obligatory obscure reference

self-deprecating yet still self-promotional witty comment


Laser Cutting and Fume Extraction

Filed under: digifab,Lasersaurs and laser cutters — jet @ 12:43


This is not legal advice or opinion on the rules and regulations for installing or using a laser cutter. These are notes on what I’ve learned and a guide for people interested in having a laser cutter.

What’s all this, then?

I’ve been working with, near, or in toxic fumes since I was a teenager. I’ve wrenched, welded, soldered, used metal working machines, worked on motorcycles and cars, and built CNC equipment, including several 3d printers and a couple of Lasersaurs. I’ve taken and taught safety classes and I’ve still made some stupid mistakes.

It’s easy and inexpensive to get home/shop level digifab equipment like laser cutters but not much out there on what it means to own and operate one.

I wrote this short introduction to laser cutters and fume extraction based on what I’ve learned in work spaces and my studio. I hope that sharing what I’ve learned helps other people interested in setting up a laser cutter.

Fume Extraction

Let’s start by defining what “fume extraction” actually is — removing fumes and particles suspended infumes from an area. Many processes we use create annoying, hazardous, or lethal fumes and fume extraction gets them out of the work area.

Some examples of fume extraction:

  • remove lead and solder fumes from the air around a soldering station
  • remove air containing viral contaminants from a safety area where someone is doing medical research
  • filter or remove greasy smoke out of a kitchen in a home or restaurant
  • remove toxic side-products of welding from a welding station in a closed room

For laser cutters, there are two specific reasons to do fume extraction:

  • remove vaporized particles and fumes from a laser cutter work space to protect the people using the laser cutter
  • clear the air inside the laser cutter to prevent fumes from damaging the media or the laser cutter equipment

Who needs fume extraction?

Anyone generating fumes that are bad for people to breathe, harmful to the environment, or that can damage the tools they are using. That’s a sweeping statement, but there’s a wide scale of materials that can be used as media in a laser cutter. On one end are people who have a business making models but of plywood or cardboard and never cut plastic or etch powder coating off of metal. On the other end is a hacker space, college studio, or Techshop where there’s a “DANGER: do not cut” list and temporarily illiterate laser cutter operators.

Fume extraction isn’t fume filtration!

Note that we’re saying “extraction” not “removal” or “filtration”. Fume extraction means moving the fumes from one area (inside a laser cutter) another area (outside the laser cutter). If you’re laser cutting something that generates toxic fumes and you have wonderful extraction, you’re just moving te toxic fumes to another location. Extracted fumes don’t disappear and an important part of fume extraction is deciding what to do with the fumes. (Saturday Night Live’s “Yardapult” is a funny but real example of what some sites consider fume extraction.)

Laser cutter restrictions

Did your laser cutter come with a manual that explains restrictions on what media you can cut and fume ventilation requirements? Start by reading the manuals and FAQs, there might be limitations on what you can cut or etch because of the materials used to build your laser cutter. One example is what your mirrors are made of — are they backed glass or polished metal? Some mirrors need routine cleaning if you’re cutting smoky materials, even if you have the best fume extraction possible.

What can the fumes damage?

Everything, starting with the person using the equipment and nearby people, then to the equipment (see below), or people near where the fumes are sent as exhaust. If you’re only cutting paper and cardboard and sending the exhaust up a legal fireplace chimney, there’s not much more risk from the fumes than having a fire in the fireplace. If you’re cutting and etching acrylic in volume and dumping the unfiltered exhaust out your garage window, don’t be surprised if the neighbors dial 911 to complain about the smell of burning plastic.

You could also be working with something you think is safe but isn’t. I no longer cut hardboard in my lasersaur because the heat from cutting the wood also does something to the glue and makes the wood sticky. Not sticky in a good, ice cream sort of way, but a sticky burnt glue that sticks to the moving parts and is hard to remove, even with solvent.

Did you read the Material Safety Data Sheet (aka “MSDS”) for the media you’re cutting and does it cover burning the material or fumes? What happens if you laser cut kevlar or styrene? (That’s your cue to go find the MSDS documents for these materials.) Depending on where the laser cutter is installed, there might be requirements from the FDA, EPA, OSHA, local business codes, labor codes, safety codes, etc. (Reminder: I’m in the US and not a lawyer, so I’m mostly going to make vague references to US legal systems and ignore the rest of the world.)

How bad are the fumes, really?

I took apart a laser cutter for parts and took photos of the wear and tear caused by fumes. It was used in a machine shop with good fume extraction and there was still a fair amount of damage to the internal parts. I don’t know what they cut but the amount of rust and corrosion suggests that it was releasing fumes you shouldn’t breathe.

What do you do with these fumes?

So you’re pulling the fumes out of your laser cutter, what do you do with them other than just vent them out a nearby window?

It still depends on the answer to: “What are you cutting?” Did you read the MSDS? Does it even have a MSDS? Note that a MSDS isn’t going to list “cutting by laser” it’s going to use more generic terms like “burning,” “melting,” “smoke,” or “vapors”.

If you’re only cutting something relatively safe, say paper or balsa, you’re creating “wood smoke” which is an easy problem to solve.

Do you know what the media you’re cutting is made of so you can find the MSDS? Before you etch a stack of Moleskin brand sketchbooks, do you know what they’re made of? PVC. Ok, so what happens when you etch and cut PVC? It releases hot chlorine gas that quickly converts to hot hydrochloric acid, and that acid is not good for a laser cutter’s internal parts or the people running the machine.

What if there’s no MSDS? This is where you get to do some science so you can figure out what fumes you’re generating. Cutting thin plywood generates mostly wood smoke, cutting MDF or hardboard means you’re also cutting a lot of glues or maybe paint. If you’re laser etching old paint, is there lead in that paint and the fumes that comes off the etch?

Plan on filtering your fumes

For recreational or hobby use it’s pretty easy to filter fumes and the cost is relatively low to that of a laser cutter. There are a variety of plans online and you can find one that fits your needs I suspect that using a laser cutter a few hours a week generates less air pollution than a gas lawnmower, but neighbors won’t complain about lawn mowers the way they will about the smell of burning plastic.

If you’re working in a manufacturing or art space, filtration could be cheap or free. If there’s already extraction for welding fumes or metalworking machines, you might be
able to use theirs depending on the fumes you generate.

If I were running a professional job shop or a hacker space a commercial filtration system that could handle the nasty fumes from some plastics and resins would be worth the investment. This also goes back to the issue of local regulations, you might have to have some sort of professional certificate or verification that your filtering system works.

Legal restrictions

If you’re renting or don’t legally own and control your space, you’re going to have to go by the owner’s rules. If you’re at a university you’ll probably need to talk to facilities, if you’re in an apartment complex that’s the landlord, or “ask your parents”.

In the US we have federal, state, county, city, local zoning, and various safety restrictions related to wildlife and waste discharge. It could be as simple as “filter your fumes and don’t annoy the neighbors” — I know a few people who have run laser cutters in their garage and never gotten a complaint.

If it’s a hacker space or business getting a laser cuttere there are additional regs to follow. There might be fire code regulations, safety requirements, or additional rules to comply with along with ventilation rules. I’ve seen local regulations where a permit (which costs money) and inspection (more money) are required for an exhaust vent larger than 4 inches in diameter. The regs can be as simple as “exhaust vent” or as specific as “industrial exhaust vent for fabrication equipment”. When I was looking to rent studio
space within Pittsburgh city limits, if I asked about “exhaust ventilation” the landlord just said “no”. No question of what I wanted to vent, they simply didn’t want to deal with exhaust issues.

Question time!

Please leave questions (and answers) in the comments, if there’s enough interest we can turn this in to a FAQ or wiki.


Upgrading HP DAT72 drivers on OS X with hp_ltt

Filed under: OS X and Linux — jet @ 11:01

Under OS X 10.9 I was unable to get hp_ltt to find the newest firmware for my tape drive in interactive mode. For some reason it couldn’t verify the signature on the file or map it to the installed drive.

Here’s my workaround using the CLI version of hp_ltt:

First, run:
./hp_ltt -f scan

This will create the file ~/Library/Application Support/Hewlett-Packard/LTT/saved_scan.txt

This file contains two lines, the second has the device path at the start and the current driver version at the end

path HBA_5383_65524
version B312

Then force a firmware load:

./hp_ltt -f firmware -p=HBA_5383_65524 file=/path/to/your/firmware/LTT_HP_DAT72X6_B604.frm

This has no feedback, all it does is blank the screen until the process finishes and the drive is rebooted for self testing.

Using scan again we can see that the driver was updated to B604:



100 years ago today

Filed under: Random and Pleasing — jet @ 10:14

I’ve been reading history trying to find more on a composer (Joseph Joachim) and got distracted by what was happening 100 years ago.

By the end of June, 1915, the Germans had started using chemical weapons (chlorine gas) in WWI trench warfare and the Turks had started what became the genocide of more than a million Armenians. By the end of the year, Cornell professor Muenter set off a bomb in the Senate and shot JP Morgan, the KKK was recognized by the state of Georgia, “In Flanders Fields” was published, the British killed thousands of their own soldiers when weather blew chemical weapons back in to their own trenches, and Germany said they’ll try to stop sinking so many civilian ships with their u-boats.

My biggest problem in 2015: planning my weekend around the endless rain and thunderstorms. I need to weld for a client which means opening the windows for fresh air but I can’t do that in the rain, attend a beekeeping pest management class if it’s not cancelled due to rain, and sort out 2nd position alto scales before giving “Hebrew Melody” another try.

No chemical weapons, no endless trench warfare, no genocides, no countries attacking mass transit systems interfering with my life.


Busy as a, well, bee

Filed under: Beekeeping — jet @ 21:08

Good contract gig, finally finishing my latest lasersaur, and because I have so much free time…. BEES!

Photos for now, but words and updates of my hive tracking spreadsheet coming soon.

photos are on Flickr

and videos on vimeo.

Testing a link to Repasky’s book on swarming.


Look, I was almost famous, once

Filed under: Hacking,Random and Pleasing — jet @ 21:00

My security/game review from 1990 is somewhat oddly quoted in boing boing.

But one can find my original in RISKS and the obligatory chatter.


Short stories limited to four lines, 80 columns, and SVR0 commands

Filed under: Random and Pleasing — jet @ 20:37

A million years ago, when 4-line sigs were the rule in the 80-column world, I decided to write short stories using only SVR0 commands.

Most of them are on 3B1 floppies I need to read and transfer to the 21st century via serial line, but here’s one I found on a USENET archive:

Grep sed “awk! man cut grep, edit banner false! get help!” Man disable
grep, split banner, join prof admin. Grep mount eqn, find path. Grep
echo spell. False cat kill admin, man. Grep find banner, make true


_Metrophage_ by Richard Kadrey, a review, no spoilers, ~long.

Filed under: Reviews — jet @ 21:38

[Historical note: I posted this to USENET in 1988. I was 21, working my way through college, and more-than-happy that I had access to USENET, something like a world-wide BBS. If there was something like Facebook or Twitter in 1988, it would have been USENET. My USENET feed (we downloaded USENET posts over modem before reading them) came from a nearby consulting firm who was hooked up to the backbone of what was then the Internet. I could post something to USENET in Houston and within 24-48 hours people in California or New York would be able to read the post. I was still getting my journalism degree and posting stuff like this to USENET sans editor, so there might be > 1 typos. And yes, I’m posting this with full USENET headers just because I want to show off that I ran a USENET host from an AT&T 3b1 in my home in 1988. :-]

— cut here —
Xref: utzoo alt.cyberpunk:257 rec.arts.sf-lovers:10844
Path: utzoo!mnetor!uunet!nuchat!flatline!erict
From: erict@flatline.UUCP (eric townsend)
Newsgroups: alt.cyberpunk,rec.arts.sf-lovers
Subject: _Metrophage_ by Richard Kadrey, a review, no spoilers, ~long.
Message-ID: <359@flatline.UUCP>
Date: 3 Feb 88 05:29:49 GMT
Organization: flatline in Houston(Montrose, really), Tx.
Lines: 97
Keywords: metrophage, kadrey, review, cyberpunk

Okedoke, I knocked _Metrophage_ off in a day and a half between classes,
so this should be pretty compleat as it’s fresh on my mind.

First off, some comments about Richard Kadrey. I heard/saw him speak
and read at Armadillocon 87 in Austin, Tx. At the time, I was very
impressed. Kadrey’s a former resident of Houston, now living somewhere in
Ca. He looks and acts like people I hang out with: surfer/neo-punk haircut,
earrings, hardcore/thrash/punk/tough clothes, but reads William S. Burroughs
and radiates an intense intrest in tech/pol/philo/everything.

So anyway, I listen to him on a panel that headlined the likes of Bruce
Sterling and Lew (“The Whiner”) Shiner.
“So he gets on neat panels at cons,” I thought, “but who the hell is
this guy that looks like he should be skating with me in downtown Houston
about 3 am?”
Well, I gave in and went to his reading. Wow. The feeling I got was a
combination of those I had when I first read _Naked_Lunch_ and
_Neuromancer_. “This guy’s tough,” I remember thinking, “then again, these
are just some short descriptive stories that rag on pols…”
After he finished reading, he or Shiner The Whiner mentioned Kadrey’s
forthcoming book, _Metrophage_.

Fast forward to the other day when I found a copy of _Metrophage_ in
the bookstore. I sped-read to finish _Infernal_Devices_ so I could
start _Metro_.

Wow. Edited by Terry Carr. Intro by Rudy Rucker. He still
keeps good company. He also includes thanks to Brian Eno, Robert Fripp,
Throbbing Gristle and Tangerine Dream “who supplied the soundtrack.”
Then an opening quote from a song by Tom Waits. Ok, so he knows a lot
of esoteric buzz-word bandnames..
(There’s a good bio of Kadrey by Rucker that goes into Kadre’s artistic
background, including his interests in surrealism and dadism.)

Ok, Ok, I’ll get on with the book review…

_Metrophage_, even though it borrows from the soon-to-be-overused
theme of central-character-is-a-smuggler-‘1 percenter’-run-afoul-of
huge-organizations, is surprisingly fresh and interesting. Kadrey
writes with a style that reflects a knowledge of street life, drugs,
W.S. Burroughs-genre-literature and a keen sense of political/social

There are some great lines and allusions in this book — from little
things to show off his intellegence/esoteric-ness (a band named
‘Taking Tiger Mountain’) to some good anarchist theory.

Our ‘hero’ is “…Johnny Qabbala, drug dealer, ex-Committee for Public
Health bounty hunter, and self confessed loser…”. How can you not
like him? Johnny’s well thought out and quite believable even though he’s
from an almost overused stereotype. He has faults, skills, and that
real sense of no-direction that I think everybody must experience at
times. His only desire seems to be to live again with his two
girlfrieds Sumimasen and Ice and to not do very much other than exist.
Well, we all know what happens to down-on-their luck drug dealers in
the near-cyberpunk-future who just want to be left alone, right?

Now the hard part. How do I review the book w/o giving away anything?

_Metrophage_ is about power and politics seen from the view of someone
that has a great dislike for anything remotely resembling any sort
of political goings on. Johnny seems almost uncapable of understanding
politics on any other level than ‘it sucks’. Ice, on the other hand, is
getting involved in nation-(world?)-wide revolution, while Sumi just exists…
It’s a book about politics, love, people and being insignifigant.

It’s also a showcase for Kadrey’s ability to write. From hearing
him speak and reading _Metrophage_ I get the feeling that Kadrey understands
surrealism on a level far above that of mere mortals. He can write
what others can only hope to see put on canvas by their own shaky,
skillless hands. I have the feeling that Kadrey could write about
high school basketball and make it almost this interesting.

Buy and read this book. In my opinion, it’s easily in the top
%2 of experimental science fiction, enjoying the company
of Gibson and Jeter. This is fiction that someone *not* into
science fiction could still enjoy — a quality that very little
science fiction has, or ever will have.

I have this eery feeling that somewhere out there, Richard Kadrey will
soon read this and either laugh at me or send me some sort of instant-death

(In case Kadrey’s out there… Remember Austin, Tx? The black-leather
jacketed skater sitting in the front row at your reading and your panel
upset because you picked on Houston? My friends and I heckled
Sterling and Shiner whenever they stopped talking long enough to make it
possible… I didn’t think you would remember… harf.)

“Occult symbols include … the ‘peace’ symbol and the Jewish ‘Star of David'”
— From the Back In Control Handbook
“$20,000 a year is a small price to not have to talk to our kids”
— Jello Biafra, commenting on the “Back in Control” program
Girls play with toys. Real women skate. — Powell Peralta ad
J. Eric Townsend ->uunet!nuchat!flatline!erict smail:511Parker#2,Hstn,Tx,77007


Facebook, contests, and privacy, oh my!

Filed under: Random and Pleasing — jet @ 22:25

Moogfest is a conference/concert where analog synth loving people like me can go to talks, build synths, and attend concerts by new, obscure, and legendary musicians who use Moog products. It’s a long, drawn-out conference worth a sentence too long by half!

Today I got email from moogfest about a contest for an iPad modified by TOKiMONSTA. Sure, a contest for a free iPad customized by an artist, who wouldn’t buy one of those tickets? (Honestly, I’d rather win a few hours in the studio with her teaching me her magic analog skills.)

So I go to enter the contest and learn I have to use a Facebook account to enter the contest. Ok, uh, sure? Wait. Who is this user “Recess” running the contest? Before entering the company I get an accept/decline that informs me:

Recess will receive the following info: your public profile, friend list, email address, News Feed, relationships, relationship interests, birthday, chat status, notes, work history, status updates, checkins, education history, events, groups, hometown, interests, current city, photos, religious and political views, videos, website, personal description and likes and your friends’ relationships, relationship interests, birthdays, chat statuses, notes, work histories, status updates, checkins, education histories, events, groups, hometowns, interests, current cities, photos, religious and political views, videos, websites, personal descriptions and likes.

Yeah, so, uh, NO. Imagine someone asking you to buy a raffle ticket for a $500 prize, but only selling you the ticket after you give them all that information.


Vacation project: put the little drill press on a big stand.

Filed under: Metalworking — jet @ 11:48

Well, “little” in that it weighs 500 pounds and not 1200 pounds like my CNC rig. A little sketching, some layout in Rhino5, then some welding. It’s not finished — it needs side panels and painting — but I’ll deal with that in the Spring after the snow has thawed.

The scale doesn’t show in the photo, but the base is about 32″ off the floor and the top of the drill press is over 6′ high. I’ll be bolting this frame to the floor before any serious use, I’m enough of a safety nerd to not want a 500 drill press toppling over in my shop.

Grizzly drill press stand


Disabling Finger / Touch Input on Windows 8, Lenovo X220 Tablet

Filed under: Random and Pleasing — jet @ 19:17

After upgrading to Windows 8 I discovered I could no longer disable touch input and keep pen/stylus input. The control panel option in many early versions of Windows 8 is missing in the release version, so there’s no obvious way to disable hand/touch input but keep the stylus input.

If you use the screen for drawing with a stylus, having your hand “help” you is not a feature, it’s a “I’m ready to sell this junk” annoyance.

Every guide I’ve found online contained instructions that didn’t work or instructions that would also remove the trackpad input.

A little hammering with brute force and I think I have a solution. I’m not sure how portable it is to systems other than Lenovo X220 Tablets running Windows 8, but it can’t hurt to try it and find out.

  1. Go into Settings, Control Panel, Device Manager
  2. In Device Manager, open the Human Interface Devices folder
  3. Look for “USB Input Device”. There are only two on my laptop, at the end of the list.
  4. Using the stylus, open one USB Input Device
  5. Open the Driver tab
  6. Click the “Disable” button, and answer the “are you sure?” questions
  7. Test touch the screen with your finger to see if you can move the device window. If you can’t move the window with your finger, next try with the stylus and then with the keyboard controls.
  8. If you disabled the correct one, close all the menus and move on. If you didn’t disable finger touch, re-enable the device, close the window, and try this with the other USB Input Device.
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