Belly pan rivets and GCR

[Tony Moore]

Hello everyone. A lot of good discussion. I am thinking about building a car myself. The GCR is clear as mud on just about everything.

I believe a belly pan should be steel. However, the GCR doesn't even hint what would be appropriate dia, material and spacing on the rivets.

I believe they should be steel also to not galvanic corrode and be 1/8" dia and about 3/4" spacing. Any advice from someone who has been there done that?

[Joefisherff]

If it is like the other formula car rules I think it calls for a minimum of .060 heat treated aluminum. Some guys like stainless steel for the durability and to get the weight of the car down low, some like aluminum and go all the way up to .125 aluminum. Some anodize the aluminum prior to attaching it. Good aircraft grade rivets - some go aluminum bodies with steel shanks and some go all steel - cherrymax or similar. I don't think there is a rivet spacing requirement (min or max) on the bellypan and the bulkheads for safety purposes. Most people bond their bellypans with either an epoxy or a more flexible bonding agent like Aircraft Spruce sells for aircraft aluminum. This prevents the galvanic (sp?) action that you speak of and also strenghthens the attachment to the frame. If you do a search on Apexspeed you should be able to find some good threads on the best practices for putting a bellypan on your car. Good luck and keep us posted on your cars progress. Depending on the construction of your frame you may need to weld tabs onto the tubes to get sufficient attachment points.

[Mike B]

This is what you're looking for:
http://www.apexspeed.com/features/bellypan/

[Tony Moore]

Thanks guys. I see a lot of good shared info here.

[Brian]

If you use a steel floor pan it has to be 18 Ga steel, either mild or stainless (or other) and it can be welded to the chassis, or rivited, bonded or bolted. Per the FF1600 chassis rules which also apply generally to FC, anyway.

I can see a welded steel floor as posing repair challenges, but you could seam-weld the sucker and get a pretty stiff floor out of it. There are several cars up here with welded steel floors.

Brian

[Charles Warner]

If you have the weight to spare then the steel option as Brian has suggested is a good way to go. Understand the repair issues when considering this option. As for ally affixed with rivets, realize it will need replacing/repairing/regluing at least every two years and probably (to be honest) every year. The glue and rivets see so much stress that it is beneficial to simply re-glue the beastie every year during the annual rebuild.