We had a very interesting visit to Bekonscot yesterday, with (by my count) 23 Members and Guests attending.
After a pleasant individual tour of the gardens we were welcomed by Brian Newman-Smith (Managing Director) who kindly gave us a 'behind the scenes tour' of the "workings" and workshops. Although a Gauge '1' Railway, Bekonscot stock runs seven hours a day, seven days a week for two thirds of the year, so they have some interesting thoughts on reliability and how to build stock to deliver good running. However, this will be the subject of an article in the December Newsletter, so no more here.
What did attract Members attention was Brian giving a very strong recommendation as to their preferred building matieral for their model buildings. They have used a product called Airex PVC Foam Sheet for some time now and Brian showed examples of building components made with this material. More in the December Newsletter but for Members present who wanted the supplier details, they are as follows.
iMPAG (UK) Limited, Draycott Business Park, Can, Dursley, Glos, GL11 5DQ
Phone: 01453 890077 eMail: composite@impag.co.uk
Airex PVC Foam Sheet is available in different densities but BK mainly use C70.75 - it is also available in different board thicknesses, 1" was suggested as being most useful.
Finally, a thank you to Mike Williams for organising such an interesting visit.
Regards,
IanT
I join you in thanking Mike for organising such an interesting visit.
I first came across Airex 30 years ago but had forgotten about it until yesterday. It is a 'closed cell' foam, i.e. under a microscope, a cross-section shows complete spherical bubbles spearated from each other by resin, that water cannot penetrate. In an open cell foam, the bubbles merge into each other, leaving passageways for moisture to penetrate. Rigid PVC foam is more malleable and ductile than rigid polyurethane foam. When impacted, it deforms but then more or less recovers its original shape, which polyurethane generally does not.
At Bekonscot, they are using it by itself for building construction, and very effective it is too. But there's another technique that is useful: you can bond sheets of card, plastic, glassfibre or other materials to each side of the foam to make lightweight "sandwich" laminates that are very, very strong and stable (even bullet-proof!). For example, I think it should be possible to make lightweight, removable, waterproof outdoor baseboards using an Airex sandwich on aluminium frames.
I'm going to try to make the platforms and building shells on my layout from this material. Maybe bridges too? Watch this space.
Regards, Ted
The real thanks should be directed towards the Bekonscot management who went out of their way to help us, keeping the refreshment kiosk open way after hours, opening up the workshops and even giving free tea and bickies.
This was the first time we had tried a non-garden GTG, and the next is in Derby on 30th October, so I hope you will give us the same great support you did at Bekonscot.
Mike
As Ted has said, Airex is used as a core is composite structures, e.g. boat hulls, aircraft cowlings, cab and intermediate ends on railway vehicles - which led me to thinking that if anyone has contacts in this area of industry there may be the opportunity to get off-cuts for modelling use.
Thanks from me too for the visit - most enjoyable and informative.
Andy
That could be an interesting thought for Modular baseboards Ted (light + strong) - but I wonder at the likely cost of using Airex like this? What would you 'surface' it with?
IanT
For outdoor portable baseboards, I have been trying to think how you could scale up some of the good ideas and techniques that are used in the smaller scales. At some of the recent model railway shows, I have seen consdierable advances in 'engineering' lightweight baseboard frames - e.g. thin plywood laminated beams drilled with enough holes to satisfy a Swiss cheese maker. The major challenge for Gauge 3 is making them from materials that are weatherproof and dimensionally stable under the loads we put on them.
I was thinking of PVC fascia cladding (e.g. soffit boards) as the outer layers of an Airex sandwich. You only need the actual track base itelf to be rigid and strong: the open scenery areas of a baseboard could be based on other, single-layer materials supported on the frame members. Textured areas like embankments could be formed with a base of chicken wire over suitable profiles, just like the smaller scales. Polypropylene mesh (sold as windbreaks for plants in garden centres) is another useful material.
I really would like to hear other ideas and especially to receive members' experiences of using different construction materials outdoors.
My ideas probably do not form the basis of cheap baseboard modules, unless you start comparing the costs against the rolling stock you want to run on them. I'm thinking of modules not only for get-togethers and exhibitions, but maybe also people who want to leave temporary baseboards oudoors on a patio, to run at weekends if they cannot build a permanent garden line.
Regards, Ted
Members might also like to consider Styrofoam. It is the blue stuff. It is also a closed cell product and very light. I would suggest that if a 65mm board were sliced up into say 200mm planks and then laminated with a 9mm ply sheet that it would stand a fairly hefty weight and still be very light. Seal with resin if you felt it neccessary
Christopher,
Can you tell me more about Styrofoam? The firm of that name seems to sell it in packs of 24 sheets only - or more! and it has a minimum thickness of 25mm. I'm looking for a single sheet c5ft xc2ft 6in on which to mount some track to carry around to shows and Styrofoam stuck to a thin ply face or maybe even a hardboard layer would seem ideal.
Do you know of a supplier, or maybe it goes under a different name?
Mike
Mike,
Have seen the pink type at B&Q, though think it only comes in a multi-packs, but could use it on a future scenic layout?!?
Derek.
Well, maybe its me, but I still can't find anything suitable.
I have a 3-way point that I'd like to mount onto a light-weight board so that it can be taken to exhibitions without damage, but isn't too lumpy. I could make a thin plywood board the same conventional way basebaords are made, but I thought a piece of this stuff might work unsupported, and I could just cut it to slightly larger than the point.
Any suggestions, please?
Mike
If all you need is a lightweight support/base for the item at exhibitions, how about the card/foam/card sandwich boards sold in artists' materials shops? Hobbycraft in Milton Keynes (near B&Q), which I know is local to you, could be worth a look.
In an earlier post, I said that I was thinking about using PVC fascia board on portable baseboards. I saw it on a layout last week where it has been used as a platform surface, mounted on wooden supports. Unfortunately it has shrunk lengthwise in less than a year, leaving gaps in the platform. Back to the drawing board!
Ted
Mike,
Still think Styrofoam edged in thin plywood or MDF would suit your requirements and would also be an ideal lightweight method of producing Ian's "Standard G3 Modules".
There is an article in MRJ 156 on producing baseboards by this method, plus Gordon Gravett has used it on his latest (French metre gauge) exhibition layout.
Individual sheets are supplied by Trylon model suppliers of Northants (NN10 8HQ) - see under "Modelfoam" @ www.Trylon.co.uk .
Also, as mentioned previously, something similar is available at B&Q, though not sure if it is the same density as true Styrofoam. I saw individual sheets in my local store last week.
Derek.
Thanks Derek. I had looked on B&Qs website and couldn't find anything like it, but the Northampton firm sound ideal.
For me this is what the forum does best. Thanks.
Mike
Thanks again derek. Pack bought from B&Q last night and looks to be just right.
Mike
I assume this is quite a dense material Mike?
As opposed to the kind of light polystyrene material that can be found used as pre-formed packing or for roofing insulation...
Also - how thick is it?
IanT
Ian,
They had sheets of polystyrene which damage too easily and are soft. They also have large sheets of a harder material which was more dense. I went however for sheets c500m x 1200mm x c50mm in packs of four which seems to be even more dense and hard to bend or break. It comes in a pretty pink colour! Two inches is a lot for a baseboard, but as Derek says, with a suitable polished wooden edging it should look quite attractive.
I'm not sure how you join the stuff. For instance, I need 1500mm length and the frame/edging could probably hold the two parts in line without gluing, but how do you fix the edging in place, especially if I shape it into a concave curve with the band saw?
Mike
Just noticed this not-very-helpful piece of advice from a manufacturer's website:
"When using adhesives, the installer should take care not to use products that contain chemicals likely to attack the insulating foam such as ketonic solvents. Celotex EL3000 contains no chemicals or solvents likely to damage the PVC membrane. When using adhesives, the installer should check the compatibility of the adhesive with the adhesive manufacturer."
Right, so no Ketonic solvents, whatever they are. I just want to know what common adhesives I CAN use. - Ralph????
Mike
As requested....
Ketones are a group of chemicals that are famous for their "fruit" smells. Acetone is by far the most famous. MEK is of course short for Methyl Ethyl Ketone. I would suggest a silicone glue the most common brands being "PINK GRIP" or "GORILLA GLUE" -use the water based type and make sure that you use hand cream or vaseline on your hands prior to using. Not because the glue will attack your flesh -but that you will be able to get it off your flesh...
Alternatively you could use a water based phenol resorcinol glue such as "No More Nails" etc
regards
ralph
Wow, that was quick. Thanks Ralph!
From the article in MRJ 156 they seem to have had problems with "No Nails" getting a thin coat spread over a large area and needed some large woodwork clamps to get a good bond with no gaps. Unibond sandable wood glue work well as long as the ambient temperature was not too high (may be a problem this weekend!!) and Copydex gave a very strong bond between foam and wood, but not foam to foam.
Hope this helps and look forward to seeing how it turns out.
Derek.
Apparently there are two types of "no more nails" - one spirit based and one low-odour water-based.
I had the former to hand and the reported problems spreading it thinly didn't materialise as it doesn't soak into the foam - it just disolves it away leaving a gently undulating surface which is fine for a model field, but not good for baseboard joints. I need to go back and buy the water-based type!
Mike
Hello Mike
Sorry to be off the ball.
Styrofoam is a building material, made by Dow Corning, and sold by Sheffield Insulations which are a nationwide company as far as I know.
It comes in various thicknesses, 25, 45, 65 etc. It is closed cell so doesnt absorb water and is blue. It should not be confused with any other colour which is not the same stuff.
It is not particularly expensive - I am just about to order 15metres sq. to insulate a floor - but the off cuts get used for all sorts of things - including wire cut coaches. (refer to FL)
I would suggest that you use 65mm and cut a board into three strips and face front, back and the two inner faces with thin (4-6mm) ply.
Use resin as a glue.
Also have a look at http://jpduval.free.fr/Galeries_photos/Resmod/Reseau_modulaire_Barnac_2008/index.html
who has produced a modular layout system that would lend itself to this sort of panel construction.
Best wishes
Cut lightening holes in it if weight is an issue. SF weighs virtually nothing. Structurally it is 'stiff' and can be cut with a sharp knife, sanded and filed
Module construction download (in French) http://jpduval.free.fr/Plans/SPEC_Reseau_Modulaire.pdf (http://jpduval.free.fr/Plans/SPEC_Reseau_Modulaire.pdf)