Blind rivets ???

[FolkBus]

Hi all

I need to attach some equipment to my MC5A roof.  Would 'blind rivets' be a good option?  If so what kind, model?  I know little about riveting, I only know my equipment need to be attached from the top.  And yes I plan to use the best sealant I can find.....leaks don't appeal to me. 

Thanks

--Mike

[buswarrior]

What sort of equipment? Weight? Frontal area for wind pressure at speed in a headwind? Rivets might be a poor choice, depending...

Happy coaching!
buswarrior

[TomC]

I would use stainless sheet metal screws with pilot holes. With either built in rubber gaskets, or seal each screw. Good Luck, TomC

[Iceni John]

You really need to attach through the roof ribs, not just through the skin.   Anything less could possibly pull out under high loads.   I made a walkway on my roof between the two roof hatches/exits, and it's bolted from underneath through each rib with a total of thirty-six 3/8" stainless socket-head bolts.   I used 1/8"-thick EPDM rubber washers against the roof skin and under the top NyLok nuts, and the recent heavy rains here haven't resulted in a single leak.   The bolts need 9/16" holes through the interior ceiling, but these are easily covered by flush-fitting plastic plugs, and my eventual cork ceiling covering will hide them anyway.   My eight large solar panels are hinged to this walkway, and supported by telescoping/sliding/hinged/pivoting stainless struts on lengths of 6061 angle that are attached to the roof the same way as the walkway.

There's no way I would attach this considerable weight and investment to my roof with only rivets.   I don't know what you intend to mount there, but you should plan for worst-case wind and dynamic loads.

John

[FolkBus]

Here is further info.

The equipment planned will be for 3-4 250watt solar panels and a covered sat dish.

--Mike

[Iceni John]

Grid-tie panels like those are 40 to 45 lbs each, so they need to be securely attached one way or another.   Imagine the wind under them while you're doing 65 MPH and a semi truck/trailer passes you.   (You should have a few inches air gap under them to prevent them from overheating on hot days, otherwise their output will be noticeably reduced.)   If you plan on hingeing them so they can better face the sun, you'll also need to consider their windload when they're raised up like a sail and a strong gust hits them.   In other words, they need to withstand upward and sideways forces just as much as gravity!

Find the ribs in your roof (magnets are good for this), and either bolt through from underneath like I did, or devise a way to securely bolt from the top, maybe using toggle bolts or some type of expanding locking fastener.   How closely spaced are your roof ribs, and what section and size are they?   (Mine are every 19", and are top-hat section 90,000 PSI steel with the open side facing out.)

Have fun!
John

[Larry B]

  If you are in the building stage and your interior is still open you could drill out a rivet at the main roof supports. Then from inside I installed a s.s. bolt, threaded end up, snugged it up with nut on outside. This made bolt point straight up. bolts where about 5/16 X 1 1/2 . From inside I put a couple of good heavy weld tacks between bolt head and main roof supports, now things can be added or removed as needed and bolt will not fall out or turn. If you count the rivets off center line of roof you will get a nice straight  row of bolts to build to.  If you can not get to inside then I would go with sheet metal screws as Tom said
           Larry B