Weaponeer.net
Welcome Guest
Not a member yet? Register Now! or Login
0 member and 37 guests currently online.
Search Forums:
Site Partners

This site is Gunny Approved

 


Site Login
Username

Password

Auto Login
Add me to the active users list


Forgot password | Register

Online Users
Total Users Online: 37

We have 0 member(s), 7 spiders, 37 guest(s), and 0 anonymous users online.

Members Online:
None.


[ View Full List ]
[Based on the last 10 minutes]

The most online was 215 and occured on March 28 2013 at 11:38am.
We had 5 members, 203 guests, 0 anonymouse users, and 7 bots online at the same time.
Todays Visitors (65):

Molding plastic
Weaponeer Forums : Casting

Posted in Casting
Members Viewing Topic: None

Post New TopicPost Reply
Prev Topic :: Next Topic
Author Message
  dcorb

Avatar
BG
BG

Joined: November 28 2004
Location: United States
Posts: 10168
Posted: February 25 2009 at 6:22pm | IP Logged Quote dcorb

Funny thing is I am not even sure what I want the MP5 grips for as I am not building an MP5. I just like the shape for use on a scratch built something. So I can use the outer shape for a mold and dream up something different for the inside.
Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb
  Status: Offline
View dcorb's Profile Search for other posts by dcorb
 
  Stomper

Avatar
Level 1 Site Sponsor
Level 1 Site Sponsor

Joined: December 06 2008
Posts: 57
Posted: February 25 2009 at 8:13pm | IP Logged Quote Stomper

midmichigun wrote:

dcorb,

Ya, the MAC is a snap. You could probably get away with the epoxy resin idea that I was talking about earlier. I was also thinking about stuffing my AK grip mold with fiberglass bodyfiller. Simply glue the two halves with the starting material.

The MP5 is alot more difficult. I gave you my best idea in an earlier post. Stomper, ya got anything for him?

 

 

Yeah, that MAC-11 grip would be a snap... as for the MP-5 grips... that internal profile (especially on the larger one) has got me stumped ATM.  I'm now piqued on coming up with a "garage" molding solution, but since the 3 brand new AR-15 lowers and 1 A3 upper that I ordered a couple weeks ago JUST arrived a few minutes ago I'm a bit distracted... I'll ruminate on this a bit and get back to you.

Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb
  Status: Offline
View Stomper's Profile Search for other posts by Stomper
 
  midmichigun

Avatar
CPT
CPT

Joined: March 01 2008
Location: United States
Posts: 1921
Posted: February 26 2009 at 9:11am | IP Logged Quote midmichigun

dcorb,

But on the other hand, if you are NOT planning to build an MP5, and just like the outside contour, perhaps you already have the solution. Simplify the internal portion of the parts and concentrate on the outside.

Stomper....

I don't know why NEW gun parts would have you distracted! You must stay on task!

Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb
  Status: Offline
View midmichigun's Profile Search for other posts by midmichigun
 
  gundoctor

Avatar
Moderator Group
Moderator Group

Joined: January 09 2008
Location: United States
Posts: 2052
Posted: March 01 2009 at 11:09pm | IP Logged Quote gundoctor

Well, finally getting around to a little work on some new patterns for making my molds with.

Here is one at step one.   Produced by using two different grips, sawing each in half and then fitting together to produce a new US grip for HK and Cetme.   After gluing the two halves, some bondo is applied to blend the contours of the junction and the thumbrest.  



I think my catalyst was weak because my Bondo is drying slow.

The lower part of the grip will also be recontoured and "bondo'd" as appropriate for the new design.  Then it will be fitted over a mandrel that approximates the interior of the original HK grip and a two piece mold created.    Then the mandrel can be placed in the mold, resin injected, and a new grip created--One that I think is a significant improvement over anything available commercially.


Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb
  Status: Offline
View gundoctor's Profile Search for other posts by gundoctor
 
  gundoctor

Avatar
Moderator Group
Moderator Group

Joined: January 09 2008
Location: United States
Posts: 2052
Posted: March 02 2009 at 1:25am | IP Logged Quote gundoctor

dcorb wrote:
Funny thing is I am not even sure what I want the MP5 grips for as I am not building an MP5. I just like the shape for use on a scratch built something. So I can use the outer shape for a mold and dream up something different for the inside.


Exactly.  Smooth the inside with clay to make your pattern so it is easy to mold and demold
Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb
  Status: Offline
View gundoctor's Profile Search for other posts by gundoctor
 
  dcorb

Avatar
BG
BG

Joined: November 28 2004
Location: United States
Posts: 10168
Posted: July 07 2009 at 7:58pm | IP Logged Quote dcorb

  Status: Offline
View dcorb's Profile Search for other posts by dcorb
 
  Inabadhood

Avatar
2LT
2LT

Joined: January 04 2008
Location: United States
Posts: 1352
Posted: July 08 2009 at 9:20am | IP Logged Quote Inabadhood

NICE!!! 

Some good ideas can be had there...

Also, I've been reading tons of stuff on the Instructables website for a long time now...

Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb
  Status: Offline
View Inabadhood's Profile Search for other posts by Inabadhood
 
  midmichigun

Avatar
CPT
CPT

Joined: March 01 2008
Location: United States
Posts: 1921
Posted: July 08 2009 at 10:03am | IP Logged Quote midmichigun

Citizens,

Yes, lets bring this thread back to life! Sadly I will have limited access/ time to work along with this...

Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb
  Status: Offline
View midmichigun's Profile Search for other posts by midmichigun
 
  weaponeer

Avatar
Admin Group
Admin Group

Joined: July 16 2005
Location: United States
Posts: 25308
Posted: July 08 2009 at 5:39pm | IP Logged Quote weaponeer

I would like to see this thread get more notice these days with other photos of the process, and ideas on projects.
Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb


__________________
Weaponeer.net survives on donations made each Month by the membership. if we don't get enough donations, our hosting provider turns off the website, and only turns it back on after the hosting fee's have been paid. Please... every donation counts
  Status: Offline
View weaponeer's Profile Search for other posts by weaponeer Visit weaponeer's Homepage
 
  Stomper

Avatar
Level 1 Site Sponsor
Level 1 Site Sponsor

Joined: December 06 2008
Posts: 57
Posted: July 08 2009 at 6:07pm | IP Logged Quote Stomper

I have been slammed with work for MONTHS... up until last week, then I got laid off.  Ain't that nice?  You work your ASS off for the company so they can maximize profits, then poof, "sorry... we don't have anything else for you, here's you final paycheck".  Flippin' economy in the People's Republic of Oregon!!  Its a good thing I have some money set aside, as well as being able to turn a few (thousand) bucks out of my workshop to help supplement the paltry amount I get for unemployment benefits.  OK, TMI... 'nuf complaining.

I now have some spare time (at least until I get another job), so I will be continuing some of the (commissioned) projets I have back-logged (mainly non-gun related) and taking progress photos.  My workshop is an absolute MESS and needs to get cleaned out first, then I have to tool up for my casting projects that have been languishing on the shelves for the last 5-6 months. 

I'll post them on these forums (maybe a new thread?) when I have something to show, you can at least apply the same principles in your projects no matter if its gun related or not.

Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb
  Status: Offline
View Stomper's Profile Search for other posts by Stomper
 
  dcorb

Avatar
BG
BG

Joined: November 28 2004
Location: United States
Posts: 10168
Posted: July 08 2009 at 7:17pm | IP Logged Quote dcorb

Sorry to hear about the job Stomper.

Excited to see your projects. 

Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb
  Status: Offline
View dcorb's Profile Search for other posts by dcorb
 
  Inabadhood

Avatar
2LT
2LT

Joined: January 04 2008
Location: United States
Posts: 1352
Posted: July 09 2009 at 9:08am | IP Logged Quote Inabadhood

I agree...  Sorry to hear about the job.

It's sad to hear all these stories about LOTS of companies laying off some of their best & most productive workers because their 'corporate views' tend to look down on their skilled & knowledgable employees as an EXPENSE rather than looking at them as AN INVESTMENT!!!

Now if they don't hire you back the second production orders come back in sometime in the future they're going to have to TRAIN NEW PEOPLE who don't know the ins & outs of their particular equipment, their machinery, their policies, and their operations!

Then they're going to be scratching their heads wondering why their production is slow in starting up!!! 

Also, I'm excited to see some of your upcoming projects too!

I have a couple ideas for some build stuff, but I don't know if it's feasible, possible, or how to go about it so I'm just biting my tongue until I can learn more about the basics of casting polymers/plastics/rubber.

This is an area where I know pretty much NOTHING, and would like to learn more...

Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb
  Status: Offline
View Inabadhood's Profile Search for other posts by Inabadhood
 
  midmichigun

Avatar
CPT
CPT

Joined: March 01 2008
Location: United States
Posts: 1921
Posted: July 09 2009 at 9:59am | IP Logged Quote midmichigun

Stomper,

I hear ya... I have been down for a few months. Hang in there and apply everywhere... something has to turn up!

I want to get this plastic thread kicking also... just in a holding pattern with Saudi coming up... and needing to save money while out of work... ya know, the usual thing.

Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb
  Status: Offline
View midmichigun's Profile Search for other posts by midmichigun
 
  dcorb

Avatar
BG
BG

Joined: November 28 2004
Location: United States
Posts: 10168
Posted: July 09 2009 at 10:23am | IP Logged Quote dcorb

Hey Mid,

maybe you can pickup some new plastic molding skills in Saudi

Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb
  Status: Offline
View dcorb's Profile Search for other posts by dcorb
 
  Stomper

Avatar
Level 1 Site Sponsor
Level 1 Site Sponsor

Joined: December 06 2008
Posts: 57
Posted: July 09 2009 at 11:02am | IP Logged Quote Stomper

Thanks for the sentiments guys... didn't mean to sound like I was whining tooooo much.  Although I'm a capitolist "pig", I believe that the "Corporatism" path our country is going down is WRONG... we're being sold out to the highest bidder by our elected "officials"... so much for their oaths to "protect & defend" the Constitution... when do you think our military will step in and uphold their oaths about "all enemies, foreign & domestic" and clear those traitors out of Capital Hill, and 1600 Penn. Ave, and seal the Southern border?  I know, one could only dream...

In my mind going to Saudi is ONLY (slightly) better than going to Iraq or Afaganistan... I believe that plastic molding (as a hobby) is forbidden over there unless you have a beard that is no less than 4" in length, are ALWAYS facing the East while doing it, and you MUST wear sandals...  

 

OK, I know all of that was random... BACK ON TOPIC!!

 

Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb


__________________
The problem with Socialism is eventually you run out of other people's money!!
  Status: Offline
View Stomper's Profile Search for other posts by Stomper
 
  orions_hammer

SM
SM

Joined: February 14 2008
Posts: 423
Posted: August 24 2010 at 4:25am | IP Logged Quote orions_hammer

How could I have not seen this thread before?  Here I'm busily milling AR lowers from a dang cutting board when I could just cast 'em, like midmichigun's doing?  And you can just watch Freeman supply casting videos on youtube?

Sign me up!

I'm going to start with some small parts, so I don't use up too much expensive resin while making beginner mistakes.  Specifically, literally the *only* gun part I haven't made myself yet is the fire control group (trigger, hammer, disconnector), mostly because imported AK parts are crazy cheap--currently just five bucks!

I think a cast-urethane fire control group would work.  The Steyr AUG uses a plastic fire control group, including hammer.  On an AK, a plastic hammer might get a bit beat up where it hits the firing pin, but you could cast in a hardened steel plate if needed. 

I ordered up some Freeman 1035 flexible urethane moldmaking resin, and cast up a little test block tonight!
Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb


__________________
See all my builds at http://www.orions-hammer.com
  Status: Offline
View orions_hammer's Profile Search for other posts by orions_hammer
 
  orions_hammer

SM
SM

Joined: February 14 2008
Posts: 423
Posted: August 24 2010 at 5:33am | IP Logged Quote orions_hammer

Here's where I started: an ordinary AK Tapco G2 double-hook trigger set.  Double hook should be a little safer, given that a trigger failure could cause the gun to fire, plus it's a lot easier to cut off the extra hook than to grow a new one!  I also like how the G2 set has straight lines, instead of the weird scoliosis on the eastern block trigger hooks.



Here's a preview of what the finished cast-in assembly will look like.  Once this is surrounded by tan flexible mold, I'll remove the AK parts, leaving part-shaped holes I can then fill with hard urethane.  I'll pour the finished product into the tip of the trigger, which hopefully will percolate down into the hammer and disconnector without leaving bubbles!


Step one in this assembly is to fill up the space between the trigger hooks, here with a slightly ground-down 3/8" thick steel bar.  Tricky part is thinking about what the space will *end up* like, after surrounding the thing with flexible urethane mold.  It seems like the channel down the middle of the trigger would be hard to extract from the urethane mold, so I'm blocking it up to leave a more convex shape.


I'm probably way over-thinking this mold design, but I want to cast accurate, repeatable, near-finished parts with holes precast.  So I'll cast in some 5mm rod, which will form the holes in the eventual parts; the rod will be held by the steel block during casting.  I may need to put a taper on these rods to have any hope of extracting them from the cast urethane parts, although they are nicely polished O-1 right now.

To mark the rod hole locations accurately, I held the parts in the right place, and struck the centers of the holes with a transfer punch.


I then drilled to 5mm, and stepped the hammer axis hole out to 11/32".  The disconnector also needed a tiny bit of clearance around its hole, which I milled in:


I punched in some "ALASKA 2010" markings, in case I want to use these parts in an Alaska Firearms Freedom Act build.  Man, it's tricky to get those tiny 1/16" letters to line up!


I made a little "boat" out of cardboard and duct tape to hold the tan molding material.  The plastic bag is a liner, although something thinner like saran wrap, or conforming like aluminum foil, would have worked better.


I added a pouring sprue, and a few little pouring channels, with modeling clay.  I then coated everything with midmichigun's patented "vaseline + isopropyl alcohol" mold release compound--it's really amazing watching vaseline *dissolve* in alcohol!  I also hit the mold with a heavy coat of hairspray.  I have no idea if any of this is really needed, but I really didn't want to destroy the mold pulling my AK parts out.  OK, ready to mix the urethane molding resin!


Wait, how much do I mix?  Well, I can calculate a rough volume for the "boat" interior as 200mL (area of trapezoid times height).  The steel die parts weigh a total of 255g, and steel's density is 7.8g/cc, so they should occupy like 33mL of the mold.  That's like 170mL total resin needed.

Luckily Freeman 1035 is 1.02g/cc (basically 1g = 1mL), so I can just weigh out 170g total (85g A, 85g B).  I'm using handy little portable electronic scale on the right to weigh components, which come in mustard-like squeeze bottles.  This resin is designed for moldmaking (alternative is a silicone rubber), so it's quite flexible yet springy.  It also looks like coffee, but doesn't taste as good!


Pot life on this stuff is 30 minutes, so I spent a good five minutes just mixing it thoroughly with a popsicle stick.  I then very slowly and carefully poured the resin into my mold boat, starting at the low corner to reduce the likelihood of bubbles.


I ended up with a little bit of excess resin, so I dumped it around a random Romanian trigger in a plastic bag, just to see if I really need all this planning and effort to make a usable mold!

Here's what's drying on my kitchen counter now.  The three dots are 5mm steel rods running through each fire control part.  There are some tiny bubbles, which is common with urethane.  I need to set up my vacuum pump with an actual vacuum chamber, and I should be able to get rid of the bubbles in future pours.


I have to wait until tomorrow until I can gingerly slice it open, and see how the mold turned out.  Fun stuff!
Agree x 3
Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb


__________________
See all my builds at http://www.orions-hammer.com
  Status: Offline
View orions_hammer's Profile Search for other posts by orions_hammer
 
  midmichigun

Avatar
CPT
CPT

Joined: March 01 2008
Location: United States
Posts: 1921
Posted: August 24 2010 at 7:59am | IP Logged Quote midmichigun

O- Hammer,

Good to see ya casting around for something to do!

This looks real good. I have been thinking about getting back into the casting thing again... glad to see that you are working on it.

The vacuum pump and chamber have been a real issue for me. I created one years ago, and had lots of problems. However, I think I have a SS and also a glass LARGE beaker that may allow me to pull down a few torrs. I do have a vacuum pump now. The valves are sorta shot, but I can pull down some water still with it, without a rebuild.

Remember that you can imbed steel or metal into your parts during casting to give you more structural strength.

Anyways.... looking forward to your progress.

Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb
  Status: Offline
View midmichigun's Profile Search for other posts by midmichigun
 
  weaponeer

Avatar
Admin Group
Admin Group

Joined: July 16 2005
Location: United States
Posts: 25308
Posted: August 24 2010 at 9:31am | IP Logged Quote weaponeer

glad to see this thread back again.  looking forward to seeing more progress.
Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb


__________________
Weaponeer.net survives on donations made each Month by the membership. if we don't get enough donations, our hosting provider turns off the website, and only turns it back on after the hosting fee's have been paid. Please... every donation counts
  Status: Offline
View weaponeer's Profile Search for other posts by weaponeer Visit weaponeer's Homepage
 
  Holloway

Avatar
MSG
MSG

Joined: October 26 2009
Location: United States
Posts: 267
Posted: August 24 2010 at 1:29pm | IP Logged Quote Holloway

orions_hammer wrote:
I then coated everything with midmichigun's patented "vaseline + isopropyl alcohol" mold release compound--it's really amazing watching vaseline *dissolve* in alcohol!



Damn, why didn't I think of that. I was used straight vaseline. I brushed it on and got streak marks in the plastic.Confused I plan on returning to my sidesaddle project when it cools down. Probably late October. I still need to piece together a vacuum/pressure chamber.
Agree Disagree Funny Informative Polite/Nice/Friendly Useful Optimistic Artistic Late Bad Spelling Bad Reading Dumb


__________________
Proverbs 18:2 "A fool does not care whether he understands a thing or not; all he wants to do is show how smart he is."

http://hollowaysgarage.wordpress.com/
  Status: Offline
View Holloway's Profile Search for other posts by Holloway
 
<< Prev Topic Casting Next Topic >>

<< Prev Page of 10 Next >>
  Post ReplyPost New Topic
Printable version Printable version

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot delete your posts in this forum
You cannot edit your posts in this forum
You cannot create polls in this forum
You cannot vote in polls in this forum
Forum Jump


This page was generated in 5.1094 seconds.