A positive pressure assembly chamber is not that hard to build either.
Short version there are two ways to get rid of dust in an environment
1) Negative pressure filtration. Block every entrance to a location, suck the air out with and whatever comes in needs to go through a filter, also leaks are where dust gets in and being lower pressure it loves to get in them. Harder vacuums are nice but not necessary and add complexity to the equation. In some ways negative pressure it is the easier method, in others it is the harder on more conventional "lying around the house" equipment (I build stuff like this for fun so I have all sorts of things in my stores, if you are more "I have a triwing now" then you may not have such things to play with).
2) Positive pressure filtration. There is a saying that shit flows down hill. This is because gravity does its thing. You do something similar here and make a box with enough clean air (which you only need the one filter for) going in such that everything leaving it is greater than the outside pressure, this means any dust going in has to go up a pressure stream, basic physics having a problem with this so it does not happen.
If you have a sand blasting cabinet then you can make one of these trivially. If not then clear plastic sheet stapled to a wood frame is enough. If you want to go full bore rubber gloves in a sealed box then OK, get enough air in and you can do with dangling strips of plastic a la fly screens or things you see in supermarkets.
All that said for something like this if it is just a one off it should be fairly doable in a room you cleaned if you leave any points during which the screen could come into contact with dust to the last possible second, have some canned air and a cloth (microfibre aren't bad but I like glasses cloths more) around to keep it all clean.
