Neutec J2r

Hello everyone,
I have been having a vacuum issue with my Neutec J2r for a couple of months now. When I first started using my J2r the vacuum always pulled right to 30 inches when I would drop my flasks in, I never had an issue with it. More recently the vacuum gauge has only been pulling between 10-15 inch, maximum.

I have tried almost everything I can think of to correct this and I can not figure out what else the issue could be.
I use 4x6 flasks
I live in New Jersey, the elevation level is about 240ft.
I have tried:
The silicone gaskets
The graphite gaskets
The woven gaskets
I have mixed and matched them trying different combinations, nothing changes.

I’ve changed the rubber bands on the flask adapter. I have tightened the bottom chamber by lifting it a hair to make sure it’s sealed tightly. I have even bought two new vacuums, still no results.
I thought maybe the flasks were an issue so I sanded the flanges to make sure they are absolutely spotless. I have also been filling the flasks up completely to the top with investment because I’ve noticed they pull a little better with more investment.
I have tested the vacuum in many different ways and the actual vacuum is great, it goes right to 30 when I cover the hole, so I know I don’t have any leaks in the hose. I’ve really narrowed it down to the adapter area. It seems nothing I do can seal it enough. Does anyone else have this issue?

Or my final thought would be maybe the hose on my vacuum should be longer? Do you find it helps to have an extensive hose, would that make the pull stronger?

Any advice would be greatly appreciated.
Thank you so much,

Have you contacted Rio Grande? Given all that you’ve tried that’s where I’d go next.

We have one of these casting machines where I work. It’s over 20 years old and still works great. The only thing similar problem that we’ve ever had is when the vacuum chamber slips down a bit and doesn’t make a good seal. But you tried that. So I’m not sure what to suggest.

That’s why I’m suggesting contacting Rio Grande.

Rio Grande recently shifted things with their technical support team. If you have a hard time finding someone with J2r experience to help you let me know. I’ve got a friend who works there and I can ask him.

Let us know what happens. I’m really curious to hear what could be going on.


While small, some of your vacuum energy goes into your house. That logic says that a shorter hose would make sense. I don’t know anything about these machines, as I don’t cast, but I worked years ago for a company that made vacuum and air compressors. Where is the vacuum measured? Leaky valves and seals in the vacuum compressor may be your problem or just leaks anywhere in the system. Good luck…Rob