From b3fb128addf870224ad4ae9431b673f26278fe6d Mon Sep 17 00:00:00 2001
From: Jake <jake.read@cba.mit.edu>
Date: Wed, 31 Oct 2018 17:31:09 -0400
Subject: [PATCH] add section head note

---
 README.md | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/README.md b/README.md
index b763b02..a65a214 100644
--- a/README.md
+++ b/README.md
@@ -106,10 +106,19 @@ This is a general BOM. For How to Make Almost Anything coordinators, CBA will co
 
 ## For Section Heads
 
+If you think you're interested in making some aluminum machines, find 0.25" stock someplace: we use [Admiral Metals](https://www.admiralmetals.com/products-services/aluminum/) most of the time, McMaster works in a pinch but prices are high. I tend to get 12" x 48" stock sheets. This is a great option if you have a waterjet (or have a friend with a waterjet, i.e. Neil) and don't mind the extra overhead of working with stiff materials: tapping things, cost, etc. But as Ben Jennet reminded me, HDPE has 'ah' GPa of Tensile Modulus (one) and 6061 is ~ 69 GPa, so, lots more stiffness. It would be cool to see labs walking away with useful machines this year. If you get aluminum, also get some HDPE - it's still useful for chassis bits. 
+
+Otherwise, McMaster will deliver 4x8' sheets of 3/8" stock HDPE (link below), one is probably enough as long as you don't want to make anything spectacularely large.
+
+Also, make sure you have the right tools. Most of these things should already reside in your shop, I'm keeping a list here just in case.
+
+Everything else I can give to you at the next staff meeting: probably in a big-ish box, but not monstrous. I hope that's OK.
+
 ### Material
 
 What | QTY | Link
 --- | --- | ---
+Aluminum 1/4" | ~ 4 - 5 12 x 48" Sheets | [Admiral](https://www.admiralmetals.com/products-services/aluminum/)
 HDPE 3/8" / 0.375" | 1-2 Sheets | [McMaster](https://www.mcmaster.com/8619k438)
 PLA for 3D Printing | < 1kg | [My Favorite](https://www.matterhackers.com/store/l/pro-series-natural-pla-filament-1.75mm/sk/MACKAE6L)
 
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