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SMT electronics assembly manufacturing forum.

Stencil sink stink


Stencil sink stink | 21 March, 2005

We have lab sink in our SMT area that we use for washing off stencils and hand tools that are contaminated with solder paste. The sink has a float in it and when the water level reaches a certain point it pumps the main basin out through a filter then down the drain. The problem is that when it runs its pump cycle the whole SMT area smells like rotten eggs. I guess the smell is from stagnant water. Even if we purge it once a week or so with clean water, it still smells awful. REALLY AWFUL ! The smell wafts through the entire SMT area and everyone starts blaming each other for ripping a nasty one. I have tried everything from bleach to those blue tablets that go in your toilet bowl. Does anyone have one of these sinks ? If so, how do you keep it from stinking ? I think it was made by a place that is out of business called Aqueous.

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Stencil sink stink | 21 March, 2005

Sounds like a flaw in your trap. It seams that during the pumping process the trap is ineffective or open, allowing normal sewer gases to bypass the trap and stink up your SMT area. This is similar to what happens when you do not use a drain for a long time and the water in the trap dries out. It results in a nasty rotten egg smell.

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Stencil sink stink | 21 March, 2005

No it's not a dry or defective trap. The exit line of the stencil sink is piped into a regular slop sink. There are no sewer gas smells coming out of the slop sink trap.

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Stencil sink stink | 21 March, 2005

Se�or Tech

Possibilities are: * The vent on the drain line is blocked. Generally when this happens, the blockage, like come critter building a nest in the pipe, is found on the roof. In this case, the smell would be constant. * Somewhere, the drain of your sink is clogged. It could be the trap is full of 'material'. In this case, the smell would come and go being less just afte draining the sink.

What kind of filter are you using to prevent solder from leaving the sink?

Do you mean: Aqueous Technologies; (909) 944-7771

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Mike Konrad


Stencil sink stink | 21 March, 2005

Hi Dave,

No... It was not made by Aqueous Technologies, who, by the way, is very well still in business!

There must be some water that is not leaving the system. High quantities of organic growth cause the smell. Does this machine have filters that may be clogged?


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Stencil sink stink | 21 March, 2005

What does the filter housing smell like (inside)? How often do you change filters?

The smell is probably from organic growth. Do you have slime growing on the inside walls below the water line?

Does the bleach temporarily fix the problem?

What is your water temperature?

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Stencil sink stink | 21 March, 2005

I agree with dave. Two things prevent oders from drains. The "P" trap and the celing or roof vent. If the system is sealed from the pump on then it should run thru a "P" trap this prevents vapors from comeing back thru the pipe. To make sure suction dose not pull water out of the P trap a vent near there needs to be installed up thru the roof.

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