Foam Core Board Speaker Enclosures?

First attempt :) Quick and dirty,with 2 little kids "helping" . This really works to prevent woodwork perfectionism.
 

Attachments

  • IMG_20190518_192126.jpg
    IMG_20190518_192126.jpg
    724.1 KB · Views: 307
Founder of XSA-Labs
Joined 2012
Paid Member
anyone have a solution for keeping the blade at 90 deg to the cut, my homebrew blocks/clamps aren't working for me in one way or another.
would a Dremel saw work? or would the spinning blade melt the foam?

Cut with several 5-7 strokes each one a little deeper. Hold your blade at about 90deg and it’s close enough as Board is only 3/16in thick. The glue will fill in the gaps.
 
anyone have a solution for keeping the blade at 90 deg to the cut, my homebrew blocks/clamps aren't working for me in one way or another.
My most recent jig worked well. It was made with a table, a fence and two strips of metal for the blade guide.
would a Dremel saw work? or would the spinning blade melt the foam?
Dremel, no I don't think so. I even tried a plywood blade both forward and reversed. No luck. It 'chunked' the foam like you see two posts up.
 
Sort of, I'll explain.
The first pic is of the bottom of one of them. Note the slot on the left is much wider than the blade but not cut the full length of the Sure Ply. The wood ruler is the fence.
The second pic is the top side with the metal ruler used as a straight edge. Picture a second metal ruler creating a guide or keyway.
 

Attachments

  • IMG_2843.jpg
    IMG_2843.jpg
    190.2 KB · Views: 276
  • IMG_2844.jpg
    IMG_2844.jpg
    146.5 KB · Views: 272
Here's another. This is using the black foam core. The brown piece is a retainer, it is elevated above the foam core so you slide the foam on top of the jig under the retainer and up against the fence on the right. Picture two metal rulers clamped to the table spaced just wider than a blade width.
 

Attachments

  • IMG_1041.jpg
    IMG_1041.jpg
    165.4 KB · Views: 246
I even tried a plywood blade both forward and reversed. No luck. It 'chunked' the foam like you see two posts up.
I've been wanting to build some enclosures like this for light weight. Would a high speed band saw cut this with minimal "chunking"? Heh, or how about laser cutting! I once visited a factory near/in Chicago that did that by moving a 10' granite table about at high speed underneath the laser...now it seems you can get a small maker space version for $600!
 
now to find a small kerf blade
I don't remember but it was probably a regular carbide blade on the table saw to make sure the slot was good and wide. I simply dropped it onto the blade making sure to use the fence so it was semi straight and of course the metal rulers did the final adjustment. As you say, it's pretty elementary but it's also very effective.
 
see that's where i have the problem i'm hoping to get cuts with a single stroke, it's the multiple passes that turn things into a mess when a minor change in angle makes the cut take off producing long thin slivers or simply cause the cut to go off.

i've been trying to create blocks to hold the knife at 90 deg (would be nice if any angle could be selected for mitered cuts)
 
Last edited:
I think you want to avoid heat at all cost. You also need precision cuts as when you go to glue the second side on, you really need near perfect edges. Those are 6.5" drivers so you can see these are the large 48" units. The last pic is the guide I attached to the glue bottle so I didn't have to freehand a bead of glue onto all those feet of foam edge.
 

Attachments

  • IMG_1042.jpg
    IMG_1042.jpg
    233.1 KB · Views: 231
  • IMG_1044.jpg
    IMG_1044.jpg
    120.5 KB · Views: 221
  • IMG_1080.jpg
    IMG_1080.jpg
    188 KB · Views: 135
  • IMG_1090.jpg
    IMG_1090.jpg
    121.9 KB · Views: 145
  • IMG_1082.jpg
    IMG_1082.jpg
    119.3 KB · Views: 322
see that's where i have the problem i'm hoping to get cuts with a single stroke, it's the multiple passes that turn things into a mess when a minor change in angle makes the cut take off producing long thin slivers or simply cause the cut to go off.

The tutorials I’ve seen (as well as my own methods) recommend a scoring cut through the paper face followed by a second cut through the foam and bottom paper layer. As Cal has mentioned a sharp blade is the key regardless of method.