Wood treatment on wooden coasters

[toofpikk]

Hi all, Im doing some research into wood construction for my dissertation. I've only got a few days until my hand in and I just realised I haven't given alternate options for some wooden elements of my project, but i thought it would be quite funky and cool to try and transition something from my hobby into my dissertation, even if it's a far fetched fantasy.

My simple question is:
does anyone have any good, academically quotable resources which explain the processes of chemically treating the wood which is typical of wooden coasters so that they are weather proof, and age better, and any other benefits they may have (less rigid, fire retardant, etc etc). The process, the pros & cons are the key bits of info that I need.

If I could get some bits of info along these lines it'd would be super useful, whether it be a manufacturer manual, website, video; anything that seems some what official rather than an enthusiasts spectator video on why and how rides function like they do. I've asked a few nerdy friends and had some quick google searches to no avail, and because of time constraints I can't properly dive into the research, as I've still got other pieces of work to tie up and was hoping that maybe some of you guys could help me out!

Cheers, ta, thanks a million if you can

 

[Hixee]

You could try BS EN 13814 "Safety of amusement rides and amusement devices" which does have sections covering materials. Specifically under Timber is references BS EN 1995 "Design of Timber Structures". It also points to "International standards" for prevention of corrosion and rot.

I won't go into more of the 'best guess as an engineer and/or goon' stuff, as you've specifically said you're not after that.

I'm afraid I can't speak for other nationality's standards (specifically outside Europe, as those are both BS EN docs). Might be able to find a link to the US/Canada/etc/or even ISO version of those documents.

I will point out that generic research into structural timber (I think often called CLT - cross laminated timber) may be useful. Has to pass a lot of requirements (cyclic wind loading, weatherproofing, fire retardation, etc) many of which may overlap with the coaster side of things - I suspect possibly included in the document referenced above. Depending on your locality, you may find many of the standards overlap. You may have already looked into this, of course (taking a punt given the topic of your dissertation), and it may not be quite relevant.

EDIT: Looked up the US standard too - although haven't looked at this in as much detail. You'd be after ASTM F2291 "Design of amusement rides and devices". Timber section also points at generic structural timber standards/handbooks.

 

[Pokemaniac]

Hmm... this sounds somewhat related to my field of study, but I've never done an academic paper on wood treatment (did one on moisture absorption in wood particle boards, however).

If you're looking for articles, I suggest checking out these journals:
European Journal of Wood and Wood Products: https://www.springer.com/journal/107
Journal of Forestry: https://jwoodscience.springeropen.com/

In my experience, the easiest way to find a relevant article is to do a search within those journals, using a few keywords off the top of your head (i.e. "wood treatment" or "waterproofing" or something like that), then go through the search results and pick a few papers that look relevant. Read their Introduction chapter, which usually sums up previous research on the subject, which often includes some good "overview" sources in the field. Look them up in the References list at the bottom of the article. Skimming through the references can be a good idea in any case, because they could be quoting other papers more directly related to what you are looking for.

You can also go the other way around: Look up the papers on Google Scholar to see how they are quoted by other papers, and what other papers are quoting those again. If good papers on the subject you're looking for exist, you will find them pretty quickly.

I will point out that generic research into structural timber (I think often called CLT - cross laminated timber) may be useful.

Cross Laminated Timber is not necessarily the same as structural timber. CLT consists of "sandwich elements" of planks glued together. CLT elements are often load bearing, but rarely exposed to the elements, so they don't undergo the same treatment as coaster wood typically does. For waterproofing and rot protection and such, I think it would be more relevant to look up cladding materials for buildings. They're the ones that take the brunt of the weather, so they're given all sorts of funny chemical baths to make them more durable - alternately, they're just painted. That works too, but it might make the architect grumpy.

 

[toofpikk]

Thank you so much for the replies guys, I'll do some digging this evening and put some stuff in some places. It's actually an architectural dissertation and I had proposed steam bent & glu-lam timber frames for an exterior load bearing structure of my building, but my lecturer had pointed out to me it is extremely rare these materials are actually exposed to elements, and are often cladded up. This massively affects the aesthetic of my design so I am seeking alternative technologies in order to be able to keep the exposed wood look without need for other materials to cover it up. It doesn't have to be in depth but I have to prove I have seeked out resolutions for this dilemma through a little bit of research, doesn't matter if it's not practised or proven specifically, which is why treated wooden coaster timber came to mind.

 

[caffeine_demon]

One thing I can remember fron the cf live to bakken years ago, was that in sweden it's allowed to treat wood with creosote, but you cant use the treated wood there, and in denmark you can use the treated wood, but it's illegal to treat it with creosote,,,

 

[Pokemaniac]

The most common way to treat timber is to boil it in a solution of copper salts, usually under great pressure to press the chemicals into the wood. Previously, I think chromium and arsenic were also used, but that's been outlawed these days, at least in Europe. Slathering it with creosote tar achieves a similar effect, but it's far more sticky and messy to work with. Also, heavily carcinogenic.

After all, the mechanism that degrades wood is usually that something (microbes, fungi, or in rare cases insects) comes along to eat it. Wood treatment doesn't necessarily make the wood stronger, just inedible. Or, rather, toxic to the creatures that try to eat it. Unfortunately, it tends to make the wood toxic to all organisms, so it turns the treated wood into a bit of an environmental problem, what with the heavy metals and such things. Modern impregnation materials are made to be less toxic than those used until the 1990s or so, which actually makes them slightly less effective. It's like leaded gasoline or asbestos insulation, really: those old products gave higher performance than what we use today, but the drawbacks were too big to be allowed. For the same reason, modern paints are less resistant to fungi than ones sold a couple decades ago.

EDIT: I think this article goes deeper into the mechanisms by which wood is degraded. Check the section "Influences on service life", subsection "technically improved resistance to wood-destroying organisms", which should be what you're looking for: https://www.tandfonline.com/doi/full/10.1080/17480270601019658 . The references of that section might also be worth further investigation.
Send me a PM if you don't have access to the full text. I'm sending this from my workplace at the university, so I can't see if it's otherwise restricted or not.

 

[The Undead Creature]

That works too, but it might make the architect grumpy.

Resistance is futile springs to mind....

Us engineers have the enviable task of trying to turn an architects wet dream into something that works by breaking as few laws of physics as possible.

It's been a long time since I did any work on a wood coaster so it's not something I've kept up to date with. But from what I can recall, the timber used on woodies is the same as that used in any other type of load bearing structures. The wood tends to suffer mechanical damage quicker than weathering or rotting on a coaster and any sections that need replacing are done by joiners who are usually subcontracted to the park and deal with ordering the new wood. Fresh planks usually came from whichever local woodyard was the cheapest/had the correct ammount.

As for the treatment process, I had dealings with one company that I know sells treated wood for construction.

Vacuum pressure treatment in Llandrindod Wells

The majority of our timber is treated in our own pressure plant using the vacuum pressure process. Freshly treated timber has a green finish.

www.caerfagu.co.uk

This explains one process of treating wood to a couple of different standards and the wood used for coasters would come under class 3. It even names the specific chemical used.