Hello. I was hoping I could get some troubleshooting/advice from you guys. I purchased some plastic cosmetic tubs from Bulk Apothecary to use with my shave croap. The problem I am having is when I fill the jars about half of the time they warp in the middle giving them an hourglass like shape.
Obviously this is not ideal for several reasons. Mostly though, I think it makes my product look unprofessional. It also makes my labels not stick as well.
Any ideas on why this is happening and what I can do to prevent it? I suspect it is just the quality of the plastic does not hold up to the temperature of the croap. I think ultimately I need to switch to tins instead. Has anyone had this happen with another type of packaging?
Are you filling them too hot? That's the only think I can think of that may cause them to warp. Melting the jar? I package mine in jars with no issues but I don't put it in the container until it's cooled down some.
I have used Bulk Apothecary's shrink wrap bands on PET containers without a problem. I have tried to clean out a used one with boiling water and they all shrank into hour glass shapes. I suspect you're getting your heat gun too close to the body of the container (rather than around the screw-on cap, which will withstand the shrink wrap heat).
I don't know if this will work or not (i.e., I've never tried it before), but what if you were to freeze or refrigerate your empty tubs so that they are good and cold before pouring the hot soap into them? At least that's what I would try.
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What about using a rubber band wrapped around the middle (so it wraps partly over the top)? Just pour right over it. I would think that might create just enough tension to keep the walls from bowing out. If you can't quite imagine what I mean, I can take a pic to show you.