Hi, I have a question to ask:- is it possible to find foam board that can be composted? I like the idea of using foam board, but not if it has a negative effect on our environment. At present I am working with recycled paper, and is a very effective medium for speaker building. My reasoning about using foam board is to try and combine the two together.
tapestryofsound
Searching on “biodegradable foam board EU” yielded this site from the UK (I’m assuming you’re in Scotland from the flag shown by your name):
Biodegradable Foamboard - FoamBoard Online
I’m sure there are others.
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Searching on “biodegradable foam board EU” yielded this site from the UK (I’m assuming you’re in Scotland from the flag shown by your name):
Biodegradable Foamboard - FoamBoard Online
I’m sure there are others.
Oh, that is outstandingly good news - I’m in!

Yes, I live in rural Scotland, and try my very best to have as little eco-impact as is possible.
tapestryofsound
I would expect foamboard to excel in the karlson application as that front cavity looks like all kinds of trouble that poorly damped wood might exacerbate. Still, I am an old carpenter so be nice to someone who can't generate a lot of respect for hot "glue."
Is there anywhere a description of what would be the best practices to work with these foam core boards? Like how to cut, fold and glue them. I am new to the game and I haven’t read yet everything in this thread. I have bought thé recommended boards and glues and I want to start doing things!
Read the first 10 pages or so. Basics are to use a sharp utility blade razor or Xacto and metal sharp edge. Cut in multiple strokes to go deeper each time. Use hot melt glue to tack in spots if piece is too large and seal with hot melt like caulking making a nice fillet. To bend curves score partial cuts in the concave side and roll board on round object of similar radius to prebend. To glue the second side panel, use PVA as hot melt sets too quickly for you to apply a leak free joint more than 20 to 24 linear inches at a time. Use lots of bracing every 3 to 4 in of span to reduce drumhead vibration from panels.
Good examples are:
Bends:
https://www.diyaudio.com/forums/full-range/225622-building-cornu-spiral-horn-3.html#post3285100
Compound bends to flat:
FH3-inspired Foam Core Mini Build
Curved cabinets:
Viva la Vifa! Curvy Cabinet DCR with TC9FD
Tractrix horns:
Presenting the Trynergy - a full range tractrix synergy.
Transmission Lines:
Low-Cost PMC-inspired TL Monitor with DC130A and DC28F
Subwoofers:
https://www.diyaudio.com/forums/ful...itio-karlson-6th-bandpass-26.html#post4226956
Really big subs and nice sealed TL's:
The Nautaloss Ref Monitor
Good examples are:
Bends:
https://www.diyaudio.com/forums/full-range/225622-building-cornu-spiral-horn-3.html#post3285100
Compound bends to flat:
FH3-inspired Foam Core Mini Build
Curved cabinets:
Viva la Vifa! Curvy Cabinet DCR with TC9FD
Tractrix horns:
Presenting the Trynergy - a full range tractrix synergy.
Transmission Lines:
Low-Cost PMC-inspired TL Monitor with DC130A and DC28F
Subwoofers:
https://www.diyaudio.com/forums/ful...itio-karlson-6th-bandpass-26.html#post4226956
Really big subs and nice sealed TL's:
The Nautaloss Ref Monitor
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Wow, thank you X for such a detailed answer! I still have something to read but your advice is great!
The RC plane DIY community is ahead of us as far as working with foam core. There are a ton of youtube videos showing how to cut and tricks on joining etc. Worth a look.
Read the first 10 pages or so. Basics are to use a sharp utility blade razor or Xacto and metal sharp edge. ... To glue the second side panel, use PVA as hot melt sets too quickly for you to apply a leak free joint more than 20 to 24 linear inches at a time. ...
I use Elmer's glue to join the last side and it seems a bit difficult without applying some pressure. If I apply pressure with clamps I normally use for wood then some spots can be seen after removing them. Probably you can use some large wood pieces to be used in between the clamps and the foam core boards, but I am afraid that the excess glue might get the wood stick to the boards.
Sorry for this maybe naive question but how exactly is the best way to do this process?
I put a big piece of flat plywood over the top and stack with all the books I have - literally 100lbs of books sometimes. Looks like a little mountain of books.
I will do that next time, I am just afraid that the plywood will get stick with the excess glue and thus I will have a bigger problem. Thanks again [emoji4][emoji108]
You mentioned several times that you use liquid Nails for sticking the last side. What do you exactly mean by that? When I search on eBay or Amazon I can only find cosmetics related fake nails and similar stuff... Do you have a link to an online store by any chance?
Thanks for everything, I start to love this sort of projects 🙂
Thanks for everything, I start to love this sort of projects 🙂
try googling "construction adhesives"
https://www.amazon.ca/Liquid-Nails-...ocphy=9001157&hvtargid=pla-348540405806&psc=1
https://www.amazon.ca/Liquid-Nails-...ocphy=9001157&hvtargid=pla-348540405806&psc=1
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Loctite PL Premium works well too.
As does Gorilla Glue
But for basic foam core builds, white PVA is just fine.
As does Gorilla Glue
But for basic foam core builds, white PVA is just fine.
Hey X, do you think something like a scaled-down Chang could be done with foamcore? Using a pair of the "usual" ~3" class drivers that are popular in these foamcore shenanigans, such as the TC9FD, 3FE25, or a single PA130-8, or even those cheap MCM drivers from Newark/Element 14?
I've attached the plans for the half chang that is meant for the FE206E. There's also the smaller Suzy Chang that's meant for the 4" FE103 and I think 107?
Something like a third-chang, quarter-chang? 🙄
I think it might be something to look into with doubled-up foamcore sides, or maybe XPS foam. Maybe even luaun plywood sides. Should be economical and easy enough to build with adequate bracing, and maybe the lower stepped area could be built as a hollow triangular chamber.
I've attached the plans for the half chang that is meant for the FE206E. There's also the smaller Suzy Chang that's meant for the 4" FE103 and I think 107?
Something like a third-chang, quarter-chang? 🙄
I think it might be something to look into with doubled-up foamcore sides, or maybe XPS foam. Maybe even luaun plywood sides. Should be economical and easy enough to build with adequate bracing, and maybe the lower stepped area could be built as a hollow triangular chamber.
Attachments
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This is a horn augmented reflex box and can't be scaled like BLH. It is easy enough to do a sim on Akabak though. What are you trying to achieve, what is max size of cabinet, are you looking for a cheap and fun experiment, or something more likely to sound great?
Certainly foam core or XPS can be used to make this.
For the driver list you gave, go with a 0.53x Karlsonator with PA130-8.
Or if you want fun with a horn, make an FHL-lite with TC9FD or 3FE25. Or go with my scaled version of FH3 (earlier in this thread).
https://www.diyaudio.com/forums/ful...pired-foam-core-mini-build-3.html#post3339779
Certainly foam core or XPS can be used to make this.
For the driver list you gave, go with a 0.53x Karlsonator with PA130-8.
Or if you want fun with a horn, make an FHL-lite with TC9FD or 3FE25. Or go with my scaled version of FH3 (earlier in this thread).
https://www.diyaudio.com/forums/ful...pired-foam-core-mini-build-3.html#post3339779
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Probably a fun project to see how I like the style, and then eventual build of larger version? Max size of cabinet depends on what is reasonable- I personally have no problem going from 36-48" tall if needed, but keeping it down to 30" makes it easier for others that like to stick to a single sheet of foamcore high.
I'm itching to build something different, and have six MCM drivers still, a couple TC9FD, and couple Fountek FE83 still on hand. I'm halfway through a cornu build but it's back burner for now.
I'm itching to build something different, and have six MCM drivers still, a couple TC9FD, and couple Fountek FE83 still on hand. I'm halfway through a cornu build but it's back burner for now.
I have those MCM drivers that look just like PA130-8 but they are not the same. Will have to measure TS parameters again. I have 8 of those too.
If I remember they wanted a small enclosure in a Karlsonator, so maybe a pair would do in a Chang type of enclosure? Since the box should be large enough, and is practically a rectangle I would think it shouldn't be too difficult to fit a pair in parallel for 8 ohms. Hmmm.
I don't have the PA130 on hand, I mistyped. Just figured it was low cost so added it to the list. Sorry for the misunderstanding. I would love to build a air of the larger K's with a pair of PA130 per side 🙂
I don't have the PA130 on hand, I mistyped. Just figured it was low cost so added it to the list. Sorry for the misunderstanding. I would love to build a air of the larger K's with a pair of PA130 per side 🙂
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