What does "Light Weight" mean?/

downhill

Adventurer
I thought I would start this conversation and see where it goes! My basic question is: What does light weight mean to you when talking about truck campers? I'm not talking about what is available, but what sounds reasonable to you??

Background: I've been adventuring in the outback since before I could legally drive. That puts it around 45 years. My very first overland camper was a 1967 VW baja beetle. I removed the back seat and built a flat deck. Then I removed the passenger seat and extended the deck out to the dash. I put a rack on top for extra gear, and my first one man back country camper was launched! I could sleep along the passenger side. I had storage under everything, and I had a little space left behind the drivers seat to cook a simple meal in bad weather. The light weight and simple design served me well.

I've had many offroad adventure rigs since those early days, one was even featured in a magazine. Every one had to be home built because there simple were no options for someone wanting good serviceable back country accommodations without a ton of weight.

I learned early that weight was a killer, whether on my back when packing, or when building a vehicle for rough use. Added weight and oversize dimensions are a huge detriment in the back country. They put added strain on suspension and frame components, raise the center of gravity, and present problems when negotiating wooded areas.

Even today, with all the wonderful modern materials, you can't even buy a sturdy serviceable shell camper that weighs under 500 pounds. Am I alone in wondering why?? Should it take 4 strong men to lift a shell sturdy enough to sleep in, cook a meal, and provide some comfort in a rugged setting? Well, I know the answer is "no". A really nice, super strong short bed camper shell can be built under 350 pounds using modern materials. Most manufactures don't even post the weight of their campers. Do they not believe the weight is a primary factor in deciding what model to buy? My conversations with a few manufactures have been frustratingly vague. It usually comes around to them saying that "nobody has ever asked for this information", and making me seem unreasonable for even asking.

So, I'm posting this because I'm wondering if I am alone in this frustration? I don't need to recreate my living room in the outback. I need a dry place to sleep and prepare a meal in bad weather. I need enough insulation to make the camper heat-able in winter conditions. Good basic shelter. Most importantly, I need it to not be more of a burden than it's worth. I need something that doesn't limit my travels, but enhances them.

Comments?
 

::Squish::

Observer
This is just me and how I segment up the marketplace
To me a "camper" is self-contained, with the exception of the bathroom
It should have at least place to store stuff, cook stuff, a source of water and a bed.

Lightweight is anything ready for camping that weighs in below around 1000#, 1200# if it's fully self contained and includes holding tanks and all of that.
There's not much in the lightweight camper market.

Medium weight is between 1200# and 1900-2000# and heavy weight is everything above that.

A sleeper is just a place to sleep and maybe hang-out out of the elements, (think truck with a camper shell/canopy with a bed in the back.)
Lightweight for those is sub 600#
 

IdaSHO

IDACAMPER
Honestly, this is where I see custom RV/Expedition vehicle manufacturers coming into play.

Regardless of shell construction, most models with similar R-value (not just "lightweight") as a bare shell come in at nearly the same weight.

Its the appliances, amenities, and options that create such a variance in weight across the MFGs.

Obviously there are a few exceptions to that rule, but in most instances it is what makes or breaks where you draw the line for weight.
 

UHAULER

Explorer
Light weight is subjective, but to me it means being under GVW by as much as possible. I had a Northstar 650 on my f350 , with normal camping stuff for a week, it weighed 9,400# with me, my wife and dog. My GVW is 9,200. I know Northstars aren't known for being light. In general I think most slide in campers have too much weight up high, most of them have the heavy parts above the bed sides, battery,water heater,furnace, refrigerator. Just getting the weight down low would make a big difference in how a vehicle handles. I think a flatbed or service bed would work good if you could put all the heavy stuff under the bed as low as possible.
 

fluffyprinceton

Adventurer
So, I'm posting this because I'm wondering if I am alone in this frustration? I don't need to recreate my living room in the outback. I need a dry place to sleep and prepare a meal in bad weather. I need enough insulation to make the camper heat-able in winter conditions. Good basic shelter. Most importantly, I need it to not be more of a burden than it's worth. I need something that doesn't limit my travels, but enhances them.
- x2!
Coming from a boat building background I find it inexplicable how the rv manufactures have ignored the composite material advances now widespread in the marine industry. Stick building? Still? Alaskan Camper is still building with 1950 era methods...It's a shame I tell you!!!Moe
 

downhill

Adventurer
Honestly, this is where I see custom RV/Expedition vehicle manufacturers coming into play.

Regardless of shell construction, most models with similar R-value (not just "lightweight") as a bare shell come in at nearly the same weight.

Its the appliances, amenities, and options that create such a variance in weight across the MFGs.

Obviously there are a few exceptions to that rule, but in most instances it is what makes or breaks where you draw the line for weight.
I think at least part of the problem, and the reason most are close to the same weight regardless of construction, is that the materials are not being utilized to best advantage. take for example 3/4 inch marine grade plywood with fiberglass cloth skins both sides. I wonder if anyone would consider that construction too light for a small truck camper? I think most people would see that as massively built. The R value of that wall construction is about 1.2. You can get the same stiffness from 1" thick Nidacore type material, with an R value of 4.1, and the weight is roughly half. So why isn't 1", 1/2", or 3/4" composite being used in building truck campers?? It is widely used in boat building.

On the subject of R-value. It is not really very applicable to truck camper construction. The reason is that such small spaces require constant air turnover to remain comfortable. It is the airflow that primarily determines the heat exchange, not the R value of the walls. I would say that an R-value above 2.0 is probably not needed in a camper. For comparison, one of my early home built campers was aluminum skinned with two layers of reflectix for insulation, totaling about R-2.16. It was essentially an insulated aluminum canopy. Hardly a well insulated affair. I did have insulated window covers to block some heat loss through the glass (another problem). That camper was comfortable down to -5 degrees with the smallest catalytic heater. A bigger issue than wall material is cold bridging, which presents real problems in aluminum framed structures, and especially where the aluminum bridges into the cabin space. That is a true heat sink, and presents significant condensation issues.
 

downhill

Adventurer
- x2!
Coming from a boat building background I find it inexplicable how the rv manufactures have ignored the composite material advances now widespread in the marine industry. Stick building? Still? Alaskan Camper is still building with 1950 era methods...It's a shame I tell you!!!Moe
our replies crossed ....similar thoughts :ylsmoke:
 

fluffyprinceton

Adventurer
Great intelligent post!

"So why isn't 1", 1/2", or 3/4" composite being used in building truck campers?? It is widely used in boat building." (or 1/2" -3/8"- 1/4" -3/16" 1/8th" panels...) One reason is the simple bonding techniques used to build a simple box aren't well known and are radically different than cabinet making or home building. You can't drive a screw into the edge or body of a composite cored panel & expect it to hold anything - paradoxically the manual skills needed to build with composites are generally much less than with wood or welding for that matter. BUT building with composite's does reward decent design skills as you very much want to have a overall design worked out so when it comes time to mount heavy stuff to composite panels you want to have hard points that bond the two skins built into the panel (but you can still add them as you go along...). So the lack of knowledge about "liquid joinery" bonding techniques, fear of epoxy and folks difficulty in getting their heads around the way those thin skins on a composite panel really do carry all the significant loads...is the main reason. It's not all techy & weird materials either - using "liquid joinery" you can make cabinets, drawers & boxes for everything from heavy steel tools to super light stuff out of ply - good ply yes - but just big box shop birch works ok if it has lots of plys & no internal voids. You can very easily 1/2 the weight of all the interior built-ins just by using thin ply with liquid joinery.

"On the subject of R-value. It is not really very applicable to truck camper construction." "I would say that an R-value above 2.0 is probably not needed in a camper. "I'm in 95% agreement...I've got 3/4ply with a glass/epoxy skin on some of the lower half of my camper & in very cold temps the cold radiates noticeable. So I wish I'd built 3/4 composite panels there instead - R-2 would be fine. More for an arctic camper IF you figure out how to get rid of your internal moisture without just blowing the heat out...Moe
 

IdaSHO

IDACAMPER
I think at least part of the problem, and the reason most are close to the same weight regardless of construction, is that the materials are not being utilized to best advantage. take for example 3/4 inch marine grade plywood with fiberglass cloth skins both sides. I wonder if anyone would consider that construction too light for a small truck camper? I think most people would see that as massively built. The R value of that wall construction is about 1.2. You can get the same stiffness from 1" thick Nidacore type material, with an R value of 4.1, and the weight is roughly half. So why isn't 1", 1/2", or 3/4" composite being used in building truck campers?? It is widely used in boat building.
Yeah, 3/4" marine is WAY overkill for any camper. Done right, you can get away with 6mm (1/4") marine on the exterior, laminated to XPS foam, and skinned with luan on the interior.
My testing has shown that in many cases, I can even get away with 4mm marine, and reduce the panel weight by nearly 30% My next prototype will be done as such.

On the subject of R-value. It is not really very applicable to truck camper construction. The reason is that such small spaces require constant air turnover to remain comfortable. It is the airflow that primarily determines the heat exchange, not the R value of the walls. I would say that an R-value above 2.0 is probably not needed in a camper. For comparison, one of my early home built campers was aluminum skinned with two layers of reflectix for insulation, totaling about R-2.16. It was essentially an insulated aluminum canopy. Hardly a well insulated affair. I did have insulated window covers to block some heat loss through the glass (another problem). That camper was comfortable down to -5 degrees with the smallest catalytic heater. A bigger issue than wall material is cold bridging, which presents real problems in aluminum framed structures, and especially where the aluminum bridges into the cabin space. That is a true heat sink, and presents significant condensation issues.
Cold bridging will always be a concern, regardless of materials. Obviously metal framed units are worse than any other material, but there are work-arounds. Creating thermal breaks is a start.

My research and testing has shown that the #1 way to create a more EFFICIENT camper is by adding insulation.
Lots of fun numbers to throw around, but the gist of it is that for every bit of insulation you add, you reduce your dependence on a heating or cooling source.
This means you can go longer on one tank of fuel, or simply lighten the load and go with less. Best part about it is that insulation is LIGHT, so its a win-win.

Additional insulation also negates much of the condensation issues you speak of.
If the cabin is insulated well enough, then the interior surface never gets cold enough to condense moisture.
Condensation issue = GONE. Its a simple matter of dew-point.
Air exchange helps, but in many cases it simply isn't needed if insulated well.
Obviously you cannot stop breathing.... Its a small space, and simply opening the door once or twice a day is typically enough.

So for true full-time 4-season, go wherever you want campers, I always push for more insulation.
It is a small space, so R-value is not very relative to home R-Value numbers.

I see R7 or so in an RV being equivalent to R30 or so in a home
 

downhill

Adventurer
Great intelligent post!

"So why isn't 1", 1/2", or 3/4" composite being used in building truck campers?? It is widely used in boat building." (or 1/2" -3/8"- 1/4" -3/16" 1/8th" panels...) One reason is the simple bonding techniques used to build a simple box aren't well known and are radically different than cabinet making or home building. You can't drive a screw into the edge or body of a composite cored panel & expect it to hold anything - paradoxically the manual skills needed to build with composites are generally much less than with wood or welding for that matter. BUT building with composite's does reward decent design skills as you very much want to have a overall design worked out so when it comes time to mount heavy stuff to composite panels you want to have hard points that bond the two skins built into the panel (but you can still add them as you go along...). So the lack of knowledge about "liquid joinery" bonding techniques, fear of epoxy and folks difficulty in getting their heads around the way those thin skins on a composite panel really do carry all the significant loads...is the main reason. It's not all techy & weird materials either - using "liquid joinery" you can make cabinets, drawers & boxes for everything from heavy steel tools to super light stuff out of ply - good ply yes - but just big box shop birch works ok if it has lots of plys & no internal voids. You can very easily 1/2 the weight of all the interior built-ins just by using thin ply with liquid joinery.

"On the subject of R-value. It is not really very applicable to truck camper construction." "I would say that an R-value above 2.0 is probably not needed in a camper. "I'm in 95% agreement...I've got 3/4ply with a glass/epoxy skin on some of the lower half of my camper & in very cold temps the cold radiates noticeable. So I wish I'd built 3/4 composite panels there instead - R-2 would be fine. More for an arctic camper IF you figure out how to get rid of your internal moisture without just blowing the heat out...Moe
Moe,
It's true, the key is joinery. Most people don't even stop to think that the glass sheet that sits a couple feet in front of them on their daily commute is held in by "glue". It has been for decades. The technology to join things with adhesive has been in use for decades, but perceptions are hard to change. When did the space shuttle program start?...around 1980?? 37 years ago the tiles that shield the shuttle during re-entry were glued on!

You are also right that moisture is a major concern in a closed space. On average, one human will lose about 400ml per day through breathing. They will lose another 200 to 400 through the skin. Say 600 ml per day per person, that is 25 -50 ml/hour just from sitting in the camper! Overnight that is 1 1/2 cups of water produced and thrown into the air. Imagine how damp things would be if you put that water into a spray bottle and emptied it into your camper. Actually, I don't have to image it because I have spent significant stretches living in campers in all weather conditions. You have to have constant air turn over.

Some way to exchange that air while retaining the heat would be good!
 

downhill

Adventurer
Yeah, 3/4" marine is WAY overkill for any camper. Done right, you can get away with 6mm (1/4") marine on the exterior, laminated to XPS foam, and skinned with luan on the interior.
My testing has shown that in many cases, I can even get away with 4mm marine, and reduce the panel weight by nearly 30% My next prototype will be done as such.



Cold bridging will always be a concern, regardless of materials. Obviously metal framed units are worse than any other material, but there are work-arounds. Creating thermal breaks is a start.

My research and testing has shown that the #1 way to create a more EFFICIENT camper is by adding insulation.
Lots of fun numbers to throw around, but the gist of it is that for every bit of insulation you add, you reduce your dependence on a heating or cooling source.
This means you can go longer on one tank of fuel, or simply lighten the load and go with less. Best part about it is that insulation is LIGHT, so its a win-win.

Additional insulation also negates much of the condensation issues you speak of.
If the cabin is insulated well enough, then the interior surface never gets cold enough to condense moisture.
Condensation issue = GONE. Its a simple matter of dew-point.
Air exchange helps, but in many cases it simply isn't needed if insulated well.
Obviously you cannot stop breathing.... Its a small space, and simply opening the door once or twice a day is typically enough.

So for true full-time 4-season, go wherever you want campers, I always push for more insulation.
It is a small space, so R-value is not very relative to home R-Value numbers.

I see R7 or so in an RV being equivalent to R30 or so in a home
Condensation occurs when the surface is below the dew point. Surface temperatures of cold bridged areas can be far below the cabin temp. You can be at 70 dregees in a camper and have condensation or even ice. Glass and bridged aluminum are the worst offenders. Even minimally insulated wall areas are usually fine unless you get into truly arctic conditions as Moe described. Air exchange isn't needed if the insulation is good enough??? I just don't know what to say to that. Even if you could somehow keep the condensation from happening, the humidity level would be unbearable. This is why we wear goretex instead of down jackets with a plastic shell. If you are running a heater, and breathing you are also consuming oxygen.
 

rruff

Explorer
Yeah, 3/4" marine is WAY overkill for any camper. Done right, you can get away with 6mm (1/4") marine on the exterior, laminated to XPS foam, and skinned with luan on the interior.
My testing has shown that in many cases, I can even get away with 4mm marine, and reduce the panel weight by nearly 30% My next prototype will be done as such.
Very overkill! I'm planning to use 3mm Okoume in and out, with a polyester fiberglass skin. The fiberglass adds a very light and durable layer. I made one 16 years ago with cheap luan on both sides plus fiberglass extrerior. Plenty solid. 4mm Meranti would be even stronger. I'm using 6mm only for the floor panels.

Additional insulation also negates much of the condensation issues you speak of.
If the cabin is insulated well enough, then the interior surface never gets cold enough to condense moisture.
Condensation issue = GONE.
That makes sense. It might not save you a lot on heating if you are keeping it well ventilated, but it will cut down on condensation.
 

fluffyprinceton

Adventurer
Yeah, 3/4" marine is WAY overkill for any camper. Done right, you can get away with 6mm (1/4") marine on the exterior, laminated to XPS foam, and skinned with luan on the interior.
My testing has shown that in many cases, I can even get away with 4mm marine, and reduce the panel weight by nearly 30% My next prototype will be done as such.[/QUOTE

You've gone a middle way in that a panel using XPS foam & ply skins - while lighter - is a long way from using a structural foam with enough compression & shear strength to make a true structural composite panel where the skins carry the majority of the load. I'm not saying your approach is inadequate in any way but it's much heavier than using structural foam - it's also much cheaper & because you are building a structure with a structural internal frame it's a building concept much easier grasp for anyone with typical clad frame house building experience - so it's easy to see the popularity of that approach in the DIY teardrop trailer community - but your really significant weight savings will come only by moving to true structural sandwich composite panels.

DIY structural sandwich composite panels are not hard to make without needing vacuum pumps & infusion but it's definitely a conceptual leap for most - the same excuse just doesn't fly for the manufactures who can invest in the gear & skills to do it routinely. Just hire some boatbuilders! One thing about slide-in truck campers is they are relatively standardized at far as the basic dimensions so even just 2 building molds would cover the majority of the trucks - plus it's routine for boatbuilders to use expandable molds so some basic customization of camper size can can be done with the existing molds...

Marc @ XP camper is an interesting case - his construction is a true structural sandwich composite - but all the built-in furniture, high end appliances, systems & 75gal h20 & 27gal black h20 tanks really push the weight up. So I guess the truth is not enough people want a light weight camper since they will just fill the damn thing with crap till the truck groans anyway...He's certainly a bright spot in the camper building world.

Market wise the low hanging fruit would be a big enough composite camper for a Tacoma. Now that's a interesting design & engineering problem to sink your teeth into...but if successful it would certainly sell! Moe
 

IdaSHO

IDACAMPER
Condensation occurs when the surface is below the dew point. Surface temperatures of cold bridged areas can be far below the cabin temp. You can be at 70 dregees in a camper and have condensation or even ice. Glass and bridged aluminum are the worst offenders. Even minimally insulated wall areas are usually fine unless you get into truly arctic conditions as Moe described. Air exchange isn't needed if the insulation is good enough??? I just don't know what to say to that. Even if you could somehow keep the condensation from happening, the humidity level would be unbearable. This is why we wear goretex instead of down jackets with a plastic shell. If you are running a heater, and breathing you are also consuming oxygen.
I dont know what you are in such disagreement with. You quoted my entire post, and it contains everything you seem to reciting.

Condensation requires moisture and the proper dew point.

Assuming you are using zero methods to get rid of the moisture, all you can work with is the dew point.

Dew point is the temperature at which the moisture in the air visibly forms into liquid.


My simple point is that by increasing the insulation value, you will reduce the chance of even getting to that dew point.

Is this incorrect??


Also, I never said air exchange wasnt needed. I thought I made that very clear. You even quoted it.

What I did say is that in many cases it isnt. How often do you open the door? How long do you stay within the cabin without leaving?

Even in North Idaho winters, we are rarely in our camper for more than 10 hrs without opening the door or hatch.

In my experience, simply opening the door for a brief period is enough to exchange plenty of air.

In sub zero temps, with a well insulated camper, 2-people, two dogs, for weeks at a time, we have zero condensation issues. A bit forms on the window frames, but that's it.
 

IdaSHO

IDACAMPER
You've gone a middle way in that a panel using XPS foam & ply skins - while lighter - is a long way from using a structural foam with enough compression & shear strength to make a true structural composite panel where the skins carry the majority of the load. I'm not saying your approach is inadequate in any way but it's much heavier than using structural foam -
It is a middle ground in some regards, no doubt.

Question though... in the same statement you say "while lighter" and "much heavier". So which is it?

I went XPS due to a lot of reasons. One of the biggest is R-value per inch. What are you referring to as "structural" foam? How does it compare thermally?
 
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