Better price / source for plastic or aluminum bar stock?

Hi all -
I'm suffering sticker shock in getting some material for a project.
I need bar stock, either aluminum or plastic in 3/4" thickness by 3"
wide. Perusing the McMaster catalog I'm finding Delrin at about $20 per foot, Polyethylene at about $5 per foot, Polypropylene at about $4.50 a foot, PVC at about $11 per foot and 6061 aluminum at about $20 per foot.
Yikes!
I've prototyped the project on delrin - and it would work for what I have in mind, but is any of the cheaper materials equally good for machinability?
The 'poly' group (PVC, PE, etc) looks like a nice cheap option, but will it gum up when I mill deep, narrow slots through the material? (I'm taking 0.1" pecks in the delrin and getting OK finish)
Any better pricing on similar material, preferably closer to Portland, Oregon?
Thanks in advance,
Carla
Science is like sex: sometimes something useful comes out, but that's not why we're doing it. -- Richard Feynman
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Mcmaster, MSC, etc... are real handy, but real expensive. But it sounds like you need to visit the local recycle dump, you can literally find bars of unmarked aluminum all over the place for pennies. Especially if there's any aerospace companies in the area.
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On 5/25/2011 11:55 AM, Carla Fong wrote:

cncplastics.com
interstateplastics.com
boedeker.com
Just to name a few..
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On Wed, 25 May 2011 08:55:24 -0700, Carla Fong

=============see http://www.use-enco.com/CGI/INLMK32?PARTPG=INSRAR2 http://www.use-enco.com/CGI/INLMK32?PARTPG=INSRAR2
also http://www.speedymetals.com/pc-2306-8351-34-x-3-6061-t6511-aluminum-extruded.aspx
http://www.interstateplastics.com/Natural-Extruded-Acetal-Plate-Sheet-ACENE.php?sku ¬ENE&vid 1105251143-3p&thickness=0.750&dim2=1&dim3=3&qty=1&2=Price+it+%3E%A0%A0
-- Unka George (George McDuffee) .............................. The past is a foreign country; they do things differently there. L. P. Hartley (1895-1972), British author. The Go-Between, Prologue (1953).
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RCM only
On Wed, 25 May 2011 08:55:24 -0700, Carla Fong

Crazy, isn't it? Have you tried TAP Plastics there?

What kind of finish/tolerances are you looking for?

Try scrappers on eBay and the scrap metal yards around Portland. For PVC, try a local home center's siding/trim aisle or contractor's center.
I'm looking at extrusions right now and am aghast at the $8-11/ft prices, too. I'll probably weld up some square or rect steel tube instead, but it has skyrocketed, too.

I love it!
-- Education should provide the tools for a widening and deepening of life, for increased appreciation of all one sees or experiences. It should equip a person to live life well, to understand what is happening around him, for to live life well one must live life with awareness. -- Louis L'Amour
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On 05/25/2011 08:55 AM, Carla Fong wrote:

Check the Yellow Pages. There's still some brick & mortar stores in the PDX area. I know there are some in Tualatin/Tigard area, and the NW industrial area between where Monkey Wards used to be and the St. John's bridge has (had, a few years ago) a Metal Supermarket.
McMaster is for folks that need a little bit of this and a little bit of that, need it right now, and don't want to waste time looking. For which you pay a premium.
If surplus is OK you may also want to check out Clackamas Steel. They have a fairly big shed full of aluminum scrap and another full of brass. No plastic. I don't recall seeing any rectangular-section stuff there the last time I was in, but that's a while ago and things change.
--

Tim Wescott
Wescott Design Services
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On Wed, 25 May 2011 08:55:24 -0700, Carla Fong

If you can live with x-country shipping: http://www.yarde.com/cgi-bin/dropshop.pl?alloy `61-T6511+&form=FL&size1=++0.7500&size2=++3.0000 Yarde's prices on drops are generally close to what you'd pay for full bars in small quantity on an open account.
These folks inventory their plastic drops and prices are reasonable, but you have to call to see what's available. http://www.laminatedplastics.com/plastic-materials.html
--
Ned Simmons

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On 5/25/2011 10:55 AM, Carla Fong wrote:

You should look for local sources first. With any mail-order place, you are paying extra for cutting, and then paying even more for shipping.
Aldo if you like Delrin (acetal) then you'll end up paying for Delrin, because there's nothing else like it. No other plastic machines as well as it does. ...All the other stuff I've ever seen is not dimensionally accurate or straight, plus is slippery (hard to clamp), soft, gummy and/or stringy.
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PVC is pure shit....very very bad juju...suggest bid it WAY high...purposefully force your competitors to get stuck with the job instead.
Flat stock is typically laminated from several layers of thinner material and it tends to fracture and largish chunks will break away from the parent material seemingly at random.
Additionally, it is a death sentence to your machinery and to operators as well because it releases chlorine during machining which combines with moisture in air and in the mucous in your lungs and the result is copious amounts of hydrochloric acid and next thing you know you will be coughing and short of breath and your eyes will be all reddish and burning.
Also, if using soluble oil as coolant, the oil comes out of suspension and forms a film on your chips, acting very much like a tramp oil skimmer on steroids so you can figure on kissing your coolant mix goodbye...and the water in your coolant very quickly turns highly acidic due to the above mentioned chemical reaction which will ruin your ways and your way covers and will get into your spindle bearings and into any pinholes in your sheetmetal and will severely corrode everything that it touches.
Probably all of this is STILL not listed the MSDS but anyways, you've all been forewarned.....
--






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Carla Fong wrote:

McMaster Carr has never been shy about their prices - they're like the convenience store of industrial stuff. I once ordered a 12" x 24" piece of Lexan, and they had it in the warehouse. A couple of years ago, the shop got moved, and the boss called McMaster and bought a crane.
They have to pay for all that inventory and bookkeeping; you're much better off to find a real supplier. I don't know if they still have yellow pages, or where you are in the world, but if you're doing production, it will really pay off to shop around for local vendors for stuff like that.
Good Luck! Rich
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I buy all my bar stock at speedymetals.com.
i

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I find best prices for Al is Reliance Metals rsac.com and Plastics,I get Delrin regularly from Professional Plastics professioalplastics.com
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    [ ... ]

    Hmm ... what *kind* of milling? I would use horizontal milling cutters for thin slots, but if you only have a vertical spindle milling machine, you are probably stuck with skinny end mills. If so -- keep the speed down (a lot of these melt easily) and keep a continuous flow of compressed air to both carry away chips, and to cool the endmill and the workpiece.

         Close to Portland? No chance of *me* knowing of them.
    [ ... ]

    I *like* that!
    Good luck,         DoN.
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Carla Fong wrote:

Sorry if this has already been answered, Carla. Most of the replies seem to be cheaper sources (maybe?) and didn't actually answer your first question.
YES. Most of those plastics will try to gum up the works.
I can't swear to mill or lathe, but my planer suffered cruelly from swarf stuck to the rollers.
I had to (as Johny-5 said) DIS-ASSEMBLE....
--

Richard Lamb
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Your planer? You have a metalcutting planer in a hobby shop?
How big is it? How old is it?
--
Ed Huntress



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Ed Huntress wrote:

She is talking about "plastics" Ed.
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Richard Lamb
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So what kind of planer are you talking about? When you just say "planer" on a metalworking NG, I naturally assume that you mean a metal planer.
What are you talking about, a power hand planer for wood? Or what?
--
Ed Huntress



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Ed,
Keyword = "rollers"...
--




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PrecisionmachinisT wrote:

Love that, Carla!

(from PM)

Thanks PM. Ed knows that. He's smart.
He just likes to bust people's asses if they give him a ladder tall enough. Which was not my intent responding to Carla. Plastics will truly mess up anything the swarf can get into. That's all I wanted to say.
Ok, so, yes Ed. My current metal working capabilities are quite primitive. Chop saw, files and a mig welder. If I can't knock something out with that in a couple of days labor, it gets farmed out and I pay for it.
Having said that, I'll also say that that's now, not then. :)
I have built more than eight airplanes.
Seven little single seat baby buggies and one welded steel tube 200 mph two seater. "More than" because it gets hard to count after that. A set of Pitts Special wings (mostly wood, but I learned how to bend aluminum leading edge sheets with a vacuum cleaner. Neat Trick). Several pieces of Van Grusven RV series airplanes, 11 or 12 custom fiberglass cowlings, hand formed (hammer and stretcher) compound curved cover pieces in aluminum, windshield and window framing for a bunch of antiques, etc...
And several other jobs - not a whole airplane, but significant pieces. Welded steel, bend and riveted aluminum, molded fiberglass (and tooling!).
Kept me in beer and cigarette money.
But these days I'm just a simple sailor... I build boat stuff. And I deal in softer materials. Wood, fiberglass; the hardest stuff I play with is stainless steel or bronze - neither of which are very hard by metal standards. A saw and files work well.
It's ok. He was just being bitchy.
Ed, hey man, have some watermelon. It seems to be sweet this year...
--

Richard Lamb
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