Looking for: Small Metal Casting Foundry In Los Angeles

Hello to all in this group,

A) I am looking for a small foundry in the Los Angeles area ( I am
based in Silverlake)able to do ultra accurate investment casting of
aluminium from wax
(this is a small pitch gear design).

B) Please give me a good source for me to obtain wax for me to cast
from a silicone mold. ( I have never molded wax before, so I am not
sure wether it needs degassing before casting, in which case I may
need to vacuum cast is this a factor in wax selection?) Perhaps you
could give me a good source of info on the subject of molding wax (for
casting or other objective)

C) Eventually, I may need to create a permanent pattern to cast
accurate aluminum gears I would appreciate sources of information on
this.


A1) It would be nice if the small foundry I find in Los Angeles can do
both processes referenced in "B" and "C".

Regards Steve

Scorsi wrote:
Hello to all in this group,

A) I am looking for a small foundry in the Los Angeles area ( I am
based in Silverlake)able to do ultra accurate investment casting of
aluminium from wax
(this is a small pitch gear design).

B) Please give me a good source for me to obtain wax for me to cast
from a silicone mold. ( I have never molded wax before, so I am not
sure wether it needs degassing before casting, in which case I may
need to vacuum cast is this a factor in wax selection?) Perhaps you
could give me a good source of info on the subject of molding wax (for
casting or other objective)

C) Eventually, I may need to create a permanent pattern to cast
accurate aluminum gears I would appreciate sources of information on
this.


A1) It would be nice if the small foundry I find in Los Angeles can do
both processes referenced in "B" and "C".

Regards Steve

If You like to get informed about small casting supplies look here at my
site:
http://www.schmuckfabrik.de/englisch-index.htm


--
Heinrich Butschal
casting technologies
http://butschal.de/werkstatt

Ultra accurate investment casting might work for you , however you dont
define the actual accuracy you want. Without that your not going to get
anywhere with casting.
From what you seem to want to achieve , youll need to go the pressure
die casting route. Try talking to that type of producer. , more of
those in the Auto trade than any where else. Your cheapest bet is China
.. Most of out small production Co's have moved their work to that
country.

"Scorsi" wrote in message
...
Hello to all in this group,

A) I am looking for a small foundry in the Los Angeles area ( I am
based in Silverlake)able to do ultra accurate investment casting of
aluminium from wax
(this is a small pitch gear design).

[What do you mean by "ultra accurate"? Casting, by its nature, is not going
to reproduce an object exactly the same size as an original part. There will
be shrinkage in the mold, shrinkage in the cast wax, and shrinkage in the
metal. If you've figured out all these shrinkage factors and enlarged your
wax gear appropriately, then it will come out the right size, but it's
difficult to do this to very tight tolerances. Most parts like this are cast
first and machined later - it sounds like you want to reverse the process.]

B) Please give me a good source for me to obtain wax for me to cast
from a silicone mold. ( I have never molded wax before, so I am not
sure wether it needs degassing before casting, in which case I may
need to vacuum cast is this a factor in wax selection?) Perhaps you
could give me a good source of info on the subject of molding wax (for
casting or other objective)

[I've never heard of wax being vacuum cast, but that doesn't mean it's
impossible, I suppose. Wax and other pattern-making supplies are available
from Kindt-Collins:
http://www.kindt-collins.com/index2.html There is some general information
on waxworking, moldmaking, and casting in the Alt Sculpture FAQs:
http://users.lmi.net/drewid/altsculpture_faqs.html ]

C) Eventually, I may need to create a permanent pattern to cast
accurate aluminum gears I would appreciate sources of information on
this.

[Permanent molds usually want draft to release from the mold, so I'm not
sure this will work with your gear pattern. You'd want to show it to the
die-casting house, if you decide to go this route, and ask them.]


A1) It would be nice if the small foundry I find in Los Angeles can do
both processes referenced in "B" and "C".

Regards Steve

[I think you'll want to figure out another way to make these, if you really
must. But are you sure they can't just be purchased somewhere? Try WmBerg
for a start: http://www.wmberg.com/prgears.html . Another thing I should
mention: aluminum is not a great material for gears, since it is soft and
wears easily. Of the various alloys of aluminum, the kind used for casting
is one of the softest. Are you sure you can't use steel or bronze? You can
get lengths of spur gear stock in these materials and turn your gears to the
correct width on a lathe, then bore or ream them to your desired shaft size.
This is a lot more accurate than casting, and also much cheaper and easier.]

Andrew Werby
www.unitedartworks.com

"ted.frater" wrote in message
. ..
Ultra accurate investment casting might work for you , however you dont
define the actual accuracy you want. Without that your not going to get
anywhere with casting.

Sorry, for my nebulous use of "ultra accurate". You are right about
shrinkage of course, howwever I am not too worried about shrinkage as
all critical parts will be cast using the same process. Any
constraints can be taken care of on my lathe. This does not mean that
I will not take account of shrinkage though.
My use of the accuracy phrase was meant to convey that I want nice
clean parts.
Its no point doing this if they will not mesh properly. There is a lot
of time invested in designing these.

From what you seem to want to achieve , youll need to go the pressure
die casting route. Try talking to that type of producer. , more of
those in the Auto trade than any where else. Your cheapest bet is China
. Most of out small production Co's have moved their work to that
country.

I was at a Westec convention talking to some Chinese companies that
did this. The process is just priced out of my league right now. But,
if I had the budget, I would much prefer to do it this way. I may
enquire further.

Steve

"Andrew Werby" wrote in message
. ..
"Scorsi" wrote in message
...
Hello to all in this group,

A) I am looking for a small foundry in the Los Angeles area ( I am
based in Silverlake)able to do ultra accurate investment casting of
aluminium from wax
(this is a small pitch gear design).

[What do you mean by "ultra accurate"? Casting, by its nature, is not going
to reproduce an object exactly the same size as an original part. There will
be shrinkage in the mold, shrinkage in the cast wax, and shrinkage in the
metal. If you've figured out all these shrinkage factors and enlarged your
wax gear appropriately, then it will come out the right size, but it's
difficult to do this to very tight tolerances. Most parts like this are cast
first and machined later - it sounds like you want to reverse the process.]

Please see my reply to Ted's previous post. I was very unclear I
admit-I simply wanted to imply to any small Los Angeles foundrys that
I wanted nice clean parts, ie not a sloppy job.


B) Please give me a good source for me to obtain wax for me to cast
from a silicone mold. ( I have never molded wax before, so I am not
sure wether it needs degassing before casting, in which case I may
need to vacuum cast is this a factor in wax selection?) Perhaps you
could give me a good source of info on the subject of molding wax (for
casting or other objective)

[I've never heard of wax being vacuum cast, but that doesn't mean it's
impossible, I suppose. Wax and other pattern-making supplies are available
from Kindt-Collins:
http://www.kindt-collins.com/index2.html There is some general information
on waxworking, moldmaking, and casting in the Alt Sculpture FAQs:
http://users.lmi.net/drewid/altsculpture_faqs.html ]

Thankyou for this source of wax casting supply I will check this out
fully. Well, I am not sure if air bubbles are a problem in wax casting
as air can be with RTV silicone, urethane and resins. If air bubbles
in the wax can mess up the surface of a metal casting then I assume
you have to degass the wax. I AM guessing though, I am not an expert
in this-yet.




C) Eventually, I may need to create a permanent pattern to cast
accurate aluminum gears I would appreciate sources of information on
this.

[Permanent molds usually want draft to release from the mold, so I'm not
sure this will work with your gear pattern. You'd want to show it to the
die-casting house, if you decide to go this route, and ask them.]

I will probably have to modify some aspects, but it shouldn't be too
difficult




A1) It would be nice if the small foundry I find in Los Angeles can do
both processes referenced in "B" and "C".

Regards Steve

[I think you'll want to figure out another way to make these, if you really
must. But are you sure they can't just be purchased somewhere? Try WmBerg
for a start: http://www.wmberg.com/prgears.html .

These are hypoid type gears computer calculated, designed and
simulated. I am going to produce them using SLS then silicone mold
then wax cast. Wax cast sent to foundry.


Another thing I should mention:
aluminum is not a great material for gears, since it is soft and
wears easily. Of the various alloys of aluminum, the kind used for casting
is one of the softest. Are you sure you can't use steel or bronze?

Well, I am still in the prototype stage on this project. Wear may be
useful to me to aid meshing if my "real world" design is just a little
off . I intend to send the final parts for hardening. However, I would
certainly not rule out casting in bronze or steel if feasable. Also,
these are for low rpm, low load function.

You can
get lengths of spur gear stock in these materials and turn your gears to the
correct width on a lathe, then bore or ream them to your desired shaft size.
This is a lot more accurate than casting, and also much cheaper and easier.]

I will be using a lathe to get the shaft size perfect etc when I get
the metal parts back.

Steve

If You like to get informed about small casting supplies look here at my
site:
http://www.schmuckfabrik.de/englisch-index.htm


Thankyou Heinrich, I will check out this site fully.

Steve

On Sat, 28 Feb 2004 21:51:47 -0800, in rec.crafts.jewelry
(Scorsi) wrote:

Please see my reply to Ted's previous post. I was very unclear I
admit-I simply wanted to imply to any small Los Angeles foundrys that
I wanted nice clean parts, ie not a sloppy job.


There are any number of jewelry casters specializing in small custom cast
parts, and normally, they expect to produce nice clean castings. You're
problem may be finding one of these firms that knows beans about casting
aluminum. Higher melting metals are much more their specialty. Aluminum
requires somewhat different handling, and needs, for good castings, the
selection of the right alloys as well. I don't know any castings in the L.A.
area, but if you can deal with mail order, there are a number of firms I can
suggest that you could try. Don't know if they'll do it, but it's worth the
phone call, and getting casting done via mail can end up cheaper than running
around town getting it done locally, at least if traffic problems and parking
fees in L.A. are anything like they are around here, where getting a box to UPS
or fedex, and shipped, is easier and cheaper than finding some downtown firm,
wading through traffic, paying a parking garage, etc... Let me know if you
need those names.


B) Please give me a good source for me to obtain wax for me to cast
from a silicone mold. ( I have never molded wax before, so I am not
sure wether it needs degassing before casting, in which case I may
need to vacuum cast is this a factor in wax selection?) Perhaps you
could give me a good source of info on the subject of molding wax (for
casting or other objective)


Thankyou for this source of wax casting supply I will check this out
fully. Well, I am not sure if air bubbles are a problem in wax casting
as air can be with RTV silicone, urethane and resins. If air bubbles
in the wax can mess up the surface of a metal casting then I assume
you have to degass the wax. I AM guessing though, I am not an expert
in this-yet.


Normally, in jewelry type casting at least, the molds are made so as to be
fully closed, rather than open faced. A small funnel shaped opening is
provided to a channel into the part cavity, and of course the mold is cut apart
so that it can be dissembled, usually into two halves, and reassembled with
proper registration of the halves. Silicone RTV molds have less or no
shrinkage in the mold process, but the molds aren't as strong as a vulcanized
mold. For your purpose, though, they should be fine. The wax is generally
injected into the mold with an air pressure driven wax injector which keeps the
wax at a closely controlled melt temperature, and uses fairly low air pressure
(a few psi) to drive the wax into the mold. The cuts that allow the mold to be
seperated, as well as, if needed, additional vent cuts in the mold, allow air
in the mold to escape, but are too thin to allow wax to leak, beyond, perhaps,
faint mold lines. The placement of the cuts when the mold is first made is
hopefully such that any such faint lines are either of no consequence, or
easily cleaned off of either the wax model, or the casting. Injection waxes
are made with a number of variant properties, including controlling of
shrinkage in the cooling wax, flexibility, durability, memory, and resistance
to getting shrinkage "dips", where the wax model ends up with a concave surface
on flat areas, even though the mold did not have such. The size, detail, and
weight of your models will dictate what waxes to choose from, and they are
available from most jewelry tools supplier, including www.Gesswein.com,
www.contenti.com, www.riogrande.com (in no particular order, and these are just
three major dealers who's URLs I happen to remember). Contenti in particular
is well priced, and has extensive casting supplies, including RTV rubbers and
waxes. So does Rio Grande, though their catalog is not on the web.

Shrinkage of the wax model as it cools in the mold will likely be your biggest
problem for shrinkage, as it both shrinks, and can cause some distortion of the
model. Air bubbles are not usually a factor. Their is not generally air
included in the wax, if it's melted properly, and any bubbles that are in the
wax end up usually imbedded in the wax. They don't stick to the mold surfaces,
so they don't usually break the surface of the wax model, and as such, have
little impact on the casting. If they are very close to the surface, then
subsequent vacuum investing procedures can burst them, but this is, frankly,
more rare than some wax workers believe. There are, for molds of exceptional
complexity, or high production needs, wax injectors that pull a vacuum on the
mold before switching to the wax injection mode, so that the wax is injected
(still by air pressure) into a mold that's free of air, and therefor free of
back pressure that might cause incomplete fills of the mold. These machines
are VERY expensive, and many smaller casters don't bother using them. Most of
the time, with a bit of care, you get just as consistant and good results with
standard wax pots.

If your models are very large (by jewelry scales) and thick, then you may
indeed have trouble getting standard jewelry casting equipment like this to
fill a larger mold, since then the shrinkage of the wax as it cools does indeed
become an increasingly problematic concern. In a few cases, larger molds like
this do better as open faced molds that are not injected, but just poured by
hand. But usually this is stuff who's size is more in like with small
sculpture, than it is with jewelry sized work.




C) Eventually, I may need to create a permanent pattern to cast
accurate aluminum gears I would appreciate sources of information on
this.


Your RTV mold can be fair permanent. If you are careful with it, you can make
hundreds or thousands of wax models with such a mold. Vulcanized rubber molds
can be good for several decades of frequent high production work, but to make
those, you do need to start with a metal model, rather than your SLS one.


These are hypoid type gears computer calculated, designed and
simulated. I am going to produce them using SLS then silicone mold
then wax cast. Wax cast sent to foundry.


Depending on the size of the part, and the degree of surface finish you wish,
consider using a model made on a Solidscape machine. Last I heard, these can
be produced with surface finishes that are about an order of magnitude better
than most other RP processes, including SLS. it's enough better to make a
substantial difference in how clean and smooth your finished castings will be,
if you wish to not have to remachine the cast surfaces. I suspect the model
will cost you more, but you really only need one to make the RTV mold. If you
wish a metal mold, have the Solidscape model burned out and cast just as one
would do with wax. it casts very well (this is it's main use. These models
are too fragile for much else, unlike the SLS models)


Well, I am still in the prototype stage on this project. Wear may be
useful to me to aid meshing if my "real world" design is just a little
off . I intend to send the final parts for hardening. However, I would
certainly not rule out casting in bronze or steel if feasable. Also,
these are for low rpm, low load function.

You might also check out some of the zinc based alloys. They can cast very
smooth, generally have less shrinkage than aluminum, some of them are
surprisingly hard, some are self lubricating, and the stuff is cheap by
comparison. It's actually quite commonly used in the type of lower load, lower
rpm, less costly gears that you're trying to make. Aluminum generally is
hardened only by a hard anodizing process, and since this is a surface film on
the metal, rather than any deep process or intrinsic property of the metal,
once it wears down, you then have a higher friction and higher wear rate again.

One advantage of the zinc based alloys is that they melt low enough that it's
possible to cast them directly into some of the silicone rubbers, meaing you
can make a mold directly from your model, into which you then cast the metal
directly, eliminating the whole wax model part of the process. its capable of
considerable economy and accuracy. The best of these rubbers need to be
vulcanized, and do have a little shrinkage, so you'd go about it by making your
RP model (preferably Solidscape type), directly casting the model, doing any
fitting/cleanup on that model as needed, and making your vulcanized mold, or
several of them if you like, from that casting. You'd then cast your multiple
end parts directly in those molds. Depending on your mold type and end metal
and process, etc, this could be centrifugal casting in a standard jewelry type
casting machine or the faster, higher production "spin casting' machines which
are often used for high production casting of low melting white metals of this
type (much costume jewelry is made this way from these alloys), or for smaller
runs, it's even possible to cast some of these alloys just with hand pouring
directly into the rubber molds. However, to the best of my knowledge, aluminum
alloys melt a bit too high for this type of direct casting into a rubber mold,
and it needs to be lost wax cast in investment molds. That, of course, is a
good deal more costly than the direct casting into the rubber molds that you
can do with the low melting white metals.

The folks at Contenti have extensive sections of their supplies for this type
of white metal casting. So does Gesswein, and you might also look up Romanoff
co.

Hope this is of use.

Peter Rowe

Scorsi wrote:
If You like to get informed about small casting supplies look here
at my site:
http://www.schmuckfabrik.de/englisch-index.htm


Thankyou Heinrich, I will check out this site fully.

Especially here is a presentation of possibilities to cast structures
smaller than 1/1000 part of a mm in highly developed casting
process:
http://www.schmuckfabrik.de/Mikroguss_Butschal.htm
I´m sorry it´s only in german, however the pictures are impressive.

--
Heinrich Butschal
casting technologies
http://butschal.de/werkstatt

Making a stirling engine??

Les