Molding gun frames- possible methods and materials.

[mike-hunt]

Any ideas on Molding gun frames as an alternative to the more costly and time consuming method of machine milling ? If some one was considering manufacturing a small number say 10 to 50 identical frames for a 9 mm semi auto pistol what would be an affordable and effective material to use? I was considering a heat resistant plastic reinforced with carbon fibers or some kind of ceramic I believe zirconium ceramic is the most suitable but can't find any info on manufacturing methods for this ceramic.I also found this product called tooling plastic and thought it would be ideal if it could withstand the heat and stress of gunfire. http://www.hobbysilicone.com/resin.htm#tooling
There must be past posts on this so far my searches have only come up with large lists of unrelated posts.

[chemdude1999]

I like your idea and believe it is worth pursuing. However, even moldings and castings have to be finished machined. I was going to purchase a 6.5 Creedmore rifle this year. Instead I got a small mill (not the mini-mill, couple steps up) from Grizzly. Put back some money and get the right tools. It is well worth it.

I do like the idea of castings. I would be more interested in metal castings. I know Springfield Armory uses investment casts for their M1's. A 9mm handgun wouldn't need that kind of strength. My concern would be insuring the thorough homogeneity in the material (metal or plastic) as inclusions and other imperfections can cause failure.

Perhaps checking out some of the charcoal furnace methods of pouring metal and castings is worth another look. It is very cheap and you could duplicate easily. The key would be the sand molds.

As for plastics, what does Glock use?

[mike-hunt]

Metal casting is something worth looking into I found this video on building an AR-15 from an aluminum casting http://www.diyguns.com/product_info.php?products_id=29
dremel attachments should be suitable for any machine work on aluminum or plastic. some nice ones here. Http://vanda-layindustries.com/
I still like the idea of casting in plastic as it only requires mixing two liquids in equal parts and you have a set frame in around 30 minutes.
The plastic used in Glocks is called "polymer 2 "I can't find much information on it . It may be a only used by Glock and unavailable for perchance as a raw material.

[a3990918]

I also found this product called tooling plastic and thought it would be ideal if it could withstand the heat and stress of gunfire.

The only tooling resin that I have any experience with is used for filling in warn spots on machinery beds and ways or to level out low spots on tables etc. It is very hard and long wearing but alas, I feel it would be way too brittle and unable to withstand the stress and loads of firing and stopping the slide on recoil.

Metal casting is something worth looking into I found this video on building an AR-15 from an aluminum casting

This was a forging, not just a standard casting that an ameatur with a charcoal or propane furnace could cast. Forgings are many times stronger and more durable than a casting is.

I know that you are trying to avoid any machine work, but if you can find someone that you trust who has access to a CNC Mill, I feel that would be the way to go. Write up the program, insert a billet of whatever the material De Jour is and let it do its thing. High repeatability and parts interchange. You could probably find someone who works at a machine shop to do these for you on the side. Just grease his palm a little to make things go easier...:D

[Demolition Man]

You can cast metals, but, I'd stick with investment casting as opposed to sand casting. You aren't making a Gingery Lathe, you're making a firearm...a tiny cannon, held by a person, needs to be tolerant of high pressures.

I'm with a3990918 on this one, CNC mill it. If you want to do it on your own, there are hobbyists out there who have hooked up CNC equipment to the mini-mills and such that you can get from Harbor Freight. It's not the fastest solution, being such a small mill, but you can easily make several same-type parts out of the same piece of billet, and make several guns in the time it'd take you to hand mill one.

Of course, your own CNC mill would come in handy for working on your legal guns as well, you can make your own triggers and such.

[hybrid]

Basicaly let me start out by telling you that I have a vast amount of knowledge on the techniques required to produce parts via hand made or production runs.

Casting plastic in itself is not difficult persay but it is not in the grasp of most civilians tooling wise.

You must understand what type of plastic you want to use and most of these plastics are a single use item, meaning that when if finaly hardens it will not be reusable.

The next thing is understanding casting techniques in general. To pour cast an item is to have a weak item. In metals, pourcastings are generaly dirty, porous and non structural. The first step in creating something stronger is to spin-cast the part. This is the mold on a turntable and is spun to push the material out and compact it on the outer edges of the molds, creating a more dense part.

In plastic however, most things are pressure cast. Meaning that the molten plastic is under extreme pressure and the nozzles are aligned in the molds and the product is forcibly pushed into the mold and squeezing out the air.

There are several troubles with plastic molding.

1) the mold must be made. Generaly these molds are machined out and then finished. If you do not know anything about mold making you will not understand the difficulty of finishing. This is a complex subject that can get into a large discussion.

2) Plastic selection.............wow, there are so many issues here Im just going to leave it as a serious problem

3) Equipment. Youll need mills, lathes, edm burners and various other things to build your prototype and then you have to mirror it into a mold. This can take months for the skilled person, years for a layman.

It would be far wiser to get some community college classes on drafting and then cad/cam programming. Buy yourself a cheap used CNC mill and make yourself the parts. An entire gun can be made with a mill and lathe and you can make a quality gun no less. Trying to go the polymer route without an enourmous (and creating an interest in what youre doing) sum of money is a bad idea.

Good luck

[mike-hunt]

Yes a c.n.c mill does seam the way to go and not as expensive as I thirst thought .Wile I am still shore plastic or ceramic casting would be possible the time spent experimenting and testing would not really make it practical and it doesn't look to be the cheep alternative I had hoped .Thanks to all for your help seems I still have quite a bit more research and learning to do.

[megalomania]

You could use 2 part liquid plastics that catalyze when mixed and harden. A family member of mine uses these in his business to make large structural and decorative parts. The hardness of the plastic depends on the ratio of the components, and in general it can harden up to a nice high density plastic material.

If you go the extrusion molding route you will need to exclude air as most plastics decompose when exposed to oxygen beyond their melting point. The steel blocks need to be internally water cooled... I have worked at several companies that make plastic extruded parts, duplicating that kind of equipment is very difficult.

[amachinist]

Loctite produces a compound, Loctite® Fixmaster® Steel Liquid, could easily be used as a casting material for a frame blank with steel inserts for the slides. Examine the Glock and the calico for ideas on how to shape the slides. Secondary coating will be required, this compund will corrode.