PVA for PLA

I don't have time to get to my printer for the next week or so, but as soon as I can get back I'm definitely trying the diluted PVA on top of glass to get the PLA to stick.

I was having lunch with a friend Friday, whining about my problems getting the blue PLA to adhere, and he said (paraphrasing here), "Isn't there some kind of glue or coating you can put down on the surface to get it to stick?"  Doh!!  Suddenly all the posts I had read through that talk about using a PVA and water mixture seemed much more important, and I couldn't wait to get back to the forums and blogs and find out how to make my own dilutions and get back to printing.

I think I had dismissed those methods before because my experience with the gold PLA on glass over a HBP had been so positive.  The thought of having to do some secondary operation and paint on a coating of some type seemed like an unnecessary extra amount of work, so I had put those methods out of my mind while I tried to find the right combination of extruder and HBP temperatures to get the blue PLA to adhere.  After a few weeks of frustration, though, the idea of painting on a film of diluted PLA seems like a very small price to pay to get the new spool of PLA to stick without problems.

I picked up some PVA glue (Elmer's) at Wal-Mart a couple of days ago.  I went with the classic tube of white glue with the orange top (http://www.elmers.com/product/detail/E1322?filterPath=school).  They also were selling a spray-on product that seemed interesting (http://www.elmers.com/product/detail/E422?filterPath=craft).  I'm curious if anyone has tried this, since spraying on a coating of glue could be a very quick and easy way to prep the glass surface.

I've decided to first try a dilution of 1:8 PVA:water on a cooled glass surface.  I've seen posts about mixtures stronger than that resulting in the parts not coming off of the glass (without taking some of the glass with them, at least):  http://forums.reprap.org/read.php?262,141761,141761  I've also seen posts suggesting that using this ratio on a heated glass plate works well:  http://richrap.blogspot.com.au/2012/06/more-scrap-art-gearboxes-and-panelmax.html

I'm a little worried that the piece of glass I have is not very tough.  I got it out of a flatbed scanner that I was throwing away.  I will try the cooled glass coated in PVA mixture, and if that doesn't work I will first try to thicken the mixture.  If that still doesn't work I will use the coating over a heated build surface.  Either way, I have a plan with potential for success, and that's really all I need to stay excited about the next steps :)

D