Author Topic: Injector always sucking air  (Read 673 times)

Offline durguin

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Injector always sucking air
« on: 11/12/20 22:58 UTC »
Hi all, Sorry if it's a duplicate but can't find answer so...

I started pouring soft plastic baits couple of weeks ago and I am having problem with my injector since. It's a 6 oz do-it injector. I tried ecerything, heating it, washing it, oiling it, I even changed the two seal rings but still, I am sucking air every time. I tried pouring plastisol right in it and it worked well but I don't like this method because I don't feel it's a safe way to proceed... So what am I doing wrong ? I checked videos on youtube and i don't see what I am missing... Thank you for your help in advance!

Offline WALLEYE WACKER

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Re: Injector always sucking air
« Reply #1 on: 11/13/20 00:29 UTC »
durguin  When I pull plastic into the injector I put the injector so it is touching the bottom of the Pyrex and before I go to inject I pin it agents the side of cup and purge some plastic out so there is no air it the injector. Then I inject the mold you need to have a little more plastic than what you need to fill the mold or you will suck air into the injector. 1/2 a cup equals 4 oz. I always do 1-2 cup batches because I’m pouring enough molds so there are 12 or more bait’s being made in a round. Make sure you pay attention to how much the mold or molds your pourIng takes too fill them and write down how much plastic it takes to fill plus the recipe so you can duplicate it when ever you want.Hope this helps you.
May your days be filled with sun shine and you always have a tight line. AMEN

Online ctom

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Re: Injector always sucking air
« Reply #2 on: 11/13/20 07:16 UTC »
durguin,

Try this. When you are ready to inject and the injector is empty, put the nozzle directly into the cup of plastic about 1/2". Pull up o the injector handle about 1/4" then immediately inject it back into the plastic in the cup WITHOUT actually removing it from the plastic in the cup, then just as quick pull plastic up into the injector for you mold fill. keeping the injector as upright as possible. Don't fuss with the nozzle having plastic on it as it will act as a seal when its pushed down into the injection port. Now inject your mold. If you are doing a couple molds in succession just go from the first to the second, third.....with the injector being held straight up.

I don't ever pop the nozzle and fill the tube by pouring as too much air can get into the injector and can be tough to get out if the plastic skins before the injector is stood upright.  Pulling that initial tiny bit of plastic into the tube then expelling and refilling quickly creates a seal on the injector plunger's face and can help eliminate any air being pulled into  or being passed from behind the seals on the plunger.

Offline Lines

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Re: Injector always sucking air
« Reply #3 on: 11/13/20 08:12 UTC »
Durguin,
I really don't have any other advice to add, but would like to welcome you to custombaits.com
There are many YouTube videos showing injection methods. Hopefully you can get this resolved.
I'm sure you will.

Online ctom

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Re: Injector always sucking air
« Reply #4 on: 11/13/20 08:30 UTC »
Thanks Lines.....I was going to start my post with a welcome and got interrupted.

Welcome aboard durguin!

Offline brandx112679

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Re: Injector always sucking air
« Reply #5 on: 11/13/20 12:08 UTC »

 I do as Walleye Wacker does, as never have trouble with gitting air in my injector. There is no wrong way as long as you get the air out.
 Wanted to welcome you to the forum.

Offline efishnc

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Re: Injector always sucking air
« Reply #6 on: 11/13/20 18:28 UTC »
I also used to get air in my injector/injections and tried various methods to stop this (with no real success) until JerryV, one of our long lost forum administrators, told me about pouring plastisol directly into the injector.  For me, this was a game changer and I'll never go back to drawing it in. 

However, I understand you don't feel safe with this (yet) and may never will, so I will offer some advice that I also received related to your dilemma (but never used because I was happy with the results from pouring into the injector)... try wrapping your plunger piston with some teflon tape (aka plumbers tape) to create a tighter and wider sealing area inside the injector... again, I never used this advice, but it came from another forum member and sure sounds logical.  Best of luck!

Online Lamar

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Re: Injector always sucking air
« Reply #7 on: 11/14/20 07:12 UTC »
  I always suck the plastic in and then tip the injector nose up and purge the air out. Or in other words inject slowly till you see plastic come out the tip. Then you know for sure all the air is out of it. Then inject the mold.

Offline Les Young

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Re: Injector always sucking air
« Reply #8 on: 11/14/20 17:11 UTC »
Welcome aboard. I always pull plastic into the injector while holding straight up & then get over the cup with the injector right above the cup with the handle section lower then the edge of the cup & i push slowly  until i get pure plastic to purge the air out & then inject & never have a problem.

Offline durguin

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Re: Injector always sucking air
« Reply #9 on: 11/14/20 19:07 UTC »
Hi all!

First of all thank you for all your welcomes and also the great answers, it is very appreciated!

I did not had time to try your tips yet but wanted to clarify that it is not only a bit of air my injector is sucking, sometimes it ends being only half filled and I am missing plastisol to fdill the mold.

For the advice with the teflon tape over the piston, do you mean over the seal ring ? And are you talking about white teflon tape like the one used for pool ?

Thank you alla agin for your help, I will come back as soon as possible to give you news!

Offline bassinfool

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Re: Injector always sucking air
« Reply #10 on: 11/17/20 10:45 UTC »
I pour the plastic directly into my injectors which completely eliminates the possibility of creating an air pocket.  However, this is dangerous and the risk of burning yourself if not being extra cautious and wearing the proper safety equipment cannot be overstated.  I have been doing things this way for years and have never been burned, but I always take extra precautions and am as safe as I can possibly be to avoid injuries.  Working as a trauma and burn ICU nurse for >5 years has led me to desire to never be burned.

Offline durguin

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Re: Injector always sucking air
« Reply #11 on: 11/17/20 16:29 UTC »
Hi all,

ok so using some of your comments, I succeeded to use my injector correctly but not all the time. So I ended up pouring the plastic directly on it, using heat resistant protection gloves and with great precautions.

I still don't think it's the best way to go and I will continue to try to understand what I am doing wrong, but for the moment I am better like this, or I will end up trashing all the stuff over frustration... :)

I am currently looking for some king of claw that I could install on the side of my working table, over the concrete floor directly to pour inside the injector without even having to hold it at the same time. I think this may be the best solution for me.

Tanx again and I will come back here often!

Offline efishnc

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Re: Injector always sucking air
« Reply #12 on: 11/17/20 21:27 UTC »
For the advice with the teflon tape over the piston, do you mean over the seal ring ? And are you talking about white teflon tape like the one used for pool ?

Yes, around (on top of) the O-ring.

Online bryanmc57

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Re: Injector always sucking air
« Reply #13 on: 11/18/20 07:15 UTC »
I draw plastic into my injector straight from the cup and I never have an issue with air in the injector..  Pouring hot plastic into an injector just sounds like a recipe for disaster to me (yes I know there are some that do it).  Logic says that any air in the injector should rise to the top when the injector is vertical. 

Offline Apdriver

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Re: Injector always sucking air
« Reply #14 on: 11/18/20 09:21 UTC »
I draw plastic into my injector straight from the cup and I never have an issue with air in the injector..  Pouring hot plastic into an injector just sounds like a recipe for disaster to me (yes I know there are some that do it).  Logic says that any air in the injector should rise to the top when the injector is vertical.

+1 on Bryan’s comments. For the life of me, I can’t understand if this is an injector issue or a process issue.