Okay;
A little tutorial here. Sprue-Goo--(Glue?) Is just that! It is still glue. Granted-Polluted glue! Polluted, Well yes, It has particles of plastic now imbedded in it.(I/E Contaminated Glue) You Can use it to glue stuff together, but because of the product in it, it won't hold as well. Now as a filler it is awesome! Because what you have done is use the glue to liquify plastic chunks.
That is why it is perfect for that. It's glue, so it melts the surface of the subject, it is plastic, because of the liquified chunks in it which bonds to the original plastic. So, when you sand a Grey hull or fuselage with Sprue-Glue the same color you have, No discolored seams.
Plus, being the same plastic, no problem in paint coverage, Why? No dissimilar materials! I keep in my work area, Eight Bottles of Sprue - Glue. The eight basic colors. Plus I have also created clear, clear (Green, great for aircraft lights and yes, clear Red for the same plus tailight lenses over chromed light units.) now some will wonder about this one. Clear, ClearSprue - Glue) This is made from only one type of kit. Cars and Aircraft that have exyremely clear sprues. Plus a VIRGIN Bottle of glue divided in half.
That's why I always clean out my old glue, and larger( Floquil and Poly "S" ( Yeah-I still have some) Bottles. Then I clean the inside of the caps to remove any sign of the original product contained within. Air dry for two days, then Take the Virgin Glue and pour half of it in the clean empty bottle. Now take the very Visually clear, and Yes, you can chop up broken canopies and windshields too!
There you have it Clear sprue glue that can be used for a lot of things. I have even spread it on a spoon to test it! After drying for a week I had a visually clear spoon shaped Bubble. Yes, they are fragile! But you'd be surprised what uses the Clear has. How about thin enough to work as window maker. Yes, No more yellowed airplane windows!
One more important fact. If you do a TOM Daniels kit or another colored molding, Take the sprue and make a small amount for this kit! You'll be glad you did. Now last thought . Remember two very important things here. Virgin Glue and Super Clean Bottles! You can label them according to where you got the plastic and then keep a selection of useable ( Sprue-Gloo) colors on hand. Over the years I have amassed about thirty colors and two shades of clear( Smoked and Regular clear).
Here,s a related fact: Did you know why the bottle of glue seems to weaken over time? It's NOT the times you have opened the bottle and it has gassed off. It does that till the last drop. It is the times you have ( Probably Hundreds) Let the little brush touch the plastic surface when gluing. Instead of letting capillary action remove the glue in the brush you touched the surface. No Harm, No Foul ,Right? Wrong! What you do each and every time you do that is transfer molecules of plastic to the glue bottle! Hence you un-intentionally contanimate it!
That's why after a week or so of gluing parts the nice VISUALLY CLEAR glue is now Frosty or Misty looking. It now has plastic particles in it. Learn to rely on Capillary Action for the transfer. Now, it's No Harm,No Foul! Why? Because each an every one of us has done it, Some for years and never given it a thought! I learned about this using a different type of glue for a different kind of project. I used Glue that been used on Smoke Colored Lexan ( I didn't know) on a Clear fish Tank Assembly. The thing had these awesome and neat Smoke colored Seams. My Bad! I bought the thing for my fish. But, that's how I learned. At least my friend who let me help him didn't get stuck with that tank. But he showed me why it happened. He also had a PHD and Masters in Chemistry. So he was able to make this here engineer understand what happened.