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Help me finish my polystyrene cab build

#22
IMG_20190110_114008086.jpg
This is what I was thinking currently. I omitted the port from the drawing because I am not good at drawing. I will also laminate the front of the front panel or loctite coat it.
 
#23
neal sanger said:


Well I saw tech ingredients (a particularly excellent youtuber) building speakers from transducers mounted to foam board and I was curious how it would translate to a traditional speaker cabinet. I was thinking of just surfacing the box in loctite 200 to give a little added toughness. Carbon fiber would be great, but I do not know how to work with it nor do I have any of the necessary tools. Additionally, I think the epoxy needed to seal carbon fiber would simply eat right through the foam. I can't really justify all of my design retroactively, but I'm taking notes on everyone's input.
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Epoxy won't eat the foam you've used, unless you let it get too hot and it burns a hole. Perhaps you are thinking of polyester resin, like old school surfboards and windsurf boards were/are made of. That'll eat EPS right quick.

For mounting drivers and other high loads, high density pour foam and plastic or metal inserts are a classic water toy approach that can work quite well. These guys used to be a few blocks away from me and they have lots of useful tooling and materials, should you decide to go deeper down this rabbit hole: Link Removed
 
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#26
neal sanger said:
Do these foam/epoxy methods necessitate the use of a vacuum sealer or an autoclave?
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Nope, not at all. Although it may be pretty tough to implement without proper glass or other skins on both sides. And bagging is definitely better for larger panels and the like.

We used to do this sort of stuff in my old back yard perfectly happily back when my roomie and I were doing casual commercial repair work. But you do need to be very fastidious about using a moon suit, gloves, a respirator, and so on. I've lost a few friends along the way who blew that off, it's a very nasty business. Vacuum bagging and using prepreg carbon is actually a lot safer in many ways.
 
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#27
I appreciate the warning, I'm pretty sensitive to fumes and had some bad experiences doing HVAC work and doping seams in both well ventilated and poorly ventilated areas. The adhesive I've been using is pretty low VOC. I may try it in lieu of epoxy at least on this build as I do not have any of that gear nor the budget for it currently, but I would love to hear all about the process.
 
#28
neal sanger said:
This definitely won't be a gigging cab since the foam is super fryable. I guess I could just screw the baffle to the backing plywood, but I designed the cab mainly to weigh very little while being huge and having fat low end. To support that goal, I was planning to use 3/8" plywood and it would not do a good job holding screws. Perhaps I could glue on some wood blocks on the rear of the wooden backing board where baffle mounts and retain my weight savings while increasing the security of the mount.
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Very cool idea man! What about simplifying and using toggle bolts or wing nuts to hold your speaker to your plywood baffle? When u want to replace the spkr the wings will just drop inside the cab and be easily retrievable and reusable...
 
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#29
Jockey said:
Very cool idea man! What about simplifying and using toggle bolts or wing nuts to hold your speaker to your plywood baffle? When u want to replace the spkr the wings will just drop inside the cab and be easily retrievable and reusable...
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I like that idea. I was initially thinking that I want the baffle itself to be removable or at least a separate piece as only the actual baffle section would need to be 1/2" or 3/4" ply and the backing panel could be 3/8" ply. I like the idea of using toggle bolts or wing nuts to attach the baffle to the 3/8" section. This would require essentially no modification to the design.
 
#30
I apologize for sounding ignorant, and I'm not trying to sound negative, But is this a little bit of the why does a man climb a mountain syndrome?

I love it when people do things that are out of the box, but usually I can see why they're trying to do it. Is there a reason you're trying to do it this way?

Good luck?
 
#35
Delta Delta, not exactly. I'd be gluing 3/8" ply (reinforced with glued wood blocks for the mounting screws) to one side of the foam and bolting a baffle to that. I'd probably put something on the front of the panel, but it would not be held by bolts.
 
#38
neal sanger said:
I like that idea. I was initially thinking that I want the baffle itself to be removable or at least a separate piece as only the actual baffle section would need to be 1/2" or 3/4" ply and the backing panel could be 3/8" ply. I like the idea of using toggle bolts or wing nuts to attach the baffle to the 3/8" section. This would require essentially no modification to the design.
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Neal I love what you are doing!
I suggest using these (or similar) backing washers...McMaster-Carr
 

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