SLOB project

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Ray P
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#286 Re: SLOB project

Post by Ray P »

Good news, I've just bought an 'offcut' of 18mm birch ply big enough for the two baffles for £10!
Sorry, I couldn't resist!
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pre65
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#287 Re: SLOB project

Post by pre65 »

Ray P wrote: Sun Nov 13, 2022 10:07 am Good news, I've just bought an 'offcut' of 18mm birch ply big enough for the two baffles for £10!
Well done Ray, a veritable bargain. :)
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Ray P
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#288 Re: SLOB project

Post by Ray P »

I picked up the birch ply offcut over the weekend and it is top notch material - really chuffed with the purchase. I've now cut it down for the two baffles and started to make the cut-outs for the drive units.

The base sections of the SLOBs are almost ready for finishing too.
Sorry, I couldn't resist!
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Ray P
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#289 Re: SLOB project

Post by Ray P »

As I mentioned before, I have a pair of Aural Bryan 8in. full range untis for the SLOBs but I also have a pair of their supertweeters.

Is there a rule of thumb for locating the supertweeters on the baffles; vertically aligned or offset towards the inside (of the stereo pair) and how far away from the full-range units?

Cheers
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IslandPink
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#290 Re: SLOB project

Post by IslandPink »

I'd say vertically aligned, and as close as possible.
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Ray P
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#291 Re: SLOB project

Post by Ray P »

IslandPink wrote: Wed Nov 23, 2022 9:41 am I'd say vertically aligned, and as close as possible.
Thanks Mark
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Ray P
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#292 Re: SLOB project

Post by Ray P »

Assembly of both base (bass) sections complete and first coat of finish (wiped on satin polyurathane) applied.

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Ray P
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#293 Re: SLOB project

Post by Ray P »

I've just applied the third coat.

I'm not 100% satisfied with my work as, whilst I'm getting a nice surface finish, I have some 'staining' from the polyurathane glueing-up process, that I didn't sand away for fear of cutting through the outer layer of the ply, but these bass 'cradles' will be largely out of sight so I'll live with them.
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Toppsy
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#294 Re: SLOB project

Post by Toppsy »

A bit late posting Ray but I have been preoccupied with my 'Swansong' speakers and have now started a new winter build project, and no not another pair of speakers.

Shame about the staining from the polyurethane glue, but as you say most the lower part of the SLOB speakers particularly the bass section is largely out of sight so may not be so noticeable when they are assembled in full. I have to say though that I have never used, nor felt the need to use, polyurethane glues on any of my speakers. If asked I would always recommend either a basic white PVA wood glue or Aliphatic resin wood glue for speakers. My preference being the latter. Both are water based glues that sand very easily, dry clear, and do not stain the bare wood. Any excess glue squeezed out during the clamping can be wiped off with a damp cloth.

The best polyurethane varnish I have found is General Finishes High Performance https://generalfinishes.com/wood-finish ... hane-water. This is a water based polyurethane varnish that one can apply with a paint pad and gives a superb streak free finish. Even brushed on, the finish is the same, but 3-coats applied with a paint pad ticks the box for me. Highly recommended.

Following your progress with interest.
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Ray P
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#295 Re: SLOB project

Post by Ray P »

Toppsy wrote: Fri Dec 09, 2022 12:21 pm Shame about the staining from the polyurethane glue, but as you say most the lower part of the SLOB speakers particularly the bass section is largely out of sight so may not be so noticeable when they are assembled in full. I have to say though that I have never used, nor felt the need to use, polyurethane glues on any of my speakers. If asked I would always recommend either a basic white PVA wood glue or Aliphatic resin wood glue for speakers. My preference being the latter. Both are water based glues that sand very easily, dry clear, and do not stain the bare wood. Any excess glue squeezed out during the clamping can be wiped off with a damp cloth.
Cheers Colin.

I like polyurathane glue for general woodwork as it is very resilient to damp and the like and can help with gap filling, an inevitable situation with my woodworking skills. I used it to glue the bass baffle to the side panels and it would have been fine had it not foamed out through the dowel holes - I switched to PVA glue after that experience! Anyway, it's not the end of the world and as I'm applying the finish the staining is becoming less visible - of course, the problem is that I know it's there! The finish I'm using is Rustins satin polyurathane, oil based and diluted 50/50 with white spirit and applied with a rag with just a very light rub with a soft scouring pad between coats - I'm quite pleased with the result as it soaks into the wood well, toughening it up, and it doesn't look as though there is a plastic film on the surface like varnish can give.

As I have to work in, or just outside, my garage there's a bit of a brake on progress because the cold conditions aren't great for finishing work and it's too cold to be progressing the shaping of the baffles.
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#296 Re: SLOB project

Post by steve s »

Toppsy wrote: Fri Dec 09, 2022 12:21 pm This is a water based polyurethane varnish that one can apply with a paint pad and gives a superb streak free finish. Even brushed on, the finish is the same, but 3-coats applied with a paint pad ticks the box for me. Highly recommended.

Following your progress with interest.
I used to love using paint pads colin, back around '77 I even painted the father in laws cortina using a pad, after the body repairs and new panels I fitted dictated the need ( how cars have changed since ?)

After s couple of hours t cutting I was well impressed with the finish.
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vinylnvalves
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#297 Re: SLOB project

Post by vinylnvalves »

Toppsy wrote: Fri Dec 09, 2022 12:21 pm A bit late posting Ray but I have been preoccupied with my 'Swansong' speakers and have now started a new winter build project, and no not another pair of speakers.

Shame about the staining from the polyurethane glue, but as you say most the lower part of the SLOB speakers particularly the bass section is largely out of sight so may not be so noticeable when they are assembled in full. I have to say though that I have never used, nor felt the need to use, polyurethane glues on any of my speakers. If asked I would always recommend either a basic white PVA wood glue or Aliphatic resin wood glue for speakers. My preference being the latter. Both are water based glues that sand very easily, dry clear, and do not stain the bare wood. Any excess glue squeezed out during the clamping can be wiped off with a damp cloth.

The best polyurethane varnish I have found is General Finishes High Performance https://generalfinishes.com/wood-finish ... hane-water. This is a water based polyurethane varnish that one can apply with a paint pad and gives a superb streak free finish. Even brushed on, the finish is the same, but 3-coats applied with a paint pad ticks the box for me. Highly recommended.

Following your progress with interest.
Interestingly I find the opposite with PU glue, as it doesn’t get absorbed like water based glue, a light sand and the witness is removed. Also if you use the spirt based PU varnish, it doesn’t even show if not sanded off. I generally find cascamite glue the worst, needing heavy sanding to remove any spills. I generally seal with a coat of finish before i glue up where possible, and mask.
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Ray P
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#298 Re: SLOB project

Post by Ray P »

Been busy with this project today. The base (bass) sections are all but finished and this afternoon I have been working on the baffles, cutting the holes for the drive units, rounding over the edges etc. so they're ready to start receiving some coats of varnish. The light went pretty quickly so some pictures another time.
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Ray P
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#299 Re: SLOB project

Post by Ray P »

Quickly put together one of the SLOBs to have a look today...

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Ray P
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#300 Re: SLOB project

Post by Ray P »

Another picture with the baffle properly bolted to the base section

Image

and one of the other base section showing the baffle mounting arangements (the intention is to have the baffles quickly/easily removable)

Image
Last edited by Ray P on Tue Jan 03, 2023 10:19 pm, edited 1 time in total.
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