I just got my first vintage fountain pen, a short Sheaffer Balance. Because of its size, I would prefer to write with it posted, but it already has two hairline cracks at the open end of the cap. I was thinking of using a small length of heat shrink tubing and putting it over the end--covering the gold band and going to the end of the cap--to help hold everything together. Do you think this will provide enough reinforcement to allow me to post the cap and keep the cracks from growing? If others have done this, are there special considerations or hints you'd be willing to share? (I have seen the forum posts recommending MEK for crack repair, but in my understanding, even if I repair the cracks with MEK, new cracks are likely to form if I keep posting the cap because of the thinness of the lip.) Thanks all!