Thread: How to get this surface totally flat?

You could use Urethane glue, I think its Urethane anyway, its the glue that foams up as you use it.

Al

lots of glue and big screws.

Thaught you'd cut them all the same size didn't you
The trimming fairy came in overnight and took small amounts off all the different bits

one other option is to trim all the irregular bits with a belt sander..... yep

dont worry tooo much about entire lengths of edge.... near the corners is important the screws will pull the gaps down elsewhere.



In future be absolutely fastidious about cutting same size bits...... the same size.
Do not rely on the calibrations of your fence to repeat accurately.
either measure blade edge to fence with a good steel rule
or
set your fence and cut all dimensions the same witout resetting the fence.

Oh yeh.... been there too.

now the next question is how do I make all my exterior edges match up perfectly?
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belt sander too

but don;t tell anybody

cheers

Run a bead of 'No more nails' along every edge. Just don't expect to get it off again though!
This glue should fill gaps of up to a one mm or two.

Thanks for the tips guys.

Regarding using urethane glue or selleys no more nails, how well would these products bond mdf as compared to using proper woodworking glue?

the liquid nails products are realy not all that strong but the poly is pretty tough.

how big are these gaps anyway.

unles they are huge a good pva should be fine.

remember to scre the panels down

if you find any gaps after that.... you can bung them then.

If the gaps are more than half a mm.... you realy need to solve the problem rather that just bunging things up.

you'd be surprised what you can fix with carefull application of a belt sander

cheers

One of the more viscous polyurethane glue/sealants would be the go I reckon, ie. the ones that come in a cartridge, such as Sikaflex (expensive but good), Selleys new Adhesive & Sealant (ditto), or Bostik Gold Flex (economical - about $9 a tube).

I'd go the Bostik.

Better choice than a building adhesive such as liquid nails I reckon.

I'd have no concerns about it sticking together properly, the polyurethanes stick like tish to a blanket.


Cheers................Sean

Speaker looks interesting, is that what is called a bandpass design?

Is it a subwoofer? What is the advantage over a plain ported enclosure, is it more efficient or something else?

Edit: checked out one of your earlier links, seems it's an enclosure for a single full range speaker. Looks like you've put a lot of work in, be interested to hear how it works out.

If that trimming fairy took a lot off some of the panels, I'd cut a sliver of MDF (or rip solid timber) and sandwich it between the edge and the side with glue both sides - why not, who is going to be crawling around in there looking? Interesting design... heavy too.

Set up your router in a 'Sled' then set up 2 slides either side of the cabinet (Speaker) so they are equally spaced about 25 mm or so above the faces you want to surface they must be exactly matched and true.
You can then skim backwards and forwards across these slides with the router/slide assembly and machine all the partitions etc. to the same hieght.
You could set the router to the depth of the 'worst case' and take all the other 'high' parts to this level.
You would want to take the bare minimum off so as not to upset the tuning of the enclosure.

I know it sounds a bit complex but it will make a good job of it.

Hope this helps Looks like a good job so-far.

Wayne

I dont reckon those gaps will be all that much... maybe grab some wood dust and mix it with pva glue and wipe it on all mating surfaces the glue will adhere and the dust will bond filling any small gaps it finds... do it well enough an you wont have much cleanup which being pva you just give it a cleanup as you go and with the final sand nothings left to say it was there cheep easy and in this instance Id think the KISS method would be ideal...

mmm but then... one should if youve done everything else PERFEK get really anul and toss that useless buggared ill fitting mongrel of a thing in the scrap bin and start all over again and this time GET IT BLOODY RIGHT!!... ahem... I did say you could not that you would or even should just that you could if you were an anul sorta fella that is

Thanks for all the advice guys, given me lots of good ideas to think about.

I originally had all the pieces cnc cut but in some cases there were still minor differences of less than 1mm.

So far I have caulked any gaps that have occured, but I wouldnt be able to do that in most places once the side panel goes on.

Scooter: It's a back loaded horn loudspeaker. Will be very efficient and only require a few watts to drive loud and deep.

Wixy use a sanding board. Grab a peice of thick MDF around 600-700mm x 100mm and glue a sheet of quality 60# sandpaper on. Then with a thick pencil scribble all ove the area to be sanded. Then with your sanding board sand of all the high spots. It wont take long to get it totaly flat and even.

I would run a bead of sellys roof and gutter (silicone)....that stuff sticks to anything......then screw down every 50mm all around but only softly .....let the roof and gutter set and dry, then final tighten (firmly) by by gaps ....and if you need to take the cover off in the future, you can ...

Do an old car audio trick they use on roughly cut subboxes, get your self some fibre impregnated bog/resin, the K&H brand is called Karlglass(spelling? sounds like that).
Mix it up spatula it on all surfaces to be joined/sealed then place on your panel then just brad gun it in a few places, leave it to cure for 24hrs.
It will fill gaps and glue at the same time, wait several days before installing the driver as the curing fumes can effect the speaker suspension(particularly foam surrounds).