Improperly sealed imitation gold leaf on paintings

I have a question from an artist about resealing *potentially*
improperly sealed imitation gold leaf on his paintings created
within the past 4 years:

In his acrylic paintings he uses sealed imitation gold leaf and
copper leaf sealed with Golden Acrylic Soft Gel (gloss).  He used
this instead of the recommended MSA varnish because it caused
immediate oxidation (green discoloration) when he tested it.  Also,
his studio has no ventilation, so he really does need to use a water
based product.  However, he just learned from Golden's materials
support that the soft gel he's using is apparently porous and over
time oxygen, ammonia, and water vapor could reach the metal, causing
discoloration.

At the moment, he has a painting in his studio he did 4 years ago,
in this way, and the copper is perfectly untarnished.  But now he's
worried that in a humid environment, and over years, the acrylic gel
coat won't hold up.  He has heard of water-based Incralac being used
and is wondering if he can use it over the acrylic gel coat that is
already there.  Although he has heard that it dries quite "hard" and
his paintings are on canvas (i.e. not a rigid support).

He has noted that leafed areas that he's accidentally missed while
applying the Soft Gel topcoat have tended to show oxidation within
weeks if not days.  The pressing issue is not so much how to seal
this kind of leaf but how to deal with paintings he's already done
(potentially improperly).

Should he try to use the water based Incralac over the acrylic gel
coat for extra protection?

Opinions please?


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                  Conservation DistList Instance 29:46
                 Distributed: Saturday, April 23, 2016
                       Message Id: cdl-29-46-016
                                  ***