How to Make a Fiberglass Subwoofer Box

Step 7 7. Working Around Obstructions

On my vehicle there is an moving part of the trunk that would come in contact with the box when you close the trunk. It is very important that you note and obstructions and create a clearance in your box. Now is a good time to do it, before you begin to install your speaker rings. Create a necessary jig out of MDF to create a pocket in your box. Then use wooden dowels and hot melt glue to secure the piece in place where it encounters the obstruction. Once it is in place you can fleece and fiberglass the area around it (step 10), or wait until your speaker rings are also in place. It is up to you what you do, but I recommend working on the obstruction area first because it will be easier to lay fiberglass on the inside.