Machinable ceramic

[Noitoen]

Seeing the tiny spark plug of the tiny I.C. engine I thought this machinable ceramic would come handy for such jobs. http://www.corning.com/specialtymaterials/products_capabilites/macor.aspx see the MACOR Product Information Sheet for details. http://www.rs-components.com/index.html has some rods and plates in their inventory.

 

[John S]

Have you checked prices out on this material ?

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=1583095

£50 for a 100mm length of 15mm diameter, that's just under 5/8" x 42 for the cousins and about $85


John S.

 

[Maryak]

Gee - Mistakes could prove expensive, one might even suggest job threatening. :-\ :-X

Best Regards
Bob

 

[Noitoen]

Didn't say it was cheap. I's good to know you can count on specialized materials. There might even other suppliers with better prices.

 

[Tin Falcon]

mcmaster Carr in the Us has a nice selection but not cheap a 3 inch long piece of 3/16 diameter is 22 bucks.
Tin

 

[tel]

Also available here but still not cheap.

 

[ieezitin]

There is a cheaper source.

Use the TIG welding cups. it’s relatively the same material and massed produced, another advantage is they are round which helps with holding purposes and come in different sizes.

Ceramics are not that hard to machine either. I did it 30 years ago with HSS bits. Now saying that what I worked on was bonded to a steel drum so the holding problems were not apparent to the ceramic being brittle.

I have never tried to machine these cups so I can not tell you how to do it. Just a suggestion to an alternative.

All the best. Anthony.

 

[Tin Falcon]

Gee - Mistakes could prove expensive, one might even suggest job threatening. Undecided Lips Sealed

that stuff is cheap compared to some stuff like platinum. 1/16 rod a foot long will run about a thousand bucks. Not only had you better not blow any tolerances but you had better not lose any chips either. I worked with a guy that had to machine that kind of stuff. first thing clean the machine spotless. Do not make any mistakes . Recover every possible chip. The blank was weighed before machining . the part was weighed and the scrap was weighed it had better add up with minimal loss . Oh yea there is a security guard watching your every move. Fun Huh????
the spot price of platinum is around 1400 usd/oz
Tin

 

[fcheslop]

I use ceramic fuses .Carefully remove the ends and you end up with a nice tube they come in different sizes and are a lot cheaper than machinable ceramic.Especially if your heavy handed like me always seem to break the bloody things when first setting up the carb.
regards and best wishes

 

[lee9966]

Ceramic fuses, nice. Thanks for that idea, I will be looking into it more.

Lee

 

[fcheslop]

Hi Lee,you'll find that once you get the ends of the tube is a little thinner than TIG welding shields but I've never had a problem with them tracking.The pic shows my Little Angel fitted with a home made 1/4by32tpi rim fire plug using a 20mm 500ma fuse body .Just looked at it a little closer and it has as RS logo on the body. Ive seen smaller fuses fitted to multi meters.Hope this helps
regards best wishes

 

[Lauri]

Hi.

I am also interested in finding a supplier for machinable ceramic material. I would like to make a combustion chamber to my engine of it. I have some ideas why I think it would be worth trying in my case.
I was googling the subject a little and bumbed into a material called "Ceramatest 400", it looks quite promising. My only worry is how it will accept the thread for glow plug (UNEF 1/4-32) but a riveted/glued -in aluminium insert is an option also.

Lauri

 

[Tin Falcon]

Mcmaster carr carries 4 or 5 grades of machinable ceramic most a little pricey some extremely expensive
look here:

http://www.mcmaster.com/#machinable-ceramic/=m1vclh
Tin

 

[myrickman]

The machinabe ceramics are described here. http://www.corning.com/docs/specialtymaterials/pisheets/Macor.pdf
It is a premium material so pricey... This brochure gives a nice summary.

 

[Tin Falcon]

Yes pricey the Macor mentioned in the fantastic product bulletin above will set you back about $7 -$10 per inch for 3/8 diameter depending on what length you buy (3" min) . pricey but not as bad as DuPont Vespel polymide bearing material. . IIRC that stuff goes for $35 per inch.
That said most model hit and miss engines do not get real hot. only warm and folks have sucessfully used corian for an insulator. Even if you thread the insulator ican not imagine musch stress on that part.
Tin

 

[Lauri]

Thanks, I'll check McMaster-Carr. I don't really care of the price as long as I can get it (I need 30mm dia. barstock).
This is not for hit&miss engine, I want to try ceramic because the burning process is too cold at the moment, thus unstable. I can stabilize the process with differend combustion chamber shape (more squish band & turbulence) but that tends to chage the engine's behaviour. Our engine is for control line aerobatic class, where stability and certain kind of behaviour is desirable, power is not an issue. L

 

[WCPenney]

I'd be cautious of the expansion of the center electrode in Macor. Many years ago I helped prototype a UV curing chamber. Everything we used for a shutter warped or sagged under the bulb. We ordered a very pricey 1/4" sheet of Macor and dropped the ball with insufficient clearance for the stainless fasteners. The corners of the plate shattered around the fasteners in the testing oven. I don't remember the specifics (temp, time, grade of stainless, etc...) but I do remember we weren't close to operating temp. Just food for thought as it is expensive material.

 

[Tin Falcon]

Mcmaster car carries 1" 25.4 mm and 1 1/2 diameter 30 mm may be tough.


Maryland metrics carries al kinds of metric tools, hardware etc a possibility.
Tin

 

[Lauri]

Now I've ordered some Macor in 1,25" dia. We'll see what happens.. L

 

[carlos_alegria]

y la formula quimica y procedimiento que?