DIY Lightweight Composite Cab Build

[phoenix742]

This is one of the coolest things ever! If you ever get the itch to try for a bigger cab, I'd definitely be interested... but either way, get this thing finished and post some sound clips! If it sounds as good as it looks, you've got a sure winner.

 

[Petebass]

And screws on the outside are not an option in my natural-finish world.
.

Absolutely. When I said pocket joints are better for furniture than for speaker cabs, that includes speaker cabs like yours which can double as furniture.

 

[Passinwind]

Absolutely. When I said pocket joints are better for furniture than for speaker cabs, that includes speaker cabs like yours which can double as furniture.

You're not the first guy to say that Pete!

 

[Petebass]

Zac, while we're talking screws and joints, how do you attach the speakers themselves to he cab? I don't imagine T-nuts would work, but I am after all a fibreglass noob........

 

[Passinwind]

Zac, while we're talking screws and joints, how do you attach the speakers themselves to he cab? I don't imagine T-nuts would work, but I am after all a fibreglass noob........

You can mix epoxy and high density filler and thread that. Or you can use high density pour foam for inserts and either thread it or inset something tough in it before it cures, or glue in something like plastic with threaded metal inserts using high density filler and/or glass to stiffen things up at the bond to the lower density foam, which is what sailboards typically use. IIRC Zac did something like the first one, but I'll let him tell the tale.

 

[Stumbo]

... I said pocket joints are better for furniture than for speaker cabs, that includes speaker cabs like yours which can double as furniture.

FYI, a pocket joint is a butt joint.
http://sawdustmaking.com/About Joints/about_joints.htm

 

[zac2944]

Carpet looks great. Well done!

Were you planning to make a metal grill with bent edges? If so, do you have access to a panbrake? If not, I have a couple of ideas that might be of help.

Yup. I've got a piece of 1/2" 18Ga. flat expanded steel. I don't have a brake, but I'm able to bend the edges using a couple pieces of wood and a hammer. It works pretty well.

 

[zac2944]

Zac, while we're talking screws and joints, how do you attach the speakers themselves to he cab? I don't imagine T-nuts would work, but I am after all a fibreglass noob........

I posted this a few pages back, but here it is again.

They are ment for weld-on and mold-in applications. I glue them in place so that they could be removed if need be.

 

[zac2944]

You can mix epoxy and high density filler and thread that. Or you can use high density pour foam for inserts and either thread it or inset something tough in it before it cures, or glue in something like plastic with threaded metal inserts using high density filler and/or glass to stiffen things up at the bond to the lower density foam, which is what sailboards typically use. IIRC Zac did something like the first one, but I'll let him tell the tale.

For the corners I will be using the technique you first mention. I will drill blind holes, fill the holes with epoxy and filler, then once cured drill and tap the filled epoxy. I did some tests with this technique and it works very well for certain applications.

You can also mold-in the threads by inserting a screw into the filled epoxy before it cures. Just need to make sure you coat the screw with some sort of mold release before hand. I used soap and Vaseline and both worked well.

I didn't want to use molded-in threads or molded-in inserts for mounting the speakers in case something ever happened to the threads. Repair would take a bit of work. By gluing in the inserts that I'm using, repair only requires heating up the glue with a soldering iron, remove and replace. Installation is also very easy.

For the corners I'm using a special technique because the thickness of the foam core and the location of the mounting holes on the plastic corners doesn't allow me to use inserts or t-nuts. I can't drill a through hole because the location puts t-nut in the foam core. Sort of hard to explain.

 

[kaiser_sosea]

any updates? its been three whole days...

 

[lurking_bassist]

have you considered honeycomb blanks and vacuum bagging a low cost carbon fiber? maybe even a kevlar/carbon fiber/fiberglass hybrid?

lots of great options out there... you can even get a great deal on carbon fiber pre-fabbed sheets for laminating onto a proofboard. the end result is a super lightweight, mirror finish, extremely durable box. you can even "tune" the panels you use BEFORE assembly by adjusting width/height/thickness... you can "seam" the panels with a carbon fiber 1" tape on both sides after epoxying the joints... best of all... it will be HIGHLY manufacturable (yeah, new word, i know) after you develop your final prototype.

i would love to hear feedback on this idea...

 

[Bard2dbone]

Aw crap. I kind of wish I hadn't just read this thread.

Now I have to start reading up on fiberglass construction. :scowl:

I want to build my own near-weightless cabs now.

Until this thread I was just waiting for someone to market the cabs I want.

Dang it. My wife is going to be so made when I start buying stuff to do fiberglass in the garage.

 

[spaz21387]

Wow this looks really nice. I just wish you would do a 4x10 or a 6x10 cab. This could turn in to a business. As far as I know I dont know anyone building really lightweight cabs like this

 

[Crockettnj]

CRIPES!

Oh man, you are KILLIN me with that white can and fabric grill. D'ja HAVE to cover it?!?!?

 

[texasgreg]

Aw crap. I kind of wish I hadn't just read this thread.

Now I have to start reading up on fiberglass construction. :scowl:

I want to build my own near-weightless cabs now.

Until this thread I was just waiting for someone to market the cabs I want.

Dang it. My wife is going to be so made when I start buying stuff to do fiberglass in the garage.

Me too, me too, me too!

I used to do some very light repair on a fiberglass boat we had years ago. It was difficult but not very difficult. But it takes practice.

Really do like this cab. It looks rocking in white.

I'm a drummer who has taken up the bass so forgive the following...

QUESTION: Could you cover an amp cab in the sort of plastic laminate used to cover drumsets? It is lightweight, durable, and can be attractive. You'd have to have some sort of trim for the edges, as the laminate doesn't do 90 degree angles, but trim pieces from plastic would be easy to fabricate.

I know Kustom had the padded glitter stuff but this is different. You could cover the cab with any number of colors, from sparkle to glitter to a pattern like black oyster pearl.

Not that there is anything wrong with Tolex, mind you. In Houston in the booming 80's, when folks seemingly had money to burn, I saw several lead guitarists of the blues persuasion that had bootmakers and upholsterers custom cover their mesa boogie and fender combos with a variety of animal and snake skins. It was also very popular to somehow incorporate a Texas Flag in the design if at all possible.

I've seen a big band who covered their wooden monogramed music stands with a drum wrap, matching the drums of their drummer, and that was kind of cool, in a big band, retro sort of way.

For that matter, what about a rare wood veneer? Like say a tasty makassar ebony or african rosewood? Bubinga you say?

Since I've read that the master-fiberglasser cab builder here will be using muffling on the interior of the cab, wouldn't some form of thicker cover aid in that quest?

I know drums respond to covering materials that are placed on them, and more likely, the glue used to attach the covering. Are amp cabs the same way?

 

[Rick Auricchio]

Since I've read that the master-fiberglasser cab builder here will be using muffling on the interior of the cab, wouldn't some form of thicker cover aid in that quest?

The padding has to be inside the cabinet.

 

[texasgreg]

CRIPES!

Oh man, you are KILLIN me with that white can and fabric grill. D'ja HAVE to cover it?!?!?

That cab in white is the shizizz!

 

[kraigo]

I know drums respond to covering materials that are placed on them, and more likely, the glue used to attach the covering. Are amp cabs the same way?

I'm also a drummer who plays bass (there seem to be a lot of us here). I love the idea of getting a purple sparkle bass cab to match my Ludwigs!

The ideal bass cab's panels don't vibrate at all, so covering a cab with drum covering (see Invalid Link Removed or www.drummaker.com for example) would probably not be bad, but I think it'd probably scratch up pretty quickly. I know the aforementioned Ludwigs go in gig bags when they leave the house. It'd look great for a while, but rat fur carpet or pickup truck liner would probably be more durable.

KO

 

[zac2944]

The drum wrap idea would be pretty sweet with all the options out there, but I don't think it would hold up, and application would be difficult. Here's a quote from Kraigo's suggested sites:

Glass glitter wraps are extremely brittle, and must be handled with extra care. Precision Drum Company will not take responsibility for any breakage while working with this material.

Some of the pearl wraps shrink slightly over time.

Wraps should not be exposed to long periods of direct sunlight. Dark colors like black gloss, black diamond pearl, and charcoal may bubble as a result.

There is a reason why so many cab builders use Tolex, carpet, or truck bed liner.

 

[zac2944]

have you considered honeycomb blanks and vacuum bagging a low cost carbon fiber? maybe even a kevlar/carbon fiber/fiberglass hybrid?

lots of great options out there... you can even get a great deal on carbon fiber pre-fabbed sheets for laminating onto a proofboard. the end result is a super lightweight, mirror finish, extremely durable box. you can even "tune" the panels you use BEFORE assembly by adjusting width/height/thickness... you can "seam" the panels with a carbon fiber 1" tape on both sides after epoxying the joints... best of all... it will be HIGHLY manufacturable (yeah, new word, i know) after you develop your final prototype.

i would love to hear feedback on this idea...

Low cost carbon fiber?!?! There's an oxymoron for you.

I believe I addresses something similar in post #197.

S2 glass, carbon, prepregs, vacuum bagging, etc would all be great, but again too hard to justify. Like most things there is a diminishing return. Consider my method resulted in a 9lbs empty cab. This same cab from plywood would be 35-40lbs. Material cost for the composite cab was something like $150-$200. Material cost for the plywood cab would be somewhere around $50. So for an extra $100-$150 I was able to reduce the weight of that component by close 30lbs! Now lets say you went all out with fancy foam, carbon fiber, etc. Maybe you could build an equally stiff/strong cab that only weighs 4lbs. Super. But now material cost for that cab are now $500-$600+. Is 4 lbs worth an extra $400? Not for this guy. And don't forget you'll need all the molds, vacuum equipment, ovens, etc. See what I'm getting at?

Same idea. Buying carbon panels gets expensive very quick and only ends up saving you a few pounds at the most.