Panels and pennies

PCB panels are pretty nice, but not cheap especially for large, one-off projects. Such as for example the Kosmo sequencer I’m planning: The panel is 20 by 40 cm and I don’t even want to think about how much that would be in PCB.

There are various other options: People have used plywood, plexiglass, for that matter cardboard, but let’s talk about aluminum. Ray Wilson used to like 0.063″ (1/16″, about 1.6 mm) aluminum 6061 T6 sheet. Per LMNC, sheet alumin(i)um cut to a choice of metric sizes is available from many vendors on eBay.co.uk at low prices with free shipping — that sequencer panel would cost about £5. In the US? Never mind metric sizes, even in Imperial units you don’t have many similar vendors on ebay.com.

So you can get off eBay and look for websites for companies that do cut to order sheet aluminum online. The results are weird.

The first place I checked (one I’ve bought from in the past) wanted $18.55 plus shipping for five pieces of 0.063″ 6061 T6, 7.87″ by 3.94″ (10 cm by 20 cm). Another quoted $33.93 for the same. Two others wanted $80.60 and $81.60! All for the same thing as far as I could tell: same quantity, gauge, size, grade, finish. They all had much more similar prices for one piece, but the latter two didn’t discount for multiples.

And then at midweststeelsupply.com, their price for five 10 by 20 cm (or the Imperial equivalent) pieces was $12.55. Yes. You read that right.

(One detail: Generally these places quote a cut tolerance of either ±1/16″ or -0 +1/8″. If you’re hoping for a piece that’s exactly 7.875″, well, you can hope, but it might be 8″ instead. And some of them don’t let you ask for a size that isn’t rounded to the nearest 1/8″. So if you want 10 cm (3.9375″) you can order 3 7/8″ and hope it runs large, or 4″ and hope it doesn’t.)

Okay, so it’s crazy. Factors of nearly seven differences between different suppliers. Factors of two to four or more higher than in the UK. The latter may be attributable to tariffs. The former, I don’t know, it makes no sense unless it’s just that some places simply don’t want to bother with small pieces in quantity.

Then I found out Nolan’s Mill and Metal here in Syracuse does, contrary to the impression I’d had, do single small pieces. I emailed for a quote on 200 by 400 mm and was told $9.07 — no shipping, of course. I replied “Great, I’d like to place an order” and they said “There’ll also be an inbound UPS fee.” “How much is that?” I asked them. “$13”, they told me. “Thanks!” I said, and put in an order with Midwest Steel.

Which I was a little worried about. With prices that low, is there a catch? I figured placing an order was the only way to find out, and not a lot of money sunk if it turned out bad. I ordered one piece 3″ by 31.5″ (that’ll be for the new case, you’ll see), one piece 7.875″ by 15.75″ (the sequencer), and five pieces 3.875″ by 7.875″ (for modules to be named later). I ordered 3.875″ on the latter figuring I’d rather they were a little under 10 cm than a lot over. Total price including shipping, $47.32.

Ten days later the order arrived. (There are only four of the 10 by 20 cm pieces in the picture, for some reason, but I did get five.) Everything looks to be somewhere between the dimension I ordered and about 1/16″ or so over. One of the small pieces, for instance, I measured at 99 by 200 mm. That’ll do. You can see there are some very noticeable scratches — mostly you’re seeing the worst side, there’s less scratching on the other. I don’t know if this is any worse than one should expect or not, but by the time I choose the better side, maybe do some sanding, and paint or paper or whatever, I’m pretty confident I can live with it.

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