MC9-12 Wall Screws

[jcdillin]

So i'm slowly getting to the point where i'm going to be putting the inner walls back on MC-12 after replacing sections of chair rail, has anyone done metal self tapping screws instead of replacing the rivets? Couldn't I just do some stainless self tappers that way if I ever have to pull a panel I can get it back off without drilling rivets? Or i'm setting myself up for trouble with galvanic corrosion?

Or above that could I just use some 1/2" plywood? I've heard those panels are structural but I would think the combination of plywood with the same amount of screws instead of rivets would achieve the same thing with a bit of noise isolation. I was planning on putting plywood over the aluminum panels anyways for the interior.

[DoubleEagle]

Steel screws would be stronger than Stainless, use heavier coated ones with torx heads. Avoid Chinese thin ones, and test them in scrap pieces first to see if they avoid snapping when you draw them up tight. Self drilling ones would save time, but they do not always drill well.

[ArtGill]

I used a flat head screw that would pull down into the wood to make a flat surface.  These screws have a fine thread and a drill point.  But I found they work best in you drill first.  Speaking of drilling from my experience I have found drill bits from Byler?sp Rivet Co. are the best.  Made in America.  My Eagle has Coden Steel and it is hard and the Chinese junk bits are just that, Junk.

[jcdillin]

I used a flat head screw that would pull down into the wood to make a flat surface.  These screws have a fine thread and a drill point.  But I found they work best in you drill first.  Speaking of drilling from my experience I have found drill bits from Byler?sp Rivet Co. are the best.  Made in America.  My Eagle has Coden Steel and it is hard and the Chinese junk bits are just that, Junk.

Thanks for the heads up on the bits, have been going through plenty with this project.

[Tom Y]

I put the metal back on then put 1/2 plywood on. Used rivets on the aluminum, screwed the plywood. Just my way but happy with it, never planned to go into the side walls.

[TomC]

Course, my bus is just steel supports. I screwed 1 x 2 fir strips horizontally to the vertical steel supports. Then had 2.25" spray foam installed. The covered with 1/4" plywood on the walls screwed into the 1x2 fir strips, and 1/8" plywood on the roof that bent to the roof line. Has worked well for 22 years, and can be un screwed at any time. Good Luck, TomC

[Seangie]

I did similar to Tom.  Instead of spray foam, I cut sheets of foamboard insulation and sprayed the edges in.

Then I used a layer of reflectix on top of the insulated bus frame for a thermal break to keep the heat from transferring from the bus frame to the wood. The reflectix was held in by 3/4" furring strips.

 Inbetween the furring strips was another layer of 3/4" insulating foam board sprayfoamed in and then the walls (1/2" Plywood painted with clearcoat on the inside to protect the wood from any water leaks/condensation) on top of that.

If I started from scratch Id have just sprayfoamed the whole thing still using something for a thermal break.

But to answer your original question, I used 1.25" stainless self taping sheet metal screws to put in the furring strips.  They worked great.  Was best if you predrilled pilot holes with a small bore drill bit.  Then the screws would glide right in and hold tight.

-Sean

PS - I too have an Eagle all steel frame coach that eats chinese made screws and bits for breakfast.

[Oonrahnjay]

... But to answer your original question, I used 1.25" stainless self taping sheet metal screws to put in the furring strips.  They worked great.  Was best if you predrilled pilot holes with a small bore drill bit.  Then the screws would glide right in and hold tight...

     What head on the screws, Sean?   Countersunk flathead??

[Jim Eh.]

I used sikaflex. The screws I used to hold the plywood panels over the original aluminum skin while the sika cured were simply drywall screws - steel stud type (different pitch on the threads). Pre-drilling a pilot hole was a must. I will simply be using even more sikaflex to install my cover paneling. Investors - buy your stock in the Sika Group because I will be driving their sales up when I get to that point 

I had put up about 4 sheets of chipboard to start then I had an interruption this winter. After 3 months the glue smell still permeated from the chip board so I decided to remove it and go with regular 3/8 plywood. I spent more time removing the broken wood off the ribs from the sikaflex tearing the wood apart than it originally took me to install it.

[jcdillin]

Thanks for the input everyone, for the price of rivets I decided just to rivet the panels back in place and then i'm going to attach my plywood paneling to that with self tappers. I might even put a 1/4" layer of insulation between the two.

[jav9956]

I have gotten great deals on zinc coated self drilling screws great for wood to steel on e-bay. The seller is Lexar Industrial. Shipped from USA (pretty sure they are made in China). They still work great and at the end of the day all the materials are sourced from China no matter where they are made...