Polypipe for ply sleepers

[Julian Gascoyne]

I'm sure I read somewhere about a technique to use when glueing plastic chairs onto ply sleepers. The idea being to paint a substance called polypipe (from the plumbers merchant) onto the ply sleepers to sort of 'plasticize' the sleeper first and hence improve the adhesion between chair and sleeper when applying the butanone.

I thought it was from Iain Rice's book on track building but I can't find it in there. Maybe someone mentioned it to me at an exhibition demo stand?

Anyway, I went to the plumbers merchant to ask, but of course 'polypipe' is the trade name for a range of plastic pipes, so it must be polypipe 'something gunky' that I'm looking for.

Has anyone any idea what I'm on about? Or did I just make it all up?

Thanks
Julian

[Wizard of the Moor]

This technique was described in Exactoscale's trackbuilding manual when they first introduced their plastic chairs.

I can't remember when it was, but certainly when Bernard Weller was still at the helm.

[Russ Elliott]

Here's what I wrote in the CRS instruction sheet:

'Polypipe' is a commercial solvent gel used by plumbers for welding plastic pipes and tubes. It can be brushed, sparingly, over wooden timbers, and will impregnate the wooden surface, to aid subsequent solvent bonding of plastic components. A wipe of ordinary solvent onto the wood before applying Polypipe, or diluting the Polypipe with normal solvent, will aid the impregnation. Bostik PVC Weld Cement M5417 is an equivalent to Polypipe.

[Julian Gascoyne]

Thanks for the replies.

I guess 'Polypipe Solvent Cement' is the stuff required.......

[jasp]

There are plenty of solvent cements for plastic plumbing, not just Polypipe if you are having difficulty locating Polypipe

[Andy G]

My experience has shown that you do not need this. Just use MEK (aka butanone) to fix the chairs to the ply. Note that MekPak is not MEK these days. I actually asked Bernard about the requirement for the polypipe type solvent in the light of my experience showing it wasn't required. His comment was that as they didn't know where people would be using the product they had to recommend something that was absolutley 100% going to work. Personally it's overkill.

Andy

[grovenor-2685]

Just use MEK (aka butanone)

When I looked up the product data sheet for Polypipe from the links given, it turned out to be Butanone
Keith

[martin goodall]

I always understood that MEK (Methyl Ethyl Ketone) is very dangerous. I confess that I was not aware that MEK = Butanone. Is that right?

I don't even like the smell of Mekpak (which, as already stated, is not M.E.K., if it ever was). Slater's re-formulated it again few years ago, but I have no idea what it is. After a quick exchange of e-mails with Tony East (a PhD who is an industrial/academic chemist who lectures at a university in the US) we agreed that one should not be breathing any of the vapours from these solvents.

So, wimpish though it may seem, I now wear a respirator whenever I am using any sort of solvent, even the common-or-garden ones like Mekpak. If I see on the label of a solvent bottle "Use only in a well-ventilated space", I translate that as "Wear a gasmask when using this solvent", as well as opening the window to disperse the vapour.

These solvents probably won't kill you in the short-term, but they are all to a greater or lesser extent carcinogenic, and so you really do need to take steps to ensure you don't breathe the vapour. The only reliable way to do that is to wear a respirator fitted with an activated carbon filter. (A dust mask would be totally useless for this purpose.)

Incidentally, I learnt recently that iso-cyanates (as used in super-glue) are implicated in the development of prostate cancer.

And on that happy note - enjoy your model-making, gentlemen!

[Chris Mitton]

Hi all

Wikipedia's article on Methyl Ethyl Ketone suggests Martin is being a bit over-cautious (although it does imply it might be psychotropic - wow!). However, for an authoritative picture try this, Oxford University chemistry department's Safety Data Sheet on the stuff: http://msds.chem.ox.ac.uk/BU/2-butanone.html. It does say inhaling the stuff "may be harmful" but doesn't say in what way. It's also apparently soporific - or was that the effect of securing a couple of hundred chairs in one session?

Regards
Chris

[nberrington]

Incidentally, I learnt recently that iso-cyanates (as used in super-glue) are implicated in the development of prostate cancer.

I knew there was reason I prefer etched brass : lead in the solder to maintain the lead in the pencil.

Regards

Neil B

[allanferguson]

I do sometimes look at the workbench and wonder which is more dangerous -- the bottle of Butanone or the glass of Bowmore. Either way I reckon dementia or a stroke will get me first! But I don't let my grandchildren anywhere near the workbench (or the whisky bottle!)

Allan

p.s. Has anyone else dipped the flux brush in the whisky and taken a sip of the phosphoric acid......?

[nberrington]

p.s. Has anyone else dipped the flux brush in the whisky and taken a sip of the phosphoric acid......?

Funny you should mention that. Here's the mise en place of my workbench last night. The toxic flux is the small plastic shot glass in front of the ruler. I almost used whiskey as flux more than once! Now granted the "frog" is quite medicinal, so one might not notice, but it's a darn shame to adulterate a decent single malt with anything!

Come to mention sips of phosphoric acid - it is the principle preservative in Coke, so we drink it all the time. It probably accounts for the terrible dentition of many Northern communities in Canada. (Acid + sugar - preventative dentistry).

[Julian Gascoyne]

My experience has shown that you do not need this. Just use MEK (aka butanone) to fix the chairs to the ply. Note that MekPak is not MEK these days. I actually asked Bernard about the requirement for the polypipe type solvent in the light of my experience showing it wasn't required. His comment was that as they didn't know where people would be using the product they had to recommend something that was absolutley 100% going to work. Personally it's overkill.

Andy

Hi Andy

I was going to try some experiments both with and without the solvent cement to see what worked best. But I think I'll take your advice and just use the butanone.

Thanks for posting
Julian

[Brian T]

Thanks for the replies.

I guess 'Polypipe Solvent Cement' is the stuff required.......

Just come across this thread....

The stuff you need is Polypipe Pipe Cleaner. When plumbing this is used prior to using Polypipe Solvent Cement in order to clean the plastic tubing prior to bonding.

The Pipe Cleaner is simply Butanone, nothing more, and works exactly the same as the stuff purchased from model shops (unsurprisingly!) when bonding chairs to sleepers. However, it's a fraction of the price and comes in a very nice stable container that is hard to knock over

HTH

Brian

[DougN]

I thought that the PVC pipe weld (which I think you know as Polypipe) has a primer here in Australia that is Acetone. (my guys on site know when it has been primed as the colour is a red dye on the pipe!)