Wood vs Metal

[Beachvbguy]

I think I broached this subject inside another thread a while back, but I'm not sure I've really come to have enough definitive information on this topic.

I notice that virtually all the builds I've seen, both here and on Youtube use lumber as the primary construction material, when there's an option (obviously bathrooms and some other areas require other materials.)

Given that my imagination for my conversion is more predisposed to using metal for my walls, counters, shelves, etc, re-purposing industrial or office components where practical.

I'm curious to know what people think/know the primary reason for the choice of wood is. I've considered the following possibilities:

1. cost
2. ease of construction
3. weight
4. aesthetics

As always, all feedback is appreciated

 

[brokedown-SKO]

I think your list is accurate. Most folks are just using metal to connect wood together.

 

[musigenesis]

I'm planning to use quite a bit of steel for my interior fittings. In fact I just finished building my bed frame out of 1.5" angle steel and expanded steel sheet; it's only 1.5" thick as opposed to a wood frame that would need to be 3" or 4" thick to be as strong (although the steel bed is murderously heavy thanks to my overbuilding it). http://www.skoolie.net/forums/f11/rusty-87-build-thread-27741-15.html#post367246

I'm thinking of building my cabinets and shelves out of (much thinner) angle steel and the same expanded sheet (which I can get pretty cheap) and some wood trim in places. Using the expanded sheet instead of solid wood will help my storage areas breathe, although I don't know if that's really all that important since I've never lived in a bus before.

One issue with using metal for interior fittings is thermal conductivity and the need for a thermal break between the metal inside and the metal of the bus. This table: Solids, Liquids and Gases - Thermal Conductivities gives the thermal conductivities (basically the inverse of R-value, with smaller values meaning better insulator) for a variety of materials (metal values are here: Metals, Metallic Elements and Alloys - Thermal Conductivities). The values relevant to buses are:

• Polystyrene (XPS): 0.03
• Wood: 0.15
• Mild steel: 54 (not a typo, no period there)

Wood conducts heat five times more readily than XPS insulation (which also corresponds to the R5-per-inch of XPS and the R1-per-inch of wood). But steel conducts heat 1800 times more readily than XPS (and 300 times more than wood).

With steels shelves and walls etc., there would be a natural tendency to want to just attach the stuff (welding, screwing or however) directly to the bus. But any kind of metal structure that is inside your living space and attached directly to the walls will absorb heat from inside and readily conduct it to the outer skin (outside of your insulation) where it convects away; the more of these metal penetrations your living space has, the harder your heat source will have to work to maintain a given temperature (the metal will also tend to be colder than the rest of the inside).

My steel cabinets and shelves will either be resting on the plywood floor for support or suspended from the wood furring strips on the ceiling, so none of it will be directly connected to the metal of the bus.

 

[Beachvbguy]

I'm planning to use quite a bit of steel for my interior fittings. In fact I just finished building my bed frame out of 1.5" angle steel and expanded steel sheet; it's only 1.5" thick as opposed to a wood frame that would need to be 3" or 4" thick to be as strong (although the steel bed is murderously heavy thanks to my overbuilding it). http://www.skoolie.net/forums/f11/rusty-87-build-thread-27741-15.html#post367246

I'm thinking of building my cabinets and shelves out of (much thinner) angle steel and the same expanded sheet (which I can get pretty cheap) and some wood trim in places. Using the expanded sheet instead of solid wood will help my storage areas breathe, although I don't know if that's really all that important since I've never lived in a bus before.

One issue with using metal for interior fittings is thermal conductivity and the need for a thermal break between the metal inside and the metal of the bus. This table: Solids, Liquids and Gases - Thermal Conductivities gives the thermal conductivities (basically the inverse of R-value, with smaller values meaning better insulator) for a variety of materials (metal values are here: Metals, Metallic Elements and Alloys - Thermal Conductivities). The values relevant to buses are:

• Polystyrene (XPS): 0.03
• Wood: 0.15
• Mild steel: 54 (not a typo, no period there)

Wood conducts heat five times more readily than XPS insulation (which also corresponds to the R5-per-inch of XPS and the R1-per-inch of wood). But steel conducts heat 1800 times more readily than XPS (and 300 times more than wood).

With steels shelves and walls etc., there would be a natural tendency to want to just attach the stuff (welding, screwing or however) directly to the bus. But any kind of metal structure that is inside your living space and attached directly to the walls will absorb heat from inside and readily conduct it to the outer skin (outside of your insulation) where it convects away; the more of these metal penetrations your living space has, the harder your heat source will have to work to maintain a given temperature (the metal will also tend to be colder than the rest of the inside).

My steel cabinets and shelves will either be resting on the plywood floor for support or suspended from the wood furring strips on the ceiling, so none of it will be directly connected to the metal of the bus.

Yeah, While I don't imagine I'll be in too many frigid environments, I am still planning for an totally insulated bus, and it's probably not that difficult to use some material as a psuedo barrier for the conduction of heat from outside in or visa versa. Your idea for wood strips, for example, would solve that.

I just wonder if that would detract from the sturdiness of shelves, desks, folding tables, etc, vs attaching to the existing metal frame components. I'm going to the H.O.W. show and then the Skoolie Swarm for a couple of days after, and I'll try to educate myself a bit there. It seems like wood would be "easier" in some ways to shape to the irregular contours of a bus, but in other ways, it seems like you could do some cooler stuff with metal, given its relative superior strength.

I just watch a documentary of some guy who welded this 2 story whale from tubes to take to Burning Man..... so now I'm kind of motivated to make some cool stuff for the bus... But I don't want to overkill or overweigh or make the whole project too complex, or costly.

Anyway, thanks for the inupt.

 

[musigenesis]

Yeah, While I don't imagine I'll be in too many frigid environments, I am still planning for an totally insulated bus

Since I'm mostly concerned with cold weather, I usually talk about insulation in terms of preventing heat from escaping. But that's just shorthand - it works the same but in reverse for hot weather. It's actually even worse if it's hot and you're in the sun, because the skin of your bus will heat up even more than the air temperature, and that heat will conduct through the metal and into your interior fittings, making your AC have to work harder.

I just wonder if that would detract from the sturdiness of shelves, desks, folding tables, etc, vs attaching to the existing metal frame components.

It would definitely detract from the sturdiness, no doubt.

 

[Beachvbguy]

Since I'm mostly concerned with cold weather, I usually talk about insulation in terms of preventing heat from escaping. But that's just shorthand - it works the same but in reverse for hot weather. It's actually even worse if it's hot and you're in the sun, because the skin of your bus will heat up even more than the air temperature, and that heat will conduct through the metal and into your interior fittings, making your AC have to work harder.



It would definitely detract from the sturdiness, no doubt.

Maybe there's a way of engineering some kind of heat/cool sink... like you'd do for welding something thin....

 

[musigenesis]

Maybe there's a way of engineering some kind of heat/cool sink... like you'd do for welding something thin....

Your bus is basically a giant heat sink already, that's the whole problem. The engineering trick is to insulate your living space from it.

 

[Beachvbguy]

Your bus is basically a giant heat sink already, that's the whole problem. The engineering trick is to insulate your living space from it.

There must be a way to turn that into an advantage..
Since I'm more likely to be frying in the desert than freezing in the tundra, maybe I could use the exterior heat for some kind of backup water heater? drive a turbine?
Lol

 

[musigenesis]

maybe I could use the exterior heat for some kind of backup water heater?

Put a pot of water on the roof and prove yourself the master of thermodynamics.

 

[Ronnie-SKO]

"House on the Rock" in Wisconsin has a whale a few stories high made out of steel. It is in a building with ships models and a winding balcony that goes around the perimeter up to the top of the building, giving a good view of the whale. Very well done and realistic, including a row boat in it's mouth. We saw it last summer on a trip to Minnesota.

Wood is nice to work with for most and for simple stuff takes less skill. For me I like the warmth of wood. I have a wood shop and machine shop so either is fine to work with for me.

Will be at H.O.W. also and the swarm

 

[Iceni John]

I HATE wood! I hate the way it warps, bows, splits, swells and shrinks with humidity changes, and generally has a mind of its own. I also hate how it's impossible to hold tight tolerances in wood, not that it really matters anyway - I can more easily hold a few thous tolerance in metal than a 32nd in wood. So for me, wood is only used in non-critical areas or for aesthetic trim, such as the pine trim around each side window or spacers for each of the tanks under the floor. I also don't much care for its inconsistent appearance: I gave up trying to match the grain and color on the window trims, so now there's slight discontinuity from one window to the next. Maybe I'm just too particular for my own good, but I prefer a very simple clean look with little visible grained wood - my bus will be more minimalist Nordic-meets-Bauhaus, with cabinets from IKEA and lots of aluminum trim on the edges of the walls and overhead cabinets. Walls are covered in pale grey Celtec board, and the ceiling will be white FRP. No rustic log cabin look for me! Most RVs' interiors make me want to barf, with their oppresive heavily-grained wood and yucky carpet everywhere; my bus will be the complete antithesis of that. Le Corbusier said that a house is a machine for living in, so my bus is just a mobile version of that.

John

 

[neversayneverbus]

Wood can always be painted to look like metal. I personally like some wood grain, but I don't want to overdo it. For example I like the flat white look of a drywalled ceiling. I plan on making an arched ceiling in my bus to get rid of the normal curved look. And finishing the wood paneling to make it appear to be drywall.

It's much cheaper to use wood, and as others have said, the thermal conductivity is much less and will help with heating/cooling. The right paint and finish will make it look like metal. As far as strength, wood has more than enough. Also the more weight on your rig the worse your gas mileage will be and more wear and tear on other moving components.

 

[Beachvbguy]

"House on the Rock" in Wisconsin has a whale a few stories high made out of steel. It is in a building with ships models and a winding balcony that goes around the perimeter up to the top of the building, giving a good view of the whale. Very well done and realistic, including a row boat in it's mouth. We saw it last summer on a trip to Minnesota.

Wood is nice to work with for most and for simple stuff takes less skill. For me I like the warmth of wood. I have a wood shop and machine shop so either is fine to work with for me.

Will be at H.O.W. also and the swarm

Thanks Ronnie,

I'll look for your bus at the swarm. and maybe we can meet at HOW too... I'll message you my number, and try not to bug you with too many questions.

 

[Beachvbguy]

Ok, so all of the reasons I listed seem to equally apply, although not in the same order for each person. Since cost is a major factor for me, at least to get started, combined with my own mechanical/construction ignorance and inexperience, I'll plan on having significant wood elements in my initial build.

Thanks all...

 

[Ronnie-SKO]

Thanks Ronnie,

I'll look for your bus at the swarm. and maybe we can meet at HOW too... I'll message you my number, and try not to bug you with too many questions.

You can bug me with lots of questions at the know how expo, that's what we will be there for.

 

[banman]

I HATE wood! I hate the way it warps, bows, splits, swells and shrinks with humidity changes, and generally has a mind of its own. I also hate how it's impossible to hold tight tolerances in wood, not that it really matters anyway - I can more easily hold a few thous tolerance in metal than a 32nd in wood. So for me, wood is only used in non-critical areas or for aesthetic trim, such as the pine trim around each side window or spacers for each of the tanks under the floor. I also don't much care for its inconsistent appearance: I gave up trying to match the grain and color on the window trims, so now there's slight discontinuity from one window to the next. Maybe I'm just too particular for my own good, but I prefer a very simple clean look with little visible grained wood - my bus will be more minimalist Nordic-meets-Bauhaus, with cabinets from IKEA and lots of aluminum trim on the edges of the walls and overhead cabinets. Walls are covered in pale grey Celtec board, and the ceiling will be white FRP. No rustic log cabin look for me! Most RVs' interiors make me want to barf, with their oppresive heavily-grained wood and yucky carpet everywhere; my bus will be the complete antithesis of that. Le Corbusier said that a house is a machine for living in, so my bus is just a mobile version of that.

John

While I sometimes enjoy an "industrial" look, and steampunk aesthetics make me smile I'm a stone and wood kinda guy... (except when it comes to acft...) stones too heavy and bulky for a bus build so that leaves...

But I googled and found the "Celtec board" (even comes in wood grain! ) you mentioned. I like the idea of a finished panel that insulates.
But what is the "FRP" you mentioned? link or...?
Thanks!

 

[Ronnie-SKO]

FRP= fiberglass reinforced plastic. You can get white sheets of it in most home improvement stores for use in bathrooms. One side is smooth, and the other side is textured.

 

[Explorer1972]

I appreciate your asking this because it gave me starter info. While I LOVE wood and have no issue with it, we're going to be in the tropics with our skoolie and bugs + humidity + wood = bad idea. Termites are a thing. So it looks like I need to do something of half and half.

 

[Danjo-SKO]

I personally like wood. It’s more thermally neutral than aluminum or steel. But the way I see it is the best material for the job is the one to use.

 

[Dirtdoctor]

Cabinets from Ikea- I installed someFrom Ikea- within the first year of operation they were loose, breaking up, the parts just couldn’t handle the vibration of the road.
Cheers