[droht]

I want to do a very low-end build, mostly as a fun project over the holidays with my teenager.  Going to buy a kit with pre-cut flats.  Instructions are to clamp after gluing everything together, which is obviously the preferred approach.  But I don't have clamps and don't really want to buy them.  If I screw everything together when gluing is that enough?  Any other ways to "cheat" this step?  If I really have to do clamps is there a good bargain option?  Cabinet Dimensions 17.75" W x 5.5" H x 7.5" D.

Thanks for any advice.

[TomS]

Ratchet straps can work in a pinch, but are less likely to keep everything squared up.

You can get some really cheap clamps at Harbor Freight these days.

[FullRangeMan]

Good clamps are a investment, they last a whole life.

[droht]

Good clamps are a investment, they last a whole life.

I'm sure that's true, but haven't needed them for 52 years, and kind of doubtful I'll need them again.

[S Clark]

"I want to do a very low-end build, mostly as a fun project over the holidays with my teenager.  Going to buy a kit with pre-cut flats. "

Ok, you told us what you want to do.  Everyone is telling you to pick up some cheap clamps.  You want to have it be successful and be a positive experience with your kid.   98% probability the cabinet is MDF, which will likely split when you try to screw into the ends or close to an edge.  You'd have a much greater chance of success by hammering in finishing nails into pre drilled holes.

Or buy fifteen bucks worth of cheap Harbor Freight clamps as suggested and glue it up in stages.
Or not. 

[droht]

"I want to do a very low-end build, mostly as a fun project over the holidays with my teenager.  Going to buy a kit with pre-cut flats. "

Ok, you told us what you want to do.  Everyone is telling you to pick up some cheap clamps.  You want to have it be successful and be a positive experience with your kid.   98% probability the cabinet is MDF, which will likely split when you try to screw into the ends or close to an edge.  You'd have a much greater chance of success by hammering in finishing nails into pre drilled holes.

Or buy fifteen bucks worth of cheap Harbor Freight clamps as suggested and glue it up in stages.
Or not.

Yes.  MDF.  I'm coming to grips with needing clamps.  Pardon the pun.  Would six be sufficient  2 x 24" and 4 x 12" for 17.75" W x 5.5" H x 7.5" D box?  I'm really clueless about this...

[S Clark]

Yes.  MDF.  I'm coming to grips with needing clamps.  Pardon the pun.  Would six be sufficient  2 x 24" and 4 x 12" for 17.75" W x 5.5" H x 7.5" D box?  I'm really clueless about this...

Yeah, you can do it with 6. You may have to do it in a couple of steps... which isn't a bad plan anyway.  Does the kit have any deadening?  A few feet of carpet padding is worth the couple of bucks.

[droht]

Yeah, you can do it with 6. You may have to do it in a couple of steps... which isn't a bad plan anyway.  Does the kit have any deadening?  A few feet of carpet padding is worth the couple of bucks.

Six cheap clamps at HF is $30 or $35.  Does that seem right?

I was going to use Acousta-Stuf.  Is that a good choice?

Thank you!

[S Clark]

That's about right.  Acousti-Stuff is not much different from Poly Fill (for stuffing pillows, etc) at Walmart (and probably not as good as fiberglass- but glass is nasty to work with).  My experience is carpet padding glued to the inside cabinet works better.  Is this ported or sealed? If sealed, I'd use fiberglass fill.

[droht]

That's about right.  Acousti-Stuff is not much different from Poly Fill (for stuffing pillows, etc) at Walmart (and probably not as good as fiberglass- but glass is nasty to work with).  My experience is carpet padding glued to the inside cabinet works better.  Is this ported or sealed? If sealed, I'd use fiberglass fill.

Ported.  This is probably what I'll be going with:  https://www.parts-express.com/dayton-audio-mkboom-portable-bluetooth-speaker-kit--300-7166

[droht]

Is acoustic foam a good choice for dampening?

[FullRangeMan]

Is acoustic foam a good choice for dampening?

https://www.audiocircle.com/index.php?topic=100689.msg1016047#msg1016047

[Norman Tracy]

Masking or box tape can also be used for clamping small glue ups.

https://youtu.be/7JO36qSMXEQ?t=156

[droht]

https://www.audiocircle.com/index.php?topic=100689.msg1016047#msg1016047

Great thread. Thanks.

[droht]

Masking or box tape can also be used for clamping small glue ups.

https://youtu.be/7JO36qSMXEQ?t=156

Interesting. Never heard of that. There’s even “clamp tape" marketed for this purpose. But I can't imagine it would be adequate for a speaker build. Thoughts anyone?

[EdRo]

I've had to use the clear packaging tape that you can buy from Office Max , Staples or Home Depot. My cabs are curved and clamps won't work. That tape has a little stretch, so it's perfect for this job. Buy the name brand heavy duty tape though, not the store brand stuff. It makes a big difference. And, as an added benefit, epoxy wont stick to it.

[richidoo]

I use weights when I run out of clamps, but often weights are easier to set up and more precise than a clamp which usually adds a sideways component of force. I use 6x9" patio pavers, 8x16" concrete blocks, heavy toolbox, and even stacks of 20lb bags of fertilizer. Blocks cost about $1.50.  But sometimes you just need a clamp to tame naughty wood, or naughty cuts. 

The problem with screws is that the wood is displaced around the hole when the threads dig in causing a bump up in the gluing surfaces of both pieces of wood which leaves a gap. Ironically, it's best to clamp the wood together before screwing to maintain closed joint. You could also drill pilot holes and countersink them so the edges of the holes don't squeeze up. I use a 1-1/4" staple gun when appearance doesn't matter and when the assembly doesn't require further cuts, but obviously that costs more than clamps. I only use staples on speakers now for adding damping material inside sub boxes.

Is acoustic foam a good choice for dampening?

I have used self adhesive foam from parts express and I think it worked OK, but it's only 1/2" thick. On a low frequency cabinet I'd consider using the rigid foam from GR Research. Generic rubber foam is not a strong sound absorber, compared to plain old fiberglass insulation. They make 2" fiberglass for small jobs, it's good for lining ported boxes. Far better damping than acousta stuff. Just wear rubber glove and rinse skin with cold water.

[droht]

...
I have used self adhesive foam from parts express and I think it worked OK, but it's only 1/2" thick. On a low frequency cabinet I'd consider using the rigid foam from GR Research. Generic rubber foam is not a strong sound absorber, compared to plain old fiberglass insulation. They make 2" fiberglass for small jobs, it's good for lining ported boxes. Far better damping than acousta stuff. Just wear rubber glove and rinse skin with cold water.

Thanks richidoo.

I'm not using no-rez for this cheap build, so I guess the question is "are cheaper options even worth it?".  I was thinking about this stuff or similar: https://www.parts-express.com/sonic-barrier-1-2-acoustic-sound-damping-foam-with-psa-18-x-24--260-520

[planet10]

I am currently assembling a uMar-Ken flat-pak, the goal to do it with no clamps, just masking and packing tape. The small box makes it easier.

dave

[WGH]

If I screw everything together when gluing is that enough?

Yes, one advantage is you can keep working on the project without waiting a couple of hours for the glue to dry between steps.

The type of screw is important. First we need a little screw theory:

A screw should only grab the bottom board, which is why you should always use a pre-drill countersink. If the threads catch on the top board the screw will actually pull the boards apart. The threads on traditional wood screws do not have the threads all the way to the head for this reason. MDF screws have a wide, coarse thread pattern, wood screws have shallower threads and don't hold as well in MDF.

Screws from Home Depot and Ace Hardware suck because the threads go all the way to the head, pre-drilling is absolutely necessary.

McFeely's screws are designed correctly, notice the coarse, wide spaced and sharp threads, the screws are designed for MDF. Use 2" long screws for speakers. Square drive screws are wonderful, once you try them you will never go back to Phillips head.
https://www.mcfeelys.com/screw-fastener-web-store/shop-screws-by-application/wood-screws-general-purpose.html?screw_length=608


A Dewalt #8 countersink will work with McFeely screws, yes you still have to use a countersink with self tapping screws or you will blow out the MDF and make a bump.


You should use a #8 countersink with a clearance/pilot hole if using screws that have threads all the way to the head


This is what your hole should look like except countersink the head 1/8" - 3/16" so the Bondo filler has enough MDF to grab onto or it will pop out.


Q & A: Why Predrill Screw Holes?
https://www.popularwoodworking.com/american-woodworker-blog/q-a-why-predrill-screw-holes-2/