Boom box build (another one, but first for me)

[wogg]

Yup, it'll be tight, but it works! The divider on the right is gluing in now. I can't screw in the PR with that battery board there so I'll start on staining and poly finishing the polar before the other side divider glues in.

First I think I'll glue in the mount supports for the bottom and set in the 8-32 nuts. That way I can screw on the bottom (mostly) and sand it flush for finishing the MDF later.

[davidroberts]

Any reason to not just bolt both of them to the back wall off the enclosure?

[wogg]

Not really, the main downside would be punching all those wire harnesses through the dividers to get to the panels. There's actually more air in there than the picture shows, and with the lower power levels I'll be asking of that board and the class D efficiency I'm not worried about thermals.

[tomzarbo]

I've made more than a few of these radio thingys… and each time... I've found one, if not a few things that I would have done differently.

The way I look at it is: I wouldn't know what needed to be improved in Version 2.0 If there wasn't a Version 1.0. to show me.
No matter how carefully I engineer something, there are always unforeseen things that creep up.

It's all fun as long as we don't miswire something and burn our house down.

TomZ

[Millstonemike]

"Not really, the main downside would be punching all those wire harnesses through the dividers to get to the panels. There's actually more air in there than the picture shows, and with the lower power levels I'll be asking of that board and the class D efficiency I'm not worried about thermals."


I don't disagree. But develop Plan "B" now. Think of it this way ... in your configuration, at louder, sustained volume, the amp could be dissipating the heat equivalent of a 4 W night-lite bulb. Totally contained in that space, it might become a problem.

I'd shorten the harnesses. And I'd use the "linesman splice". They don't cut the individual wires at the same length. Rather, they cut each wire at a different spot. Then the joint/solder/shrink wrap of each individual wire's splice doesn't bunch up at the same place.

Box is looking good ...

[wogg]

Good input Mike. I've got a slot cut at the top back and will be doing a hole at the front bottom for a small air channel that should give a little convection flow.

The lineman splice on something like 30 22ga wires sounds like a lot of work. I've already looped and zip tied, I'll work on clearing the heat sink to make the air channel as effective as possible.

After some use I can update with the removable bottom. Hope I don't have to.

[Millstonemike]

... I've got a slot cut at the top back and will be doing a hole at the front bottom for a small air channel that should give a little convection flow.

The lineman splice on something like 30 22ga wires sounds like a lot of work. ...

... I can update with the removable bottom. Hope I don't have to.

Hear ya' on splicing the pre-made cables. Cable connectors is a DIYer bane - so many types requiring specific tools to make them. In the past, I've cut wires and removed pins to reattach the shorter wires on connectors. After thinking about it, that's the best way to go if you need to. Splices take up space too.

[wogg]

First application of Minwax Ebony. Front side is looking good, little issue on the back though. Looks like the bearing track from the router isn't letting the stain penetrate.

I'm putting a second application on this afternoon, I'll hand sand just that track line to see if I can rough up the wood and get some stain in there.

[Liberator of Magic Smoke]

Might have been something on that bearing. Silicone maybe. Lacquer thinner is pretty good for removing stuff like that, but you might end up sanding the back and re-staining. Looking good though. This is a really neat project and I'm looking forward to seeing the finished product.

[wogg]

Thanks! Actually I think it's some Tightbond rubbed in there from gluing that top panel on. Wiped it off with paper towel at the time, but I think that groove kept more than I thought.

The last project I used that stain on was sanded and re-stained about 5 times so I'm no stranger to that. ;)

[Millstonemike]

First application of Minwax Ebony. Front side is looking good, little issue on the back though. Looks like the bearing track from the router isn't letting the stain penetrate.

The bearing may have compressed/hardened the wood.

[tomzarbo]

I've had the bearing make an indentation several times with softwood or plywood. I haven't had it inhibit the absorption of stain, that I remember though.

I usually use a small trim router for trimming panels, and a 5/8 or 3/4" bit with more bearing surface area just to avoid the bearing denting the wood. Even when I'm trying to use a light touch, I still seem to push too hard. Using a trim router seems to help with my ham-fistedness.

TomZ

[wogg]

Fun with poly... I'm on my third coat now. This is after the first, little pain with brush work across all the holes. Also learned to do the critical side last to avoid unseen runs and what not.

I used 220 grit between the first and second, and 000 steel wool for the next round. I'm hoping it dries smooth, my wrist and hand are super tired from rotating the thing around and brushing in the light.

What do you think about using some rubbing compound for polishing up poly after dry? Thinking about it to refine the surface a bit more.

[wogg]

Peeping at it as it dries. Definitely going to do some light wet sanding with the block to flatten a couple spots then polish the whole thing.

[davidroberts]

That is why I always use lacquer. Never had the patience for poly.

If you do any sanding you might want to give it some time, poly takes a while to fully cure.

Build is looking good. Can't wait to hear your opinion on the results.

[tomzarbo]

After you get it as flat as you want surface wise, it might just be easiest to put one last very thin coat of rub-on poly to get your even sheen back. Minwax makes decent rub on in pints, dries fast too.
Looking great!

TomZ