Making my own soft plastic injector

[kbeeb374]

So I started getting into making my own plastics last winter with pop molds of existing baits and a couple I designed out of modeling clay.  They worked well and I still use the molds, but, as I'm sure most of you can relate, that made me want to start injection molding some baits.  The only problem was that the cheapest injector was like 40 bucks and only 4 oz. I thought I could probably make one of those.. so I called my friend who has a lathe and I drew it up on the computer.  Here is the process and results:

Starting materials:

Cutting the plunger:

I don't have pics of cutting the nozzle cuz my friend did it when I wasn't there but here is the final product and first set of baits:

[smalljaw67]

You have a good friend, just that mechanical drawing is worth $40. You are fortunate to have someone that is a skilled machinist and when I read the title I was waiting to see a bicycle pump and electrical tape and I'm happy it wasn't that. I've been witness to homemade hand injector failures as a friend had me come over to watch his genius come to life as he was going to inject some soft plastics with an injector he made himself. The result was the heat from the plastic weakened the o-ring to the point that once he started applying pressure it just gave out and hot plastic spewed everywhere. I was lucky enough to realize there could be a problem so I stood back and avoided getting burned but it was a lesson learned and I'm glad that isn't what I'm seeing here. Your buddy did a nice job to say the least.

[cadman]

Very nice machine work. I see you said you made your own cad drawings. What cad software do you use? I am a machine and sheet metal designer by trade.

[kbeeb374]

I don't know what happened to that reply... it disappeared on my computer..

Anyway,  I use solidworks at work but I also have experience with Creo, inventor and autcad. definitely fun to play around with fishing stuff on there.

[cadman]

7 minutes ago, kbeeb374 said:

I don't know what happened to that reply... it disappeared on my computer..

Anyway,  I use solidworks at work but I also have experience with Creo, inventor and autcad. definitely fun to play around with fishing stuff on there.

That's interesting, as I currently use Solidworks 2016. I didn't recognize the drawing that is why I asked. I also have experience in Auto Cad, Cadkey, and Metalsoft. Hence that's where my screen name came from.

I also design custom molds as well for my personal use. Cheaper than paying for engineering time on drawings.

[kbeeb374]

2 hours ago, smalljaw67 said:

You have a good friend, just that mechanical drawing is worth $40.

I actually did the drawings myself on solidworks after designing and modeling it.  My friend is quite skilled at many things, this being one of them. I consider myself quite fortunate.

2 hours ago, smalljaw67 said:

I've been witness to homemade hand injector failures as a friend had me come over to watch his genius come to life as he was going to inject some soft plastics with an injector he made himself. The result was the heat from the plastic weakened the o-ring to the point that once he started applying pressure it just gave out and hot plastic spewed everywhere.

Sounds like a disaster... hope no one got hurt!

 

1 minute ago, cadman said:

That's interesting, as I currently use Solidworks 2016. I didn't recognize the drawing that is why I asked. I also have experience in Auto Cad, Cadkey, and Metalsoft. Hence that's where my screen name came from.

Yeah I use 2015 SW, but my company has some weird defaults in their drawing formats Which is why it may look weird.

[kcdinkerz]

Sweet!