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Aluminum Extrusions
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Author:  etalcos [ Thu Jan 13, 2011 10:15 pm ]
Post subject:  Aluminum Extrusions
Has anybody had any experience with having small runs of Aluminum extrusions made? We're looking at re-producing some passenger car window and trim extrusions that are no longer commercially available. I understand that tooling has to be made and that's expensive, but we don't need 1/2 mile of the items we would be making.

Any thoughts?
Author:  Matt Bumgarner [ Thu Jan 13, 2011 11:22 pm ]
Post subject:  Re: Aluminum Extrusions
My company has extrusions done from time to time, including some recently.

Tooling with what you have in mind is fairly inexpensive, in the $2k-$3k range. Where you can get hung out to dry is the minimum runs, so you might end up with either a lot of extra material, or a very high piece/part price.

Matt Bumgarner
Author:  Termite7 [ Fri Jan 14, 2011 12:52 pm ]
Post subject:  Re: Aluminum Extrusions
You can always try making your parts out of cast plastic. If you have one from which to make a RTV rubber mold then you can make numerous copies from commercially available plastics.

T7
Author:  sbhunterca [ Fri Jan 14, 2011 1:48 pm ]
Post subject:  Re: Aluminum Extrusions
Quote:
Tooling with what you have in mind is fairly inexpensive, in the $2k-$3k range. Where you can get hung out to dry is the minimum runs, so you might end up with either a lot of extra material, or a very high piece/part price.


If you do opt for the higher unit price rather than high volume, be very careful that you give yourself a generous safety margin! Nothing could be worse than messing up a couple of pieces and ending up ten or twenty feet short!

Once you determine the profile you're using, you might want to post it here in case other groups need the same profile- the extra volume could make a big difference in the unit price.

The other thing to look for, via multiple vendors, is a similar profile available off the shelf, that could be easily machined into exactly what you need.

Steve Hunter
Cardinal, Ontario
Author:  robertmacdowell [ Fri Jan 14, 2011 10:33 pm ]
Post subject:  Re: Aluminum Extrusions
For small runs at WRM, we mill them down out of stock.

I find contracting parts, especially small parts, typically has a $2000 setup charge and then 50 cents per unit. If you need 40 parts, your cost is $2020. My feeling in a case like that is, make 500 parts. Pay barely 10% more, and sell the other parts to other museums for ten bucks each.

We could use a website to unite buyers and sellers, kinda like a "half.com" for railway preservation. eBay is not appropriate for that, as their fees are prohibitive for an item that will sell once every 5 years.
Author:  etalcos [ Sat Jan 15, 2011 12:39 am ]
Post subject:  Re: Aluminum Extrusions
Termite7 wrote:
You can always try making your parts out of cast plastic. If you have one from which to make a RTV rubber mold then you can make numerous copies from commercially available plastics.

T7


An interesting idea and one I've seen successfully used in the past, just not sure it would work here. One item is an aluminum window sill for an Adlake hinged window frame (think 1949 Southern Budd or Pennsy Budd) -- it's roughly 60" long and is under considerable strain holding the window into the carbody with four or five 5/16" bolts. The other item is a piece of interior finish trim from a modernized heavyweight coach. Ordinarily I would think this would be a good place for the cast plastic, but the lengths are as long as 12'. I'm not sure the plastic could be effectively produced in this length?

I have considered the CNC route for the window sill since the quantity we need is not that great, but the 60" length concerns me as far as finding a local shop to do the work. We need more of the trim, so it might be a better candidate for extrusion.

We are also having the gasket material made for the hinged window system as well. Once it goes to production we'll offer the material in the classifieds section if anybody is interested.
Author:  David H. Hamley [ Mon Jan 17, 2011 12:39 pm ]
Post subject:  Re: Aluminum Extrusions
In the early 2000s Pennsylvania Trolley Museum had produced the extruded aluminum "rub rails" for our 1938 St. Louis Car Co PCC Pittsburgh Railways 1138. The experience was quite satisfactory and reasonably economical. The result certainly looked better than the wooden version temporarily used on this car prior to its body rehab job by the ADtranz Elmira, NY plant. We still have control of the die and may be able to have this component produced for other museum restoration jobs. Contact the museum at www.patrolley.org for follow-up.
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