Heat resistant plastic

I’m making a component for my coffee machine that brews between 195-205 degrees F. I made the it out of mystery plastic (melted) and it melted. Then I did some research and cut it out of polypropylene. This didn’t melt, but it did warp enough for the part to not be usable for my purpose.

I don’t want to go with aluminum since it will “absorb” the heat of the water coming out and drop the temperature too much.

I’m looking for ideas on what options I have for super heat resistant plastic. I need it around 1/4 thick and 6x6 inches.

Usually nylon comes up for easily machined — is being flexible okay? Make a mold and use silicone?

1 Like

Should have specified, it needs to remain rigid. It is a showerhead piece to disperse the water evenly over the grounds. The polypropylene was ok for a minute or so, but warped and then wasn’t dispersing the water properly.

You should make sure the plastic is certified for direct food contact. One such material is Ultra-High Molecular Weight Polyethylene (UHMW-PE). Maximum service temperature is about 200°F, so that might work for your application…
https://www.eplastics.com/sheets/uhmw

2 Likes

Nylon is an OK choice if you are sure on the temp (only water contact keeps it below boiling, which is OK for Nylon. Steam or hot metal surfaces may be higher. Note that continuous contact with boiling water is not recommended, and Nylon is hella hygroscopic-- it will swell and degrade over time) and it will be intermittent service, PTFE (teflon) is excellent, PEEK is pricey but a little less machinable than nylon.

This type of part is often made using a water resistant thermoset, to eliminate softening, or made easily replacable.

1 Like

I second @WillAdams thought.

Machine a silicone part via mold, then have it backed by something structural (aluminum, G10, PP)
Silicone safe and knock some of the heat down for the underlying component.

Silicone isn’t nearly rigid enough. They are made of polypropylene. Most of the pots are. Just a different grade. Nylon would probably be ok, HDPE OR UHMW won’t hold up to anything over 180f. Don’t even try any polyethylene. Polypro is usually good to boiling.

9266K86 - PTFE, 6" x 6" x 1/4"

1 Like

Silicone could just be the ‘skin’. With an underlying rigid component.

If it’s some sort of shower head the silicone skin part could feature multiple nipples/funnels that protrude below the rigid item. Therefore, silicone takes the heat and hits the mark on food safe, but mechanically attached to the structural item below for rigidity. Without knowing the design/space limitations off hand this is hard to verify, but again it an option from outside looking in.

Another shot in the dark - revisit the alloy option with thin stainless or copper and add a heating element off the side. Food safe and the temps are kept up to minimize loss of heat.

1 Like