Can L gaskets be machined on a lathe or multi axis machine centre?

[bry1975]

Chaps,


A daft question can L gaskets be machined on a lathe or multi axis machine centre? the gasket material needs to be slightly elastomeric/rubbery as will need to be water tight to 15Bar minimum.  Diameter around 30mm I.D and O.D. 34mm, height 2.5mm  L section thickness 1mm.



Thanks in advance.


Bry

[John Hill]

How about use the lathe to make a mould and cast your own from liquid neoprene, or some such? 

[bry1975]

Interesting idea John,

I don't have a machinist lathe and haven't got into moulding or casting yet.

Any of you guys made moulds to cast rubber then?


Bry

[crankshafter]

Hi Bry.

I think it could been done but......  
there are some special set up regards this. I have had it done by a company(here in Norway) who have the right setup/machines to do it. not so expensive I think. search the Web and I'm sure you will find someone "near you" who can help you out.
CS

[bry1975]

Thanks Crank,

Actually sent an email this morning but waiting for a reply, I think a slightly hard rubber L gaskets would be ok as long as it has some give.

[PekkaNF]

I have turned few grommets and buffers out of rubber rod. I had to make sharp tools (really sharp) and used water based emulsion for cooling and lubrication. One old book recomended MILK

I could not get any decent results before cranking up some high rpm and had to use fastest movements (feed) I could manually crank. On slow speed the apparent viscosity of the rubber is low, i.e. it turns bad, like you try to turn chewing gum, speed somehow seemd to "solidify" or "harden" it. Too much dwell and the rubber burns! Nertheless, I had to resort thin "blade" to cut it and some sorth of sharp/smooth thin leather punch like "barel drill" to make larger holes. Parts come out really smooth and clean. Any attempts to sand it turned it to a rough, not smooth. More speed?

I could imagine that part turned from the solid and lastly sut out with sharp cut out looking tool. Hand turning or grinding were disautros attempts. I imagine that this depends completely of the material. I made parts to my friend to rebuild very old moped, he got a piece of rubber that looked "authentic" rather than to technical properties.

Pekka

[bry1975]

Thanks Pekka,

Certainly sounds like fun it's been years since I've worked with rubbers or elastomers.

[Lew_Merrick_PE]

Bry,

1) Casting in "rubbers" (i.e. usually room temperature vulcanizing materials -- which have a much broader array of materials available these days) is quite simple.  I often cast up prototype rubber parts this way using a plaster of paris mold and a 125 cc syringe (usually available from the local horse doctor) with good success.  Here in the U.S. materials are readily available from Shore A scale 15 durometer up to Shore B scale 80 durometer.  Silicones are the most readily available of the casting materials.

2) Machining of "rubbers" (i.e. elastomers) is best done by freezing the materials.  Liquid nitrogen is what is used commercially.  I use dry ice and alcohol.  Your cutting tools have to be dead sharp.  Whatever fixture you are using to hold the part should allow you to remove the part and reinstall it in case you need to refreeze it as you go.  Be sure that the "rubber" is not deformed when you place it into the "freezing mixture."  Other than that, this is not a problem.

[Bogstandard]

Bry,

I will see what the experts say no doubt they wont reply.

With quotes like that, I for one wouldn't answer, even though I do have some experience of silicone moulding that were a lot more complex that you are trying to do.

If people want to reply they will, but trying to force them into it will guarantee you don't get replies.

You also don't give a reason for asking why you want to make them. If it is for that pressure vessel in your other post, then anyone even offering to help would be leaving themselves wide open if anything went wrong with such a dodgy exercise.

There are times when you do it yourself, and other times when you need to dig deep into your pockets and let the experts do it for you. Things like that are expensive because of all the R&D and hundreds of man years experience that goes into producing them, and you are looking to make it in a kitchen or back yard workshop.


Bogs

[djc]

With quotes like that, I for one wouldn't answer...

I believe the original poster was referring to the commercial company to whom he wrote, not to anyone (professional or amateur) on this board.

[bry1975]

YES very sorry I was referring to the firm I emailed I wasn't referring to any of the members on madmodders Bogs.