for those that dont know, "extrude honing" aka "abrasive flow machining" is a way to smooth/polish/deburr materials by forcing a semi-solid "liquid" filled with abrasive through or around them.
there is a company called "extrude hone" that does this for you. the benefits are that can create a very nice surface and completely polish every nook and cranny.
so im wondering what it would take to do this yourself, since it sounds so simple.
patent 3521412 seems to be the origin of this technology, or very near it. its from around 1966.
to sum it what ive learned so far:
in regards to the abrasive material, the patent mentions a "combination that worked" as GE silicone putty SS-91 along with boron carbide as the abrasive, and a couple other things to grease it up and soften it a bit.
I cant find SS-91 for sale, im not sure GE even makes it anymore. But some cross referencing of searches for "silicone putty" as its called in the patent, seems to suggest that it is _literally_ Silly Putty!! If you dont believe me do some searching and I bet you'll come to the same conclusion. SS-91 gets called "bouncing putty" and also "pink commerically available putty" , it appears to be a "non newtownian" fluid that looks alot like the stuff on extrude hones site. Every physical characteristic described in the patent fits it.
It should be noted that extrude hone offers many different grades of and durometers of putty and abrasives. And even the patent mentions that there are many combinations that could work. So this may be just one, and maybe the easiest one to acquire.
It looks like silly putty is pretty expensive, or at least, you have to buy hundreds of dollars worth. I could be wrong about that, as I only did about 30 minutes of research. Ill try to see if I can get a few pounds worth somehow.
Anyways, the silly putty mixed with the abrasive (aluminum oxide, boron carbide, etc.. nothing special) gets forced through the part at 500 to 2000 psi with cylinders, presumably hydraulically activated. The patent describes all this in excruciating detail. Oh, did I mention that there are many other patents on this technology, some much more modern. So if you want to know how they do it its no secret.
So...if we can come up with the following:
-a cylinder of some kind that can hold about a milk cartons worth of the putty/abrasive slurry, and can be pressurized at at least 500 psi
-some kind of hydraulic activator or motor that can power the cylinder
-a few pounds of silly putty
-a few pounds of abrasive grit (boron carbide, aluminum oxide)
-some adapters to connect the cylinders to the intake ports and combustion chambers that can withstand 500+ psi
-some simple circuitry to operate the cylidners back and forth until we get the results we want
then weve got our own extrude hone machine! perfectly polished manifolds and heads with no effort!
i think the method to push the cylinder could be accomplished a million ways...its the cylinder itself that i cant think of a solution. i guess you could just make one out of a steel pipe and some kind of piston with a grease seal..there must be something from harbor freight that does that..what about a grease gun? dont those operate at very high pressures?
i know you can get aluminum oxide sandblasting grit from harbor freight..in fact i have a 10lb jug of it..so thats no big deal
the silly putty material _can_ be purchased..its just expensive. $80 for 5 lbs...and thats LITERALLY silly putty, the toy. its got some other stuff in it that im not sure will be good or bad for this application. its probably time to call dow corning and ge and see if the real stuff can be purchased in small quantities...
i think it would be pretty simple to weld up adapters for the ports and combustion chambers..
there is a company called "extrude hone" that does this for you. the benefits are that can create a very nice surface and completely polish every nook and cranny.
so im wondering what it would take to do this yourself, since it sounds so simple.
patent 3521412 seems to be the origin of this technology, or very near it. its from around 1966.
to sum it what ive learned so far:
in regards to the abrasive material, the patent mentions a "combination that worked" as GE silicone putty SS-91 along with boron carbide as the abrasive, and a couple other things to grease it up and soften it a bit.
I cant find SS-91 for sale, im not sure GE even makes it anymore. But some cross referencing of searches for "silicone putty" as its called in the patent, seems to suggest that it is _literally_ Silly Putty!! If you dont believe me do some searching and I bet you'll come to the same conclusion. SS-91 gets called "bouncing putty" and also "pink commerically available putty" , it appears to be a "non newtownian" fluid that looks alot like the stuff on extrude hones site. Every physical characteristic described in the patent fits it.
It should be noted that extrude hone offers many different grades of and durometers of putty and abrasives. And even the patent mentions that there are many combinations that could work. So this may be just one, and maybe the easiest one to acquire.
It looks like silly putty is pretty expensive, or at least, you have to buy hundreds of dollars worth. I could be wrong about that, as I only did about 30 minutes of research. Ill try to see if I can get a few pounds worth somehow.
Anyways, the silly putty mixed with the abrasive (aluminum oxide, boron carbide, etc.. nothing special) gets forced through the part at 500 to 2000 psi with cylinders, presumably hydraulically activated. The patent describes all this in excruciating detail. Oh, did I mention that there are many other patents on this technology, some much more modern. So if you want to know how they do it its no secret.
So...if we can come up with the following:
-a cylinder of some kind that can hold about a milk cartons worth of the putty/abrasive slurry, and can be pressurized at at least 500 psi
-some kind of hydraulic activator or motor that can power the cylinder
-a few pounds of silly putty
-a few pounds of abrasive grit (boron carbide, aluminum oxide)
-some adapters to connect the cylinders to the intake ports and combustion chambers that can withstand 500+ psi
-some simple circuitry to operate the cylidners back and forth until we get the results we want
then weve got our own extrude hone machine! perfectly polished manifolds and heads with no effort!
i think the method to push the cylinder could be accomplished a million ways...its the cylinder itself that i cant think of a solution. i guess you could just make one out of a steel pipe and some kind of piston with a grease seal..there must be something from harbor freight that does that..what about a grease gun? dont those operate at very high pressures?
i know you can get aluminum oxide sandblasting grit from harbor freight..in fact i have a 10lb jug of it..so thats no big deal
the silly putty material _can_ be purchased..its just expensive. $80 for 5 lbs...and thats LITERALLY silly putty, the toy. its got some other stuff in it that im not sure will be good or bad for this application. its probably time to call dow corning and ge and see if the real stuff can be purchased in small quantities...
i think it would be pretty simple to weld up adapters for the ports and combustion chambers..
