Help me finish my polystyrene cab build

[Downunderwonder]

I also glued a the front panel to the baffle backboard and pressed it with some heavy things. This will also be drying for the next two weeks. The last step will be cutting the finger joints and gluing the top panel (followed by a probably 3-4 week cure time).
View attachment 3307345

I am not seeing the purpose of the wood square with square hole, maybe I am not seeing it right.

 

[neal sanger]

Mike, what scheme did you employ for internal bracing?

 

[neal sanger]

Down under, it's to stiffen the front panel and provide mounting points for the front baffle

 

[neal sanger]

I glued some blocks to it the depth of the foam panels so I'd have a solid bit to screw down the front panel into so it would be removable.

 

[Downunderwonder]

provide mounting points for the front baffle

I think you don't want to be relying on screwing through the foam to secure the ply baffle by sandwiching the foam. Better to glue the ply to the front and hope for the best. In case you have to remove the driver a few times you can always rotate it into some new holes if they get too chewed up.

 

[two fingers]

Mmmmm......Shiiiiinyyyyy....drool

 

[neal sanger]

I just don't know how I could mount it to the foam without the vibration from the driver chowdering up the foam. That's why I went with he wood blocks. It's possibly the weakest element in the can design.

 

[Fat Freddy]

Perhaps you are taking this whole thing a bit too seriously? You might want to open yourself up to the little bit of humor that's being offered.

"Little bit" being the operative phrase...

 

[neal sanger]

I honestly have no idea how it will shake out till it's done.

 

[alaskaleftybass]

Mike, what scheme did you employ for internal bracing?

@neal sanger , it sounds like positive comments from @Mike Arnopol who is our resident guru. If anyone knows it will be him. When asking a question, add an @ sign and type out the username and it will alert the user you asked a question.

Thank you for sharing your unique experiment. Ignore those posting snide remarks-- I can't even guess why when someone is trying to do a new project. Best of luck and maybe Mr. Arnopol will drop by with more advice.

 

[Wisebass]

Hi Neal

I honestly have no idea how it will shake out till it's done.

"The journey is the destination" is a saying attributed to Confucius…

If you recall, I'm doing this for fun.

Im not going to duct tape it. That' s a dumb idea

"The journey is the destination" is a saying attributed to Confucius…

You know? A lot of us have been on journeys (trips), with cars that were held together with duct tape…

Have fun!!! That' s what building things on your own is about!

Wise(b)ass


btw: I can imagine using foamglass instead of polystyrene. And drywall profiles for the bracing and….duct tape

edit to add: duct tape!

 

[Downunderwonder]

I just don't know how I could mount it to the foam without the vibration from the driver chowdering up the foam. That's why I went with he wood blocks. It's possibly the weakest element in the can design.

Yeah, but mounting to the blocks just transfers the chowdering action to the back while squidging the baffle. That's why I suggested giving up the removeable baffle plan in favour of glue.

Worst case you can still slice out the entire front with Mum's bread knife for a do over if needs be.

 

[JimChjones]

If he puts a light ply layer on the inside surface as well as the outside and bolts through it will hold together just fine. The wood blocks will deal with the compression and ply each side, preferably glued to the foam, will distribute everything.

 

[neal sanger]

@JimChjones that is pretty much exactly what I did

 

[seamonkey]

Marine foam core panels or even foam core doors work with the same technique.

Dig out the foam on the ends of the panels and glue in blocking to hook them together.

Factories do a good job of gluing the foam and plywood skins together.

 

[neal sanger]

@seamonkey where could I buy marine foam?

That sounds like a cool idea.

 

[neal sanger]

 

[neal sanger]

 

[zon6c-f]

View attachment 3309744

Getting there!

Keep at it!

 

[JimChjones]

@seamonkey where could I buy marine foam?[/QUOTE]

The structural foam as used in marine applications (also aerospace, Motorsport etc) is a lot more expensive than styrene foam . You wouldn't want to use it without a carefully thought out structure. If anything it would be less effective than your styrofoam used on its own.

This is an example of the stuff... Link Removed

It would be interesting to try something - the potential is there for a moderately light, but very high stiffness and also very expensive cabinet. It would fascinate me to AB a sandwich construction cab against an internally identical birch ply one, but I just don't have the facilities for sufficiently sophisticated testing, nor probably quite the energy.