I am still waiting for the chance to get over to Maryland and pick up the Super Jolly that my friend found for me on Craigslist. In the meantime, I've been pondering my options to make it doserless. I love the look of the metal funnels sold by espressoparts, and I believe that in low production runs the $177 price tag is justified... but I have a hard time dropping that much on a simple funnel. From what I've heard, metal funnels also face static problems, while plastic ones do not.

This got me to thinking.... what if I could make a similar funnel, but out of Kydex plastic? For those of you who are not familiar with Kydex, it is a thermoplastic that is produced by KYDEX, LLC in Pennsylvania. It is most often sold in sheets, and once heated, is easily formed. It has excellent toughness and hardness. I am familiar with it because it is often used as a replacement for leather in the manufacturing of gun holsters. It is also frequently used in aircraft interiors, as it is extremely rigid.

I am thinking that perhaps I could buy a sheet, heat it, and form it into a funnel. I have actually formed Kydex before, I used it to form a custom fitted cheek rest to my rifle. All it takes is a wallpaper heat gun and a little time, and it becomes quite pliable. One of the major concerns I had was the surface finish. Most Kydex that I have seen has a fairly rough, "grainy" finish to it. This is usually done to improve wear resistance and mask scratches. However, according to Kydex Technical Brief 165 (TB-165), Kydex can be produced in a variety of surface finishes, including "P-A Smooth", which is a polished, high-gloss finish.

So... has anyone else considered, or even possibly attempted using Kydex for this purpose?

Thanks!

Caleb

Here's an excellent photo I found online that shows the various surface finishes that Kydex comes in.

Note the almost mirror-like finish on the PA Smooth option:

It looks similar to the material that OE uses for the funnel inside of their Pharos.

I am not familiar with the Pharos. I will have to check that out.

Looks like a funnel similar to the espressoparts version would have to have 4 "cuts" in it. Not sure if these cuts could be thermally welded together once the funnel was formed?

Jeff wrote:It looks similar to the material that OE uses for the funnel inside of their Pharos.

OE's website describes the funnel as "ABS Plastic". I believe the original Pharos did not include this funnel, and it was added as a later upgrade to the "Pharos 1.1" as doug describes it. There are several good pictures of the funnel on this thread.

caleb105 wrote:From what I've heard, metal funnels also face static problems, while plastic ones do not.

I've always heard it the other way around. A metal funnel could be grounded and avoid any static problems while plastic, unless conductive or metalized often has static issues. When I use a plastic canning funnel to pour my roasted coffee into canning jars, the chaff electrostatically sticks to the side of the funnel. This is kind of an advantage if you want to reduce the chaff in your jar. I never see the chaff stick to the aluminum pans that I use when culling my coffees, just plastic.

Interesting idea.

Standard ABS is just as easily formed and would end up being cheaper. We use Kydex for thermoformed parts in transit bus interiors and aircraft interiors mainly because it can comply with flammability and anti-graffiti regulations. It ends up costing at least twice the price of standard ABS.

yakster wrote:I've always heard it the other way around. A metal funnel could be grounded and avoid any static problems while plastic, unless conductive or metalized often has static issues.

Perhaps I got it backwards. Anyone else have input on this? Don't they sell "anti-static" screens?

Mahlkonig's "Lab" grinder has as a feature a metal grinds cup and a grounded platform for it, so at least one high-end manufacturer believes that grounded metal is a good option. Anti-static screens, from what I have seen, while perhaps useful in production environments, prevent "home" techniques that involve cleaning the grind-delivery chute of the grinder.

ok... here's my understanding. Someone correct me if I am wrong.

I was under the impression that it is not the funnel/doser that applies a static charge to the grinds, but the burrs and the act of grinding. So as the beans are ground, the small grind particles pick up a static charge. If the funnel or doser is conductive (and not grounded), then these statically charged particles will want to stick to it. To prevent this sticking, the following methods have been employed:

1 - Use a static screen. This screen is grounded to the body of the grinder, and helps to remove the static charge from the grinds before they ever reach the funnel

2 - Use a metal funnel that is grounded to the body of the grinder. That way, even when the statically charged grinds come in contact with the grinder, the charge is passed through the grounded funnel and there is no longer an electron attraction between the grinds and the funnel

3 - Use a non-conductive funnel (i.e. plastic) that will result in a weaker electron attraction between the charged grinds and the funnel surface.

Am I missing something?