A History of Pyro & The First Modern Injection Molding Machine

[peteski]

On 9/13/2019 at 4:20 AM, charlie8575 said:

That's achieved by machining nozzles with different feed sources into the moulds.

Charlie Larkin

I suspected as much, but it is still amazing feat of engineering to me. The liquid plastic feed rate has to be just right so the right amounts of the colored plastic do not overflow into where the other color will be injected.

[DumpyDan]

On 3/20/2013 at 3:28 PM, Greg Myers said:

Model History 101. Everyone should read this, thanks Casey.

Well said, and I second that.

[Bugatti Fan]

Does anybody know where all the old Pyro moulds went to? Have they been acquired by any company with a view to reissuing them?

They had quite a substantial range of car kits way back, mostly in 1/32nd scale and a limited few in 1/24th scale.

[Mike999]

19 minutes ago, Bugatti Fan said:

Does anybody know where all the old Pyro moulds went to? Have they been acquired by any company with a view to reissuing them?

Lindberg/Round 2 has some of those molds and still re-issues them.  In 2008 it re-issued the ex-PYRO Model T shown below, along with some other former PYRO 1/32 kits:  '32 and '36 Ford roadsters, '40 Ford coupe etc.  

Back in the 1980s Lindberg re-issued a bunch of the old PYRO kits, including the '32 and '34 Plymouth roadsters.  Those kits had 1/32 scale 6-cylinder engines, often swiped by military modelers.  

Many of the PYRO 1/32 kits haven't been seen since the 1960s and are probably gone forever.  Like the '34 Plymouth 4-door sedan and the '52 Chevy station wagon (which was a fictional 2-door wagon that Chevy never made).

Edited September 17, 2019 by Mike999
goof2

[Casey]

On 1/16/2019 at 10:43 AM, Casey said:

A good look at ejector pins, and an insert for what appear to be 1/16 scale valve covers:

Again:

 

[Casey]

On 2/19/2019 at 10:23 AM, Casey said:

The below top image shows:

1) The sprue is only the channel into which molten plastic flows and enters the mold

2) The runners are what distributes the molten plastic to each individual part after it enters the mold

3) The gate is the entry point from a runner to each individual part

 

Here's a really large, clear image of one of he ex-Aurora monster molds, in which you can make out the various areas shown in the diagram above. Not 100% sure on this, but I believe the individual inserts (which are all bolted(?) into the mold base from the backside?) are made of Beryllium-Copper, which gives them their, well, coppery color:

[Bugatti Fan]

In a post in section 1 of this thread, Snake mentioned that he had the Pyro 1/48th scale Gloster Gladiator kit and said that people speak highly of it. The Gladiator kit actually originated over here in the UK and was part of a small range of inter war aircraft kits made by a company named Impact. I think that a Hawker Fury, a Bristol Bulldog and a Fairey Flycatcher were the other three. They may have made some pioneer aviation subject as well. They were not in production foe very long before the moulds were shipped to the Pyro Company. The quality of those kits was very good and would stand up well against more currently made kits. It would be interesting to see who has those moulds now.

[Tom Geiger]

Early in this thread I had mentioned the location of the Pyro facility, but had not done the research.  Above is a drawing from a Pyro kit showing “Pyro Park”. 

Here’s a view of the facility in 1954. The site was built in Union NJ which was sparsely populated at that time.

 

And by 1979.. 

And here we are today. The plant is long gone and a Home Depot occupies the site today. See the up an sprawl that took place! Union is a very dense place today. 

Edited May 20, 2020 by Tom Geiger

[Casey]

A look at Monogram's Morton Grove, IL, factory, circa 1962: https://modelkitreviews.proboards.com/thread/1499/craft-march-1962-monogram-article

Hat top to Bill E. for posting the pic of Roger Harney, which got the ball roliing.

[Casey]

On 1/16/2019 at 10:43 AM, Casey said:

A good look at ejector pins, and an insert for what appear to be 1/16 scale valve covers:

Adding the image again:

 

While taking pictures of the 1/25 Revell '72 Olds Cutlass Custom (convertible) kit's parts, I took a few extra shots of the area occupied by both the standard and W-30 dual scoop hood. You can make out the half-valve(?, not sure what this specific union is referred to as, in this context) which can be rotated to either allow or forbid molten plastic to flow into each specific hood cavity, while still allowing plastic to flow through half of the runner. In the above mentioned kit, only the standard hood is included, and is shown below next to an empty spot where the W-30 hood would be located.

Here's the group of parts:

 

Close-up of both (slightly misaligned) open and closed half-valve inserts(?):

Edited December 2, 2021 by Casey

[SfanGoch]

The hexagonal shape is a sprue bush, which is rotated to allow or restrict flow of the injected styrene to different parts of the mold insert.