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Old 04-07-2016, 04:03 PM   #11
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The weather is warm enough now that I'm going to start stripping the rivets and old insulation too. The centers don't punch out of the rivets like people have said in threads here. I've got a nice punch with a four pound hammer and these rivets don't even dent. Apparently I've got a lot of grinder and air chisel work ahead of me, or am I doing it wrong?

I'd like to retain the structural integrity of all that sheet metal inside, but honestly I can't see myself riveting it all back in place. It's a fair amount of weight that the old hippies got rid of first thing, or the ones that insulated anyway. On the other hand that perforated metal would be easy to screw things to on the interior surface.

I agree that even a wooden surface on the interior helps to maintain the rigidity the metal previously provided. I'm kind of wanting to get away from cold metal surfaces and wood looks nice with it's own insulative qualities.

My current bus is never going to be here like an old log cabin in 100 years. If you get 10 or 20 years out of a bus it's already paid for itself many times over. Besides, it gets us out there where we meet lots of people and see things you can't see from living on real estate.
I've found peoples suggestions on rivets here to be well meaning but ineffective. A good compressor and a punch bit on the air hammer is what got the thousands of rivets out of two buses I've worked on this year.
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Old 04-07-2016, 05:33 PM   #12
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I'll give that a whirl. Thanks.
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Old 04-07-2016, 06:13 PM   #13
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About one in every ten or twenty will really fight ya, but just gotta keep going and eventually the mandrels all push through. Maybe three on my bus had to be ground off with an angle.
After the mandrels are gone, the rivets shear off with a chisel bit in said air hammer.
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Old 04-07-2016, 06:22 PM   #14
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About one in every ten or twenty will really fight ya, but just gotta keep going and eventually the mandrels all push through. Maybe three on my bus had to be ground off with an angle.
After the mandrels are gone, the rivets shear off with a chisel bit in said air hammer.


Do you drill first?

I haven't ever punched out a rivet before. Could yo give a quick primer on your successful methods?
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Old 04-07-2016, 06:33 PM   #15
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I'll add my two cents:

The vehicle body flexes. It does so with an inner and outer layer of sheet metal, or not. The way it's designed, with the two layers of steel, causes a box beam to form the length of the structure on top.

When you push the entire frame in torsion stress by, for example, putting maximum weight on opposing wheels on opposing axles, the body of the vehicle will follow the twisting of the frame rails in a parallelogram, as intended. If it didn't, the seams would pop open, and the sheet steel would buckle.

Without a formal understanding of the reasoning behind school bus body construction, I would postulate that the box beam sections formed in an unmodified school bus are designed to provide crush resistance against a full rollover of the vehicle.

This I believe is specified by DOT 49 CFR 571.220 - School bus rollover protection.

If you skim the regulation, it's mostly a testing specification. The tests would place the inner steel skin into massive tension stress bearing the weight of the vehicle force transferred from the ribs.

So, what Bluebird, Thomas, IC, and others (and probably everyone else) do is pick the conservative approach to building the bodies nearly the same - inner, ribs, outer skin, and follow the crush test CFR when a new design is released. It'll probably pass, if the design is the same because physics.

I believe newer vehicles are now designed to intentionally decouple the chassis from the body in a rollover.




When someone modifies the roof structure by raising it, pull the inner panels, add inside structure, EVERYTHING we do to make them a skoolie, the existing test and certification invalidates this test.

I would postulate that nearly every bus build I see, if this test were performed afterwards, would fail the above mentioned test for varying reasons - everything from massive weights in the cargo bay (batteries, water storage) to interior walls made from steel or wood, showers, cooking appliances, woodstoves, fridges, couches, you name it.

Some of those items will deflect and bend, others become deadly spears, or blunt trauma objects when you washing machine a bus on the highway.


So what we're left with is the operational life of the vehicle if it's driven a lot of miles. Going back to the box beam construction analysis of the structure, I'd say that the chord length afforded by the depth of the ribs affords little strength to the structure under normal operating parameters. This is to say - driving and not crashing.

That inner skin is simply a passive engineering element in those situations. I think some stiffening to the body is afforded by that skin, but removing the interior skin isn't causal of exceeding the the exterior skin and fastener working limits.

Turn the bus on it's side or upside down, and it's the active structural element, and in for a world of hurt.

Now, having put that down on the record for saying basically yes it's weaker - I still removed the inner skin, lifted the roof, etc. Why? I don't need school bus safety standards, and there are competing design requirements: weight, serviceability, thermal, inspection, and more. The riveted steel skin is still far superior to the fiberglass composite panels and wood framing of the "sticks and staples".
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Old 04-07-2016, 06:34 PM   #16
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Do you drill first?

I haven't ever punched out a rivet before. Could yo give a quick primer on your successful methods?
nah no need, just punch out the mandrels and then shear em off. Takes about a second or two per rivet once you get into the rhythm.
The mandrels are hardened and will just eat up drill bits.
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Old 04-07-2016, 06:38 PM   #17
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I'm looking forward to some hammer time. Even air hammer time.

I'm surprised at the quality of the steel in the rivets and the panels. I thought it would be soft steel. All I've done with my punch and 4# hammer is chip the paint. I've got the air tools, but I'm thinking I'm going to wish I hadn't started this before I'm finished. Everything tends to get so involved on projects. If I get that insulation in I'll be much happier next winter. I'm in the mountains and when the valley has a frost, I get the freeze.
I've been living in this bus for four months, minus the fact that I've got a bathroom 50 feet away. I really don't want to start doing the doody in the bus if I can help it. I was planning on carry one of those small tank type portable toilets for extreme emergencies. What I don't use tends to get thrown out. If I'm in town, there's lots of bathrooms and not so many parking places. If I'm in the country, there's lots of bathrooms and lots of parking.
I can see why townies don't want a passel of converted school buses around, even with some very nice and well meaning people living in them. I think living in these if great, but they weren't really designed for towns. Actually they're for whatever you want them to be for. I don't like going to town, but that's where the keep the food.
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Old 04-07-2016, 06:39 PM   #18
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I'll add my two cents:

The vehicle body flexes. It does so with an inner and outer layer of sheet metal, or not. The way it's designed, with the two layers of steel, causes a box beam to form the length of the structure on top.

When you push the entire frame in torsion stress by, for example, putting maximum weight on opposing wheels on opposing axles, the body of the vehicle will follow the twisting of the frame rails in a parallelogram, as intended. If it didn't, the seams would pop open, and the sheet steel would buckle.

Without a formal understanding of the reasoning behind school bus body construction, I would postulate that the box beam sections formed in an unmodified school bus are designed to provide crush resistance against a full rollover of the vehicle.

This I believe is specified by DOT 49 CFR 571.220 - School bus rollover protection.

If you skim the regulation, it's mostly a testing specification. The tests would place the inner steel skin into massive tension stress bearing the weight of the vehicle force transferred from the ribs.

So, what Bluebird, Thomas, IC, and others (and probably everyone else) do is pick the conservative approach to building the bodies nearly the same - inner, ribs, outer skin, and follow the crush test CFR when a new design is released. It'll probably pass, if the design is the same because physics.

I believe newer vehicles are now designed to intentionally decouple the chassis from the body in a rollover.




When someone modifies the roof structure by raising it, pull the inner panels, add inside structure, EVERYTHING we do to make them a skoolie, the existing test and certification invalidates this test.

I would postulate that nearly every bus build I see, if this test were performed afterwards, would fail the above mentioned test for varying reasons - everything from massive weights in the cargo bay (batteries, water storage) to interior walls made from steel or wood, showers, cooking appliances, woodstoves, fridges, couches, you name it.

Some of those items will deflect and bend, others become deadly spears, or blunt trauma objects when you washing machine a bus on the highway.


So what we're left with is the operational life of the vehicle if it's driven a lot of miles. Going back to the box beam construction analysis of the structure, I'd say that the chord length afforded by the depth of the ribs affords little strength to the structure under normal operating parameters. This is to say - driving and not crashing.

That inner skin is simply a passive engineering element in those situations. I think some stiffening to the body is afforded by that skin, but removing the interior skin isn't causal of exceeding the the exterior skin and fastener working limits.

Turn the bus on it's side or upside down, and it's the active structural element, and in for a world of hurt.

Now, having put that down on the record for saying basically yes it's weaker - I still removed the inner skin, lifted the roof, etc. Why? I don't need school bus safety standards, and there are competing design requirements: weight, serviceability, thermal, inspection, and more. The riveted steel skin is still far superior to the fiberglass composite panels and wood framing of the "sticks and staples".
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Old 04-07-2016, 06:59 PM   #19
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I'll add my two cents:

The vehicle body flexes. It does so with an inner and outer layer of sheet metal, or not. The way it's designed, with the two layers of steel, causes a box beam to form the length of the structure on top.

When you push the entire frame in torsion stress by, for example, putting maximum weight on opposing wheels on opposing axles, the body of the vehicle will follow the twisting of the frame rails in a parallelogram, as intended. If it didn't, the seams would pop open, and the sheet steel would buckle.

Without a formal understanding of the reasoning behind school bus body construction, I would postulate that the box beam sections formed in an unmodified school bus are designed to provide crush resistance against a full rollover of the vehicle.

This I believe is specified by DOT 49 CFR 571.220 - School bus rollover protection.

If you skim the regulation, it's mostly a testing specification. The tests would place the inner steel skin into massive tension stress bearing the weight of the vehicle force transferred from the ribs.

So, what Bluebird, Thomas, IC, and others (and probably everyone else) do is pick the conservative approach to building the bodies nearly the same - inner, ribs, outer skin, and follow the crush test CFR when a new design is released. It'll probably pass, if the design is the same because physics.

I believe newer vehicles are now designed to intentionally decouple the chassis from the body in a rollover.




When someone modifies the roof structure by raising it, pull the inner panels, add inside structure, EVERYTHING we do to make them a skoolie, the existing test and certification invalidates this test.

I would postulate that nearly every bus build I see, if this test were performed afterwards, would fail the above mentioned test for varying reasons - everything from massive weights in the cargo bay (batteries, water storage) to interior walls made from steel or wood, showers, cooking appliances, woodstoves, fridges, couches, you name it.

Some of those items will deflect and bend, others become deadly spears, or blunt trauma objects when you washing machine a bus on the highway.


So what we're left with is the operational life of the vehicle if it's driven a lot of miles. Going back to the box beam construction analysis of the structure, I'd say that the chord length afforded by the depth of the ribs affords little strength to the structure under normal operating parameters. This is to say - driving and not crashing.

That inner skin is simply a passive engineering element in those situations. I think some stiffening to the body is afforded by that skin, but removing the interior skin isn't causal of exceeding the the exterior skin and fastener working limits.

Turn the bus on it's side or upside down, and it's the active structural element, and in for a world of hurt.

Now, having put that down on the record for saying basically yes it's weaker - I still removed the inner skin, lifted the roof, etc. Why? I don't need school bus safety standards, and there are competing design requirements: weight, serviceability, thermal, inspection, and more. The riveted steel skin is still far superior to the fiberglass composite panels and wood framing of the "sticks and staples".
Well said Aaron. I think the comparison should not be with an intact school bus, but with a manufactured motor coach. In that case, a modified school bus is much safer than sticks and staples.
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Old 04-07-2016, 08:06 PM   #20
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Let's agree that it's not good to wreck either one.

I've seen large trees fall on a bus, and you could still crawl through the bus. I'm guessing the survive-ability would change considerably in a bus that had a roof raise compared to the intact bus structure.
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