Wood for trestles?

ge_rik

ge_rik

British narrow gauge (esp. Southwold and W&LLR)
Country flag
I`ve been following Korm`s account of his trestle build with interest and am planning to build a very small trestle for my newly completed mill siding based on the trestle across the River Blyth on the Southwold Railway

SRTrestle.png

What`s the general opinion on the best type of wood to use? It won`t be immersed in water continuously, only when I run the stream, but it will have to survive the ravages of the weather in NW England in a North facing garden in part of the garden which is constantly in the shadow of the house. Moss grows here with absolutely no encouragement.

I`m assuming treated hardwood would be best - yes?

The main members seem to be 14"x7", 12"x12" and 8½" x 9½" and I`ll be building to 15mm (or maybe 16mm) scale

Rik
 
Hi,

If you can find any Red Cedar would be best; I has some from an old Alton greenhouse that was being taken down, and used that on my short trestle.

It is expensive, perhaps Alton themselves could assist?


Here is one source for you

http://www.southgatetimber.co.uk//products/details/Western_Red_Cedar_20_x_45mm_P_A_R__Fencing

cost is shown as £1.99 per metre, and they do list other sizes as well.

A `near Manchester` supplier is at

http://www.laver.co.uk/doclib/clears_bro.pdf

they are at Cadishead.


Here is mine; it sits on plastic footings by the way, and the trestle alone is 68" long and 16" high

[ATTACH=full]180955[/ATTACH][img]



Yours Peter

 

Attachments

  • lhside1.jpg
    lhside1.jpg
    161.5 KB · Views: 235
Actually, treated hardwood would be less desirable. The wood of choice by pressure treatment companies is Yellow Pine.

That said, it's not the best wood to model small members from. Newly purchased treated lumber will twist and turn as soon as you turn your head. Milling small members from it can be frustrating. It has a tendency to have these hairs or strings of wood fibre that cannot be sanded off easily. If you find some older treated lumber, it will be easier to machine, but you'll have more waste as it has had time to dry out, split and check. So getting smaller members out of it will take some effort.

A better choice of wood for exterior use would be one of the Mahogany species like Ipe`. While pricey, the amount you would need will not break the bank. Most good lumber yards sell Ipe`. It can be purchased in 3/4" or 5/4" boards. If you have a table saw you can rip the members you need with relative ease. You'll need a sharp blade however. Ipe can be tough on cutting tools.

Many people think that Cedar is a good wood for use in the elements. If it is constantly wet, as in a water tower, no problem. But if it is subjected to wet and dry conditions, like in a ground contact situation, it will "rot". Actually it softens and then falls apart.

Now if you want to add a bit of your own natural protection use boiled Linseed oil mixed with some Turpentine. Turpentine can still be had these days. Let the wood soak or simply brush the mixture onto the finished bridge. This process will have to be repeated every couple of years. But you can do it in place. Bottom line however is that Ipe or any of the tropical mahogany species will do fine on their own.
 
Thanks for the info, chaps. I don't have the kit to be able to produce my own stripwood sections and so will have to find a source off the shelf. The quantities I'll need mean that the cost won't be phenomenal. I've found mahogany, oak, walnut, obeche, spruce and basswood on ebay in various dimensions. I'm torn between mahogany and oak at present as I assume they will be the hardest.

Great looking trestle btw, Peter

Rik
 
If you want to see what wood lasts look at what boat builders use or used to use.
Oak will last a long time untreated if the end grain is not water logged.
The easiest stuff to get hold of is the African red mahogany moulding strips than the DIY shops and timber merchants stock. I had some of this on my old railway and it lasted over 15 years outside. Don't buy the pail ramin strips though as they only last a few years.
 
funandtrains said:
Oak will last a long time untreated if the end grain is not water logged.
Click to expand...
Does that suggest it needs to be sealed in some way?

Rik
 
ge_rik said:
Does that suggest it needs to be sealed in some way?

Rik
Click to expand...
No, Oak and many other woods will last for a long time without any treatment at all. Think about it, there are Tudor oak framed buildings that are 400 years old that have lasted without any treatment. You just have to be able to let the wood dry out after any rain. You don't need to paint hardwood decking either, people only do it because they don't like the grey colour wood naturally weathers to.
 
Arthur Aardvark said:
Rik,
This link to the pdf gives further information on the types of wood, sizes etc, possibly help you with your final decision on choice and suitability for your project.
http://www.wood-supplies.com/downloads/catalogue2012/complete.pdf
Click to expand...
Excellent - thanks. The suppliers on ebay didn't have all the section sizes I needed and I was trying to work out ways of gluing thinner sections together to make the right sizes. This source has all the sizes I need.

Intrigued by the genuine antique oak possibly sourced from the Armada ships - not that I'll be using it


Rik
 
funandtrains said:
No, Oak and many other woods will last for a long time without any treatment at all. Think about it, there are Tudor oak framed buildings that are 400 years old that have lasted without any treatment. You just have to be able to let the wood dry out after any rain. You don't need to paint hardwood decking either, people only do it because they don't like the grey colour wood naturally weathers to.
Click to expand...
I'll probably stain my model to represent the creosoted timber which would have been used in the SR trestle.

Rik
 
ge_rik said:
I'll probably stain my model to represent the creosoted timber which would have been used in the SR trestle.

Rik
Click to expand...
n which case why not use real creosote? You can still get it the best way to do the job would be to cut your timbers to length then stand them in a deep narrow container for 24 hours and let the end grain take the stuff up. If you cant get creosote the next best thing is used oil from a diesel engine thinned down with " natural turpentine" and soak as before.... I assure you this will give you at least 10 years of protection that is how long some fence paling's I treated have been going and there is no sign of deterioration.
 
Personally I would worry about the stain as even old creosote treated softwood as the surface bleach down to grey after a few years.

Also don't use steel or plated steel screws as they will corrode, use brass.
 
funandtrains said:
Personally I would worry about the stain as even old creosote treated softwood as the surface bleach down to grey after a few years.

Also don't use steel or plated steel screws as they will corrode, use brass.
Click to expand...
I got a pack of round-headed brass pins from the Llanfair Show last year so I'll probably use those (with a dab of superglue to help them stay put)

Rik
 
ROSS said:
CREOSOTE. Now banned in the UK and the substitute is crepe.......
Click to expand...
I remember real creosote. I doused the timbers of the fence with it, which was erected round our house when we moved in 30+ years ago - and I still have the timbers from that fence - in fact some of them have been used as trackbed on the elevated section of my railway. Still love the smell. I mixed the creosote with old engine oil back then to eke it out (and get rid of the engine oil). Pity they've banned it - though no doubt there will be places where it can be bought under the counter. Just need Del-Boy's phone number (sorry UK-centric reference).

Rik
 
On the issue of using Oak. Be sure that it is not Red Oak. Try to get White Oak.
 
Madman said:
On the issue of using Oak. Be sure that it is not Red Oak. Try to get White Oak.
Click to expand...
funandtrains said:
You can buy stainless steel nails, screws and pins for fixing external timber if you need more strength.
Click to expand...
Thanks chaps
Useful info

Rik
 
If you go with Oak, do NOT use any form of steel fixings..
Acid in Oak will rot them out in no time.
 
PhilP said:
If you go with Oak, do NOT use any form of steel fixings..
Acid in Oak will rot them out in no time.
Click to expand...
That I did not know - thanks

Rik
 
PhilP said:
If you go with Oak, do NOT use any form of steel fixings..
Acid in Oak will rot them out in no time.
Click to expand...

I would think that stainless steel would be OK
 
You must log in or register to reply here.
Back
Top Bottom