[RE-wrenches] cleaning modules

[Peter Parrish]

If your rust (iron oxide) problem is a tough one, I have a great “rust
remover”. It’s called “Naval Jelly” and its pretty powerful stuff (contains
phosphoric acid). Use rubber gloves, and in the case of a thin layer of
rust, you could dilute it with water. It will attack paint and probably
anodized Al frames as well.

Undiluted, the stuff is a gel so it can be applied to a sloping surface.

The iron oxide gets converted to iron phosphate which is water soluble and
washes off.

The nice thing about Nava Jelly is it is non-abrasive and it removes the
iron oxide via a chemical process. In other words it doesn't affect glass,
which leads me to my next point.

Over the past ten years there has been a series of manufacturing
improvements to PV modules. Fairly recently, PV module manufacturers have
been applying a very thin dielectric layer to the top surface of the
tempered, low-iron glass. This anti-reflective (AR) layer is extremely thin
and some cleaning solutions and mild abrasives will attack the layer. Even
fingerprints can attack the layer. I suspect that Naval Jelly will attack
the AR coating.

I haven’t researched any of the “cleaning agents” that are on the market
that are supposed to be used with PV modules, but I would be very cautious
of using anything but a very mild detergent with PV modules with an AR
coating.

In the case of Tom DeBates situation, the modules probably don’t have an AR
coating and either naval Jelly or a mild abrasive (that doesn’t scratch
glass) should work.

- Peter

Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
peter.parrish at calsolareng.com  
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885

 
________________________________________
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Jason
Szumlanski
Sent: Thursday, December 30, 2010 9:38 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] cleaning modules

Yup – soft scrub works great in my experience. Rinse well. Never had a
problem. Although, never took a microscope to the glass surface after use


Disclaimer – I’m not buying you a new panel in the event of damage!

Jason Szumlanski
Fafco Solar

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Kent
Osterberg
Sent: Thursday, December 30, 2010 12:27 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] cleaning modules

Tom,

Textured glass would complicate matters, but I'd try ceramic stove top
cleaner.  The fine abrasive partials might be just the ticket.  

Kent Osterberg
Blue Mountain Solar, Inc.


Tom DeBates wrote: 
hello Wrenches,
  I recently purchased some used modules. Unfortunately, they were mounted
near a railroad track and many have a film of rust on the front surface. I
have tried a few products; Dawn, Simple Green, vinegar (5% acidity),  and
Krud Kutter to safely remove the rust. So far the vinegar seems to be best
when considering cost, disposal ,etc. But it still takes a good amount of
time and "elbow grease". Today I will try CLR.  Has anyone else run into a
similar situation? If so, what products and/or methods did you use to remove
rust stains?
  Awhile back I had to remove some urethane caulk from the face of module
and had to resort to a solvent-based chemical (acetone....yes, acetone) with
disastrous results.....
thanks,
tom 

Tom DeBates
Habi-Tek
524 Summit St.
Geneva,IL. 60134
630-262-8193
fax 630-262-1343


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