adding improvement, then sell?

I recently found a really good axe that I want to sell, but it has no Haft. Can I add one then sell it, or when I add something is that like customizing where I can't sell it to another person?

It does have a Grip

you can upgrade an item without customizing it. most weapons have 2 separate upgrade slots, corresponding to the prefix and the suffix of the name.

Add what you like, just don't go to the weapons NPC and customize it. I actually do this pretty often, as I commonly have weapon upgrades to weapons I don't use. If I find a good purple weapon that only has 1 upgrade, I will often add another upgrade to it to increase the appeal to buyers... and increase the price.

thanks Lasher, just what I wanted to know