Hi All. (No its not a Ghost!) Your questions are a bit hard to answer without seeing more of a design. But here goes. With (at least) three projects (I assume all trading the same electronics back and forth) you want to use screws into nuts/screw-certs to mount your E-tronics into your airframes. How you build that "mount" in the airframe is up to you. But, give some thought to modularity and accessibility. You'll want to use the same electronics in all your projects (kind of. we all end up buying more and different as we learn and take on new challenges), so keep that in mind. You're also going to need enough access to get your tools, fingers, hands, etc into that e-bay to mount things and or to test/check them when something isn't quite right and you're standing at the rails in the heat and they want to launch the row. Personally, I've always liked the PML CPR design. At least as a model. I've built a number of their CPR-based kits. and also scratch built a number of projects depending on use electronics that have their "mounting ends" on them.. No, you are not then forced to use pistons. Nor even the PML charge holders. Its just a design idea. But modularity and re-usability are the keys. Hope that helps! Rich From: roc-chat-bounce@xxxxxxxxxxxxx [mailto:roc-chat-bounce@xxxxxxxxxxxxx] On Behalf Of Dave M Sent: Monday, June 18, 2012 9:22 AM To: roc-chat@xxxxxxxxxxxxx Subject: [roc-chat] Electronics Bays I have three rockets with diameters of 2", 3" and 4". I have purchased electronics bays for each. I want to get started experimenting with the electronics so I was thinking about setting up the 2" rocket with one or two altimeters, then do the timers, etc. before I put electronics into the 4". There's obviously not a lot of room in the 2" but hoping I can start with that. My question is this: should I secure the ebays with rivets or screws or should I glue them into the bodies? I kinda want to leave myself some options while I get the electronics down and dont have ebays permanently fixed. Is this a good or bad idea? Also, some of the ebay mfrs also talk about gluing one end of the ebays caps permanently to the ebay tube. Do I want to do this or leave both sides free (no glue) for easier access?