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#1
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Casting using air pressure
I'm currently thinking about and designing a simple way to cast using air
pressure. It would work similiar to some steam casting methods I have seen from time to time. My current thinking is a simple frame to hold the necessary parts with an air supply from one of several possible sources. The top of the investment which would still be hot from burnout (or not) would act as the crucible where the silver was melted. A gasketed closure then clamps onto the top of the cylinder holding the burned out investment and air pressure applied quickly in one motion. My question is what pressure do you think I need to apply and how long to keep it applied. Would it be better to apply a lower pressure (say 5 pounds) initially and then increase it? Would a lower pressure contribute to porosity of the casting? Thanks, Mike in Arkansas |
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#2
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Thought this posting got lost in digital hell. Already ask this in a much
later posting. Sounds like 15 pounds or so is a starting point. Still working on a simple mechanical mechanism that will automatically apply the air pressure when the handle is closed Thanks to all that replied to my later query about this. Mike in Arkansas |
#3
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Peter, I'm not entirely sure it's AOL's news server! I've noticed several
of my posts delayed by more days than I ever would have imagined....sometimes 2, 3, 4 days! And I use an entirely different server. "Peter W. Rowe" wrote in message ... On Wed, 23 Jul 2003 22:15:03 -0700, in rec.crafts.jewelry ojunk (Mike72903) wrote: Thought this posting got lost in digital hell. Already ask this in a much later posting. Mike. I've put this reply message in the group, rather than just email, in case it provides relavent insight for others who's posts may seem delayed. The posting does seem to have been unusually delayed. It reached me just today, yet bears a posting date of the 16th, a week ago. (I'll append the original post with headers that I recieved to the bottom of this post, in case you wish to ask the AOL news admins about this... Your second, followup post was posted to the group on the 19th. Not really all THAT much later, considering the delay between when you probably originally sent it on the 18th, and when I approved it. I can't anymore check the original headers for the original date on that posting, as I don't keep them that long. It is indeed unusual for a message to get hung up in servers that long. You might indeed wish to inquire of AOL's news admins just what might have happened. It's pretty clear in the path headers where the post got hung up. " ngpost-m2.news.aol.com", (the AOL news server you connected to, I think), passed the message on the 16th, to "imo-r03.mx.aol.com" (probably an AOL server), which passed it to "chi6sosrv11.alter.net", also on the 16th. It passed it , to the "chi6-2.relay.mail.uu.net", which sent it to the Earthlink mail server, and then to me, today on the 23d. The question is why the message got hung up on the "chi6sosrv11.alter.net" and "chi6-2.relay.mail.uu.net" transfer. The path doesn't show a transfer between these two servers, so I presume it's in an internal network between the two, with one being on the alternet domain, and the other being a uu.net relay servers. The relay is what knows my email address, and can then forward it to me. I presume that what happened is that for some reason, that particular uu.net server was down for a time, or otherwise misplaced or delayed the post. Below are the headers of todays post, as I recieved it. Hope this is of some use or interest.... Peter Rowe moderator rec.crafts.jewelry Status: U Return-Path: Received: from chi6-2.relay.mail.uu.net ([199.171.54.99]) by killdeer (EarthLink SMTP Server) with ESMTP id 19FmXy2Gh3NZFlr0 for ; Wed, 23 Jul 2003 09:59:21 -0700 (PDT) Received: from imo-r03.mx.aol.com by chi6sosrv11.alter.net with ESMTP (peer crosschecked as: imo-r03.mx.aol.com [152.163.225.99]) id QQoxqa07421 for ; Wed, 16 Jul 2003 19:06:12 GMT Received: from ngpost-m2.news.aol.com (ngpost-m2.news.aol.com [172.20.17.108]) by imo-r03.mx.aol.com (8.8.8/8.8.8/AOL-5.0.0) with ESMTP id PAA23369 for ; Wed, 16 Jul 2003 15:05:50 -0400 (EDT) To: From: ojunk (Mike72903) Newsgroups: rec.crafts.jewelry Date: 16 Jul 2003 19:04:54 GMT Organization: AOL http://www.aol.com Subject: Casting using air pressure Message-ID: I'm currently thinking about and designing a simple way to cast using air pressure. It would work similiar to some steam casting methods I have seen from time to time. My current thinking is a simple frame to hold the necessary parts with an air supply from one of several possible sources. The top of the investment which would still be hot from burnout (or not) would act as the crucible where the silver was melted. A gasketed closure then clamps onto the top of the cylinder holding the burned out investment and air pressure applied quickly in one motion. My question is what pressure do you think I need to apply and how long to keep it applied. Would it be better to apply a lower pressure (say 5 pounds) initially and then increase it? Would a lower pressure contribute to porosity of the casting? Thanks, Mike in Arkansas |
#4
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GhostMouse wrote:
Peter, I'm not entirely sure it's AOL's news server! I've noticed several of my posts delayed by more days than I ever would have imagined....sometimes 2, 3, 4 days! And I use an entirely different server. Peter, Do you think this could also be related to my post that did not reach you at all afew days ago, about which I emailed you? In that case, the problem may be on your end? Abrasha http://www.abrasha.com |
#5
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On Thu, 24 Jul 2003 17:55:04 -0700, in rec.crafts.jewelry Abrasha
wrote: GhostMouse wrote: Peter, I'm not entirely sure it's AOL's news server! I've noticed several of my posts delayed by more days than I ever would have imagined....sometimes 2, 3, 4 days! And I use an entirely different server. Peter, Do you think this could also be related to my post that did not reach you at all afew days ago, about which I emailed you? In that case, the problem may be on your end? Abrasha http://www.abrasha.com It's quite possible, and even likely, that this is the root of this sort of problem. Note, though, that this isn't at my end, just as it's not at your end. It's in the middle... It's not my ISP, nor yours, but apparently the relay servers, most of which are connected either to uunet, or to one of the university systems. The number of such relay servers varies. It used to be there were about a dozen of them. Then at one point, someone on the moderators listserve said it was down to four or five. Not sure where it's at now. But whatever the number, when one goes down, or otherwise has problems, it's trouble for the moderated groups, since unlike normal newsgroup messages, which can reach a news server usually by more than one path, moderated posts go via email between the original news server and the moderator. If the relay servers loose a message, there may not be duplicate copies floating around the net to fill in... I'll send copies of the header block on this recent delayed message to the moderators list serve, and see what folks there say. Some of those people are amongst the folks who manage these underpinnings of usenet and the moderation relays... Peter |
#6
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Oerhaps related is the fact that another NG I monitor (alt.autos.subaru)
recently began acting up - not retrieving/loading messages or requiring multiple retires to load. Didn't used to behave that way. Seems better today than the last week or more. Wonder why there is no news of anything specific going on? Carl 1 Lucky Texan Peter W. Rowe wrote: On Thu, 24 Jul 2003 17:55:04 -0700, in rec.crafts.jewelry Abrasha wrote: GhostMouse wrote: Peter, I'm not entirely sure it's AOL's news server! I've noticed several of my posts delayed by more days than I ever would have imagined....sometimes 2, 3, 4 days! And I use an entirely different server. Peter, Do you think this could also be related to my post that did not reach you at all afew days ago, about which I emailed you? In that case, the problem may be on your end? Abrasha http://www.abrasha.com It's quite possible, and even likely, that this is the root of this sort of problem. Note, though, that this isn't at my end, just as it's not at your end. It's in the middle... It's not my ISP, nor yours, but apparently the relay servers, most of which are connected either to uunet, or to one of the university systems. The number of such relay servers varies. It used to be there were about a dozen of them. Then at one point, someone on the moderators listserve said it was down to four or five. Not sure where it's at now. But whatever the number, when one goes down, or otherwise has problems, it's trouble for the moderated groups, since unlike normal newsgroup messages, which can reach a news server usually by more than one path, moderated posts go via email between the original news server and the moderator. If the relay servers loose a message, there may not be duplicate copies floating around the net to fill in... I'll send copies of the header block on this recent delayed message to the moderators list serve, and see what folks there say. Some of those people are amongst the folks who manage these underpinnings of usenet and the moderation relays... Peter -- to reply, change ( .not) to ( .net) |
#7
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On Thu, 24 Jul 2003 21:32:34 -0700, in rec.crafts.jewelry Carl 1 Lucky Texan
wrote: Oerhaps related is the fact that another NG I monitor (alt.autos.subaru) recently began acting up - not retrieving/loading messages or requiring multiple retires to load. Didn't used to behave that way. Seems better today than the last week or more. Wonder why there is no news of anything specific going on? Carl 1 Lucky Texan Anything related to the way you actually read or download messages on the groups, both moderated or not, will be related only to issues at your own ISP. Unless you read the groups at some remote site, such as google, newsgroups are generally accessed through the local news server at one's own ISP. When you read the groups, generally your never actually connecting to the internet, except as needed for local connections within your ISP's setup from one division of your ISP to another, such as from the modem you call into, to their actual servers. Usually, these are dedicated connetions however. This would be why there's "no news". it isn't global to the net, unless of course there's something like some sort of common virus or worm or something that's attacking news servers (haven't heard anything of the sort). The problem this thread discussed is a situation unique only to moderated groups. In unmoderated groups, you send a message to the group, and it can appear immediately in your listing of messages on the group, because you're seeing it appear essentially on the same server you sent it to. Other subscribers at your ISP will also see it then. Once your news server accepts it, it then sends it out over the net to all the other news servers, which may get it quickly, or not, but each is different. Any delays in this, however, are not apparent to you, unless you access some other news server on another ISP. One way to do this is to send a message, see it appear on your ISP's news server, and then see how long it takes to appear on Google, or one of the other "pay for service" news services one can subscribe to. Most folks don't do this. With moderated groups, anything you send to the group is accepted by your news server, but instead of showing it on it's own listings and then broadcasting it to the news feeds, it shunts it to an email server, which sends it to one of the several moderation relay servers. These then forward the messages to the moderators, who approve them and post the messages to their OWN ISP's news server. That server then lists it normally and sends it on the newsfeeds, where, eventually, your own news server will get it and show it. The speed with which these transfers take place can vary a lot, from a few seconds or minutes, to several hours, if the servers are very busy. Usually, it's pretty quick. Delays in the moderation relay servers are quite unusual, however, since there are only about 500 moderated groups in usenet, and most are fairly low volume, thus the relays shouldn't get overwhelmed. Certain types of spam or denail of service attacks can do it, but then it tends to be system wide, rather than just selected messages being delayed. My guess is that one of the several relays is having internal problems of some sort. Hopefully, it will get sorted out... Peter Rowe |
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