I'm not sure how strong the Troy Bilt model is. It may not be designed for heavier brush applications. However that does not mean you can't do it. Check if Troy Bilt recommends any type of blade. If they explicitly say not to or don't mention it then, I'd try the smallest lightest blade you can find. There are some three blade units out that look fairly light. Take it slow and easy and you should be okay. If your unit has a flexible shaft it is likely less able to handle brush cutting. Typically solid shafts are used when brush cutting is an intended purpose. With that said, I use my flexible shaft a couple times a year for the last 4 years doing brush cutting.