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Vent Residue Cleaning

#21157

Vent Residue Cleaning | 14 August, 2002

For relow ovens the general approaches are: * Clean the vent pipe. * Replace [a section of ] the vent pipe. * Clean the flux trap on newer ovens. * Do nothing and wonder where that brown slime that is dripping on the boards is coming from.

For wave solder machines the general approach are: * Clean the vent pipe. * Replace [a section of ] the vent pipe. * Do nothing and wonder why someone called the fire department.

Questions are: * What do do? * For 'cleaners', how do you clean flux residues from your venting system? * How often do you clean / replace piping? * Are you a high / mid / low volume shop? * What type of flux do you run?

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dragonslayr

#21167

Vent Residue Cleaning | 14 August, 2002

in other words- who gets stuck with the latrine duty? (have seen American Graffiti, where the "effluent" was burned off with diesel fuel, Lord help the person who got stuck downwind!) The thought of having to swab a tube with some sort of cleaner makes me cringe. The cleaner will probably need to be at least mildly caustic to be effective. (TSP) The ensuing pile of filthy rags, mops, bottles brushes, etc. would assuredly have to be handled as hazardous waste.

A bit of rework of an existing vent system can minimize the future potential of little brown, gooey spots, dripping from the vent tubes. I have actually seen a hot glob of brown goo drip onto an operators head. He knew about the problem - his solution was to avoid walking under the drip potential and to constantly wear a baseball cap. He had experienced hot goo on his scalp at least once.

My short teerm solution was to have all the joints of the vent tubing wrapped with a metallized version of duct tape. That stopped the constant drips. Secondly, I had a "P" trap installed so that the condensed flux residues would pool in a trap filter. That area could be pulled/cleaned/replaced periodically. A good HVAC contractor can evaluate you venting system and make recommendations to minimize the problem.

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CAL

#21190

Vent Residue Cleaning | 16 August, 2002

I do know Zestron makes a flux residue remover .....but to what degree I can say. Contact Andreas at Zestron for more info.

Cal

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#21203

Vent Residue Cleaning | 16 August, 2002

I use Kyzen's Aquanox SSA cleaner in a heated parts cleaning tub to clean anything with flux condensate on it. When heated to 120F, the stuff melts away like ice under hot water. When the cleaning solution is loaded, I send it in an evaporator. The sludge is sent to a recycler. We have 3 reflow ovens running 24h/5days. we use no clean paste. 1 oven has flux reclamation and I clean all the filters - heat exchangers - aparatus once a month. The exhaust ducts and hoods are checked every month and cleaned as needed, average every 6 months. The ducts are either the flexible kind or short sections rigid ducts, so they can be coiled and fit into the tub. Let soak for 30 minutes; Bang! brand new shiny ducts...

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scwalsall

#21261

Vent Residue Cleaning | 21 August, 2002

Regarding the non-adherence of this maintenance schedule......should we expect to see flux condensate on our solder joints?? Possibly leading to solder joint contamination, dry joints, solderability issues in production etc.??

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#21268

Vent Residue Cleaning | 21 August, 2002

No, you should expect to globs of stuff that is a bit reminiscent of chewin´┐Ż ´┐Żbackee on yer boards.

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dragonslayr

#21274

Vent Residue Cleaning | 21 August, 2002

am reminiscent of a time, after some hard duty at the local drinkin hole, having sneezed and my vent pipe expurgated. ooowwweeee - what an em bare ass ment

won't go into details about clean up method or fancy swabbin tools or high tech fluids required, let alone installing a filter trap

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#21291

Vent Residue Cleaning | 22 August, 2002

In an oven with flux reclamation system, once the circulation is prevented by accumulation of flux in the heat exchanger, the flux will condense where it can, and some of it will coat your PCBs with a uniform layer of flux on the parts/ joints/ goldfingers, etc... boards become sticky to the touch. It's a good incentive to "stick" to the maintenance schedule.

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