Insulation effectiveness tests

[malconium]

Vernon,

I have a couple of thoughts regarding your results that might help set things in perspective.

I don't think that there is anything that you could do with your experiment that would make the temperature that you read on the inside skin be less than the ambient temperature of the inside of your trailer. In case number #2 for example the temperature that you measure is only 2 degrees higher than the ambient temperature inside the trailer. The only way that your results could get down to as low as 89 degrees would be if absolutely 0 heat is getting through the insulation to the inner skin. That is not going to be possible. I think your results look good in that respect.

It is not unreasonable for the outer skin to be hotter when you have better insulation. The reason is simple enough. Basically you have removed one means of releasing the heat that hits the outer skin. I think that you will find that this is a natural consequence of insulation of any type. If the heat can not go to the inside of the building then it can only be released back to the outside domain. Since the outside is hotter to begin with less heat can be released in that direction. That amount of extra heat is not too likely to hurt the aluminum and you would certainly prefer it to stop at the outer skin that let it get inside.

I too am a bit suprised that the uninsulated one does not show more heat on the inner skin. Howerver there could be some factors that cause this. Experiment case #1 with no insulation does in fact have some insulation. The air gap does help some as shown in your results. Also I think the fact that the outer skin temperature for the other 3 cases are higher needs to be taken into account somehow in light of my first observation above. Also remember that all of your outer skin pieces are tied together. Notice in your photograph that the uninsulated outer skin test case is surrounded by an area where the outer skin is directly exposed to the inside where the temperature is 89 degrees. Could it be that this is actually cooling off the outer skin in that area some?

For some side by side comparison of some similar test cases that I did take a look at the following thread and especially my posts #59 and #82

http://www.airforums.com/forums/f474...red-13363.html

Malcolm

[NorCal Bambi]

Someone said that there is no such thing as a dump question. With that said here is the question. I wonder how an Airstream would react to a covering of Gold Leaf. Many space craft are covered with gold foil to protect them from heat. There must be someone out there with enough money to experiment with this. And how cool would a gold twinkie be. Some practical questions. How much would it cost. How much weight would be added. How long would it take. After all didn't the man have a gold Airstream? I did several experiments with a sandwich insulation on my Bambi restoration. I'm not sure what real affect it had, but we are pleased with our trailer. This question might be fun for those like me who have too much time on their hands.
Don

[Wabbiteer]

The raw solar radiation in space is almost double what punches through the atmosphere and reaches the ground yet in space there is no 'air' to rub against objects and carry that heat away... so gold is used since it reflects solar infrared heat better than a 'silvered' surface.

Did you know gold is self-healing on the molecular level? High energy particle craters in gold film that has any clumps that were not separated from the metal film migrate back into an orderly matrix, kind of a scratch healing thing. Important for things left up there a long time...

The typical thickness of gold leaf is about 100 nanometres or 0.0001 mm.

To give you more ammo for thought...

At a thickness of 100 nm, one square metre of gold leaf corresponds to 0.1 cubic centimetre or just 2 grams of gold. In Imperial measurements, one ounce (28.34 g) of gold corresponds to about 200 square feet (about 20 m2) of gold leaf. (Wikipedia)

(Thanks for the rainy day exercise.... we are 6-1/4 inches short of rain this summer, of course when I have all my carpentry tools and wood outside it decides to rain. I'm back to puddle stomping)

[filterman]

What about outgassing? A greenhouse person said these foams outgass. I know you can get two large cans of about 10 cubic feet of foam at tap plastics for around 300 bucks but I am worried about gassing my air with volatile compounds. Any ideas?

Originally Posted by rangebowdrie

If using sprayed-in-place polyurethane foam, be sure the AS is leveled-out well , before spraying. The foam is very rigid, and will not allow the shell to flex very much,(this is a very good thing). As to the effectivness of the foam, it is perhaps a complete order of magnitude better than almost anything else commonly available at reasonable cost. This is based on a good quality foam of around 2-2.5lbs. per cubic ft. density product. The difference between sprayed foam, and air bubbles or fibergass batting is simply amazing. If possible, run wiring inside of plastic conduit, with junction boxes at key locations, to permit later removal, or pulling-thru new wiring. The sprayed foam will also almost completly eliminate the problems of trapped condensation within the shell. Foam such as this is rated with a "K" factor, rather then "R" factors, as fiberglass is. Go for it. The foam is also FAR better as a sound barrier. It is so far ahead of anything else, there is no second place.

[boatdoc]

Urethane foam out gassing;
Out gassing is only one problem with Urethane foam in a Airstream. Since it takes a chemical reaction of two components, it out gasses heavily during set up. However, not all gas escapes during set up and it continues to do so for ever as bubbles break down with time.

Second issue; Foam during set up process creates a considerable amount of heat which is transfered into aluminum skin. Aluminum having a high rate of thermal expansion will bubble out, and it may not return back to original shape. In areas where foam gets trapped in chamber without expansion relief, it will bulge out your walls.

Third issue;
True Urethane Foam comes in different density weight per cubic foot. Two pound density is quite fragile and it deteriorates quicker than four pounds density. With four pound you are doubling up the total weight. There is no way to stop the flexing in Airstream trailer. With time, as the trailer flexes the foam will start to fragment in areas of most flex. As the fragmentation takes place very minute particles go airborne to be distributed by your furnace or any other source of air movement. As the bubbles continue to break down the gassing out continues since the gas is trapped inside the bubbles. In essence Rigid Urethane foam is best used in stationary chambers where a movement is not an issue. IMHO you are making a mistake of your life. Thanks, "Boatdoc"

[filterman]

This sounds like the this stuff
16 LB Density Urethane Foam Common Applications: This 16LB density foam is essentially as hard as a rock, you would need a hammer in order to make any dents in this product. Can be used for sculpting or the casting of objects that require superior toughness and strength. More questions? [Try our Foam FAQ.]
Cat No.Kit Size(net weight)Approx. CoveragePriceFOAM-16044 LB Kit1/4 Cubic Foot$20.50FOAM-161616 LB Kit1 Cubic Feet$62.00FOAM-168080 LB Kit5 Cubic Feet$244.005 or more kits of the FOAM-1680$232.00 / KitProduct Information:
Free Rise Density: 16.0 lbs cubic ft.
Expansion Rate: Approx. 4x Liquid Volume
Buoyancy (flotation): 46 LBs per Cubic Ft.
*Physical Properties:
Parallel Compressive Strength: 580 psi
Tensile Strength: 450 psi
Shear Strength: 230 psi
Flexural Strength: 750 psi
The problem with this foam is the high curing temp. The better choice which is supposed to be green and cures cold is.

• <LI class=style6>2 Formulas - Fast Rise E-84 Fire-Rated Surface Spray and Slow Rise, Low-Pressure Cavity Fill Formula <LI class=style6>Closed Cell Polyurethane Foam Insulation - Expands 8 to 1 for better control and less waste. <LI class=style6>R-7 Per Inch - Low perm rating makes it practically waterproof <LI class=style6>Easy to use, portable and recyclable - Completely self-contained kits. No power supply or additional machinery required! <LI class=style6>Toll-Free Technical Support - 100% guarantee against defect
• Air Seals, insulates, soundproofs, water resistant, 1000's of uses!

E-84 Fire Rated Polyurethane Foam Insulation Kits Tiger Foam™ is a FEMA and HOMELAND SECURITY registered supplier of Hurricane Relief and Rebuild Materials! If you are a registered contractor with FEMA or their SUBS INQUIRE HERE

Tiger Foam Insulation™ has NEVER contained Octa or Penta BDE's or VOCs, CFCs or Formaldehyde.

Originally Posted by boatdoc

Hi rangebowdrie;
Yes, it would blow your mind of how many different products there are in the foam specialty market. In my ha'y days, I used to drive a Tunnel Hull race boat for Sunoco Fuels [the only Sunoco sponsored boat] APBA 841. Prior to introduction of Safety Capsules, high speed related accidents used to end up in serious injury or death, as the very light and fragile hulls came apart. Sunoco, being concerned about my safety have sent a prominent US aircraft development company to make my boat so called "bullet proof". Two men came in large sophisticated trailer conversion and went to work with 1/2 lbs weight per cubic foot of installed foam. Each tunnel hull was blocked off with special heat shrunk film and 1" hole was drilled at each tunnel hull bow. Boat was hung with bow up at 45 degree and foam was poured in. Excess foam discharge hose was affixed to the pour holes so that the expanding foam would not come in contact with outside gel coat. Apparently there was no solution to clean that excess. Cockpit was then bagged for vacuum forming. Three hours later one man has emerged from a trailer with a 20 lbs mull and piece of plastic in hand. One man held the piece of plastic against the foam filled hull, the other swung the mull as hard as he could while my heart was at my throat. The mull bounced back spinning the man around. Please feel secure now, he said. They had me sign agreement not to allow anyone to have a piece of it, so that it cannot be tested for chemical properties.
All expanded excess foam was collected by them and loaded into their trailer. Not a scrap was left to be found. When I quit racing some years later the boat was purchased back by the company who poured the foam for destruction. There is your sign in today's technology. Thanks, "Boatdoc"

[filterman]

Hummmmm Very interesting never head of the avions being big lemons because of insulation failure or rotting.

Originally Posted by Melody Ranch

I still believe in spray foam insulation....the correct kind.

Its been used, its effective, its light weight, it stays put, etc, etc.

http://avion.gradeless.com/1972Avion/1972_AVION_12.jpg

[boatdoc]

Hi filterman;
Why would anyone want to put 16 lbs density foam in a Airstream? How can you apply it on vertical surface? Even if one could apply 1" thick layer can you tell us how much weight it would add in 26' trailer at 16lbs per cubic foot? Thanks, "Boatdoc"

[ticki2]

Originally Posted by boatdoc

Hi filterman;
Why would anyone want to put 16 lbs density foam in a Airstream? How can you apply it on vertical surface? Even if one could apply 1" thick layer can you tell us how much weight it would add in 26' trailer at 16lbs per cubic foot? Thanks, "Boatdoc"

I think Filterman was pointing to the Tiger Foam , which according to their specs is 1.75 lb density. The other is structural foam , whole other animal.

I can attest to my 40 year old Avion TC foam insulation holding up just fine with no distortion in the aluminum skin so someone got it right a long time ago.

As an aside , I bet the saturated fiberglass in the belly pan weighs more than 16 lbs a cubic ft.

[filterman]

boatdoc what I meant about the 16lb foam was that this is probably what was used in your boat. on the weight lets say on a 31' by 8' wide we got 240sf rounding down for the curved edges at one inch that would take 20cf of foam at 1.75lbs per cube thats about 36lb so double it for two inches to 74lb of foam to do the bottom. Check my math I did this in my head.The only problem I see is the foam going to crack or will it hold . I would take my chances with foaming the bottom maybe go with a little mor density like one step up but not too stiff as it would get heavier and then have less flex. To do the whole trailer I would guess to be about 300lbs. SO HERE IS MY FINAL ANALYSIS. THE ONLY INHERENT RISK IS WILL THE FOAM HOLD UP AND DO YOU WANT THE ADDED WEIGHT. Ticki is your avion foamed under the floor and if so how does it look. Gotta go seal some windows (vista on my rig) Thanks all

[boatdoc]

Hi filterman;
Sorry, I was under impression that you were promoting the use of 16 lbs density.
I was told that the foam used in my Race Boat weighted 2.5 lbs per cub/ft, but it was crossed linked with undisclosed but very expensive component.

All and all I do not see how you can install a pour foam on a vertical surface. It would have to be sprayed and that is not a DIY job. Constant moisture will eventually penetrate the surface with time. In addition, IMHO 2 lbs density foam is much too fragile to be installed under flexing condition. Zep has done plenty of extensive research on this subject, pointing the way to what works and does not. I respect his findings. One should also consider the cost vs the value in effectiveness. Thanks, "Boatdoc"

[Wabbiteer]

A point to remember - "closed cell" is a general term as there is still 3-7% "open cell" foam bubble structures that can hold liquid moisture - and then those flaws will work over time into the larger volume.

Just pointing to SOB trailer that used a spray foam is like saying putting wide tires on a Pinto will make it handle like a Mustang!

Inviting bids from chemical suppliers with exacting material property requests, doing trials with various components proportions, having applicator contractors on hand with a performance clause in their contracts... Then with a specific insulating foam having the trailer construction details modified to accommodate the product, not forgetting they are using all-new materials, supplied to design specification and assembled with proper material cleanliness and primers/bonding agents... the list goes on and on...

If Line-X or Rhino-Liner could add 90% by volume a silica micro-sphere or some other inert insulation additive just having that sprayed in from window height up might be a real sweet application.

[ticki2]

Filterman , the floor in the Avions is a sandwich , 3/8 ply , 1" foam , and 3/8 ply . The walls and roof are sprayed on . I see no reason that spray foam would not adhere to the underside of a plywood floor .

Boatdock , I don't think anyone is proposing trying to fill the walls with foam while the interior walls are in place , I believe that would be a big problem . The application would be sprayed in which works fine for vertical walls and ceilings .

Wabbeteer , I don't get your analogy between an SOB and an Airstream . The comparison given was between an Airstream and an Avion which have the same riveted aluminum construction .

I find the nay sayers very puzzling . Why question whether something can or should be done when it has already been done successfully many years ago . Which product to use does merit discussion .

[Wabbiteer]

You're entirely welcome to nurse puzzlement quietly of this advice those long experienced Airstream owners are discouraging the use of foam.

I've seen a new 60's vintage owner reduced to near-tears while showing a jumble of shattered foam stained by rust where the frame iron had simply vanished. There are a finite number of vintage Airstreams and their expected long life means any modifications made may haunt several unsuspecting future owners with a bunch of trouble if care is not taken.

Do you know why POR-15 is so highly recommended? It has a unique property of not being undercut by rust - the rust will not break the bond of the paint and laterally progress and just that would be the case of using foam on/at iron work.

I've seen the Vulkem sealant slathered over the rear end-cap of my 39-year-old trailer hold water like a wineskin - but it held it. Yes, other leaks and benign neglect made that a nonissue but physical properties so well tuned to last nearly 40 years... that is part of what makes an Airstream lasting 60 or 70 years a good start on an even longer life.

Avion is not Airstream even if resembling it in some aspects - thus the Pinto to Mustang analogy. You have no knowledge of the trade-secrets used to mate materials in the Avion, or the processes required to duplicate them but are willing to encourage others to reinvent the wheel. So, yes, you hear nay sayers.

[boatdoc]

Originally Posted by Wabbiteer

A point to remember - "closed cell" is a general term as there is still 3-7% "open cell" foam bubble structures that can hold liquid moisture - and then those flaws will work over time into the larger volume.

Just pointing to SOB trailer that used a spray foam is like saying putting wide tires on a Pinto will make it handle like a Mustang!

Inviting bids from chemical suppliers with exacting material property requests, doing trials with various components proportions, having applicator contractors on hand with a performance clause in their contracts... Then with a specific insulating foam having the trailer construction details modified to accommodate the product, not forgetting they are using all-new materials, supplied to design specification and assembled with proper material cleanliness and primers/bonding agents... the list goes on and on...

If Line-X or Rhino-Liner could add 90% by volume a silica micro-sphere or some other inert insulation additive just having that sprayed in from window height up might be a real sweet application.

Thank you Wabbiteer. "Boatdoc"

[filterman]

that has been sprayed with foam in 2006 and lets say that money was not an object to the builders, then you would have mobi (here's your pinto looking like a mustang) Mobitat - Total Luxury Mobile Living now lets say I talked to Will at Tiger spray on foam and he verified it was Tiger foam in the mobi (all walls ceiling and undercarriage) and it was 1.7lb closed cell foam which does absorb some water on the surface but does NOT waterlog unless it is submerged for a long time. So coating the frame with POR=15 is recommended before hand. My main concern is sweating and not so much the insulation r value of about 7 per inch. Here are the calculations 600bf of tiger foam is 760.00 (one kit) it would take about four kits (whole rig) to do two inches (r-15) or two kits to do one inch (r-7) About 150lb for one inch and 300lb of added weight for two. If you use foam board the walls will still sweat, if you use the pink crap it will mold and soak water. If you use epoxy paint on the interior you still need insulation. I hate fiberglass and dont like the toxic fumes from foamboard if there is even a small fire can you say poison by the time you wake up if you do. The bubble wrap will not hold into place with aluminum tape been there know that. So what then. Let the walls sweat and put a new floor in every ten years and just brush the corrosion of with a wire brush when you see it. Then there is this stuff II-205 Handi-Foam Commercial Vehicle Spray Foam - Professional Kits - Discount Professional spray foam kits. Handi-Foam Commercial Vehicle Spray Foam was developed specifically for use in a vehicle's undercarriage, engine compartment and frame,it can also help to reinforce the structure! Can you say sagging tail?
I wonder if this company has good insurance so when all the motorhome frames start to rust through they can stay in business. Look I think this can be done just need help figuring it out. Pour foam is out of the question too hot and takes too long to set up for a wall. MOBI is Ohh very cool. This is why I went with a as. HUMMM on a mission... Whats wrong with a avion? I think they are good units. CLASSIC 1987 AVION 34-W TRAVEL TRAILER. Lets solve the problem and figure out which foam to use and in twenty years if my frame rusts so be it.

[boatdoc]

Hi filterman;
You are absolutely right. It can be done as it was done, if the cost is not of importance. Are you trying to convince yourself and the rest of us that R value of 7 is worth the enormous cost and effort? If you think it is, go for it. Prodex gives you R-14 with 1" air space for 1/10 of the cost and 1/50th in weight. I agree with you that aluminum tape will not always hold up, but 3M has adhesives that will. Adhesion depends on surface cleanliness especially when installing aluminum tape. I do not know what interior wall corrosion you are speaking of. My argosy was made in 1973 and three years ago when I took off the inner walls, the inside was whistle clean. The only corrosion I had was in the contact area of rear steel head plate to aluminum.

It is one thing to be determined to accomplish certain task, but it is another when it comes to a achieving worthwhile gain for the money. Not everyone can afford to play with their money. At times we are determined to do things for ourselves when we can afford to be inventive. Example is my hydraulic leveling system which I am building for my Arg. The difference is that I have materials, machine shop capability and engineering know how. Is it cost effective? No, despite the fact that I have machined my own pistons, made my own lines and have hydraulic pumps. I have engineered it so that the entire system will be enclosed in the belly pan and not be visible when retracted. I do not want scissor jacks hanging from underbelly of my trailer. Some may say that it cannot be done, just watch me. My reason for it, is not to prove a point. After my accident I am finding it difficult to set up screw jacks because of my injuries. I would be ashamed to ask my wife to set up jacks, and that is my reason for doing it. Would such a set up be considered worth while for everyone? No, but it is to me. You then, should proceed with spray foam in your trailer rather than make attempts to convince how such application would benefit everyone. Thanks, "Boatdoc"

[wworx]

hey boatdoc,
I'd be interested to know specifically which 3M adhesives you'd note that would work over the long term for purposes of securing insulation?

[filterman]

Boatdoc thanks for this info "Prodex gives you R-14 with 1" air space for 1/10 of the cost and 1/50th in weight. I agree with you that aluminum tape will not always hold up, but 3M has adhesives that will. Adhesion depends on surface cleanliness especially when installing aluminum tape"
What is your recommendation for the minnesota mining and metal tape? Thanks Save your plans on those jacks I amy be interested in having you make me some in the future. And it really just about trying to make it perfect isnt it? Afterall its fun to create and experiment. Ok so I think I have rear end separation and found a 34 foot frame from a roll over for 300 bucks so I was thinking could I use that frame and my shell and have the extra three feet for a gene box? I am probably gonna have to replace the floor so I will have to raise the body and instead of working this frame I would just pull it out and use the other, it has new axels also. What you think?

ps airstream did make an arctic package in the 60's the floor was eurethane foam sprayed; so I am told by Empire in Ca.

[boatdoc]

Originally Posted by wworx

hey boatdoc,
I'd be interested to know specifically which 3M adhesives you'd note that would work over the long term for purposes of securing insulation?

Hi wworx;
Stuff to use is MMM 4200 Fast Cure. Cut nozzle on the cartridge as little as possible. You do not need a large bead to attach bubble foil. It cures in 24 hours giving you plenty of time to work with. Wipe excess with damp rag. Be sure to wear protective gloves. Stuff gets in your pores in your hands, and it will have to wear off once it sets up. "Boatdoc"