Fountain pens are amazing. They write smoother with less effort. The inks have a variety of useful, cost effective, beautiful, and at times permanent properties.
I started using them circa 2012 and I'd like to say that I didn't look back, but I did. I put the wrong ink (India ink) in my first pen and it ruined the pen. My next pen came free with my bottle of Noodler's Kung Te Cheng. However, these Platinum Preppy's got cracks and leaked. My next upgrade was to a Pilot Metropolitan. Now these are enjoyable writers, but I found that if I didn't use them daily they dried out a little and they were hard to get started. Tired of fighting with them, I put them in a bin on my shelf for about five years.
About a year ago I found myself reconnecting with my favorite fountain pen retailer: Goulet Pens. Turns out they have been very busy over the last decade creating amazing YouTube videos educating you on all things fountain pens. They even have a shopping guide dedicated to Fountain Pen Tools for Sketching.
I have one and only one recommendation for someone new to fountain pens who wants to use them with watercolor. It is a TSWSBI Eco. I would get one with a Fine or Medium nib to start with. Here are some key features:
Ink Capacity: This pen holds a lot of whatever kind of ink you like. If you fill it up before a weekend away sketching you won’t run out.
Demonstrator: The clear bodies on these pens allow you to see at all times exactly how much ink is in there.
Ready to Write: You don't need to use this pen every day. In fact I've gone weeks in between uses and it is still ready to go. This was a big frustration for me with the Pilot Metropolitan.
Posts: This means that you can put the cap on the back of the pen securely. If you are out sketching or if you have kids, this is a very important feature.
Value: You get all these features at a very reasonable price. $31 seems like an expensive pen, but the ink is very cost effective and even more fun.
Lamy makes some great pens too. My brother in law swears by a Safari and keep my Al-Star with my on the go sketching kit (mostly because it doesn't fit in my pretty pen holder on my art desk). I also enjoy a Studio because it feels substantial and it makes me feel fancy. Liz Steel loves her Joy. I love that you can swap out the nibs easily on all these models, but sometimes I get surprised that the ink ran out. Just make sure you get a cartridge converter to go with your Lamy.
The TWSBI Diamond 580 is marginally more enjoyable to write with than the ECO for almost twice the price. The cap doesn't post nicely, but it is always inked up at my work desk and I reach for it all day long.
I have a couple other pens and there are certainly many better pricier pens on the market. However, for a budget friendly pen that you will not outgrow I recommend the TWSBI ECO.
I will do a more detailed post on ink, but to quickly pick an ink that is permanent for doing watercolor on top of I would go with either De Atramentis Document Ink Black or Noodler's 54th Massachusetts.
These reviews are purely from my own personal experience and I do not profit financially from you taking my advice.
Please share in the comments your favorite fountain pens for sketching. Do you do a watercolor wash over your ink?