We use contact cement to laminate cylinders with HPL and because of it, sometimes you see a bubble (maybe too much glue in that area) or a high spot from something trapped under the laminate. Is there a better way to apply HPL on the cylinders - a different glue and a vacuum bag maybe? Also, what method works best for making the seams disappear?
From contributor C:
In my experience, the main cause of bubbling when working with HPL, cylinders, and contact adhesives is that insufficient pressure is exerted when rolling the surfaces together, because it is very hard to roll and get even pressure on a round object. To a lesser degree, insufficient drying of the adhesive will result in bubbles, especially in areas that have had too much adhesive applied.
Assuming the first scenario to be the case, I've seen some people get acceptable results when they used a homemade scraper or paddle out of hardwood. Essentially, they made a paddle with a 3' - 4' long handle and a blade about 6" wide. This allows the worker to get really good leverage on the paddle and put a lot of pressure to the glue line. Most of the time they attach the HPL at the center and then work the two ends around the cylinder to meet on the opposite side.
Using the paddle, go over the lamination 3 or 4 times to ensure that you have forced 100% of the two surfaces together to maximize the bond strength and minimize the chances of bubbling.
As for making the seams disappear, good measuring and cutting to get the seam reasonably close seems to be the industry norm. I've always thought, though, that masking off the last several inches of the ends to prevent them from bonding and laying the laminate so that it overlaps a bit and then cutting with a laminate knife (carefully) would give the tightest seam. This is similar to how flooring seams can be cut. Once cut, the masking is removed and the HPL bonded. A bit of Seam-Fil and you're done. All of the above said, the best way would be to make two halves with PVA in a vacuum bag.