| Apocalypse! [message #43350] |
Fri, 12 December 2003 20:05  |
Mike.e
Messages: 471
Registered: May 2009
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Illuminati (1st Degree) |
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well its complete! -my 40hz basshorn (practise one for the 8" woofer glued it lastnite. Subjective sound=
quieter than expected
Very nice quality!
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| YAY for Joiners! [message #43355 is a reply to message #43353] |
Fri, 12 December 2003 21:55  |
Mike.e
Messages: 471
Registered: May 2009
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Illuminati (1st Degree) |
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I know,im SO GLAD they guy cut it perfectly *phew* it was as perfect as could be,the stuff up was me not ensuring the flare was in correct position. but i knew id have to make a practise one,before making a good one for lab12. now il see how much performance i can squeese out of the lab12, im looking at 104db efficiencies and 1600cm ONLY mouth area and 299cm length that il have to cram in somewhere. Also next time il get silicon sealant with a LONG straw on the end,so i can reach deep into the horn while one side is off! More CAD /hornresping now..and compromises..and design conflicts.. :P..u know the story. Cheers
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| Re: No fasteners needed for complex glue-ups of horns [message #43357 is a reply to message #43356] |
Sat, 13 December 2003 04:41 |
Mike.e
Messages: 471
Registered: May 2009
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Illuminati (1st Degree) |
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Like this,and Side B gets the same treatment,before side A is glued. Practical? i dont mind using screws to keep the panels clamped(i have no clamps) For the lab12 horn il have to buy silicon sealant to ensure its sealed,rather than squirt 500ml of PVA woodglue down a join ,half of it missing as the bottle cant actualy fit in the tight folds :P Cheers!
At moment im modeling up 32hz basshorn ,but having trouble making the rear sealed chamber as small as it should be -while keeping the horn length what it should! :-S It only takes me 1hr to CAD a horn,but its trial and error to get a horn that has no wastage :-S
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| Re:Not exactly [message #43359 is a reply to message #43357] |
Sat, 13 December 2003 06:10 |
BillEpstein
Messages: 886
Registered: May 2009
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Illuminati (2nd Degree) |
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Lots of ways to skin that cat but what I was trying to describe eliminated the inevitable change of position caused by the torque of the screws. No fasteners go into the sub-assemblies at all.
I put your "A" side on the bench, outside down. Located the sub-assemblies and drew lines around them. Then put the glue on one side (edges) of the subs and placed them within the lines. It's important to push down on the subs so they flatten out the glue a little and become "stuck". Otherwise any subsequent action, placing side "B" or putting weight on "B" may cause movement.
So now side"A" has subs glued to it.
Place side "B" on top, and, since you don't have clamps, get the Brittanica or Madonna's coffee table book or a piece of concrete, etc and weight down side "B". No glue between the subs and "B" at this point. Next day you remove "B", spread glue on the exposed edges of the subs, replace "B", position it square with a few nails and put the weight back on. I used 1 1/4", 4 penny finish nails, 2 on one side and 2 more on an adjacent side just to maintain square while I weighted "B". Be sure to countersink them which really improves the mechanical action and allows them to be easily hidden. All the weight required is enough to flatten the glue just as you did by hand in the first step to glue "A". 24 hours later it's done.
The main thing about this method is eliminating using screws to fasten the sub-assemblies at all. Just let the urethane adhesive do it's job. BTW, I am NOT talking about Gorilla Glue or other brands of that type. They expand as they dry and they dry hard. Very bad for creating an airtight seal. What is called for is any of the various brands of Urethane "construction" adhesive that comes in a cardboard tube and requires a caulking gun. It becomes tacky rather quickly at almost any temperature, does not expand as it dries and remains permanently flexible so acts as a sealant. Once the sub-assemblies have sat in it for a few minutes you could actually turn the whole thing over and they would stay put. The "squeeze-out" is a bit of a bother to remove. Try to remove it too soon and it just gunks up your scraper or knife. Wait too long and it's really tenacious. It peels right off after a couple of hours, tho'. If it's quite dry, you can cut or chisel along the edge of the glue bead and then it peels okay and sand the residue. Worth the trouble.
I realise all this borders on pedantry but describing a mental image is so hard. I talk to people all day about theur kitchen or deck or pole barn ideas and it gets pretty hilarious at times when something clear in their minds just doesn't come across in words. Of course they think I'm a Cretin.
Here's an interchange between myself and Steve Culton on wiring up a fairly simple on-off switch, DPDT, I think. Real Abbot and Costello stuff:
Who's On First
Creating is more like performing than listening
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| No fasteners [message #43374 is a reply to message #43359] |
Mon, 15 December 2003 05:44 |
Mike.e
Messages: 471
Registered: May 2009
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Illuminati (1st Degree) |
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Thanks bill, So the subsections are simply squeesed together?
dont i need to just slightly apply pressure on them laterally to be sure? i think a no screws way would be much more attractive and it doesnt move the panels too..a few kg pressure is enough? so a few bricks,i have those about. i use selleys aquadhere wood glue PVA ,works fine for me.
Cheers!
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