I'm replacing some of the rivets on the Barth. It seems most are 3/16" dia. Those holding running lights appear to be 1/4". Question is grip range. Aluminum skin to aluminum tubing is how thick? If tubing wall is 1/4", I would use either .251/.375 grip range. If tubing wall is more than 1/4" probably use .376/.500 grip range. What is the wall thickness of the aluminum tubing Barth used?
I will use alum rivet/aluminum mandrel 'closed end' type rivet since they are more moisture resistant and the mandrel stays in the rivet 100% of the time. Would appreciate any advice. BTW, Alcoa Fastening Systems make all this stuff.
Jim

Jim,

Barth didn't use tubing for wall studs. They used a "Z" brace that is only slightly thicker that the wall thickness. All the rivets I have replaced were in the 1/4" grip range. Some of the larger (3/16" dia) rivets needed to be in the 3/8" grip range.

Bill G

Bill, did they use the same "Z" brace for the roof? What about the curved areas that connect the roof and the walls? Thanks
Jim

Jim,

Somewhere in the archives is a series of pictures that shows the interior of a Barth without the inner panels. I believe it shows the roof as well. Also, there was a fellow who built out the back of a 22 footer with a "bustle" and framed it out to the roof. He also posted pictures of the inner wall framing.

I am not sure how the roof is framed. There may be tubing there, but I don't think so. I also believe the framing of the rounded corners was done with flat aluminum braces tied to the roof and wall pieces. The aluminum braces were cut with a radius and flange and the skin was wrapped over it. Look for the pictures, they will give you a good idea. Bill NY and Barthbluesmobile have both rebuilt the inside of their units and could help you significantly here. You migh try to PM them.

Bill G

In keeping with Barth's claim to aircraft construction techniques, I use Cherrymax rivets.

My limited peeling back of interior panels has shown me no Z sections, just channels in both sidewalls and roof.

I have a bit of ceiling loose right now, and will go outside later today or tomorrow to double-check.