth the effort I feel.

 

1929387508_RMwebASE06.jpg.8c6d80f846b70a900812eaef329e7d0f.jpg

 

 

  • Like 1
  • Craftsmanship/clever 1
Link to post
Share on other sites

Izzy. Thanks so much for that comprehensive reply. I appreciate your effort. I was starting to think it was the composition of the chairs, so you may very well be right. I am going to get hold of some c&l chairs and see if they work any better. I guess if I don't figure out the issue I'll always wonder what caused it. 

Hand in pocket again lol. 

Link to post
Share on other sites

  • RMweb Gold
Posted (edited)

@Haggerleases

 

Hi,

 

As an aside, have you seen the 3D Plug Track which I'm working on in Templot? This is EM:

 

more_s1_4-jpg.1706

 

more_s1_2-jpg.1708

 

more_s1_3-jpg.1707

 

3D printed chairs are a press fit into "sockets" in the timbers. Which could be 3D printed as above, or several firms offer laser cutting of plywood track bases from Templot files. The socket is just a simple rectangular aperture.

 

No glue, no solder, no gauges needed.

 

It is all still being developed, but there is enough in the latest Templot release to do plain track. In any gauge or scale or radius.

 

More info: https://85a.uk/templot/club/index.php?threads/3d-printing-plug-track-from-228a.229/

 

p.s. the bottom side-flange on the 3D printed sleepers is intended to be hidden in the ballast. It strengthens the sleepers alongside the sockets.

 

cheers,

 

Martin.

Edited by martin_wynne
p.s. added
  • Like 2
  • Informative/Useful 1
Link to post
Share on other sites

I've used Butanone to stick C&L chairs to all sorts of substrates including card, foamboard, wood.  No problems at all.  No need to 'prime' with anything.

Link to post
Share on other sites

  • RMweb Gold
1 hour ago, 5050 said:

I've used Butanone to stick C&L chairs to all sorts of substrates

 

The OP on this topic is trying to stick Exactoscale chairs. We don't know that it is the same polymer as C&L chairs.

 

Martin.

Link to post
Share on other sites

4 minutes ago, martin_wynne said:

 

The OP on this topic is trying to stick Exactoscale chairs. We don't know that it is the same polymer as C&L chairs.

 

Martin.

 

 

I have never known any issues with Exactoscale chairs and I use both C&L and Exactoscale chairs in equal measures. However Phil at C&L told me because of the compounds of the plastic used, Butanone is the best and recommended product to use. Though with plastic to plastic I have used other makes,

 

I have found when using Butanone with ply timbers the best results are when you flood the joint with solvent 

Link to post
Share on other sites

46 minutes ago, martin_wynne said:

 

The OP on this topic is trying to stick Exactoscale chairs. We don't know that it is the same polymer as C&L chairs.

 

Martin.

I know Martin, just following on from other posts relating sticking to substrates other than ply sleepers.  I've also used the same methods with Exactoscale items.

  • Like 1
Link to post
Share on other sites

  • RMweb Gold
42 minutes ago, 5050 said:

I know Martin, just following on from other posts relating sticking to substrates other than ply sleepers.  I've also used the same methods with Exactoscale items.

 

The problem is that the OP's Exactoscale chairs won't stick with his butanone.

 

Since no-one else reports a similar problem, either his Exactoscale chairs are a different polymer, or his butanone isn't butanone.

 

I'm leaning towards the conclusion that there may be significant difference in the performance between industrial grade butanone and 100% laboratory grade.

 

Martin.

Link to post
Share on other sites

On 26/07/2021 at 13:13, martin_wynne said:

 

That's dichloromethane, not butanone.

 

I've been wondering whether the advice to use butanone for ABS is only good for plastic-to-plastic bonds? It has to be a very pure grade to be effective. Dichloromethane is better, but it's a very nasty chemical:

 

Toxicity

Even though DCM is the least toxic of the simple chlorohydrocarbons, it has serious health risks. Its high volatility makes it an acute inhalation hazard. It can also be absorbed through the skin. Symptoms of acute overexposure to dichloromethane via inhalation include difficulty concentrating, dizziness, fatigue, nausea, headaches, numbness, weakness, and irritation of the upper respiratory tract and eyes. More severe consequences can include suffocation, loss of consciousness, coma, and death. DCM is also metabolized by the body to carbon monoxide potentially leading to carbon monoxide poisoning. Acute exposure by inhalation has resulted in optic neuropathy and hepatitis. Prolonged skin contact can result in DCM dissolving some of the fatty tissues in skin, resulting in skin irritation or chemical burns.

 

Not to mention the utterly awful pong.

 

Don't use it to make your own Polypipe mixes.

 

Take care.

 

Martin.

 

I quite like the smell of Plastic Weld. In fact I use it in preference to other stuff wherever I can for that reason :)

 

However, I do use it in quite limited sessions and don't hang around in the same room afterwards.

 

Nigel

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...