| Author |
Message |
mike merrill (Mikemerrill71yahoocom)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 01, 2006 - 9:06 am: | |
I have my roof raised and am fitting the caps,I ordered 5x10 sheets of .065 alum for siding,what I would like to know is what to use to seal it with and if it needs to be heated before riveting it all on and if it dose what is the best way to put sealer on all of the framing and heat it and then rivet it as the adhesive has such a short working time,Cliff what was the adhesive you used from byler that you said you liked so much any help appericated thanks to all for all of your help,Mike |
dug
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 01, 2006 - 9:28 am: | |
I cut mine in 5 foot sections. Made it a little easier to handle. Welded some brackets that looked like a "v".
I ran a bead across top frame, then slid alum in. Clamped the brackets to the frame, and the alum set in the bottom of the "v".
Then used a portable heater to heat top, and put 1 rivet in middle top. Then I removed the brackets, and sikaflexed the rest of the frame.
I rivetted from top to bottom, then middle out, pointing the heater at the section I was working on.
http://www.droppedstone.com/1975%20MCI/DSC00099.JPG
HTH,
Dug
75 MC8
Arcadia, FL |
captain ron (Captain_ron)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 01, 2006 - 10:06 am: | |
I didn't use heat at all but you should rivet top of sheet first. all the way across. or you will get rinkles. |
Marc Bourget
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 01, 2006 - 10:59 am: | |
The purpose of heating the aluminum is intelligently discussed in Dave Galey's Bus Converter's Bible in a chapter entitled "The Steel Case".
His experience argues that pre-heating is pallative. You need to heat while installing as an ATTEMPT to put the skin in tension so that, when the temp climbs, since Aluminum expands faster than steel, the Aluminum always remains in tension, avoiding the appearance of "wrinkles". Dave feels the benefits are transitory, as the tension affects the rivets, things relax, tension goes away and wrinkles "magically" reappear.
Assuming you wish to proceed anyway, Guaging the temp of Aluminum is problematical as the heating is more or less localized and it's hard to measure and maintain the 130+ temp, [(aluminum gives no visual clue as to temp - until it melts, that is!!!) + (assuming you leave the bus light colored, more if dark paint)]
I guess it'd be nice to have a bus sized oven, (or ship the bus to Iraq in the summer just to rivet it up) but either solution is impractical, if not impossible.
I maintain the best "thermometer" is the aluminum sheet itself. Mark the sheet at intervals, offsetting the marked point "inward" by the distance calculated to equal the expansion of the aluminum at the selected temperature. Your "helper" heats the aluminum, locally, (i.e., in the area you're riveting) sufficient to expand and maintain the mark to meet the midline of the next structural member to where your riveting is proceeding. I suggest this process because it's more likely that you'll maintain a uniform temp in the working field, than you'll be able to obtain trying to keep the whole sheet up to temperature.
Another less viable approach, is to make a fixture to clamp one end of the (full length) sheet you're installing and tension it with a forklift, come along, a spare elephant, or whatever!
Something I've never seen proposed is just the reverse. If the average ambient is 80 deg, and you want to "protect" from wrinkles to 130 deg(a difference of 50 deg.) why not pick a 90 deg day and cool the involved structural memebers with ice, until you finish riveting? Delta "T" is Delta "T", regardless of whether it is up or down.
All else considered, the abhorrance of "wrinkles" is to me, just another form of "Johnson" envy. I utilize the serenity prayer to combat the refusal to accept the things we cannot change requesting the wisdom to know the difference.
Coefficient of Expansion is a fact of the physical universe. If a smooth sided bus is that important to me, I should save my schekels and buy one!
Food for thought!
Onward and Upward |
Bryce Gaston (Busted_knuckle)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 01, 2006 - 12:55 pm: | |
There is a way of knowing yer temp of the aluminum by using an infered thermometer sold at Napa (and I'm sure other parts stores) for about $90 just point shoot and it shows the temp! Even has a red beem for aiming purposes it tight areas like checking for a hot bearing or a cool clylinder, hot/cold spots in a cooling system many uses! I don't usually get in on the "conversion process threads" as I have no experince in it! But thought this might be useful1 Bryce aka Busted Knuckle |
Cliff (Floridacracker)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 01, 2006 - 1:00 pm: | |
Mike,
When I put the aluminum on mine the outside temp was 85 degrees and it was sitting in the sun. According to the coach builder down the road I would have no problems and no heating required at that temp and so far so good. I know your up in a little colder country so I would use one of those blower heaters to warm it up. I beleive Fred Hobe has an article on Coach Conversions about doing just that.
I will look up the exact name of the adhesive I used and e-mail you when I get home today.
On working with the sealer; There was no way that I could keep up with the cure time on any sealer with the amount of rivets I had. 3000 to date. What I did was to put the panel in place, cleco across the bottom at the columns, then put adhesive/sealer on the seams only where it was behind the frame and I had no access from the inside, then sealed the joints from behind when I was done riviting. Tested with a pressure washer and no leaks. I started riviting at the bottom and worked my way up and forward as the straight end on the bottom was exposed and the wild end was under the roof aluminum.
Also, What I did to hold the overlap end was to strategically put a piece of channel up with one rivet on each end and then clamped the open end with a couple of C clamps with blocks. After it was up I didn't need any help and then I drilled out the temp rivets and put in a backing plate and rerivited. The rivets look like they are part of the original design as this process was repeated down the entire coach.
Your making me tired just thinking about it!
Good luck and great meeting you at Bussin 2006
Cliff |
Cliff (Floridacracker)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 01, 2006 - 1:04 pm: | |
Bryce,
I have one and it is one of those tools that falls under "Best money I ever spent" categories.
Cliff |
Bryce Gaston (Busted_knuckle)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 01, 2006 - 1:12 pm: | |
Cliff I agree it lays in the top of my tool box on top of those thousands of $ in tools! |
Marc Bourget
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 01, 2006 - 2:18 pm: | |
Bryce,
I augment your comment by adding that "simple" infrared thermometers will not record an accurate temp of polished aluminum as they are calibrated on a "black body" standard and aluminum emits less than the std black body. What you need for accurate temp on aluminum is a contact thermometer or a Infrared that has adjustable emissivity ($150+ vs. $70, typically)
As a "poor man's" calibrator - If you have a piece of aluminum and a tire sitting side by side in the sun, you can shoot both and add the difference to any subsequent reading taken from aluminum. It should be close enough for "govt work" IYKWIM |
dug
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 01, 2006 - 3:39 pm: | |
I used an infrared gun. The cheapo kind. Just read the frame temp.
Dug
75 MC8
Arcadia, Fl |
Rob King
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 01, 2006 - 8:57 pm: | |
Hi Mike
I have finished that part of my conversion and like Cliff said, boy I am glad I am past that part. It wasn't hard work but required consistent, persistent, patient, perserverent work. Here is what I did in detail on my Prevost. Yours maybe different if a different type bus. BTW, I did this in the summertime in the direct sun.
1.Starting at the back and working forward, I cut my formed aluminum to the proper length to cover the steel supports with an overlap at the front of 3".
2.Applied 2"x1/8" butyl tape to all steel supports that were to be covered.
3.Placed the formed aluminum on the buytl tape covered steel supports GENTLY so as to not attach it by pressure except for the top rear corner which I attached with a rivet.
4. I then had my wife, who was on the inside of the bus, use a propane powered weed torch, available from many farm stores for about $40, start heating the aluminum from the top rear forward. When the aluminum stopped expanding lengthwise and widthwise, I installed a rivet on the top middle section and then the top front section of that peice. While she continued to keep the heat on the aluminum, I worked the next line down starting again from the rear forward. I allowed spacing of about 10"-12" from that line to the next line. I made sure that each line would match up for the finished lines of rivets. When I finished riveting the sheet on with these temporary intermittent lines, which for me took 5 lines, she then shut off the heat. I then went back and put finish rivets in all the necessary lines to match the rest of the bus. Needless to say, you apply alot of heat initially to get the sheet heated but much less heat to keep it heated. That is a trick which will take sometime to learn. If you overheat the aluminum, it will distort way out of shape making the riveting process a fight so only heat until the length and width movements reach the maximum. Putting marks on the steel and aluminum with sharpies will help you see the expansion of the aluminum.
5. I started the next piece in exactally the same way with the addition of spreading butyl caulk, not butyl tape, available from the home center as rain gutter caulk, on the front side of the existing aluminum piece and overlapped the new piece onto the existing piece by 3".
6. Repeat the process until all is covered. Sit down in a lawn chair with your favorite beverage in hand to admire your handy work.
Here are some mistakes I made. I went to the same farm store and bought rivets thinking in my ignorance that they would hold. Boy was I wrong. The first time I moved the coach, several of them worked loose. So I had to drill them out, reheat some areas again and then place the proper rivets. Caveat-buy the right rivets first
Second mistake-I didn't buy drill bits from the rivet company thinking I could get them at Lowes' or HD and cheaper. What I found was the bits from the home center weren't as sharp and dulled quicker. Further, the rivet company had bits that were just 1/64" bigger than the rivet giving a tighter bond. Also, in most cases, that size bit wasn't available at the home center so I got some holes that were to big and gave sloppy rivet bonding. Thankfully, I had put in to small a rivet in the first place and had to go back with bigger ones later, so though it was a lot of work, it still turned out well.
Third mistake-I didn't buy a good drill bit sharpener, like Drill Doctor, until late in the process. Though it cost about a $100 for the Drill Doctor, it would have saved me more by resharpening the bits from the rivet company. There are many good drill bit sharpeners out there, this is just the one that I could get a $15 rebate on, so I chose it.
I got my rivets from Jeff at Byler Rivet in Dallas but I know there are other companies and they maybe closer/cheaper/more accessable to you. BTW, I still have about 15 rolls of butyl tape left over that I would almost give away if you choose to use this technique.
Hopefully this helps. If I can help more, just email me, skykingrob@hotmail.com, put bus in the re line so I don't delete you. Good luck and have lots of cool drink at hand for the process. I covered 16' on each side of my coach and it took me 1 1/2 days to get it done.
Rob
91 LeMirage
Missouri |
tony bare
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 08, 2006 - 12:00 pm: | |
A 96A mci parked beside us at a bluegrass festival and he showed us his conversion. I asked him about skinning the windows and he said that he did it a little different. He welded a piece of round stock ( don't know the size) horizonally down the center of the windows to be covered. When the aluminum was installed it made a very slight bend over the round stock. You had to eyeball down the side to see it. He claimed that that slight bow was enough to keep the skin from wrinkling. It was hot summertime and I didn't see any wrinkles. |
Carl Olson (Carls_mci_9)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 08, 2006 - 8:37 pm: | |
When I did mine I tried heating,it looked bad.My dad showed up and said to make a piece of angle iron with a loop drill holes to attach to edge of aluminum and stretch with a come along.Work from back to front.Had to use fork lift for pull on last piece.I thought he was slipping but it worked perfect. He said B+B told him what to do. |
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