Stevie’s 12” FRFR Cab Build Thread (Basschat Cab v3)

[LukeFRC]

48 minutes ago, funkle said:

I have been called away to my in-laws. Further construction may be light today. Next significant updates may be Tuesday. 

No rush

[funkle]

Seeing how my port is dried nicely after three coats of black primer, I fitted it and glued it in. Also got the front panel fitted and clamped it up to dry overnight.

That’s it till Tuesday chaps. Have a good one!

***SEE NEXT POST! DO NOT LET THE BAFFLE/CAB DRY IN THIS POSITION; LIE THE CAB BACK ON THE REAR PANEL***

Edited August 27, 2019 by funkle

[funkle]

Ok. A fair bit has happened since I last posted. I have made a mistake, in fact two mistakes, and it will be useful to pass on the lessons from these, so others don’t make the same ones. 

You’ll see in the last post I laid the cab flat on the baffle whilst I was glueing the baffle up. In retrospect, that was a mistake. Here’s why:

When I flipped the cab back over and tried to fit the right hand panel, everything lines up fine at the back, but the baffle at the front around the woofer (and where the braces are) is actually curving inwards a little bit.

I suspect the soft plywood of the baffle warped a little with the pressure of the rest of the cab pressing on it. (I didn’t receive it warped; the dry fit of the cab was absolutely fine when it came.) So that was mistake one; letting the cab dry this way and in this position.

Mistake two - I didn’t use the right side panel to keep the fit of the baffle when I glued the baffle in. If I had done that, and left the right side panel in ‘dry’ whilst glueing in the baffle, the baffle would have likely come out just right. 

So....

Let me introduce you to my new friend, which I hope you do not need to buy, and probably won’t if you avoid my mistakes.

The spreader clamp.

Can be used as an ordinary clamp, but has a bolt which allows it to be flipped around. £20 for a set of 4 from Screwfix. (https://www.screwfix.com/p/spreader-clamp-set-4pcs/2646v — I didn’t want 4, but was the cheapest set I could find, most online decent ones are around £10-15 for single one, and the other cheaper Screwfix options I could have chosen from weren’t in stock. So I got the  2 x 6” and 2 x 12” set.)

The one at the bottom is flipped around to be a spreader. Works great. 

So, with some wiggling and jiggling, I have very gently pushed the baffle out with the spreaders (being careful not to break it). Then I’ve dry fitted the right, top, and bottom panels to make sure everything fits. It does.

(The spreaders can be seen inside the woofer area and one sticking out the hole for the horn. The other clamps are just to make sure that everything goes flush when I put it all together.)

So that was interesting. I’ll leave it like this for a bit and focus on another part of the build, because I want to be fresh for glueing it further and check and recheck the fit a few more times before I put glue in. 

Edited August 27, 2019 by funkle

[funkle]

Another quick tip, very minor. 

You can see a lot more wood through the port hole than you think. I went back yesterday and spray painted a bit more to deal with this. 

Just FYI. 

[funkle]

Here’s an in-joke on Basschat if there ever was one...handles!

I drilled through the top panel through the existing holes, just trusting to the CNC cutter here. I posted early in the thread about my concerns about the pre-drilled holes. I used my little gadget for straight drilling, because I’m paranoid about making sure the holes are 90 degrees and T-nuts install properly. I think it’s just as well I did....read on.

Then the T-nuts go in. Hammered in with the soft faced hammer. 

Then a test fit using the M5 hex head screws that go into the T nuts. It all works out, but it is a little finicky going in. I started with the 4 screws that actually go through the bar part of the handle, and then did screws diametrically opposite to each other. Had to back out on one screw once and do the others instead, then returned to it last. I strongly suspect any holes not drilled straight would have been an issue. Nonetheless, the result looks good and feels solid:

I’ll take it apart again and reassemble after I’ve glued the top panel in and painted the cab etc. But this bit of work and planning is done. 

Edited August 27, 2019 by funkle

[RichardH]

Here's a quick tip for when cutting the pipe for the port. If you're using a normal panel saw (as per for timber etc), then use a blunt one. I was cutting some drain pipe recently, and my super sharp panel saw caused the pipe to shatter in one place. I then tried again with an older saw I keep for odds and ends, and it worked much better.

Edited August 27, 2019 by RichardH

[stevie]

I had the same problem when I tried to cut the tube with a chopsaw - it shattered when I'd nearly finished the cut. It was fine with my normal saw, which is probably blunt anyway..... Pete's tip about marking the cut all the way round is a good one. If you try to judge it by eye you'll end up with two parallel cuts at the end.

[stevie]

It's worth pointing out that I'll be changing the hole size in the next batch of cabinets to make fitting the handle much easier. While the bolts and T-nuts in Pete's cab are totally bombproof, they're overkill.

So the holes will be sized to take 5.0 X 30mm woodscrews, which are listed in the Parts List.

[stevie]

And remember....... you can never have too many clamps.😀

[funkle]

26 minutes ago, stevie said:

And remember....... you can never have too many clamps.😀

This is so true. I love clamps now. I’m borrowing more for the next stages. Seriously. Lol

[funkle]

@stevie informs me I glued the handle brace the wrong way around. I did wonder, but when I did the dry fit it seemed to work both ways, blocking neither the rebate in front of it nor the small brace on the front baffle that it fits under. So I stopped worrying about it and just did it any which way 😂

[stevie]

Yes, I see what happened now. You can fit it either way. The cutout was designed to allow the vertical brace on the baffle to mate with the top panel without the circular brace getting in the way. But I then decided to shorten the front panel brace so that it would fit under the handle reinforcement brace instead. So either way round is OK.

I suspect that's probably too much information for most folk.🙂

[VTypeV4]

Good work - fascinating thread! Keep it coming and if it sounds as good as it's starting to look, it'll be a winner.

[funkle]

Ok. Some updates before more bass practice and sleep. 

After half a day with the spreader clamps inside the cab, and the other clamps helping to give the desired shape overall, the right side panel now fits easily into the cab. The plywood here is apparently malleable; this reinforces the lessons learned earlier. 

After a few goes of fitting and refitting, I also noticed that the port shows quite a bit of the right hand panel when looking into it. So the right panel got sprayed as well, at the top.

After that was done, I glued in the right hand panel. Finally. 

You’ll notice I learned my second lesson from earlier - after clamping and wiping off some excess glue, I loosened off two of the clamps slightly and tapped in the top and bottom panels (dry) to make sure they fit in and that the correct shape is preserved whilst drying. Then I tightened the clamps up again. 

I only have four 24” F clamps and I wanted to put some more pressure on, so I piled some books on. It’s probably not necessary, or as good as another clamp, but it does do something.

Back of the cab looks good as well...(photo is a bit dark, but hopefully you can zoom for detail)

Back on track, I think. 

Tomorrow, I’ll try and get time to do the top and bottom. Then I can start rounding off edges, plan the feet, and paint it. 

Edited August 27, 2019 by funkle

[funkle]

Bottom on. Incredibly messy. I put a lots of glue on, and I think most of it squeezed out. Lol.

Top perhaps later or tomorrow. Borrowing a sander if I can for next steps. 

[funkle]

Had time for the top. 

The clamps (apart from one that has broken a little bit, visible at the front right) don’t quite fit on the cab with their plastic end protector pads on. So I had to take them off, which makes me a little nervous for applying pressure. I’ve tightened things a little gingerly. I’ll take them off in a few hours. 

Current total weight of the cab this afternoon before I added glue to the top: 16 lbs. That seems to bode well. 

[stevie]

If you find your clamps have left a depression in the wood, you can usually fix it by wetting the depression slightly. That will cause the wood to expand back into shape.

 

[funkle]

Ah, nice one. I’ve just taken the clamps off and there are very slight depressions. I’ll try the water trick. 

I need to see if there are any gaps which need filled after all the hi jinks. Probably not, but even a very small defect should be filled; paint doesn’t hide gaps.

I’ll start sanding when I can after that. I also need to start experimenting with Tuffcab and different rollers/ways of applying it. I need to practice on scrap first. Stevie has already given me some useful tips on using it. 

[Chienmortbb]

Damp cloth over the top and an iron works  as well. 

As for the clamping, ,you can over tighten and the glue does not need megatons of pressure. 

If you are short of clamps, put one in the centre with a sacrificial piece of wood stretching the length of the cab. This will apply pressure to both ends. 

Funkle, you can get a really good rounded edge just with a sander. I tried it first on the prototype and had the same results on the alpha builds that Stevie and I did. We both got really good results. 

Edited August 28, 2019 by Chienmortbb

[Chienmortbb]

10 minutes ago, funkle said:

Ah, nice one. I’ve just taken the clamps off and there are very slight depressions. I’ll try the water trick. 

I need to see if there are any gaps which need filled after all the hi jinks. Probably not, but even a very small defect should be filled; paint doesn’t hide gaps.

I’ll start sanding when I can after that. I also need to start experimenting with Tuffcab and different rollers/ways of applying it. I need to practice on scrap first. Stevie has already given me some useful tips on using it. 

PVA is not a great gap filler but works well if mixed with sawdust. However I suspect you will have few gaps. 

I also sealed the rounded corners with PVA as TuffCab adheres well to it. I fact I might well prime the whole cab with it when I build mine, although I might still cover it with some form of vinyl. 

 

[funkle]

Hmm. I'm regretting putting the top on before I did the felt.

For the build, I've mostly just been following the original thread, where the cab gets constructed first, then the fitting out afterwards. In the part where Stevie is starting to fit it out, he comments that 'It is much easier to do the felt with the top off'....a detail I had let slip by me by today. Ah well. I'll just have to go super slow with the felt when it happens. 

  

[LukeFRC]

2 hours ago, Chienmortbb said:

Funkle, you can get a really good rounded edge just with a sander. I tried it first on the prototype and had the same results on the alpha builds that Stevie and I did. We both got really good results. 

Would you recommend this over using a round-over bit on a router? 

[stevie]

You can also sand the corners by hand using some 40-grit sandpaper followed by something finer. An orbital sander is nice, of course, but it's not absolutely necessary.

Blue Aran say that Tuff Cab doesn't cover filler very well but that's not been my experience. I also found, unlike Chienmortbb, that it doesn't adhere well to PVA glue. So, experiment first.

This kit has been machined to quite tight tolerances. So there shouldn't be any gaps. I think it's OK if the joins show, as long as they're even.

Edited August 28, 2019 by stevie

[stevie]

10 hours ago, LukeFRC said:

Would you recommend this over using a round-over bit on a router? 

If you're a pro woodworker, use a router. However, I tried it with my router and made a complete mess of it. Honestly, it's really easy to round off the edges using sandpaper.

Edited August 29, 2019 by stevie
To fix a confusing post.

[stevie]

2 hours ago, Chienmortbb said:

As for the clamping, ,you can over tighten and the glue does not need megatons of pressure.

That's a very good point.