casting small plastic parts

[Paul Saffold]

Anyone with experience casting small plastic parts?

I have a broken magazine follower for a .22 rifle that has been out of production since 1987. I have searched online for a replacement but have not found one. I'm wondering about casting one myself. There are kits, it looks to be simple. One concern is bubbles trapped since the shape is long and thin.
Suggestions and comments welcome.

235912

[Greg R Bradley]

Buy a Delrin rod from McMaster Carr and make your part on a lathe.

[Paul Saffold]

No lathe:(

I think I will try a follower from the same manufacturer (Remington). The current production (552/572) looks very similar to the one from a 582. Both are tube-fed 22s.

[Eric DeSilva]

You might take a look at this book, or see if you can find it in a library: http://www.amazon.com/Build-Plastic-Injection-Molding-Attachment/dp/1878087312/ref=sr_1_3?ie=UTF8&qid=1341329946&sr=8-3&keywords=injection+molding

I'm still scratching my head that there are plastic parts inside a gun.

[Steve Meliza]

I've cast small plastic parts, but nothing that small and subject to that much abuse so I'm not sure how well it would last. I'd try the CR-600 resin from Micro-Mark (http://www.micromark.com/casting-and-molding-supplies.html), but for the cost of the mold rubber, release agent, and resin you'd be far cheaper to pay someone to turn you a new part. Either a gunsmith or small parts machinist should be up to the task.

[Jerome Stanek]

I would try to retro fit a newer style

[David G Baker]

If Tap plastics is still in business they can give you good advice. My brother cast pistol grips that you couldn't tell from the real thing. He also cast tail lights for old Packards that he restored and you couldn't tell the difference from the original.

[Myk Rian]

I'm still scratching my head that there are plastic parts inside a gun.

It's a small plunger in the feed tube. Connects to a spring that pushes the shells to the bolt. A piece of turned wood would work in a crimp.

[ray hampton]

If Tap plastics is still in business they can give you good advice. My brother cast pistol grips that you couldn't tell from the real thing. He also cast tail lights for old Packards that he restored and you couldn't tell the difference from the original.

David , the tail lights lens got a number that told the year of the car, how are the number change each year

[Greg R Bradley]

I originally suggested buying a Delrin rod and using a lathe to make your part. If you don't have a lathe, you could easily make one or two with a drill press and a file, even a hand drill and a vise in a pinch.

This was based upon the part usage and the shape of the part. As Myk pointed out it was obvious what the part was and I suppose turned wood would work for a while but I sure wouldn't want splinters coming loose.

I am a bit familiar with plastics as I used to manage the technology for a company with a couple dozen plastics engineers manufacturing plastic injection molds and making plastic parts, mostly for the medical industy. The plastics wasn't my expertise but a bit certainly rubbed off.

[Tom Stenzel]

The original plastic broke. Why not try brass or aluminum?

I've made similar parts by chucking a metal rod in a power drill (no drill press or lathe here) spinning at a low RPM, and grinding it to shape with a Dremel.

You probably only need to get the ends cut accurately to make it work. The middle section would just need to be cut away to minimize weight and resulting inertia.

It's not fast work but you never would have to do it again.

If you do decide to use plastics make sure you test it with whatever cleaning solutions you use.

-Tom Stenzel

[David G Baker]

Ray H.
Most of my brother's Packards were from the 30's and he wasn't having any luck finding the ones he wanted so he made them from lenses borrowed from friends. He may have made them just to prove that he could. He was a machinist by trade so he had the skills.

[Mac McQuinn]

Paul,
PM'd you w/ possible source for what your looking for.
Mac

[Paul Saffold]

Thanks Mac. I'll check it out.

Greg & Tom, if Mac's lead doesn't work out, I'll try brass and files. I've got enough of them around.

Thanks for all the suggestions. Paul