REFLECTOR: Coarse/Fine BID

[keithhallsten at quiknet.com]

I think the use of peel ply make far more difference in whether or not you have a leak than which weave of glass.  The weight of fine bid and course bid is almost identical, so I wouldn't worry too much about substituting one for the other.  However, it's easier to get air bubbles out from under course bid than fine bid, so there is some difference.  When I asked the factory guys about this issue they said that they are not using fine bid anymore, and course bid could be substituted.  

For fuel sealing surfaces, you definitely don't want to get carried away with weight reduction - go ahead and make sure you have sufficient epoxy to fill any voids, then use peel ply to give you a finished surface and pick up any excess. 

Keith Hallsten, XLFG


<Jorge Bujinda wrote:>
The manual calls for fine BID to reinforce the vertical and horizontal 
seams of bulkheads and baffles (Fig. 9-16. Fuel baffle and bulkhead 
location.).  Although up until now I have used coarse BID almost 
exclusively, I ran out of fine BID glassing the Divinicel for the fuel 
tanks and I am about to start glassing the baffles and bulkheads.
1.  Can coarse and fine BID be used interchangeably?
2.  Can I use coarse BID to reinforce the horizontal and vertical seams 
of bulkheads and baffles without increasing the risk of leaks?  Seems to 
me like the fine BID would seal better due to a tighter weave.  Am I 
wrong?
4.  Is there a difference in weight between the two?