>>> 20may03 #11298-18250 +++ #14542 From: Budd Davisson Subject: Re: Deck. side and bulkhead material > Erbman, Others: Would appreciate some suggestions as to the type, > thickness of aluminum for the baggage(freight) deck, front seat deck > and forward deck. Also for rear bulkhead and sides. The Bob suggests .032 for the floors but most I've seen are going to 1/4" marine ply for stiffness. For the bulkheads go as light as you feel like since it's just there to keep things from hitting the fabric. bd +++ #14543 From: Del Rawlins Subject: Re: Deck. side and bulkhead material Having had occasion to remove the 1/4" ply floorboard of an aircraft in service, I can see the value of a flooring material with some flex to it, like the .032 aluminum. You would just have to make sure it is well supported underneath. -- Del Rawlins +++ #14721 From: "Bruce A. Frank" Subject: Deck. side and bulkhead material I have a friend who has done something I find extreme intriguing. He has taken 1/8" luan (I do not know how this is spelled and cannot find it in my dictionary..the thin layer of wood on hollow doors...OK?) and laid one layer for fine weave fiberglass on both sides..Just enough epoxy to fill and stick it to the wood..the surface has an ever so slight texture to it. I could not break this material with hands or feet even propped up on a block of wood (supported my 265 lbs spanning about 15" between two pieces of 2X4). Incredibly resilient, very light weight and impervious to moisture. Reduces noise much better than aluminum...no drumming or buzzing if a screw loosens)This is what he will be using on his floor, side walls and baggage compartment's rear bulkhead. Another cool thing is that it is easily painted if you tire of the natural wood color showing through (like a finely finished wood table). But an even more interesting thing is that he plans to laminate light cotton print material (fabric shop cloth) between the wood and fiberglass. Looks like wall paper. Depending on your taste can be extremely attractive...paisley interior anyone? Bruce A. Frank +++ #14728 From: "bearhawk260" Subject: Re: Deck. side and bulkhead material If anyone viewed, as I have, the Rutan instructional tapes of him and Mike Melville discussing the moldless technique of airplane building you would have watched them make a panel as you described out of foam and fiberglass. The tape goes on to cut and build one of the lower winglets, but anyway, this piece was very strong. I would think using "luon" as a core meterial increased strength. Very interesting idea. How will you secure this to the tubes for the floor and etc? Make sure you have your mounting plates, if using screws for mounting purposes, well bonded using flox and several additional layers of fiberglass surrounding the plates. good idea, something to add to my folder for future reference... hugh #584 +++ #14738 From: Wayne Meier Subject: Re: Deck. side and bulkhead material It's spelled "Lauan" I don't think the 1/8" lauan doorskins are the greatest materials to use for the floor and bulkheads, even if covered with glass and epoxy. Marine grade plywoods in okoume (light weight) or Sapele (stronger) in a 4mm or 6mm thickness are what I plan on using. The benefits of marine grade vs. others is the quality of adhesives and veneers. If anyone building a Bearhawk is interested in using plywood, I would be happy to supply it and I will rough cut the panels to size for UPS to minimize costs. Wayne Meier #324 +++ #14753 From: "Bruce A. Frank" Subject: Re: Re: Deck. side and bulkhead material > How will you secure this to the tubes for the floor and etc? Make > sure you have your mounting plates, if using screws for mounting > purposes, well bonded using flox and several additional layers of > fiberglass surrounding the plates. Actually this fiberglass/lauan material is not pulling against an screw head. It isn't as if a small headed screw would pull through under load. The screws just hold it in place. The tube structure behind it takes the load. My plan is to drill the holes for the screws, touch the holes with a spot of epoxy to seal any edges, then use raised edge counter sunk stainless washers with stainless flathead fine thread sheet metal screws. (all my attachment tabs have applied stainless Tinnerman (sp?) nuts). Bruce A. Frank +++ #14755 From: "Bruce A. Frank" Subject: Re: Re: Deck. side and bulkhead material A builder here in CA was killed when his plane, completely constructed from lauan, fell apart from saturation with gasoline from a tank leak. But all his stuff was just varnished and glued. Fiberglass and epoxy convert lauan into a different material. It is cheap, less expensive than foam around here. Easy to work and fit. Rigid enough to hold shape before the fiberglass is applied (unlike thin foam) Hardly does more than provide the spacing of the fiberglass (as with foam). Pleasant to look at when finished with only fiberglass and epoxy. Slightly heavier than foam. Heavier than aluminum. Quieter than aluminum. Pretty well saturated with the epoxy so water proof glue less important. Certainly marine plywood is nice, but expensive. Not very attractive "au natural" (clear finish). If I am going to spend the money then cabinet grade birch plywood (or for a beautiful look, teak). Then again the darker strains of lauan, when finished, looks a lot like teak. I was under the impression that the darker woods were actually mahogany! Judging by the strength of the piece on to which I stood and the absence of need for much strength in this application; the imperviousness to water when finished this way, I though it a reasonable choice over sheet aluminum. Bruce A. Frank +++ #14758 From: "bearhawk260" Subject: Re: Deck. side and bulkhead material If the floor will be supporting people/cargo, I thought you said you would be using this for the floor as well, the material will be stressed at the screw location. There will be tension type loads. This will cause the fiberglass to fail. Or, am I not thinking correctly? If supporting the floor by several crossmembers, portions of the floor will under compression and tension. Please correct me if you have another idea, as I was thinking about using this system as a strong flooring material, might be easier to use alum. hugh #584 +++ $Id: 2.4-Interior,v 1.1 2003/05/22 03:28:58 bentonh Exp $