See-thru cases

[The Monkey]

I've seen a bunch of great examples of amps cased up in Hammonds with a see-thru top panel. How do you guys do this? What material and tools are used? Is it difficult?

Thanks!

[kin0kin]

Acrylic sheet, aka plexi glass. It's easier than cutting steel you can get them from homedepot or look in yellowpages for plastic.

[jerb]

post above me covers most of it but a few things should be mentioned:

it cracks easily so if possible have the place your buying from cut it to the exact size you need.

Dont take off the tape/paper covering it until your completely done

if you drill any hole in it make sure you do it on the lowest speed setting on your drill or you'll melt it

for more information browse computer modding forums such as bit-tech.net or [H]arf Forum

[Juergen]

I went to Home Depot & Lowe's and couldn't find any plexi thin enough to slide in the rails of the Hammond. I did find a cheap 5x7 picture frame with a glass cover that was the right thickness. Unfortunately I had to cut off about a 1/2 inch. I was lucky to get it cut without cracking it. I'm not a fan of cutting glass. The advantage of glass is that it doesn't scratch as easy as plexi. Later I had to take it out temporarily for some tweaking and it dropped and broke I'm going topless for now

[The Monkey]

Thanks all. Plexi doesn't sound as easy as I'd hoped. Maybe I'll go with some saran wrap...

[jerb]

id advise against saran wrap.

plexi is very easy, it can be cut with a dremel, hand saw, aswell as almost any thing that can cut wood. You can even shape it with head.

It does scratch easily though

I think you should atleast try it, it will cost less than <$5 for all the plexi you need for your amp so why not? if the scratches worry you, then you can always switch to glass

personally I think you should atleast give it a shot...

[ericj]

Originally Posted by jerb

Dont take off the tape/paper covering it until your completely done

if you drill any hole in it make sure you do it on the lowest speed setting on your drill or you'll melt it

Some minor criticisms.

Not all acryllics are alike. Plexiglass(r) is Methylmethacrylate, also known as polymethyl-2-methylpropanoate, often sold under the "Lucite" and "Perspex" names, and is much harder, much more scratch resistant, and much easier to work with power tools than what Lowes and Home Depot sell as "Acryllic".

If it feels like you can just about dig a fingernail into it, it's not plexi/lucite/perspex. It's some other acryllic thermoplastic.

The soft stuff - and at the Home Depot here they sell the cheap acryllic right next to the Dow Lucite(tm) - if you use a speed that is too slow, it will not only melt but the surface around the cut will deform.

If you work it too long, which is more than a second or so, it has a tendency to become fluid and coat your tool, and boil on the surface of the cut, and burn slightly, and stink. It then leaves behind a crusty yellow surface that you have to grind off with something.

When i was enclosing my nixie clock with quarter inch cheap crappy acryllic, we found that we damaged the sheet a lot less when cutting it on the table saw at the highest speed than at a low speed, and just getting it across the blade as fast as we would if it were hardwood. Helps to have a very sharp blade with a lot of teeth.

My friend has a very cheap drill press that just doesn't go particularly fast, so we used it at it's usual speed, and had the best luck when we got in and out as quickly as possible.

When I've worked Plexiglass(r) or Lucite(tm) with power tools, I've never had any of these problems. I've cut a lot of genuine, expensive plexi on band saws using the same blade and speed as i would for wood with no burning or melting, and real plexi doesn't melt onto the drill bits quite as readily as the cheap stuff.


if you use a hole saw on any thermoplastic though, don't think you can do three or four holes before pulling out the slugs, you'll be sorely disappointed. Take the time to pull out each one after each hole. Since it becomes fluid on the cutting surface, when it cools it's larger in diameter than a slug of wood would be, and a PITA to remove.

For real bragging rights, chemically weld your plexi enclosures with acetone.

[ScubaSteve87]

For real bragging rights, chemically weld your plexi enclosures with acetone.

Nail polsih remover will work? Just throw some on the joint?

[jerb]

no, usually you combine pure acetone and plexi scraps together, stirring them periodically (days?)to produce a very thick glue that will weld the joints together

[Nisbeth]

What I've been using on my amps is a 1.5mm sheet of some sort of PU (polyurethane) bought from a model-building shop. It's soft enough to be cut with a pair of scissors (although that's only conditionally recommended) and slides right into the grooves on the hammond and similar cases. A unibit makes perfect holes in it and I'd recommend this over acrylic or PC any day


/U.

[Dougigs]

Thanks Nisbeth -- I'd been wondering about this too, and what I needed to know was the thickness. I'll order 1.5mm. I'd been curious because the slots for top plates on Hammond cases are not exactly straight -- they're stepped at the edges. I suppose 1.5mm Perspex will flex a bit.

One piece of advice from my experience: To drill holes in Perspex or acrylic, use a stepper bit. As mentioned above, run it on low speed. Stepper bits are great for plastic -- they actually polish and bevel the edges of the hole for a very nice appearance (much like they do with aluminum, but even better). The $50/25 pound cost of a stepper bit is one of the better investments a DIRer can make. (They're worth buying on EBay -- as are Perpsex sheets).

I have built several power amplifiers in Perspex enclosures -- I use 5mm thickness if I'm actually building a chassis out of Perspex; I usually get a fabrication shop to put it together and polish it for me. This is quite affordable: Most large cities have several plastic fabrication shops that will make one-off units for you for under $140/70 pounds. They're used to such projects, since museums and art galleries and stores are constantly getting them

[kin0kin]

like ericj said, Lucite has much higher scratch resistance and it's often more solid as well, more importantly...it's crystal clear compared to some cheaper acrylc. You do not need to worry about cutting it yourself, they will usually cut it for you FOC when you buy it

[The Monkey]

Originally Posted by kin0kin

like ericj said, Lucite has much higher scratch resistance and it's often more solid as well, more importantly...it's crystal clear compared to some cheaper acrylc. You do not need to worry about cutting it yourself, they will usually cut it for you FOC when you buy it

That sounds good. Is Lucite easily workable enough to be a front panel?

[kin0kin]

They looks sweet as front panel, especially a black acrylic, you'd wanna use 1/4" for front panel. You can search for Garbz's dynalo, it's a clear acrylic with the rear painted black...IIRC.

Good arcylic feels like Sapphire Crystal, fine scratches can be fixed easily with some 2kgrit sand paper and polishing compound. Imho, they are the easiest to work with, much more than wood.

[MASantos]

Originally Posted by Nisbeth

What I've been using on my amps is a 1.5mm sheet of some sort of PU (polyurethane) bought from a model-building shop. It's soft enough to be cut with a pair of scissors (although that's only conditionally recommended) and slides right into the grooves on the hammond and similar cases. A unibit makes perfect holes in it and I'd recommend this over acrylic or PC any day


/U.

If you got it at a model building shop, it is probably lexan. Lexan is a type of polyurethane which is used in RC cars bodies and as armor in robots.(Batle bots).