Originally Posted by
charlie b
Well, first, is it something you would consider valuable or an 'antique'. If it is I would not touch it. Take it to a pro. Much of what is discussed here might ruin any value it has.
If not, then the difficult part is fixing the cracks. How did they start? Was there impact damage of some sort or did the stock split due to age? If due to age then I agree with the fill method of 'fixing' it.
I would fix the cracks first, then worry about the masking tape residue. That way you won't get any of those chemicals in the cracks and prevent adhesion.