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joe406

Pre-Heating injectors

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I'd be interested in hearing techniques on pre-heating injectors.  I am working in a cold environment and oftentimes the plastic is solidifying while I'm still injecting.  Besides smaller batches, I'm not sure what to do.  All of the videos I watch the plastic seems to stay fluid longer.  My target temperature is 350 and right now I'm using MF plastic but my next order is Dead on.  For me it is a race to get the injection done.  Thanks,

Joe

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I work in an unheated garage.  I have a cheap electric hot plate.  I have a metal sheet on top of it.  When I start getting ready to pour I place my injectors and molds on the metal sheet and turn on the hot plate.  By the time I get the plastic ready to inject everything is good and warm (sometimes too warm).

BTW:  I try to pour and shoot around 315 to 330, less chance of scorching.

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Sometimes I shoot new molds I make with just 1 cup of plastic to test them out in my garage in the winter... so I know the pain of using a cold injector as temps can be in the 30s-40s.

I now have a couple 2x4 blocks I use to rest the injector on with the tip / end sitting pretty far off of the wood  - under the tip of the injector I have a small alcohol lamp lit to heat it.  I don't have the injector in the flame - but above it an inch or so... it get's the tip HOT.... after 1 or two shots to warm the body of the injector up, the lamp does a pretty good job of keeping it warm/hot enough to shoot without too much of an issue.

One note - I'm pretty sure this isn't great for the o-rings... but I bought a bag of 10 o-rings from McMaster Carr - so losing an o-ring or two every now and then isn't ta big deal.

  J.

 

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I really got my butt handed to me trying to pour without preheating and doing the dual injector.  Everything just seems to cool to fast.

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Get you a high sided griddle and set the dual injector in it. Set the blending block on one of the edges. While you get the plastic heated it will warm the injector and block. Then set your Pyrex’s on the griddle to keep,it warm while you shoot. Even in cold weather this will keep you flowing. 

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I use a propane torch.   Torch a 6 oz injector for 30 seconds & it's ready to go. 10 oz I torch for 1 minute.  I have been heating injectors like this for several years. I have had no O-ring problems & no tube problems.

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Frank is spot on . That’s the Easiest way I have found to do it. Really makes a difference when doing lams. And keeping two cups warm for multiple shots on one heating.

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I use a propane torch to heat injector and molds if I need to. Griddle to keep things going for multiple shots to keep the plastic and injector hot.

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I put mine in a toaster oven set at like 150-200 degrees. I only leave it in for a couple minutes and also pre-heat my molds that way to. Work awesome in the winter when the garage is in the 30s-40s.

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On 4/4/2019 at 9:09 PM, Frank said:

Get you a high sided griddle and set the dual injector in it. Set the blending block on one of the edges. While you get the plastic heated it will warm the injector and block. Then set your Pyrex’s on the griddle to keep,it warm while you shoot. Even in cold weather this will keep you flowing. 

Thanks for all of the suggestions.  I would probably get into some trouble with my wife if I started using the torch where I'm working and have been using the toaster oven but it is just too small.  I got a griddle and will try it this week!

Joe

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I work in a garage in Denver and it can get pretty cold during the winter. I use a 80,000 BTU torpedo heater to heat the garage and I place molds/injectors on old paint cans in front of it to warm them up.

A couple of my molds will likely benefit from preheating all year round so I'm going to keep a small supply of diesel on hand for the heater.

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