Junctionmad Posted January 20, 2017 Share Posted January 20, 2017 (edited) I have just finished a test " plank " baseboard as a test run to constructing the mega project that is claremorris. These are 6mm European Birch , cut on a computerised table saw. with 120mm box section construction , 3" GRP tape and polyester resin bonded. The strengthening pieces were initially tacked together with hot melt adhesive The overhang is deliberate , as I intend to place all the servos motors for points and signals , DCC dropper common points and layout bus electronics ( MERG modules ) on the vertical side, with as little as possible underneath ) . The final baseboards will have 12mm ends to facilitate joining to others flatness is 0,2mm over the length , module is 1500 x 380mm, final baseboards will be 1500 x 800mm ( in places) , these larger units will have a double box section , ( each box section is approx 300x300mm).At present I dont see the need for diagonal supports , Im trying to avoid diagonals as they cause access issues Twist , measure by picking one long corner up , is about 20mm before the far side lifts, but in reality this isnt terribly relevant as the board is supported on trestles . The whole baseboard can be lifted and held by one hand . also Im doing some trials on sound deadening , this is 3mm nitrogen blown UV stabilised foam , ( from efoam.co.uk). I have an electret microphone hookedto a scope and so will be able make comparative measurements, I well test this against cork and direct to baseboards. The track shown is Exactoscale bullhead code 75 nickel silver, its this or the new PECO bullhead that Ill use Edited January 20, 2017 by Junctionmad Quote Link to comment Share on other sites More sharing options...
Broithe Posted January 20, 2017 Share Posted January 20, 2017 Fillets in the open face would get rid of a lot of the twist, if it bothers you much. Quote Link to comment Share on other sites More sharing options...
Junctionmad Posted January 20, 2017 Author Share Posted January 20, 2017 where exactly ? . Quote Link to comment Share on other sites More sharing options...
Broithe Posted January 20, 2017 Share Posted January 20, 2017 Just triangular plates in the corners of the open side, if that makes sense. Struggling to find a suitable picture... Quote Link to comment Share on other sites More sharing options...
Broithe Posted January 20, 2017 Share Posted January 20, 2017 (edited) Just triangular plates in the corners of the open side, if that makes sense. Struggling to find a suitable picture... Triangular plates of plywood, glued into the open underside of the box. Sort of like this welded assembly. They'll still leave you access underneath, though there will be a little restriction - you could even curve in the long side of the triangles, with little detriment to the improved stiffness, but a little better access. The more of the open side that you 'plate' in, the stiffer the assembly will be. Try it with a cardboard box and you'll see the significant improvement. If the bit of twist that you have is a concern, that is. Edited January 20, 2017 by Broithe Quote Link to comment Share on other sites More sharing options...
Broithe Posted January 20, 2017 Share Posted January 20, 2017 At last - this sort of thing - these keep the open face of the box stiff whilst the lid is not in place. Note - beware of Googling terms like "stiff gusset", you get picture of things that aren't made of plywood.... Quote Link to comment Share on other sites More sharing options...
Junctionmad Posted January 20, 2017 Author Share Posted January 20, 2017 thanks yes actually I originally had the idea of a lattice of ply that fitted over the box structure. but its very wasteful of ply. at this point its way way stiffer then say ply and 2x1 etc , so I have little concern . glassing in those gussets would be awkward to say the least. The original idea is not new, its been discussed and built in serval forms by Scalefout members and discussed on their forum I will do a full sized baseboard module next The idea is also that the baseboard can be turned upside down, to act as a support structure for an open baseboard type system , in that case each box section has the rectangular ply " top" cut away , ( which is now the bottom ) to provide access I think the triangular gusset as per your picture is primarily used to provide strength to the side walls from buckling inwards or outwards. in my case the twist is in effect diagonal across the length of the baseboard module . so I think the gussets may be adding strength in an area that doesnt need it . The method to further stiffen such movement , which was discussed on the Scalefour forum was diagonal bracing , but Im trying to avoid those as it interferes quite significantly Quote Link to comment Share on other sites More sharing options...
Broithe Posted January 20, 2017 Share Posted January 20, 2017 OK. Quote Link to comment Share on other sites More sharing options...
Noel Posted January 23, 2017 Share Posted January 23, 2017 Looks good JM. Never seen that style of box structure before. Quote Link to comment Share on other sites More sharing options...
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