Steering rack gaiter

I am finding it difficult to get the correct steering rack gaiter for my car so i thought about making one in TPU. Its not quite there yet but I have produced a near perfect one using the thick walled file. The thin walled file may work as a single layer/spiral vase print but I am still working on that. I am a noob at Solidworks so it is far from perfect but it looks reasonable. The topmost bellow surface tends to still be porous which is a combination of not being able to hold it still and a