The Home Machinist!

Wasn't sure if this belonged here or in the junk drawer, but I'll be machining the part, so it's here for now.

Our Boy Scout troop has a bunch of water jugs we use when we camp where there is no water available.

These are the ones we use:


There is a little plastic cap that fits inside the retaining ring that holds the spout when it's closed and serves as a cap on the end of the spout when the spout is deployed.

It looks like a flat disk with a little tube on it.

The scouts, or course, lose them and the manufacturer does not provide replacements.

What plastic would be suitable for this?

It has to be food grade and machinable. Something that is not brittle as well.

I have a pile of mystery white and grey plastic but I'm not sure what they are.

I have thought about gluing velcro to the center of the cap and the opposing side on the top of the can, but I'm not sure even that will help.

Steve

polyethylene and polypropylene are safe bets, but it's the actual manufacturers resin that get's approved, not the generic material. (IE, DuPont SuperDuperHDPE XYZ, not "hdpe").

Might want to ask your local plastics supplier for a food grade material.

Couldn't you cut up a cheap polyethylene cutting board?

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People who say, "Google is your friend" need to talk to a Chinese dissident.

check usplastics.com

Polyethylene is what milk jugs are made of. I would buy UHDPE (Ultra high density polyethylene), Enco sells it in round and sheet. It cuts easy will not break is safe, and cheep. use very sharp tools with a large rake. the stuff can not be sanded smooth after you are done so you need to cut to a finnished surface. OK they say you can sand it but good luck. anyway that is what i would use.

When I cut plastics on the lathe I use a medium run speed, a lil bit slower than where I turn steel with a sharp sharp bit and with a really fast feed rate. I try to land at finished size from way out to get a super smooth finish. Slow feed melts the surface some and leaves it rough. If you try to take a small finish cut it leaves rough surface showing all your tooling marks.

Ertalyte (R) or PET-P. Food grade and easy to machine. Will not absorb moisture and is stable at elevated (210 deg. F) tempertures. From personal experience with this plastic, it machines good with sharp tools and high speeds and feeds. Drills easily at high feed rates and sharp high clearance drills. Not very hard, kind of like nylon but not as stringy. It is quite dense and somewhat heavy as plastics go. It has good wear resistance too. I used it to make strainers for milk jug filling machines.

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Bruce Mowbray
Springville & Southern RR
TMB Manufacturing & Locomotive Works

I have a pile of plastics in the drawer, but not sure what any of it is.

I have an email in to a local plastic supplier ( http://www.modernplastics.com )to see what they have in drops.

The PET-P sounds like a good choice. The Modern Plastics has drops of that. Pretty cheap - we can make a pile of caps for less than $10.

Steve

Make a test piece and give the water jug to some kids who get on your nerves. If they're still around a week later, you're golden.

_________________
People who say, "Google is your friend" need to talk to a Chinese dissident.

We already gave them the tent that leaks. Hasn't stopped them so far.

Steve

Looks like you're way ahead of me.

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People who say, "Google is your friend" need to talk to a Chinese dissident.

Back to the Scouts; it would seem there is a way to melt the food grade before it became carburised, that is, one layer in contact still preserves the origional rating. Seems a good time to mention something about the Scouts and the fine Men I had the fortune to learn from in my youth. I forget if they were troop leaders, bears or counselers. It just comes back now. We did lots of things kids ordinarily couldn't or wouldn't do. We had an Adult in charge. good times.