spark plug manufacture

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reubenT
Posts: 60
Joined: Wed Dec 24, 2008 11:04 pm
Location: Spencer TN USA

spark plug manufacture

Post by reubenT » Thu Feb 28, 2013 10:36 pm

Looking for someone's help to point me to source of info.
I have a need to make custom spark plugs to fit a non standard plug hole and using tungsten electrodes, they would be medium to large size and for long term low maintenance running of the engine. been searching for info on making the porcelain insulators. I saw mention of pressing alumina into a form and then sintering it, with shrinkage allowed for, no mention of how much shrinkage. I need such questions answered as; Could the electrode (TIG welding electrode) be placed in the middle of the ceramic before sintering or would the expansion of the metal with sintering temperature cause the porcelain to crack? And then what material is used to seal the insulator into the steel body?

I could experiment, but getting some prior info could save a lot of time.

JackF
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Joined: Mon Jan 26, 2009 3:56 pm
Location: Caldwell, Idaho

Re: spak plug manufacture

Post by JackF » Fri Mar 01, 2013 8:29 am

reubinT,

A friend of mine makes his "porcelain" out of Corian. He makes them from super small, 1/4" tall or so to R/C plane size. Don't know the longevity of these plugs but I never heard him mention of them wearing out. He started making his own because they don't make them small enough for his purposes. Hope this helps.

Jack.

hammermill
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Location: pendleton or

Re: spak plug manufacture

Post by hammermill » Fri Mar 01, 2013 10:13 am

although i may be going in the wrong direction for you the champion plugs for maytag motors were composed of several parts and can still be bought if you find a savy part guy. i have seen the rc plugs made with corrion insulators. several articles were published in strictly ic magazene that contained a wealth of information.

dly31
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Re: spak plug manufacture

Post by dly31 » Fri Mar 01, 2013 9:53 pm

If tungsten makes a long life electrode I would certainly think someone makes a spark plug with it that you could,modify, adapt, or disassemble to get the electrode and insulator. Look into motorcycle, aviation, jet engine, oil burners, and heavy industrial engine as well as automotive spark plugs.
Don Young

reubenT
Posts: 60
Joined: Wed Dec 24, 2008 11:04 pm
Location: Spencer TN USA

Re: spark plug manufacture

Post by reubenT » Sun Mar 03, 2013 11:53 am

I've seen the corian plug idea, but not sure I want to trust it for the application, and spark plug manufacturers do not make tungsten electrode plugs because they'd last too long and kill their repeat sales. (various inventors have tried to get them made unsuccessfully) A lot of people think industry always makes things to the highest standard possible, but that just isn't so. All industry is driven by profits, if they made stuff to the maximum and it lasted forever they'd end up saturating the market and long term sales would taper off. Long life technology left manufacturing practice far behind long ago.
I need a custom spark plug for very high compression engines that will handle the blue phoenix ignition system (or homemade equivalent) and last thousands of hours run time. normal plugs burn out after about 100 hours in the application, plus a screw plug won't fit. needs to have a machined base that clamps in. I have some alumina and china clay left from foundry activities, I'll try making some plugs pretty soon. Machining the plug housing out of a steel rod would be simple, just need the ceramic insert with a tungsten rod electrode.

hammermill
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Location: pendleton or

Re: spark plug manufacture

Post by hammermill » Sun Mar 03, 2013 6:39 pm

if it is bolting in place it sound link it will be used on a jet engine where it is not run under extreme pressure like in a dragster engine. both asumptions may be in err???

if you ever messed around with a champion sparkplut tester you would see the difference in behavior between free air and compression. not to mention getting knocked on your butt if you touched the cap.

jpfalt
Posts: 978
Joined: Sun Jan 05, 2003 12:55 pm

Re: spark plug manufacture

Post by jpfalt » Mon Mar 04, 2013 3:33 pm

Your best bet is to get a plug with tungsten electrodes and do one of two things.

You can machine the outer shell off of the plug and drop it into a custom made shell.

You can get a smaller plug and machine an adapter to put the plug where you need it.

Etpm
Posts: 4
Joined: Sat Mar 29, 2014 12:28 am

Re: spark plug manufacture

Post by Etpm » Sun Mar 30, 2014 11:24 am

Greetings Reuben,
I know, this reply is to a post nearly a month old. But it always takes me longer than I think to make prototypes so maybe the info below will still be timely and maybe helpful too.
There are machineable ceramics that can then be fired at a pretty low temperature. There is also a ceramic glue called Rocksett that is good for high temperatures. Maybe you can use the Rocksett as the ceramic or else use it to glue your electrode into a ceramic insulator. Ceramic tubes are available from folks who sell kiln supplies. And McMaster-Carr probably sells them too. They might even sell Rocksett. Flexbar used to sell Rocksett and I think they still do. The machineable ceramic may also be available from McMaster-Carr.
Cheers,
Eric

Hudson Honey
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Location: San Diego area

Re: spark plug manufacture

Post by Hudson Honey » Wed May 07, 2014 2:17 pm

A word to the wise....

Machining ceramic is extremely hazardous to ones health. The stuff comes off like a fine mist almost resemblea smoke. DO NOT BREATHE THIS STUFF. it will lead to something called silicosis....a very nasty way to die. I have turned down ceramic jobs due to this. Once ceramic gets in your lungs its there permanantly.


Pamela

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ronm
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Location: Colorado

Re: spark plug manufacture

Post by ronm » Wed May 07, 2014 7:27 pm

Etpm wrote:Greetings Reuben,
I know, this reply is to a post nearly a month old. But it always takes me longer than I think to make prototypes so maybe the info below will still be timely and maybe helpful too.
There are machineable ceramics that can then be fired at a pretty low temperature. There is also a ceramic glue called Rocksett that is good for high temperatures. Maybe you can use the Rocksett as the ceramic or else use it to glue your electrode into a ceramic insulator. Ceramic tubes are available from folks who sell kiln supplies. And McMaster-Carr probably sells them too. They might even sell Rocksett. Flexbar used to sell Rocksett and I think they still do. The machineable ceramic may also be available from McMaster-Carr.
Cheers,
Eric
Sorry, Man...the thread is over a YEAR old... :D

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