Let me start by saying that I’m new here and I know nothing about composites so please forgive me if these questions sound ridiculous. I have a small drum riser/ platform that I want to make using 2" thick Pink foam, sandwiched between layers of carbon fiber. The riser is 25 inches wide by 48 inches long. First off, can I get the strength that I need to not have this flex? The riser is supported by 4 swivel casters at each corner. The equipment loaded on top is about 70lbs distributed pretty evenly over the entire surface area. I’ve seen videos that show how carbon fiber can be made very rigid by using a foam core. I need light weight and lots of strength. Would this idea work for me using this thick insulation foam panel? If so, what type of cloth do you suggest and how many layers might I need to create the strength Im looking for. Thank you for your help and suggestions.
Yes it can work but will depend on the layers you use. Strength to ‘not have this flex’ is quite subjective of course, so depends on your need.
Is the pink foam styrofoam?
What carbon and resin is available to you?
The foam is called Extruded Polystyrene I think. It’s typically used for insulation here in the USA. As far as resin and cloth, I will probably just order online whatever the experts here suggest. Below are some links to pictures of what I’m trying to recreate. It is currently made of Aluminum square tubing for the frame and Aluminum waffle board was used for the deck. It is certainly strong enough but I want to get the weight down. Eventually I want to replace all of the metal stands on the entire set with carbon fiber. My Tom toms are made of Nomex honeycomb and carbon fiber. That’s what started this crazy idea in the first place. Thanks for your help.
Here’s some pictures of my current setup.
http://s1378.photobucket.com/user/suprkupr/media/imagejpg1_zps1c71a30d.jpg.html?sort=3&o=4
http://s1378.photobucket.com/user/suprkupr/media/imagejpg1_zpsb9182a02.jpg.html?sort=2&o=7
http://s1378.photobucket.com/user/suprkupr/media/imagejpg2_zps9d97b985.jpg.html?sort=3&o=3
http://s1378.photobucket.com/user/suprkupr/media/imagejpg2_zpsa07e8451.jpg.html?sort=3&o=0
http://s1378.photobucket.com/user/suprkupr/media/imagejpg1_zps26340f2f.jpg.html?sort=3&o=3
70lbs isn’t very heavy for that surface area, I think this could easily be achieved with 1 layer of carbon either side of a 10mm core. That would be very conservative as well, I used to make 10mm thick flat sheets for a local artist that produced works using slices of rock and old tools. The works used to end up being around 60kg’s, and my sheets didn’t see any deflection in the slightest. Mind you, I was using Divinycell core and I’m not certain how the extruded polystyrene would compare. I think it would work though.
Thank you guys for your help. Would 3k fabric work for this project or should I go with thicker fabric? I would probably do 2 layers just to be sure I had plenty of strength. Now that I know you feel one layer would get it done. I would be doing a hand layup. I can’t use prepreg as I don’t have access to an oven that big. From videos I’ve seen, it looks like I could lay this on glass or plexiglass to get a smooth surface for the top. I don’t really care about the cosmetic finish on the bottom or sides. The perimeter edges will be capped with the aluminum Diamond plate that you see in the pictures and no one will ever see the bottom. Although, I guess I could use glass on both sides to help squeeze out unwanted resin and get a nice finish on both sides. Speaking of resin, what do you suggest? Again, I’ve never done this before but I think I could manage one or two layers of fabric for my first attempt if I started with the right materials. Thanks again for your help and suggestions.
EPS is not really structural like D-cell. Shear issues at the core interface would concern me. By the looks of the equipment mounts, I’d say an EPS/carbon sandwich wouldn’t last too long.
Is your equipment is mounted to the current base with screws or through-bolts? A thin layer of laminate is not adequate to hold screws and through-bolts will point load the skin and crush the foam core. You could build a lightweight and sturdy platform with the EPS foam and luan doorskins bonded top and bottom. Doorskin still won’t hold screws very well but is strong enough for through-bolts if you use fender washers.
To use eps you need to use epoxy resin. Polyester will destroy the foam unless you seal it from my limited experience using it as a core.
Also it helps to rough the surface with 80 grit sand paper, blow it clean and wipe with a damp water cloth. Let dry completely. Then apply some resin and spread with a squeegee. Let that cure. Then scuff and bond you laminate. This has worked well for me using EPS.
If you use polyester resin. I was told to try drywall mud to the foam to seal it and bond over that. I found duct sealant (pva based) to work extremely well to both protect the eps foam and bond to the pe resin. The duct sealant is cheap and non toxic.
Yes, currently there are bolts that go through the deck to secure the upright pipes to the platform using flanges. My eventual plan is to replace theses steel pipes with Carbon Fiber tubing. If I do that I could eliminate the bolts by fusing the tubes with Epoxy to the deck. Essentially making it a single piece Carbon Fiber structure.
Thank you for that great info dallasb84. I will certainly use your suggestions when I use the EPS foam as the core.
Eps sucks as a core… Tho just saying. It’s best to use epoxy.
What core material do you suggest?
Just an FYI. I just had massive bond line failure using the pva sealer over the foam with polyester resin… No go. It performed well on small test pieces but on a big part it sucked… Don’t use it to seal eps.
Balsa wood is pretty good stuff or the PVC foam.
I’m a drummer and I have a few concerns / suggestions with your idea.
First, I definately would not use that pink foam. It is not made for this. I would use a good honeycomb core.
Second, your drums may weigh 70 lbs, but what about your weight as well as the force generated by you stomping on your kick pedal and hitting the drums. I’ve played on very heavy duty risers that all shook and flexed when you started playing.
Like someone else said, you will have major issues trying to mount your hardware by screwing it through the deck.
If I was building this I would use at minimum a layer of 600 and 200 on top and bottom of core.