Hi Manu, yes I did receive your thank you note. Sorry, I've been having some vexing computer problems and my online access is limited at the moment - hence the delay in reply. I'm glad you found it useful :)
Hi Manu, thank you for asking, re: Hi Prosenjit, I have a doubt, which I thought would be best to ask you. How good / not good it is to varnish an acrylic painting? --- I'll come back later with a longer response if this doesn't suffice, I'm kind of being threatened by impending computer doom at the moment :) Yes, acrylic varnishes are available and you can of course use it. Varnishes (and here I'm referring to varnishes used for oil painting, but should be applicable to acrylics as well) basically do two things 1) protect the painting from dirt (it can be wiped without affecting the painting itself) 2) homogenizes the painted surface, unifying matted/dry areas with shiny ones, giving a uniform surface gloss - this makes the colors look crisper, esp the darks darker. By definition varnishes are removable.
However, its also a common practice to cover the acrylic painting with a layer of acrylic gloss media (about 60:40 dilution with water, respectively). That'll also act as a protective covering as well as homogenize the sheen, although its not strictly varnish (being integrated with the acrylic layers underneath and therefore unremovable). I've used this method for quite a few years now and the paintings look alright and can be cleaned if necessary. quickly cover the painting with a broad brush and leave it to dry naturally, without upsetting the drying layers, as this may interfere with the acrylization process. Also, don't be scared if it looks milky at first, it'll become completely transparent when dry. Still, experiment a bit with your less critical works!
N.B. acrylic coated surfaces have a natural tacky-ness to them, so if you put it in contact with the glass in a frame, it might stick to the glass.
Ensure that there is some space between the glass and the surface. I stack my 'rough', unframed works between oil papers and haven't had a problem till now.
As regards commercially available acrylic varnishes you may check out these pages for more info: