Here's a tip for keeping the dust off of your Bridge over Pond design. If your local grocery store has a bakery section, ask them if you may have an empty large round plastic cake container, the ones they use for double layer cakes with the clear dome top. They might give you one for free, or at the most only charge you a dollar or two for one. If they don't have one available when you ask, ask them if they can hold one for you the next time they get more in the store.
Put your project in it to keep the dust off.
If the container looks too big, maybe they have smaller ones that will work, look around the bakery section.