1935 Chevy school bus

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Stealth Camper
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Re: 1935 Chevy school bus

Post by Stealth Camper »

ol trunt wrote:Hey SC. Thanks for the input--thats sort of what I expected. Did the Coleman ever knock the chill from the air in the Tent? Jack
Kind of warmed it up some. Kept it "near" the door flap to let air flow. CANNOT just close it up in the tent with you - the exhaust displaces oxygen. So mostly we heated just outdoors and got some of it to 'deflect'. When started with pop up trailers, could bring it indoors for a while, but still needed plenty of ventilation - open flaps. Never leave it on while asleep. 'cause you will wake up dead!!! All situations - when got into sleeping bag, heater didn't matter anyway. Until morning!

I still like the campfire with some kind of backside deflector to direct heat toward me. Never have been able to come up with a deflector smaller/lighter/more portable than a large pile of rocks behind fire to radiate back the other way. Would like to have a steel plate device, but heavy and cumbersome.
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Re: 1935 Chevy school bus

Post by ol trunt »

Hello All and thanks SC for the helpful info.

I have been working on leveling jacks for my bus. I started with a set of hand jacked Atwood brand tent trailer jacks. I modified the jacks to accept the ram from a porta power auto body tool. The jacks are installed on the frame of the bus and the hydraulic manifold and pump are ready to install. The 4 ton pump and ram seem to lift the bus with ease. The manifold allows me to operate one or all rams and locks the pressure in the rams to avoid settling. I still need to run the steel fluid lines and install a pressure switch to a warning buzzer. Perhaps I'll get it completely done by the end of the weekend. Jack

Back on the bottom of pg 33 are the rest of the pics of the jacks.Image

I've yet to be billed for the valves and fittings so I'm still enjoying how pretty they are :lol: .Image

The hydraulic pump mounts just above the manifold and the whole assembly fits in the space under the bed where it is easy to access and still is out of the way.Image
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Re: 1935 Chevy school bus

Post by tango »

Howdy Jack --- Looking sweet and glad to hear it lifts with ease. Are you planning on any kind of mechanical lock once they are up or relying on the hydraulic pressure to keep'em where yo want'em?
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Re: 1935 Chevy school bus

Post by ol trunt »

Hello All. Tango, each lift has it's own valve so once they are in position I'll just close the valves and hope for no leaks--so far so good.

A question: I've put in no less than 2" of closed cell foam insulation top, bottom, left and right sides and both ends of the bus along with dual pane windows and tight fitting roller shades. I am able to combat the summer heat but it seems that I have a tremendous heat loss in the winter. I expect most of the heat is passing through the canvas in the pop up. I'm considering making a "jacket liner" like my old uniform windbreaker had and suspending it to follow the form of the pop up. I suppose I could just close the pop up but then I'd have to bend over all the time to move around. I considered the foil sided insulation blankets but when I looked more closely it seems that they are great for reflecting radiant heat but not much good at controlling conductive heat loss which is mainly what I'm dealing with. Any ideas? Maybe a down comforter would work --it sure would be easy to store when it wasn't needed. What do you all think? Jack
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Re: 1935 Chevy school bus

Post by tango »

As I understand...there is but a single layer of canvas that makes up the closure for the popup...correct? Seems another layer of something with some insulating properties would fix the problem, but finding the right material would seem to be the trick. Has to be light, very flexible and provide significant thermal benefit. There are any number of fabrics that fill the bill these days (hunting, skiing & outdoor gear), but I've no idea where to buy any of it that isn't already a parka or some such. Maybe they can be accessed through one of the garment makers or possibly a custom tailor could track some down?
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Re: 1935 Chevy school bus

Post by Stealth Camper »

I had to make an insulated sleeve to go over the water faucet for the trailer. Ended up with something that was really too elaborate, but works very well. Found vinyl material like they use or boat covers - or maybe the sides of your tent section. Put a 3/4" layer of foam rubber between the two, then did a "wrap". Might take some 'hangers', but could maybe make a foam insulated blanket to hang on the inside walls. Or several sections like that... ??

I also used some velcro sewn along the edges for overlap connections. And a heavy duty YKK zipper....
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Re: 1935 Chevy school bus

Post by ol trunt »

Tango and SC,thank you both for the suggestions. Tango, I hadn't thought about double walling the canvas part, but that is a good idea. It would have to be removed to close the pop up because there isn't enough space between the top frame and the top of the bus to allow for any more thickness when the top is down. If I used your idea along with SC's foam rubber idea it might just work out. The translucent polycarbonate portion of the pop up is made up of two layers of material which in cross section looks like the cross section of a typical card board box and each of it's "tube" ends are sealed. The trapped air must provide at least some insulation. I'll mock up some sort of model to test this. If the polycarbonate does provide sufficient insulation then perhaps I can get away with an adaptation of what both have suggested. Oh boy-- another long hot shower during which to think this through! Jack
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Jerry Campbell
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Re: 1935 Chevy school bus

Post by Jerry Campbell »

We made a windshield cover for privacy and insulation about 10 years ago. It's about 3 ft X 8 ft. It is white Rip Stop Nylon on both sides Sewn around the edges with foil backed bubble wrap on the inside. It has worked better that I had thought. You probably don't want to use the bubble wrap but maybe quilt batting would work. It could be rolled up or folded tight or maybe in one of those vacuum bags for storage. We hold it up with super magnets.
You do nice work.
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Re: 1935 Chevy school bus

Post by somewhereinusa »

If I remember correctly there used to be some winter fronts made of some sort of vinyl that was double layer with some sort of batting inside. Kind of like a quilt. Something like the twist lock fasteners on MGB's had for their tops. Not the press the dot ones, hated them. I think some winter fronts used them too.
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Re: 1935 Chevy school bus

Post by ol trunt »

Thanks for the compliment Jerry. I had considered bubble wrap but figured it wouldn't hold up--I'd say you proved that not to be true. I'll add bubble wrap to my little experiment once I get over this lazy streak!

Somewhere, I think the same sort of fasteners are used on boat covers. They are plenty strong and would be a good bet if I can make them work with the closure issue of the pop up. This weekend I plan to build a simple test box to help me evaluate various insulating materials. We'll see what happens. Jack
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Re: 1935 Chevy school bus

Post by Jerry Campbell »

Just a couple more thoughts.
As far as I can tell the bubble wrap is still as good as new but you can see thru the rip stop nylon that the foil backing is coming off on the the places that it has been creased repeatedly. So I'm thinking that it is reaching it's lifespan , Also, I'm not able to smash it for storage as small as I would if it were a quilt batting type of material. Also, I can't throw it in the washer.
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Re: 1935 Chevy school bus

Post by ol trunt »

Hello All. Thanks for the input Jerry. As usual I'm about to say too much about too little so grab some chips and a cool one 'cause here I go.

I read up on how heat can be transferred-- the usual, radiation, conduction and convection and then I began reading about insulation and how it works. I found many interesting articles and scientific studies of insulation in of all places the camping/backpacking forums. Two themes seem to repeat themselves: trapped air and re-radiation of heat energy within the insulation. The best insulation for our purposes at least, seems to be one that traps air in a fine matrix of material in such a way that the ratio of matrix to air favors air. This apparently reduces heat loss through conduction (small amount of matrix material) and increases heat retention by re-radiating heat energy within the matrix thereby keeping it from passing to the exposed outer surface of the insulation only to be lost via convection. And thats "ducky". I'm sure others on the forum can explain all that better than I did and please do.

Enough already. I wanted to know what happens in the bus world. I began my study by fabing up a constant temp heat box constructed of a cardboard box and a 25 watt lamp. I did my little experiment in the confines of my garage where I could maintain the room temp at 68 degrees F for an extended period of time. I allowed the heat box to come to its peak temp which turned out to be 83 degrees F across its upper surface while the surface was exposed to ambient garage temperature.

As an aside, I used a China Freight IR thermometer to track heat change. I have learned that the thermometer gives faulty readings when aimed at reflective surfaces (like chrome) and that it seems to heat saturate if it is used repeatedly in rapid succession to measure the temp of a single location. The heat saturation problem can be eliminated by treating the thermometer to a cold measurement after each hot measurement. I fooled with this for an hour or so and found that I could get readings to exactly repeat themselves time after time. Therefore, I made my measurements on patches of flat black electrical tape and cleared settings before each successive reading.

I constructed test panels one each of 1/4" thick bubble wrap, two layers of 1/4" polycarbonate sheeting which looks like plastic cardboard box material, 1/2" thick single vinyl faced foam and a section of faux down comforter made of polyester. I then measured the insulating capabilities of each by sequentially placing the panels on top of the heat box and taking a series of temp readings -- a couple of hundred or so. Each test panel was allowed 20 minutes to come to equilibrium with the heat box and the ambient air prior to taking measurements. I found the results surprising.

[/b] This is the box and lamp setup.Image[/b]

I made temp measurements at 6 places on the top surface of the heat box. I later used these readings as baseline info.Image

The first measurement was on bubble wrap. Image

The next was on polycarbonate. Image[\b]

Next was the foam rubber the pic of which I cannot find!?!. Oh well.

The final measurement was made on the polyester comforter. Image

I'll take my findings with a grain of salt. I have no training in thermodynamics--but I did stay at a Holiday Inn!

I simply looked at the ratio of the temperature on the surface of the heated box and that of the surface of the various insulation panels at the upper surface/air interface and expressed the result as a percentage of the heated box surface. For example, had the hot box been 100 degrees at its surface and the test panel only 95 degrees at its surface/air interface, I defined the result as a 5% decrease in heat loss (a heat savings I suppose). This is what I discovered:

One 1/4" layer of bubble wrap------------------------------------2.4%

Two 1/4" layers of bubble wrap-----------------------------------3.1%

One layer of 1/2" thick foam rubber (auto uphol grade)-------5.5%

Two layers of 1/4" polycarbonate---------------------------------8.4%

One layer of polyester comforter---------------------------------9.8%

Here are my thoughts on the results. The higher the % the better the insulation. Looking at the physical makeup of the bubble wrap it seems that the ratio of trapped air to matrix material is about one to one.This results in a large surface area of matrix which lends itself to conductive heat loss which lessens its effectiveness as an insulator.

I was surprised that the foam rubber did not do better than it did. The ratio between matrix and air looks to favor air. Perhaps the wall thickness of the matrix leads to conductive heat loss. I looked at a cross section of both the foam rubber and a gob of cured "Great Stuff" under my microscope and found the air pockets of each to be similar in size but the matrix of the foam rubber to be many times as thick as the walls of the Great Stuff. Though I didn't test Great Stuff, we know that it has a high r value. So for whatever thats worth-----------

I tested the polycarbonate because that is what the pop up on my bus is made of. While the material is too rigid for what I want to use it for, I was pleased to see how it stacked up with the other materials.

Of the materials tested, the faux down was clearly the most effective insulation. An added advantage of the faux down is that it can be heavily compressed for storage without damage to it's structure and it is washable. The particular comforter I tested was "tube stitched". The stitching makes the surface of the comforter look like plump hotdogs lying next to each other. The stitched areas reduce trapped air to zero at the stitch thereby creating a location for conductive heat loss. A "V" stitched comforter would therefor better control heat loss by conduction.


I couldn't resist testing the samples with a sheet of shinny foil between the heat box surface and the bottom of the test panel. The results in all cases was a major reduction in the effectiveness of the insulation. I can only surmise that any positive gains in insulation due to re-radiation were more than negated by the thermal conductivity of the heated foil Image

I don't know why it should have come to me as a surprise, but the heat box required cooling between test panels. I got sidetracked with that for a while and discovered that the heat increase in the heat box is almost the reciprocal of the "heat savings" attributed to the insulation. Too much fun! Jack
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Re: 1935 Chevy school bus

Post by stuartcnz »

Good thorough testing from you again Jack. I found your descriptions to be very clear and understandable. As a stand alone piece, what you have just shown on insulation is very valuable.
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Jerry Campbell
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Re: 1935 Chevy school bus

Post by Jerry Campbell »

Outstanding, Jack. If I have to replace my windshield cover it will be with Polyester batting with "V" shaped Quilting.
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Re: 1935 Chevy school bus

Post by tango »

Hey Jack --- been mighty quiet. How goes the insulating?
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