This is how thw Vigon system works but, even with a 25 µm filter
cascaded to a 5 µm filter, it is only partially effective because the
particles are a very fine suspension and, I suspect, may even be a
semi-soluble gel before it hardens. I think that the rheological
modifiers in pastes may contribute, while the surfactant-like materials
are micellar. As such, they can "capture" a hydrophobic molecule in a
large molecular structure, much too small to be captured by mechanical
filters, but they could release the hydrophobic molecule if the micelle
broke down. This is quite a complex physicochemical phenomenon which
depends on relative bond strengths and the surface tension of the fluid.
Lime, of course, is easily prevented by deionising the water.
Brian
Dehoyos, Ramon wrote:
> Brian:
> Isn't it possible to trap all or most of the solids in a
> filter or series of filters, before they get attached to the surfaces
> and avoid the scaling on the surfaces? Or would it be prohibitive
> expensive?
> Regards,
> Ramon
>
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Brian Ellis
> Sent: Wednesday, January 10, 2007 3:57 AM
> To: [log in to unmask]
> Subject: Re: [TN] Descaling of Water Wash Systems
>
> There are two problems here. One is lime deposits and that is easy to
> handle with any weak acid (do NOT use HCl in stainless steel, though). I
> recommend dilute formic acid, but it requires careful handling (see
> MSDS). The other is deposits from the solder paste/flux/wash chemistry
> and they can be very difficult to remove, depending what chemicals are
> involved. Possibly the worst product is hydrolysed rosin which forms a
> white crud that sticks to anything and is insoluble in most ordinary
> products likely to be found in an electronics workshop. I think the only
> thing to do with it is to scrub it with an IPA saturated cloth, with
> plenty of elbow grease and patience. Do NOT use abrasives, such as
> Scotchbrite pads or pumice, as they will roughen the surface of the
> stainless steel, providing a nice key for thicker future deposits.
>
> Maybe we need Teflon/Silverstone coated machines!!!
>
> Brian
>
> Richard Kraszewski wrote:
>> To ~continue along this forum's recent cleaning track...
>>
>> What are you using for de-scaling water wash systems?
>>
>> Any recommendations would be appreciated.
>>
>> Rich K / GTS
>>
>>
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