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A project log for MultiBot CNC v2

A low cost 3D printed CNC that can be built with minimal tools yet is capable of great things.

david-tuckerDavid Tucker 05/30/2022 at 06:410 Comments

So I have been making lots of Pocket Hugs for my wife.  She now has lots of happy students with a little reminder that there teacher believes in them.  Because of this I'm running out of material and so it is time to look for a new source of wood.

So far I have just picked up a sample pack of Baltic birch from Woodcraft, however I only really need the 1/8" material, and that works out to around $8 a sheet if I keep getting the sample packs.  So it is time to try and find a better supplier.

Locally I have a Woodcraft store, a shop called WoodWorkers Source, Home Depot, and a Michaels craft store. In addition I can order wood from Amazon, a place called MakerStock, and of course Glowforge sells there own material.

My machine has a comfortable working volume of around 13"x17" if I want to keep everything on the laser bed.  I can find wood that is 12"x12", 12"x20", 12"x30", and larger sizes.  I can take a 12"x30" sheet and cut it in two with my circular saw to end up with 12"x15" sheets.

I worked up a spreadsheet with price and size information from every seller I could find (within reason) and worked out a price per cubic foot to better help compare the different sizes together as well.  Finally I added a column that compares the percent increase in cost from the cheapest source. 

https://docs.google.com/spreadsheets/d/1EW7SMuf_VrciPz5VesTx-LwNsKQrLVT78oHxsT5N9dA/edit?usp=sharing

It should come as no surprise but the Glowforge material is by far the most expensive, coming in at around $13 a square foot, when bought in quantity.  Shipping plays a big part in this, it is much cheaper to buy local (or from Amazon) than trying to ship these heavy materials around.  Michaels may have better material available in store, but all I could find online was Glowforge material.  This is still cheaper than ordering it from Glowforge directly because you skip out on the shipping.

The cheapest source by far is buying a full sheet at WoodWorkers Source and having them cut it down to 12"x30".  From there I would need to cut each in half, but it comes out to around $1.80 (plus tax) a square foot.  Amazon has some suspect plywood from China that they claim is Baltic birch for $1.90 a square foot, but the reviewers who have tried cutting it with a laser don't seem impressed.

A 12"x12" piece from woodcraft is not a great deal at $5 a piece, but buying a 12"x30" piece and cutting it in half is a much better deal.  The best idea is the full sheet from WoodWorkers Source, but sadly they are out of stock.  I will probably pick up some pieces from woodcraft as a place holder and give wood workers source a try later when things are back in stock.

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