New BassChat 8"Cab design

[rwillett]

45 minutes ago, nekomatic said:

 

If you're banned from even painting indoors I don't think anodising is going to be on the cards!

You can do anodising in the garage , it is affected by cold weather but you need to heat the solutions up anyway, you do have high current and the chemicals aren't fantastic, TBH they aren't very good at all,, but decent space, power, fresh air, respirator and slightly loose lids on containers make it potentially doable outside in the garage. Not that I'm looking to try it (yet). 

 

Painting with these special tough paints, especially with a roller, seems less desirable. I have to confess to using some paints and stuff sometime ago that stank to high heaven, and for some reason t'CFO isn't keen to repeat the exercise. I have no sense of smell (lost it 2014) so I have no issues which is part of the problem, she can smell it and I can't.

 

Rob

[nekomatic]

6 hours ago, rwillett said:

I have to confess to using some paints and stuff sometime ago that stank to high heaven, and for some reason t'CFO isn't keen to repeat the exercise. I have no sense of smell (lost it 2014) so I have no issues which is part of the problem, she can smell it and I can't.

Tuff Cab has very little odour, fwiw, so hopefully your equivalent one is the same. 

[rwillett]

Good to know that there may be little smell.

 

I also looked at speaker grills and spent a long time thinking through how to print one in four pieces and join it together using superglue, a special jig and all sorts of hard work until a rare bout of common sense broke out.

 

Previously people had mentioned using an 18" speaker grill and cutting it down. I've just checked the sizes for this against the 8" speaker cab and of course when you lay it out, they were right and I was surprised (and wrong).

 

The dashed straight lines show the inside of the 8" speaker cab, the large dashed circle is the cutaway for the Fane speaker and the small dashed circle is the port. The large solid circle is an 18" speaker grille and the smaller solid circle is a 300mm speaker grille. 

 

So the 18" speaker grille is pretty much a perfect fit, though it will need cutting down and flattening, though I can't see that being a major issue with a rubber hammer, a Dremel and a decent cutting wheel (or rather a few of them). 

 

For circa £10 per grille, this is a very cheap way to get a grille plus an hour or so of cutting.  

 

 

The other option is a small bit of rectangular hardboard with two large circles cut out with some speaker cloth which still might look nice.

 

This is the speaker lightly sanded with some filler and the corners checked for fit. These will actually be glued on with "No Nail" rather than screwed.  A little more sanding just to tidy up the front. You can just about see the t-nuts inside on the back for holding the Warwick Gnome on using slider rails. There are the same fittings on the top so the Warwick can be on the top or the back. There are holes on the side for grab handles. I don't use a strap for picking it up as I wanted the Warwick to have the option of top mounting as well as back mounting. 

 

Not sure I can paint it until I have worked out the speaker grille and how to fit it so I can easily take it on and off. I'm tending to think I mask off the corner piece areas before the Aracab goes on but would welcome thoughts.

 

 

 

[Stub Mandrel]

On 15/12/2025 at 09:57, rwillett said:

That would look great.

 

I did look at anodising some telescope parts years ago, the theory looks quite easy, its the practise that worries me...

 

It takes some experimenting, but I've done just that. I built thus scope, Including the focuser, around an ED lens cell.

 

 

 

Won a silver medal for it

 

 

[Stub Mandrel]

33 minutes ago, rwillett said:

Good to know that there may be little smell.

 

I also looked at speaker grills and spent a long time thinking through how to print one in four pieces and join it together using superglue, a special jig and all sorts of hard work until a rare bout of common sense broke out.

 

Previously people had mentioned using an 18" speaker grill and cutting it down. I've just checked the sizes for this against the 8" speaker cab and of course when you lay it out, they were right and I was surprised (and wrong).

 

The dashed straight lines show the inside of the 8" speaker cab, the large dashed circle is the cutaway for the Fane speaker and the small dashed circle is the port. The large solid circle is an 18" speaker grille and the smaller solid circle is a 300mm speaker grille. 

 

So the 18" speaker grille is pretty much a perfect fit, though it will need cutting down and flattening, though I can't see that being a major issue with a rubber hammer, a Dremel and a decent cutting wheel (or rather a few of them). 

 

For circa £10 per grille, this is a very cheap way to get a grille plus an hour or so of cutting.  

 

 

The other option is a small bit of rectangular hardboard with two large circles cut out with some speaker cloth which still might look nice.

 

This is the speaker lightly sanded with some filler and the corners checked for fit. These will actually be glued on with "No Nail" rather than screwed.  A little more sanding just to tidy up the front. You can just about see the t-nuts inside on the back for holding the Warwick Gnome on using slider rails. There are the same fittings on the top so the Warwick can be on the top or the back. There are holes on the side for grab handles. I don't use a strap for picking it up as I wanted the Warwick to have the option of top mounting as well as back mounting. 

 

Not sure I can paint it until I have worked out the speaker grille and how to fit it so I can easily take it on and off. I'm tending to think I mask off the corner piece areas before the Aracab goes on but would welcome thoughts.

 

 

 

At last we see it!

 

Well done.

[rwillett]

48 minutes ago, Stub Mandrel said:

 

It takes some experimenting, but I've done just that. I built thus scope, Including the focuser, around an ED lens cell.

 

 

 

Won a silver medal for it

 

 

 

I do like that. A good old EQ6 and is that an 80mm cell? Looks like a Canon and a Zwo (?). What's the box on the Canon hidden behind the focuser? Looks like a peltier cooler or something similar. Interested to know why it's on the side, though must be a good reason.

 

Rob

[rwillett]

50 minutes ago, Stub Mandrel said:

At last we see it!

 

Well done.

Thanks. Just noticed that one side looks like it's covered in white filler, it's not. 

 

I've filled and sanded, filled and sanded. Whilst the Armacab should hide imperfections, I'd rather not have to hide anything.

[Stub Mandrel]

1 hour ago, rwillett said:

 

I do like that. A good old EQ6 and is that an 80mm cell? Looks like a Canon and a Zwo (?). What's the box on the Canon hidden behind the focuser? Looks like a peltier cooler or something similar. Interested to know why it's on the side, though must be a good reason.

 

Rob

 

Skywatcher 66ED cell. ZWO guider on one of my home-made bitsa guidescopes.

The cooler is an online design that uses a copper plate slipped between the sensor and the next circuit board.  I 3D printed a cover to help insulate it and support the peltier, heatsink and fan. Quite tricky to get right as you have to make a heater from resistance wire to go around the sensor to stop condensation and get the right balance of cooling and warming! Camerea also has the IR/UV filters stripped out. Made a huge difference, but then I got a big cooled mono ZWO and a filter wheel.

Sadly, not got up to much since 2021. I think this one is with the ED66. After this, I'd better shut up and let the thread get back to speaker cabs!

 

 

[rwillett]

30 minutes ago, Stub Mandrel said:

 

Skywatcher 66ED cell. ZWO guider on one of my home-made bitsa guidescopes.

The cooler is an online design that uses a copper plate slipped between the sensor and the next circuit board.  I 3D printed a cover to help insulate it and support the peltier, heatsink and fan. Quite tricky to get right as you have to make a heater from resistance wire to go around the sensor to stop condensation and get the right balance of cooling and warming! Camerea also has the IR/UV filters stripped out. Made a huge difference, but then I got a big cooled mono ZWO and a filter wheel.

Sadly, not got up to much since 2021. I think this one is with the ED66. After this, I'd better shut up and let the thread get back to speaker cabs!

 

I have a WO66 shortie which is really nice, quite easy to balance without hauling an EQ6 around. I also have a TMB 100m F8 APO. This needs an EQ6 at least and is a fabulous scope but is so large and heavy it never gets used as my two slipped discs immediately complain just looking at the scope.

 

I know what you have done with the above, the really impressive bit (thought it's all impressive) is the cooling on the Canon (at least to me), that's really difficult to get just right. Everybody has gone Zwo, apart from me.

 

Anyway back to the cab making.

 

Rob

[Bassybert]

38 minutes ago, Stub Mandrel said:

 

Skywatcher 66ED cell. ZWO guider on one of my home-made bitsa guidescopes.

The cooler is an online design that uses a copper plate slipped between the sensor and the next circuit board.  I 3D printed a cover to help insulate it and support the peltier, heatsink and fan. Quite tricky to get right as you have to make a heater from resistance wire to go around the sensor to stop condensation and get the right balance of cooling and warming! Camerea also has the IR/UV filters stripped out. Made a huge difference, but then I got a big cooled mono ZWO and a filter wheel.

Sadly, not got up to much since 2021. I think this one is with the ED66. After this, I'd better shut up and let the thread get back to speaker cabs!

 

 

Wow that looks incredible!

[nekomatic]

Get an observatory, you lot - this is the cab design thread!

 

😉

[Phil Starr]

It is a really good fit and possible to get the thing cut so that the grille is centred nicely. I made a picture frame, screwed the grille to that and used velcro to fix that to the cab. I did cut the plastic covering strip to fit the edges but decided it looked better plain and I deburred the edges with a bench grinder. If I did it again I'd probably fold the edges and trim them down to 10mm. I practiced this with off-cuts and it was easier than I thought, clamping the metal between two bits of timber and beating it down. Folding it this way stiffened up the structure really nicely.

[rwillett]

And CPC have delivered some stuff. As Phil has already suggested, it neatly fits.

 

 

The middle of the grille is raised (or the edges are lowered), I'll have a look and work out what to do here. Cut and flatten or flatten and cut? As the weather is miserable, no painting today.But I have worked out how to integrate the rubber feet into the corner clamps and to allow two of these cabs to be on top of each other. Not sure that's a sensible idea, but the option is there.

 

Rob

[Phil Starr]

Flatten it first, and go gently as the paint flakes really easily

[Obrienp]

That picture looks a bit like a Smiley with a monocle 🧐.

[Phil Starr]

17 hours ago, Phil Starr said:

Flatten it first, and go gently as the paint flakes really easily

Sorry I should probably have offered a bit more advice. If you aren't used to metal bashing steel is really forgiving but you can stretch it and even bruise it if you are too rough. use a soft faced hammer in this instance and keep the hammer square to the work. Swinging in an arc will mean you are beating with the edge of the hammer concentrating the force on the edge instead of spreading it.

 

Find a flat rigid surface supported so it wont move or bend. The idea is to 'push' the metal down onto this surface. I found that I could simply push the sheet flat with my hands to start with. That takes out the convex curve but leaves the edges which have a more distinct fold in them. Turn the grille upside down and start to adress that. Use gentle blows with a soft hammer and remember you are trying to push it into shape so you can go gently and use repeated blows rather than trying to knock the hell out of it. Work steadily around the piece. You'll now find bits that were up are now down so you'll need to flip the grille again and try from the other side and it will gradually get flatter. The other thing to note is that beating the metal heats it slightly so lots of repeated blows will soften it, slowly working your way around means you'll find the metal starts doing what you want. I find it quite therapeutic

 

That makes it all sound a bit complicated, it isn't. Just work steadily and it's a job of a few minutes

[nekomatic]

Can’t remember exactly but I’m pretty sure I just squeezed mine flat between a couple of pieces of wood and a couple of clamps. 

[rwillett]

1 hour ago, nekomatic said:

Can’t remember exactly but I’m pretty sure I just squeezed mine flat between a couple of pieces of wood and a couple of clamps. 

Yep that's what I'm going to do