TL;DR
I'd like to befriend a coworker with similar hobbies and values but I'm afraid I'd either sound awkward or flirty. How can I make him understand I'd like to become friends?
Situation
I've been working in the same company for 9 months now. There's a coworker I met around the time I started that I recently got to know better after attending a programming boot camp he organized. There were 6 of us at the camp and we learned quite a bit about each other during our lunch breaks, where the atmosphere was more relaxed.
I'd like to befriend this coworker, but there are two main issues that prevent me from doing it quite naturally:
- He's a divorced man who's almost 20 years older than me and as I'm a very sociable woman. I'm afraid my sympathy would come across as flirting with him, and I really don't want that.
- I don't have many friends anymore, most of them left after graduation and I want to make new friends. It's been a while since I last befriended someone and I suspect that coming to see him and saying "Hey! You seem nice. Let's be friends!" may not work.
What I tried so far
I invited him to have lunch together at work. I accompanied him to buy some food and we came back to the office and ate with two other colleagues who extemporaneously joined us. I told him afterwards that I spent a nice time and he answered saying we could do it again on the days where he's free. This happened very recently so we haven't had lunch together again since.
Although this is not primarily driven by my will of befriending him, I send emails or come to see him whenever I'm stuck with an issue related to the language he organizes boot camps about. This gives me the occasion of asking him how he's doing, and he doesn't seem bothered by the question.
Question
How can I signify to my coworker that I'd like to spend more time with him as a friend, without sounding awkward or flirty?