I'm working on the design of a case for an odd form factor board. I'm looking at building it out of MDF since I have no skill with plexi and neither the tools nor facilities for metal work. The board is supposed to be used in hight density rack or blade applications so finding something reasonable, off the shelf, and attractive is essentially impossible. I'm planning a cardboard mockup after doing the CAD and sketchup design, but I was wondering what would happen if I used something like fiberglass resin on the mockup? I was going to pick some up and try it out, but I figured I'd check here too and see if anyone had any thoughts.
I think it would work fine, just remember that when you put the resin on that it will add extra thickness to the cardboard, so allow for this when designing it. Cardboard cases have been done before so adding fibreglass would just make it more permanent.
Upholstery shops often use cardboard & resin to seal up custom speaker mounts. So yes you can resin up some cardboard to make it stronger. Not sure about an entire case out of it tho.
doesnt the the resin in fiberglass react with the polyester, or whatever to make it hard, if it can be done then this sounds good, tell us how it goes
I saw some Bondo branded resin in the store which got me thinking about this. Drawings will help once I have done them, but my idea is to have the outside of the case as smooth and uniform as possible on the top and sides. The front will be a panel in standoffs, one at each corner. The gap between the body and the front panel is for air intake for a fan at the front of the case. I want to hinge the front panel at the top such that the hinges are not visible. Flipping up the panel will provide access to the CD-ROM, and I figure I can put the power button underneath one of the bottom floating standoffs so you push the panel near the bottom to turn the system on. I'm really going for a minimalistic look with the exception that I want to put a small LCD in the front panel. So the cable for that will have to be run through the hinged standoffs somehow. It should be clearer once I finish the drawing, but I'm not terribly good with Sketchup yet.
For several years my computer has had a door made with fine hard cardboad layers glued with epoxic glue, (12 layers, forming a board 4mm thick). Its like some hard plywood, much harder than MDF. I took the cardboard from those hanging carpets you use for filing paper sheets. I made it that way because my computer front is curved, like a wave. Its strong and even has some hinges screwed into the edge, the edge fits into a small channel in the surface of a 5mm thick piece of aluminum so the aluminum keeps the cardboard from splitting. I'm considering doing a case with this method. I think I would try now with some porous, softer thin cardboard so epoxy would soak into it, i think it probably be even harder.
I don't see why the resin on the cardboard would look bad, it should certainly hold. Just an idea, There's some corrugated plastic that's used for signs especially the ones you see around with real estate or campaign stuff on them. You can cut it with a razor knife and it should hold pretty well.
If you use a method like the one I used , you will need some moulds and a way to press cardboard . I used books.
Old cloth works good for this too. I have a set of speakers that I rebuilt with cloth and glue. Corn flakes might not work though...
I'm finding sketchup rather frustrating. I learned Autocad in college, and I'm finding sketch must less usable, mainly due to problems with editing stuff after it's created. But here is a basic idea of what I'm thinking: I'm going to put an x38ML in there. The inside will be split into two levels with the PSU, HD, and CDROM on the bottom, and the board above those. So there will need to be some internal structure to hold the mainboard up. I'm designing the individual parts in CAD. I was planning on printing them and using cardboard to check for problems. But I wondered if I could turn the test pieces into case pieces I want the finished case to be black and try to get it to blend in with home electronics stuff, but with a little hint of design. The reason for the front panel on standoffs is I want to put a large, and hopefully quiet fan at the front, but I don't want it to be easily visible. So I came up with the the idea of gaps in the case for air intake. The round trim is to try and add a little style to this. I am trying to figure out how to hinge the top two standoffs but not have the hinges visible. The CD-ROM will be stealthed behind the round trim on the bottom so I need the front panel to move out of the way to open the drive. This would also let me stealth the power button behind one of the standoffs on the bottom that will need to float with the top hinged. So you press on the front panel near the bottom to turn it on. I haven't figured out the reset button yet.
I'd advise against using that thin, singlewall crap, but if you can get good double, or even triple wall, then you're in business. Have you SEEN how strong double/triple wall is?
Perhaps 'cardboard' has multiple meanings depending on your local language I'm referring to corrugated cardboard, the stuff they make shipping boxes from. I assime he 'thin stuff' is what I would think of as card stock. If the corrugated cardboard can be reinforced in resin without having to make it a solid plate by filling all the gaps, then I was going to use 2 or 3 pieces for each part. I'll build then in layers with the corrugations rotated 90 degrees for each layer. For the round trim, I figured I could use a tube, and some Great Stuff foam. This assumes my experiments go OK. If not. then it's back to the MDF plan. Either way, I need to build the mock up, I need to check airflow with the intake fan and see if I will also need an exhaust fan.
Still not the final design. I'm still seeing if the fiberglass resin and cardboard system is up to the task and has any advantages over good old fashioned lumber. So material thickness is still unknown, and I haven't worked out how it all fits together. But here is a link to an image from the cad drawing where I was working on internal component layout and seeing about case fans. http://i221.photobucket.com/albums/dd132/Gilliad/conceptiso.jpg The rear view has a lot if stuff because I'm trying to figure out the back plate, how to handle a video card (using a 3U PCIe riser), and what I have left over for fans. I wanted a 1:1 width to height ratio, so the height ended up dictating my width. The big factors controlling the height are the CPU heat sink, getting the video card up high enough to clear the components and accommodate a larger HSF if needed, and enough clearance that a PSU with a bottom mounted fan can get airflow. I thought about mounting the PSU so the fan pulled from the bottom, but I figured the guts could be mounted to a frame that slides into the outer shell so I can try and keep it looking seamless. At the front of the case, I have a 140mm case fan, and if it gets enough airflow, and is quiet enough, I can probably use something smaller which would leave me more space for a larger video card. the on board is a Matrox, and it doesn't look like it can handle HDTV resolutions, but the board was built with an x16 slot specifically for a better graphics card. I have space on the back for an 80mm case fan up top. I goofed on the bottom, I thought I had seen a 72mm axial fan somewhere. But I can't find one if it does exist. 80 is a bit too tight, so it looks like it would have to be a downgrade to 60mm if I need one there. It is roughly 9.5"x9.5"x18.5" .
I finally spent the cash to pick up some rather basic bondo resin just to try out. I've learned a few things, 1) It eats the plastic cup I used to mix the resin and hardener. 2) Short working time. I got through most of my first mix when I noticed it becoming a rubbery. I cut back on the hardener which let me stretch it, but I need to see if it sets up correctly. 3) get the bacric really wet, if the resin starts to set whilw applying it to the cloth, you won't be able to get more resin soaked in. 4) The cardboard really seems to soak it up. I think the resin penetrated the all the way through so even the corrugations are soaked in resin. I'll double check this 'postmortem'. I got through three tests before finding my cup eaten, and gloves too sticky to keep going. I haved a single sheet coated in resin, a single sheet reinforced by fabric from an old t-shirt, and a double ply with the two sheets of cardboard rotated so the corrugations oppose one another. Yet to try: Single ply, fabric on both sides Double ply, one layer of fabric in the middle Double ply, fabric only on the outside Double ply, fabric in center and on the outside I want to see how my current experiments set up, I may have goofed and need to redo them. If they look OK, then I try and break them I'll also cut them open to see how far the resin penetrated. I have a fair amount to use for testing, so I will try a few other methods of applying it too. I want to try taking a piece of cardboard and just immersing it in the resin before pulling it put, removing excess and letting it cure. But I'm not cure how much resin this will use and if it is more like casting it as it gets caught in the hollow spaces of the corrugations I am concerned about the logistic of doing this with larger sheets like I'll need in my final design.
I need to get my camera working, it wouldn't take any pics The two tests without any fabric were very, very flimsy. The resin did not penetrate very far. I should have put some weight on the the 2 piece test, they did not stay together very well. But the test was still flimsy where they did bond. The single piece with the fabric turned out pretty good though. It's strong wen trying to bend it in one direction, but a bit weak in the other. Based on this, I think I'm going to see how the last test case I mentioned in my still to try list does.
