I built a Thien top hat collector to work with my shop vac and it works great. Later I got a Dewalt 735 planer. The chip ejection from the planer is quite strong, and it was shooting dust out the top (shop vac not attached because that would slow down the air flow). I can't find a filter that will let the air through but stop the dust. My wife's old pantyhose are not doing the job. Any suggestions?