Roof Raise Confusion

[The Rockwood Colony]

Memorial weekend I plan on raising the roof on my 77 passenger Amtran but I still have to get the materials and am still confused on a few things...

1. How much sheet metal to buy and what gauge?

2. We are doing RV windows so do I need the sheet metal shop to cut out the window slots so they have the radius corners perfect or can I install the sheets and then cut them out down the road?

3. What gauge hat channel and type of metal should I use?

4. I still have no idea where to cut through the back of the bus since we want to keep the original door for the "garage" area.

5. We just plan on using a couple floor jacks with 4x4s on them extended to the hat channels on the ceiling to raise it and then use 2x4s extended through the bus windows from one side to the other in the front and the back of the bus to evenly space the raise and for additional support. Has anyone ever done it this way and would you do it again? Will this work?

6. We are riveting the sheet metal on through the old and new hat channels and using 3m panel adhesive instead of welding. We plan on popping out the rivets above the windows and sliding our sheets up in there and re riveting just like most people do but I'm concerned because we only have one row of rivets above the windows. Not two like every other bus I've seen so is it ok to pop all of those out at once? How far should we push the sheet metal up past the rivets above the windows? How do I keep the sheet metal and new hat channel all in place while I rivet them together? I'm wondering if I should just use the adhesive during day 1 to glue the hat channels in place, let it dry for 24 hours, and then the next day start installing sheets after all the hat channels are set in place?

I AM EXTREMELY SORRY AND EMBARRASSED FOR ALL OF THE QUESTIONS BUT.. I literally have zero experience in metal work/auto body so I just need to make sure I don't screw this up! I have small children and a wife to protect so please, any advice or help would be so heatedly appreciated!!!

I really wish someone that has done a roof raise could just help so if you know ANYONE in the SIOUX FALLS, SOUTH DAKOTA area that may be able to help for some extra cash please let me know!

I would also just really like to speak to someone over the phone if not in person with experience on this type of project just to get some advice or help so if anyone is willing to do that please direct message me or email me at benjipike@gmail.com PLEASE AND THANKS SO SO MUCH!!!

 

[family wagon]

I can only tell you what "worked for me!"

1. How much to buy depends on how much opening your raise creates, how many windows you'll delete, what sheet size(s) are available in your market, the spacing of your ribs. Those all come together with some creativity on your part to figure out how to optimize the usage (and waste) of the sheets you'll buy. I don't recall the thickness of the factory skin on my bus but I used 16 gauge for the bottom half and 18 gauge for the top half re-skinning mine. Structurally some will say 16 gauge is overkill; maybe it is. Surely it's also more dent-resistant. You may not be entirely re-skinning your bus as I did, so maybe this is less important to you.

2. We did radiused corners by hand on mine. It wasn't difficult. I'd suggest it's better to do the window cut-outs after the metal is installed because this gives you some freedom to let the sheet metal be skewed one way or another without getting your windows all out of alignment. Draw onto the exterior of the metal with a marker the outline of the window. Draw another line offset toward the inside 1/2 to 3/4 of an inch. Cut there. We used a pair of 12" adjustable "Crescent" wrenches to fold the sheet metal over at the window outline. The metal through the radiused corner will need to stretch quite a bit, but it was surprisingly easy to do by hand with a simple 16 oz framing hammer. An air chisel with one bit modified made a nice hammer, too. The folded-over flange really stiffens the panel!

3. I had custom hat channel made at a local shop to fit snugly over the factory stuff. Don't mess around with trying to get the measurements right; cut out a section of your factory channel and give it to the shop with instructions to fit outside the sample (or inside, if you prefer). I picked 14 gauge galvanized steel because from what the shop had available that to me appeared most similar to the factory material.

4. You can cut above the rear door if you want to keep its original frame intact, or you can make (or have made) more material to match the shape of the top and side jambs to fill in any gaps you create by cutting elsewhere. Weld the filler sections into place. There's a bit more cost in having those parts made but it might really give you some freedom in how you cut the back wall.

5. I used scaffolding with screw jack levelers as described by nat_ster in The Four Season Prime here. The best way to search for it would be on an external search engine "site:skoolie.net four season prime scaffold roof raise" or similar. That said, your method may be equally good. There are a variety of methods used based on what each person has on hand or is interested in buying. Looking back on mine, I wish I had considered more carefully how to use a mason's string for checking alignment of the structure before and after the raise: plumbness of the walls, any sag in the roof from front to back, elevation of the roof from the floor at the four corners and points in between, etc.... now that I've scared you about that, I'll also say "it's a bus, not a piano!" :whistling:

6. There's a temporary fastener called cleco or cleko that you should look into. They're pretty nice for pinning things together when you're not quite ready to set a rivet yet. Where there's access available on both sides a machine screw can work well. Clecos aren't horrible expensive so I bought about 25 in the 3/16 size; screws are cheap so I bought 100 #10-24 by 1 inch. The screws are a little loose in a 3/16 hole but work alright. I'd definitely suggest getting the hat channel situation fully worked out all the way around the bus before getting into hanging new sheet metal.

 

[Rusty-SKO]

Memorial weekend I plan on raising the roof on my 77 passenger Amtran...PLEASE AND THANKS SO SO MUCH!!!

Cool. Get one of these - now and play with it. It will put your mind at ease.

here is coupon

 

[Tango-SKO]

The "ideal" is to use sheetmetal that is as close as possible to what you already have. Same for the hat channels. You can get a standard metal gauge for a couple of bucks at most any Harbor Freight or Northern Tool to get starting numbers. Be advised, a number of bus makers use oddball gauge sheetmetal. BB for example is closer to 15 gauge while the "standards" are 14 & 16. Just try to match as best you can.

 

[chev49]

The "ideal" is to use sheetmetal that is as close as possible to what you already have. Same for the hat channels. You can get a standard metal gauge for a couple of bucks at most any Harbor Freight or Northern Tool to get starting numbers. Be advised, a number of bus makers use oddball gauge sheetmetal. BB for example is closer to 15 gauge while the "standards" are 14 & 16. Just try to match as best you can.

Why?

I always use 18... for at least 30 yrs and never had any problems. It welds very good. is fairly easy to shape, not to mention thicker than most vehicles of today i have to work on. (metal composition is diff of course, but not a big deal)

 

[EastCoastCB]

Why?

I always use 18... for at least 30 yrs and never had any problems. It welds very good. is fairly easy to shape, not to mention thicker than most vehicles of today i have to work on. (metal composition is diff of course, but not a big deal)

My AmTran's ribs are 14ga, the skin is 18ga.
I've taken a bluebird apart, and it looked to be the same.

 

[Brad_SwiftFur]

One idea would be to head to a local bus salvage yard and cut out a couple of the wall supports. Cut these to shorter lengths for however much you plan to raise your roof. While at the salvage yard, if possible, cannibalize the skin below the windows for your sheetmetal. It will match the thickness of your bus because it came from another bus (assuming a similar body, of course.) If you need a *lot* of bus parts, simply buy a dead junker/wreck from a nearby auction, then sell it for scrap when you've salvaged everything you could use.

 

[New2Skool]

When I lifted my roof, I decided to lower the skirt down about 9 inches and to create a new "mid-Beam" so a full four foot sheet would fit perfectly.
Then, I was able to raise the roof about 16-17 inches giving myself an inch of upper sheet over lower sheet overhang and another full four foot sheet would fill the upper half.

You are right on the money about the jacks and wood framing lifting method. I borrowed two bumper jacks and made two T frames out of 2x8s doubled up.

To keep the lift centered and supported, I welded angle iron to four of the ribs and welded 3/4th inch roung tube to the angle iron. Then I fed a three foot all thread bar and held in place with two square nuts.

As I lifted the roof, I would go up a couple of inches stop, slowly and carefully walk to the corners to tighten the nuts providing support and keeping the roof straight and center.

Prep work was figuring out the interior size of the ribs, cutting tubing to size, hammering them into place covering the span of the lift, welding in place.

It was a lot of work but worth every second and every dollar. Most folks just remove the rear door and cut in the middle if there is a tilting point in the door. If you are lifting the entire roof or just parts, get everything you need ready. cutting discs, welding rods, rib inserts, jacks, oh and get a third jack it seems that the lift always tilts one way or another and needs extra support or straightening.

It is scary too, you realize when you are inside that if the roof falls you are not making it out. The ribs will hit the floor and slide to the other side before it rolls over and away from the bus. You cant jump out that fast and if you do, you have a 50-50 chance of bailing out the wrong side and may be like indiana jones running from the giant boulder.

Good luck and have fun.

 

[Tango-SKO]

The idea of staying close to original gauge is based on maintaining uniform loading across the structure. Going either much lighter or heavier creates weak points where the differing materials meet. And given the stresses a flexing body creates, there will be the potential for problems. Not saying it will fail, but there is no engineering advantage to placing lighter or heavier skin on the body unless you replaced it all.

 

[The Rockwood Colony]

Here we go

Thank you everyone for the great info! Good and bad news... the bad news is I won't be able to raise the roof this weekend. The good news is I got all of sheet metal and hat channels ordered yesterday! So exciting!!!! We went with galvenealed sheet metal and galvanized hat channel. We plan on using 3m panel adhesive 08116 and rivets to fasten 99% of the materials. The only things we are welding is the angled supports that will go under the height transition skin on the top of the bus right behind the drivers seat and the channel extensions that will be needed above the back door. The adhesive costs about $40 per cartridge but I'm not really sure how many to order. Any thoughts? Also need to figure out the best rivets for the job yet. So pumped up though!!! Oh ya, on the roof of my bus the rows of rivets skips every other rib and it just so happens that the rib on the top rib of the height transition doesn't have any fas tenets in it so I think we are just going to use long bolts across that rib that will go down all the way through the hat channel. My only concern with this is that since the hat channel will have that open hollow section that the bolts will pass through, I'm worried when we tighten the bolts down it will lightly crush and weekend that rib. All thoughts and suggestions on all of this are welcome!

Here is the order that I made to show how much everything costed... thanks again everyone!!

 

[The Rockwood Colony]

Hopefully you can see the order better here... I split the image in two.

 

[Drop out]

I've done more than my fair share of sheet metal work and I don't think I would want to learn on a job like this.

I would suggest trying a few smaller projects first so you can make your mistakes there.

I just got through reading two threads on raised roofs and how people are doing it. What I have seen is that they aren't using many of the tricks I would use.

Clecos are great but combine it with some sheet metal loops and ratchet straps and you can pull your metal tight along the side of your hat channel.

Swivel pad visegrips are great for clamping sheet metal. There are also flanging visegrips for making overlap seams that lay flat.

There are nice little sheet metal hand punch kits that are pretty cheap, they could come in handy.

Step drills are nice for sheet metal, they don't try to drill a triangular hole like a normal drill bit.

Learn how to do sheet metal layout with Blue Dyechem and a scribe.

For cutting rectangles with radius corners, cut the corners with a hole saw and then connect the dots with one of those electric shears.

One good thing about cutting out your window holes last is that before you cut you can use the part you are going to remove as a place to cleco your sheet metal loops for ratchet strap tensioning.

Speaking of shears, get a decent set of right and left cutting offset aviation snips with compound leverage (Wiss is good).

When hotrodders chop a top, they weld reinforcing frames in to the body so it doesn't move when the top is cut free. You can try that or else make good reference marks so you can raise each hat channel an equal amount. Use clamps and jacks and shims to push anything that doesn't cooperate. A few 3/4" Pony clamps can be really handy for clamping over long distances.

Read, look at pictures and ask questions before you start.

One more thing, when you are modifying a structural element, you should know what makes it strong so that you can make sure you are not going to make it weaker.

 

[The Rockwood Colony]

I've done more than my fair share of sheet metal work and I don't think I would want to learn on a job like this.

I would suggest trying a few smaller projects first so you can make your mistakes there.

I just got through reading two threads on raised roofs and how people are doing it. What I have seen is that they aren't using many of the tricks I would use.

Clecos are great but combine it with some sheet metal loops and ratchet straps and you can pull your metal tight along the side of your hat channel.

Swivel pad visegrips are great for clamping sheet metal. There are also flanging visegrips for making overlap seams that lay flat.

There are nice little sheet metal hand punch kits that are pretty cheap, they could come in handy.

Step drills are nice for sheet metal, they don't try to drill a triangular hole like a normal drill bit.

Learn how to do sheet metal layout with Blue Dyechem and a scribe.

For cutting rectangles with radius corners, cut the corners with a hole saw and then connect the dots with one of those electric shears.

One good thing about cutting out your window holes last is that before you cut you can use the part you are going to remove as a place to cleco your sheet metal loops for ratchet strap tensioning.

Speaking of shears, get a decent set of right and left cutting offset aviation snips with compound leverage (Wiss is good).

When hotrodders chop a top, they weld reinforcing frames in to the body so it doesn't move when the top is cut free. You can try that or else make good reference marks so you can raise each hat channel an equal amount. Use clamps and jacks and shims to push anything that doesn't cooperate. A few 3/4" Pony clamps can be really handy for clamping over long distances.

Read, look at pictures and ask questions before you start.

One more thing, when you are modifying a structural element, you should know what makes it strong so that you can make sure you are not going to make it weaker.

Hey! Thank you so much for the trick tips! I am researching all of them now! I know you recommend not starting to learn sheet metal work on this project but it's getting done! I'm running out of time and should have a few friends with experience there with me as well.

I love the ratchet strap idea! And all of them I guess. Nothing like a good jig!

I seriously appreciate you reaching out. You have changed the way I'm executing this for sure! If you can think of anything else that could help, in all ears!

 

[family wagon]

Alright, I'll bite: what is a sheet metal loop? My web searching isn't coming up with anything having to do with handling or applying tension to a sheet.

 

[Drop out]

Well, I'm sure I'm not the first to do this but I kind of came up with it on my own.

Cut a piece of sheet metal in a kind of bowtie shape with the middle narrow enough to hook with a ratchet strap, now bend it in half to make a "\_/" shape with the loop at the bottom and drill holes near the top corners so you can cleco it to the piece you want to pull, then hook your ratchet straps through the loops and pull against some sort of support.

I first did it with perf so the holes were already there but it worked great to tension some skins for riveting around an oddly shaped truss.

Doing it flat should work, you probably just need a tube to hook both ratchet straps on to (compression on the tube). 2" tube would probably be more than enough, 1" might want to bend or buckle if it's long like 20'.

The clecos will be going through three thicknesses of sheet but they will still hold quite a bit of shear load, I never had a problem with 1/4" clecos.

Fabrication usually needs a certain amount of improvisation if you don't have the "right" tools or jigs. That is a big reason why you want to learn on something less critical, you don't learn to improvise on your first job. Some people don't learn by their tenth...

 

[Rusty-SKO]

There are nice little sheet metal hand punch kits that are pretty cheap, they could come in handy.

I use the heck out of my roper-whitney.

 

[Drop out]

Yep, I was failing to remember that name. I have found the Chinese copies to do just as well for 1/2 the cost or less (easy to find on Amazon).

Just don't overload it too much.

 

[family wagon]

While we're on the subject of making holes in sheet metal: how does factory production make all those rivet holes? Surely they don't make 'em with twist or even step drills.. do they?

 

[Rusty-SKO]

While we're on the subject of making holes in sheet metal: how does factory production make all those rivet holes? Surely they don't make 'em with twist or even step drills.. do they?

That's what these bad boys do- you squeeze the grips and they make a perfect little hole. Different sizes, no electricity- is like a paper punch.

 

[family wagon]

Well yes, that's a start, but it punches "up to 3 1/4″ from the edge of the piece." Many (most?) of the holes in a bus are farther than that from an edge. Virtually all the holes go through two, if not three or even four plies of metal. A hand punch won't take care of those situations either. A person could punch through one ply, but it'd take some careful use of jigs and control of the temperature of the metal to pre-punch all the holes and hope for them to align when the separate parts are brought together.