Hell yeah coffee talk thread. Sometimes you need a brake from bus stuff. You guys are the best, and crack me up on a regular basis. Could be a very interesting thread
Hell yeah coffee talk thread. Sometimes you need a brake from bus stuff. You guys are the best, and crack me up on a regular basis. Could be a very interesting thread
Or we could just keep hijacking other people's threads !!!
Haha Christopher you totally are. Theres not many threads your name isn't all over. Let someone mention a/c or Christmas. Then just buckle up for the ride
Chassis: Blue Bird TC RE 3904, Flat Nose, 40', 277" wh base
Engine: 8.3L Cummins ISC 260hp, MT643, 4.44 rear
Rated Cap: 84 pax or 1 RV; 33,000lbs
Hanging Sheet Metal in the Winter...
Temps here are currently in the mid 50s with an occasional day hitting 70°. I do NOT want to put everything on hold until spring. I'm using 18 gauge cold rolled for the new skin. So, to avoid oil canning, what do you think about using one of these? I'm not planning on melting paint or anything like that but I should be able to get enough heat in an entire sheet to get it to expand don't you think? At only $20, I'm ok with using it the once and throwing it away (not literally but you get the point).
We used one of those to heat The metal on my first bus. Worked great.
We attached a come-along to one end of the metal, lifted it in place with a forklift, riveted one end, put tension on the metal with the come-along, heated and continued riveting.
Metal warps when heated unevenly and most sheet metal is produced on a coil and then flattened when it is made in to sheet so the heat makes it want to coil back up.
Chassis: Blue Bird TC RE 3904, Flat Nose, 40', 277" wh base
Engine: 8.3L Cummins ISC 260hp, MT643, 4.44 rear
Rated Cap: 84 pax or 1 RV; 33,000lbs
All of it does except the "attached come-along"... how did you attach it? Mine has a rather large hook on it. I don't know that I have any cable small enough to fit thru a 3/16ths inch hole (rivet size). I've got some 3/8ths inch cable somewhere I think.
And I don't have any fork lifts so, ... from 0:00 to about 3:00. The image alone gives it away. At 8:57 he hoists the last piece in place. Looks like a fair amount of sweat and effort into making it fit.
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Chassis: Blue Bird TC RE 3904, Flat Nose, 40', 277" wh base
Engine: 8.3L Cummins ISC 260hp, MT643, 4.44 rear
Rated Cap: 84 pax or 1 RV; 33,000lbs
Quote:
Originally Posted by Drop out
I would just try to leave it out on a sunny day.
Weekend, sunny, and warm. Not many of those left. We will have one in the middle of Feb that is 70°, sunny, and calm. Problem is, you can't plan for it.
I would leave the torch "unadjusted" on purpose tho. Just throwing orange flame everywhere instead a pencil blue blow torch (not that it would do that either).
Weekend, sunny, and warm. Not many of those left. We will have one in the middle of Feb that is 70°, sunny, and calm. Problem is, you can't plan for it.
I would leave the torch "unadjusted" on purpose tho. Just throwing orange flame everywhere instead a pencil blue blow torch (not that it would do that either).
I see no actual purpose in heating the metal. Unless you just want to keep toasty.
You're not going to heat it enough for it to matter and it cools rapidly. Its something folks think is going to matter, but just put the stuff on right and flat to begin with and it won't oil can or ripple. None of my metal work has done anything funky and I definitely don't go out of my way to work with hot metal.
I see no actual purpose in heating the metal. Unless you just want to keep toasty.
You're not going to heat it enough for it to matter and it cools rapidly. Its something folks think is going to matter, but just put the stuff on right and flat to begin with and it won't oil can or ripple. None of my metal work has done anything funky and I definitely don't go out of my way to work with hot metal.
you are probably lso working on metal in florida where its not 40 degrees outside..
that said you ultimately would want to work with your metal as close to the middle of the temperature spectrum you expect it to endure.. so if you expect 0 or 100 then 50 woud be the perfect spot.. also i was thinking if you use good heavier metal then you have less risk of oil-canning at any temperature range...
-Christopher
you are probably lso working on metal in florida where its not 40 degrees outside..
that said you ultimately would want to work with your metal as close to the middle of the temperature spectrum you expect it to endure.. so if you expect 0 or 100 then 50 woud be the perfect spot.. also i was thinking if you use good heavier metal then you have less risk of oil-canning at any temperature range...
-Christopher
I've worked with sheets of steel a LOT and never saw any benefit in making the work area any hotter.
Chassis: Blue Bird TC RE 3904, Flat Nose, 40', 277" wh base
Engine: 8.3L Cummins ISC 260hp, MT643, 4.44 rear
Rated Cap: 84 pax or 1 RV; 33,000lbs
Quote:
Originally Posted by EastCoastCB
I see no actual purpose in heating the metal. Unless you just want to keep toasty.
You're not going to heat it enough for it to matter and it cools rapidly. Its something folks think is going to matter, but just put the stuff on right and flat to begin with and it won't oil can or ripple.
You and I have covered this at least once before but I've eaten since then. What did Transcendence do wrong? My fab skills aren't going to be anywhere near as good as his to start with and his siding went to hell. Heating the metal from 45~45 to 75~85 can't be that hard. I'm not trying to get it to 250° while it's -40° outside.
Quote:
None of my metal work has done anything funky and I definitely don't go out of my way to work with hot metal.
Well, that's a damn lie!! It's always hot in FL!!
Quote:
Originally Posted by cadillackid
you are probably lso working on metal in florida where its not 40 degrees outside.
Chris beat me to it.
Quote:
that said you ultimately would want to work with your metal as close to the middle of the temperature spectrum you expect it to endure.
I've been wondering about that. Figured it stretches without showing better than it contracts. But if it's going to grown an 1/8 of an inch, then it's going to contract an 1/8" too. Pulled the number out of a neither region. I've no idea what a 10ft sheet will do.
Quote:
so if you expect 0 or 100 then 50 woud be the perfect spot.. also i was thinking if you use good heavier metal then you have less risk of oil-canning at any temperature range...
-Christopher
Sounds reasonable. Only question is what will my range be? I want to see the northern lights. That's kinda tricky at 80° in FL. I think I'm willing to skip Death Valley in Aug tho.
Chassis: Blue Bird TC RE 3904, Flat Nose, 40', 277" wh base
Engine: 8.3L Cummins ISC 260hp, MT643, 4.44 rear
Rated Cap: 84 pax or 1 RV; 33,000lbs
Quote:
Originally Posted by Drop out
You can use sheet metal scraps and clecos to create a loop that you can pull with a come-along or a ratchet straps.
I have have, never used, and never even seen a cleco in person. That I am going to fix. But aren't clecos designed for push/pull strength and not shear strength? 3 or 4 should be able to handle a hundred or maybe even a couple of hundred pounds. Not sure how much these guys are talking about with a come-along tho.
Chassis: Blue Bird TC RE 3904, Flat Nose, 40', 277" wh base
Engine: 8.3L Cummins ISC 260hp, MT643, 4.44 rear
Rated Cap: 84 pax or 1 RV; 33,000lbs
So, using Weather Underground, I checked the historic temps for the past 3 or 4 yrs for Nov and Dec. Nov is the last of the 70s. for all of those yrs. Dec for the most part is 40s and 50s. Grrrr, I'm hosed.
another thought crossed my mind.. why dont we see issues with factory made busses in various parking situations...
at times my red bus is sitting half in the sun half out.. the part in the sun is so hot you could throw an egg at the bus and it would be plate ready by the time it fell off.. yet a foot away its just barely warm..
sure you can hear the metal expand and contract when inside a bus and the sun goes behind or pops out from the clouds.. but the factory built these things where they dont buckle and then go straight.. maybe the issue is skoolie builders are so focused on rigidity that its too rigid? perhaps the holes the rivets go through need to allow for a slight bit of movement side to side? maybe adjesives were used that arent flexible? that harden to a crisp (ie JB weld.. seenthat name mentioned in this forum.).. where the metal can move against its other panels?
when you take apart a factory bus.. it seems theres a lot of 'Goo' and not so much hard cracky stuff breaking out.. maybe thats one of the tricks?
-Christopher
I have have, never used, and never even seen a cleco in person. That I am going to fix. But aren't clecos designed for push/pull strength and not shear strength? 3 or 4 should be able to handle a hundred or maybe even a couple of hundred pounds. Not sure how much these guys are talking about with a come-along tho.
I'm not sure they're "designed" for either mode specifically. In any case you could just substitute a handful of thick machine screws.
Quote:
Originally Posted by Brewerbob
I've been wondering about that. Figured it stretches without showing better than it contracts. But if it's going to grown an 1/8 of an inch, then it's going to contract an 1/8" too. Pulled the number out of a neither region. I've no idea what a 10ft sheet will do.
My untrained gut feeling is that it's better to stretch the sheet when mounting it so that it'll be really stretched when it's cold and neutral to slightly compressed when hot. When it's stretching it's guaranteed to stay flat, but when it's compressed eventually there comes a point where it gives up and buckles.
Just because it's fun to play with calculators.. there's a linear thermal expansion calculator over at engineeringtoolbox. If we feed into that 12.2m length, 0.000011 coefficient for steel, and initial and final temperatures of 0 and 40 C, it says the change in length is 5.4 mm. Converting back to familiar units that's a change of just under 1/4 inch over 40 feet when temperature changes from 32 to 104 F.
edit: what I'd be interested to know, and maybe you would too, is how much tension do we have to apply with a come-along to get a 40 ft strip of sheet to stretch by 1/4 inch (or 10 ft pieces to stretch by 1/16)? Maybe the force involved is actually practical to achieve and it would be easier than using heat.
Quote:
Originally Posted by cadillackid
another thought crossed my mind.. why dont we see issues with factory made busses in various parking situations...
I've wondered whether it has to do with the relatively narrow panels often used in the factory. Many sections are only two rib-spaces wide, so maybe 5-ish feet. On the other hand, we tend to put up the longest pieces we can manage. There surely would be a bit of movement allowed at each of those joints; maybe that helps keep expansion effects at bay?
Chassis: Blue Bird TC RE 3904, Flat Nose, 40', 277" wh base
Engine: 8.3L Cummins ISC 260hp, MT643, 4.44 rear
Rated Cap: 84 pax or 1 RV; 33,000lbs
Quote:
Originally Posted by cadillackid
another thought crossed my mind.. why dont we see issues with factory made busses in various parking situations...
at times my red bus is sitting half in the sun half out.. the part in the sun is so hot you could throw an egg at the bus and it would be plate ready by the time it fell off.. yet a foot away its just barely warm..
sure you can hear the metal expand and contract when inside a bus and the sun goes behind or pops out from the clouds.. but the factory built these things where they dont buckle and then go straight.. maybe the issue is skoolie builders are so focused on rigidity that its too rigid? perhaps the holes the rivets go through need to allow for a slight bit of movement side to side? maybe adjesives were used that arent flexible? that harden to a crisp (ie JB weld.. seenthat name mentioned in this forum.).. where the metal can move against its other panels?
when you take apart a factory bus.. it seems theres a lot of 'Goo' and not so much hard cracky stuff breaking out.. maybe thats one of the tricks?
-Christopher
I dunno. Airplanes go from 120° to -40° in less than an hour multiple times a day while seeing 600 mph winds.. Buckling airplanes would get some attention even if they continued to fly flawlessly. Who's going to get on a wrinkled airplane?
Mudda Earth says he has experience working on aircraft. Does that mean engines from a Cessna or the skin of a 737? I don't know but if he's hanging out at an airport hanger, he's going to have at least some idea how they are patched up. To see his bus buckle has me worried. I use him as an example for 2 reasons ... 1) he should know what the hell he is doing, and 2) his crinkled bus is the only one I've seen pics of and know of. Well, there was that one bus with a 3 foot raise but that thing looked like it was wrapped in tinfoil.
As for glues verses goos, I'm going to go with "maybe"? I was going to say "no" but I've only taken apart the inside of my bus thus far. There is a red colored glue for some of the interior sheet metal. I dunno what it is but just a small spot of it has the sheet metal sticking together fairly well. An actual bead and someone paying attention to applying it, and I'm not sure rivets would have been needed.
The outside seams appear to be goo. Floor to wall is goo. Windows are goo. But all of those are for weatherproofing I would think. I don't know if any of the external panels are glued to the ribs or not. Maybe they are just riveted.
I just have a hard time believing that Mudda doesn't know that a 1/4" diameter rivet needs a 3/8" hole (totally made up extreme values on purpose). Whatever the real numbers are, there has to be a "simple" formula that says 10 feet of 16 gauge needs X size holes and 12 feet of 10 gauge needs Y for "slop".