Idea's for attaching aluminum panels good or bad ???

[sammyb]

Hi Guys
Im new to the forum, I have been lurking round for a few months and am gaining lots of ideas from your valuble expertise. I am building a camper on the shortest version of a 416 unimog, so far I have the mog completly restored except for the gearbox which is still good and the camper frame built.
I have a question if the idea I have for attaching the aluminum panels is good or if anybody has a better idea ???
The frame I have built is mostly 3mm steel and between 30 and 50 mm square section, my idea is to cut the pannels to shape and then clamp them in place and mark all around the inside of the frame. Next I will lay the panel down and stick a strip of rubber 3-5 mm thick and 1 cm wide around the whole panel 10mm in from the edge. Following this I will offer the panel back up to the frame and drill holes for rivets 15 mm in from the edge so it passes through the rubber, then lay the panel back down and put a bead of 5200 or 252 high modulus silicon around the 10mm on the outside of the rubber and up to the marked line on the inside of the rubber, then rivet the panel in place. I will put nylon washers on all rivets and also dip them in duralc or Tef Gel to hopefully avoid as much metal to metal reaction as possible.
Is this a good idea or do any or you have any better ideas, time or cost is not the issues, quality of build is most important !!!
Any ideas would be greatly appreciated
Thanks
Sam

 

[FusoFG]

My camper box is aluminum panels on a steel rectangular tubing frame.

The aluminum panels are glued to the steel tubing with Sikaflex. Where 2 panels meet one panel is glued to the frame and the other panel is overlapped a couple of inches and glued to the first panel.

3M makes a similar product that is a tape.

Use a jig to line the panels up because once they make contact to the sealant they don't move.

 

[Lynn]

You might want to read up on Rob Gray's Wothahellizat chronicles. He used industrial 3M foam tape. He also came up with a slick way to locate each panel as he adhered it to the truck, IIRC using rivets that were later removed.

 

[sammyb]

Hi peter

The idea is that there is a 10 mm bead of sika then 10 mm of rubber 3mm thick followed by 10- 30 mm of sika depending on where on the frame it is. The rubber is there to make a uniform space between the aluminum and steel (3mm rubber should leave 3mm thick sika strip either side of the rubber) rubber will only have sika on edges not on the contact surface. I came up with this idea so I have a uniform thickness and can use rivets instead of guessing clamping pressures so as not to squeze out the good stuff.

As for the wothahellizthat project I read through his web site a couple of days ago, number 1 he used VHB tape wothahellizthat 2 he used high modulus silicon (sika 525) I have 2 rolls of VHB tape bought for the camper construction but have decided against using it as some areas of the frame are not perfectly flat on the welds. In hindsite I would build the camper a little different but I have the frame constructed now.

sam

 

[skysix]

Sika source

Where is the best place to get Sikaflex on the west coast?

 

[63tlf8]

As for the wothahellizthat project I read through his web site a couple of days ago, number 1 he used VHB tape wothahellizthat 2 he used high modulus silicon (sika 525) I have 2 rolls of VHB tape bought for the camper construction but have decided against using it as some areas of the frame are not perfectly flat on the welds. In hindsite I would build the camper a little different but I have the frame constructed now.

sam

Just to be different I used 0.55mm pre-painted steel and VHB tape. Had a beer with Rob in November and the impression was the both systems work. After all, #1 didn't actually fall apart. I would agree that Sika might be easier to work with as the tape is pretty terminal if you miss the alignment. I haven't quite got the need for rivets though. Bonded panels are an industry standard now with complete satisfaction as far as I can see. Is there a specific reason to add rivets to the equation?

Tony

 

[sammyb]

The idea to use rivets is to position the panels quick with pre drilled holes, I probably won't use as many rivets as if I was just riveting, but knowing me I probably will as I normally over build things strength wise.

I've worked in the yachting industry for the past 10 years so know quite a lot about the strenght of high modulus silicons and am just getting to know about VHB tape, sadly I have $300 woth of tape that won't work for me on this build. Worked well though sticking down my GPS mount on the dash !!!
And I can see endless pranks with coffee cups , cigarette lighters etc :jump:

As for buying sika, my tips: buy from a shop with high turnover (eg yacht supplies in busy areas around boat yards) make sure the place has aircon not a sweat box (sika goes of in heat) and check for long expirey date.

Question on insulation as I plan to use panels of foam, does it work better if glued to the aluminum or could I use VHB tape around the edges of the foam.
VHB is awesome stuff !!!

sam

 

[whatcharterboat]

We did an alloy bus awhile back. Haven't done one since but thought you might like the pics if they are any help. Sika was used. But then we weren't aware of the 3M tape at the time. If you can get a message to Mickldo, he is a wealth of info on coachbuilding practices using alloy sheeting. Although judging by the responses you have received to your questions, there is quite a few switched on guys here already.

From a commercial perspective only, this bus was really quick to put together using alloy sheet and therefore extremely cost effective. Our reasons for not continuing down that path were the aesthetics and overall toughness.

Hope the pics help in some way.
John.

 

[sammyb]

Thanks

That bus looks like it was built for the beaches and tracks around fraser island, I like isuzu's. I rember most people in Oz saying an Isuzu deisel was'nt run in until around 150 000 km's. When I was in Fire and rescue in NW western australia we had a huge Isuzu
4x4 an awesome truck would make an excelent heavy overland truck.

I will try and shoot a PM to Mickldo today

Thanks for the tips and pictures John

Sam

 

[4x4 explorer]

Another 2 cents worth. You might eliminate the hastle you described with stainless rivets as they are compatable with both aluminum and steel. The skin alignment is tricky with the 3M tape but that is what I used on my side walls. However. they were perfectly smooth and flat so tape worked great. I clamped a piece of flat stock on the bottom edge of the frame and would set the edge of the aluminum sheet on that. Then slowly lay the sheet against the frame. Of course I built my wall off the truck and then assembled after all were skinned.