rivets or screws????

[urbanironaz]

I am building a 5x8 teardrop with a 1"steel tube frame ..I was going to use 5"wide .063 alum ,but was told that it would be to stiff....so I am considering the alum. on a roll .040 I think or annealing the thicker stuff to soften a little .. What is the best way to attach the alum skin to the steel frame???I was thinking pop rivets or self tapping sheet metal screws?? any one have any expeirence with either method??

[doug hodder]

VHB foam tape from 3M will hold the panels in place while you install your mechanical hardware. It will also stop galvanic action between the steel and the aluminum and minimize any rattles. Pop rivets will have a hole that will need to be sealed, and I don't think you'd be able to get in there to back up a huck type rivet. The RV industry regularly uses self tapping screws, just don't overtighten and twist one off. Just my thoughts on it, other opinions may vary. Doug

[urbanironaz]

thanks for the 3m tape idea I guess a dab of silicone would seal the hole with rivets..but which is better rivets or screws for a long term?

[DBizer]

My thought would be that with expansion and contraction of the aluminum, pop-rivets could shear off and there is no way of re-tightening them. Screws would seem to be a better choice to me.

What about floating the skin under the edge, door/window trims?

[doug hodder]

Again...just my opinion. I think either one is going to be fine in the long run. There are old trailers running around that are riveted together for 50+ years. The self tapping screws are newer but done correctly I'm sure either one will give you plenty of years of service. If doing rivets, I would suggest getting a pneumatic gun to do it. I've never had outstanding results on that type of thing by just using a hand squeeze tool. I've redone a number of large truck cabs and trailer bodies using rivets, typically it's a faster method, and when it is all said and done, a cleaner appearance. I'd do a stainless screw if leaving the body in mill finish. A steel one will leave streaks on the aluminum as they rust, not a problem if you are painting however. A good point is raised about the expansion and contraction of the materials however. Personally I don't think it would be a major issue, it's not that large of a piece of material and you are going to have plenty of rivets and tape on it. Truck trailer bodies are built like that all the time, same goes for the sign industry. Check any Modernistic tear. Doug

[Jester]

thanks for the 3m tape idea I guess a dab of silicone would seal the hole with rivets..but which is better rivets or screws for a long term?

IMO the srews may be a better approach. I base this on my RV and all the rivets that they have "securing" outside skin on it. I began drilling and replacing rivets that were broken for about 3 years. After that I began using screws and found that in the past 4 years I have not replaced one screw. During the first 3 years trial I replaced a number of my previoulsy replaced rivets.

That reminds me...Myrtle trip in three weeks....need to charge theDeWalt, it's "screw time" again!!

[doug hodder]

Jester...I don't know what you have for an RV...but Airstream, Kenworth, Peterbuilt, Autocar, Mack has had pretty good results using rivets over the years as well as Trailmobile, Great Dane, Wabash, Fruehauf, and like I said, "if done correctly" Doug

[urbanironaz]

To do it right would you suggest a alum.rivet or stainless rivet??and what about fastener spacing-I as thinking every 3-4" or so....any ideas?/

[doug hodder]

I'll go out on a limb here...I'd think you could get by with a larger spacing than you are thinking especially if you are going to use a tape also. I'd figure on a pattern that would allow you to attach the sides near the top and bottom and then space the rest using whatever attachment system you decide to use evenly over the rest of the height. 6" ought to be plenty. I can't remember what a Modernistic uses. They do use a close spacing on the roof/wall attachment lip. When you figure in a door and window, on the sides, there isn't large expanses of material that really need to be attached in short increments. A good seal on the rivet on the exterior can be done with aluminum, truck cabs are done like this all the time, but you gotta make it a good riveting job. Stainless is going to be considerably more expensive and in the end be more labor intensive, depending on what you have for tooling.

Others have mentioned floating the skin. Just my opinion, but if you don't have a substrate behind it and only have vertical studs that you aren't attached to, it just might be a problem down the road.

There are any number of ways to attach material, but my opinions are only based on attempting to attach aluminum skin to steel studs. I hope this is of some info and if others disagree...well, have at me. Doug

[madjack]

...the VHB is a definte way to go...you might well want to check out some of the body panel adhesives used in the car/truck body repair business...nowadaze most body panels on vehicles are bonded with an adhesive(usually a 2part urethane)...rivets versus screws...rivets done properly are great but screws are better...but that is just my opinion...Doug is correct about the big trucks, RV's and even airplanes but they are using special rivets and an air powered rivet gun...what ever you chose, I would put some type of tape on the steel to help prevent any galvinic reaction between the dis-similar metals........
madjack

p.s. the .063 can be used, it is just a little harder to bend but a couple of straps with some boards placed under them will get it around most radiuses........MJ

[asianflava]

On the tape thing. I recently had to tape something doen with 3M tape. They recommended using 3M's Prep - Sol 70. I really had a hard time finding it locally so I wiped everything down with naptha. Some of the silicone and wax removers I've used in the past were just naptha and alcohol.

Oh and make sure it isn't too cold when you do it.

[urbanironaz]

3m vhb????is that something i will find local or do i order it ...will 3m double stick tape work ???

[doug hodder]

They now sell it at Home Depots, in smaller rolls. Doug

http://solutions.3m.com/wps/portal/3M/en_US/VHB/Tapes/

[urbanironaz]

thanks again snoop douggy for the info and the time This a is great asset for the do it yourselfer..

[mary and bob]

our Modernistic is put together with aircraft type rivets, but it has screws to attach the sides to the frame. the screws are steel, and are rusted. I'm going to replace them with stainless screws.