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wood !

Started by swbono, Sep 29, 2010, 10:55 am

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swbono

Hi.
still in the planning stage of my build.
im wondering which wood to use.
1st i thought mdf , then realised i would be replacing most of it later due to it soaking up all the rain.
then ply or osb.
Anyone used osb ?.
what thicknesses are advisable ?.
i will be using pine as well .
ps . going for a 2005 -2010 one . i Think

Scarfwearer

Most people have used ply or MDF for the panels. Apparently some of the screen props used 1/4" ply for the panels, though of course you could use thicker stuff if you want. I used 1/2" ply for mine, though the result is quite heavy.

The new series TARDIS makes a feature of the exposed wood grain, which earlier models have tended to hide, so OSB would be an odd choice as you would have to go to some lengths to hide the appearance, which would probably dwarf the price difference.

Crispin

swbono


hb88banzai

Sep 30, 2010, 07:26 am #3 Last Edit: Sep 30, 2010, 07:43 am by hb88banzai
OSB is lighter than MDF, but not as strong as regular Plywood (in any direction, but especially to twisting loads). OSB really is a compromise between the two, with some quirks of its own. Both OSB and MDF are less mechanically sound than either Plywood or Timber when it comes to things like holding nails or regular wood screws, so extra care has to be taken at connection points. Note also that while you can easily get a nice smooth (or artificially textured) surface with MDF, hiding the unique surface patterning of OSB might be a bit of a challenge.

To my mind (purely personal), MDF is evil, pure and simple, while OSB is Plywood's disabled 2nd cousin.

In contrast, regular pine or fir Plywood is a good solid workmanlike material. If the budget allows, though, you might want to consider a hardwood ply like Mahogany, Birch or Maple Plywood as it is far superior - a bit more expensive, true, but boy do you get what you pay for in something that is very strong, durable, relatively lightweight (at least compared to MDF) and easy to work (fewer voids in the laminations, fewer knots, more consistent, etc.).

Either kind of Plywood (ie, softwood or hardwood) has the added benefit over Timber that it is far more dimensionally stable (less likely to warp or change dimensions unevenly with weather conditions) and is also less likely to fall apart if it gets wet or stressed than either MDF or OSB. Just be sure to get a Plywood that is rated for outdoor/exterior use (or at least well and truly seal it on all sides and edges) if you plan on it spending any significant time in the weather as you really don't want it to de-laminate if it gets wet.

DoctorWho8

If you really want something other than wood or fiberglass for outdoor builds, you can get sheets of PVC material! :)
Bill "the Doctor" Rudloff

philipw

Quote from: DoctorWho8 on Sep 30, 2010, 01:11 pm
If you really want something other than wood or fiberglass for outdoor builds, you can get sheets of PVC material! :)
Bill "the Doctor" Rudloff


Except that pvc sheet is great if painted light color, painted blue it would move (expand) with heat greatly, causing all kinds of joint problems. Moreso than even humidity changes would affect traditional wood.

DoctorWho8

Arrr, you shot me down. ;)
Bill "the Doctor" Rudloff

Quote from: philipw on Sep 30, 2010, 02:52 pm
Quote from: DoctorWho8 on Sep 30, 2010, 01:11 pm
If you really want something other than wood or fiberglass for outdoor builds, you can get sheets of PVC material! :)
Bill "the Doctor" Rudloff


Except that pvc sheet is great if painted light color, painted blue it would move (expand) with heat greatly, causing all kinds of joint problems. Moreso than even humidity changes would affect traditional wood.

swbono

Oct 19, 2010, 03:50 pm #7 Last Edit: Oct 19, 2010, 04:14 pm by swbono
going to go with ply .
then softwood over ply for the detailing  (TG Floor boarding).
what thickness do you use for the ply and detailing surround .
was thinking 9mm or 12mm ply then  22mm tg floorboarding .
or is that just to thick .

Scarfwearer

For the panels you can use whatever thickness you like. I used 12mm (actually 1/2") but thinner or thicker would be fine. It depends how heavy you want your Tardis to be(!)

The thickness of the stiles depends on the plans you're working to, as that will actually affect the final appearance. Check the [ref board=77]Plans[/ref] board for a thickness to match the particular design you're going for. Generally speaking you'll want something between 1/2" and 1" (12-25mm)

Crispin

swbono

Thanks Crispen .
dont want it too heavy .
2005 model .
looked in the plans board but couldnt find much on thicknesses .
im currently working with bill rudloffs 2005 plan that shows the sign boxes as 3/4 inch thick but nothing else.
i agree the thickness will affect its final apperance , bit chunky etc.
i thought 9mm ply would be ok for the door and side but thought the 22mm TG boards were thick ish .
any advice ?  ???

philipw

For 2005 tardis used for the show...

all the boards are 3/4" thick all the ply is 7/32" thick. (or whatever that translates to in available material in metric.)

Based on measurements on the actual prop.

You could use any thicker wood for the ply, but this will make it light and obviously strong enough to withstand being materialized and dematerialized many times.


swbono

Oct 19, 2010, 06:19 pm #11 Last Edit: Oct 19, 2010, 06:28 pm by swbono
7/32 is 5.5mm so quite a bit thinner than i thought.
thank you Philip  ;)


Ps ..
Are the 3/4 boards angled or straight (hope there straight)
also any ideas on having 18mm ply for the outer in 1 piece rather than seperate boards ?

philipw

It's thinner than I would have guessed as well. However, the tardis I'm getting ready to build will be done with material just like the prop, so 7/32 ply.

I'm not sure I follow the angled or straight question. The panels are made from the ply with 3/4" boards attached to the outside to mimic the raised panels, then they have the bevels routed onto them and the corners chiseled. If you're asking about using a sheet of 18mm ply for this rather than separate boards, you could but ply may not do as well as solid wood would when you bevel the edges.

deck5

Quote from: philipw on Oct 19, 2010, 10:11 pm
If you're asking about using a sheet of 18mm ply for this rather than separate boards, you could but ply may not do as well as solid wood would when you bevel the edges.


Second that!  Routing a bevel into the edge of plywood will result in much wailing and gnashing of teeth.

swbono

So there angled then .on the edges of the raised bits .
ply would have been ok if it was straight thats why i asked .
no gnashing of teeth then : )
have found some ply available localy
5.5mm - £11
9mm - £14.50
12mm - £17.60
18mm - £25.50
all external grade 2440x1220mm .
will go and get 4 of the 5.5mm and a couple of 18 tomorrow .
then find some boarding for the raised bits , 4 & 6 inch wide .(6 for the corner posts )