I always use glue to baste my quilt sandwich and have learned several things. First, I ONLY use Elmer's washable school glue now (be sure and look at the bottle because there is regular Elmer's white glue that is NOT washable). My all time favorite is the Elmer's washable "clear gel" glue because it seems easier to dilute and has a really nice consistency when diluted. I love that stuff!--I wish it didn't so much more $! Also, I tried a cheap store brand but had to use more than twice as much and it turned into a real big mess. I ended up going back over it a second time with Elmer's and re-sandwiching that one. (Even then, double glue-basted, it all washed out and I had no problems quilting it either!)
I glue baste one side at a time, in thirds or quarters, depending on the fabric, size of quilt, etc. I usually start at the top and work down because I have very little space to work with but you could start in the center and work outward because I don't think it really matters as long as you can smooth everything out. I like to apply the glue to the batting and then put the back (or top) on the batting while smoothing with my hands, probably a third of the quilt at a time and I keep the rest rolled back out of the way. When I have my fabric smoothed down on top of the gluey batting I iron the fabric to set the glue and make double sure everything is smooth. I press using parchment paper between the iron and the sandwich to keep the glue off of my iron (not that it would hurt it) and yes, it does soak through -- I see dots and blobs and lines of wet glue showing through the fabric at this point (that is, if it's not too pieced and definitely on the backing fabric if it is a solid it will show quite a bit) but it will dry. I panicked the first time I saw this thinking I had used too much glue, but now I use the wet glue "spots" as a guide (when I can see them) so I know exactly how "basted" my sandwich is. Just like you would want to use a certain number of stitches a certain distance apart, you also want to make sure that the glue is distributed fairly evenly -- meaning, not perfect but making sure all areas have at least a blob or line or two every few inches--you don't want any large sections just floating without any glue at all. It should be glued all over so it will stick together with the glue acting like hundreds of little "pins." This is esssentially what you are doing -- using a temporary "pinning" technique. Just like pins, there will be areas between the glue spots that are not glued (pinned) but as long as you have enough pins, or glued spots in this case, the sandwich will stay put.
Ok, I've done the first side and I usually don't even wait for this side to dry -- I just flip it over and do the same for the other side, one third at a time keeping the rest rolled back until I'm ready to do the next third. I haven't had the back shift while I do the other side, even though it isn't all dry. After I've done both sides I hang it up with clips overnight to make sure it dries thoroughly and quilt it the next day (or week!) or two.
My "technique" for putting the glue on the batting is extremely random and rather heavy-handed. When I first tried it I was VERY nervous about applying GLUE to my beautiful fabric and hard, hard work! (Plus, I honestly did not believe that it could actually work on fabric!) I was being SO very careful and it took a while, but I had no problem. After success upon success with this gluing technique, with every quilt I have become messier (and faster!) and so now I really just hold the bottle over the batting and squeeze it while moving my hand in circles or diagonally or really any old way. I just "scribble it right on there in lines, blobs, broken lines, whatever. I use a lot more glue now to make sure I get a secure sandwich and I have never had a problem quilting it (machine not hand) and have only noticed once or twice that my needle seemed to "hit" a blob (just felt like a thick seam or something similar), but nothing happened and stitches were fine. I only dilute the glue so it's easier to squirt it out of the bottle it comes in -- I don't use any special tips at all. I have found that if I dilute it any more than 50/50 it doesn't work as well so I probably dilute it a little less than 50/50, always more glue than water so it sticks well. Even after iron setting it and letting it dry overnight you can still easily pull the fabric away from the batting if you need to reposition for some reason. I only had to do that once or twice and I just did pulled it apart while dry and then reapplied the glue and set it again, waited a couple hours and quilted it.
I have used glue on the binding in the past, and I would use it again but I usually don't take the time. I use cotton batting (have used all brands, scrim, no scrim, whatever is on sale). I'm sure it would work just as well with a poly batting. While I'm glue basting in my messy, "let's get this done" way, I often think that if anyone saw my process they would probably think I was out of my mind and had no idea what I was doing! Yes, that's how easy it is!
I would like to know if anyone has had any problems using glue -- I have been pretty darn out of control with it and have never ever had any problems. I've even gotten glue on the "right" side of the quilt while wrestling with the rolled parts unrolling while I'm gluing another section! It just dries and then washes out without a trace. I've come a long way from standing in front of weeks of my hard work with an open bottle of Elmer's glue in my hand, terrified to put it on any tiny piece of my quilt sandwich!! Washing my finished quilt is the first thing I do when I've completed the binding and I have never ever had any problems with the glue not washing out, no matter how much I've used or how many times I used glue on it.
I was really scared to do it for a long time, but now I just go at it like a mad woman and am not careful about it at all. I really hope this helps alleviate some of the fear for those of you who are really not sure about this glue basting. If I can do it in my haphazard way and never had a problem, I know you can do it! Feel free to pm me if you have any other questions I didn't answer here but I strongly suggest that you just go for it! (Use practice pieces of scrap fabric first if it makes you feel better.) Actually, after my experiences, I'm not really sure how you could do it "wrong!"