i am going to install 2 access hatches,and would like to know the best tool for the job. the hole sizes will be 6-1/2",and 4-1/2",should i use a rotozip,or holesaws,holesaws this size are very pricey($50.00)
Those are good size holes, if it was me would drill a starter hole and use a scroll or jig saw. When I drilled several holes in my floor for puring foam through used a 4 inch hole saw, ouch. Every time it would bind up, which was a lot would snap the drill.
If you have room round the holes to swing it, a jigsaw with fine blade will do the job well. For neatness, scribe a line, then cut alongside the line just so that the line is visible after, and finish with a half round file.<br /><br />Do you know that you've got clear space underneath? No stringers or bracing pieces that could foul up the saw?
I used my Roto-Zip tool with the hole cutter attachment and a 1/4" diameter, long fluted, straight carbide router bit. Made a really easy quick clean job of cutting a hole in my boats floor to install an inspection hatch. Did the same on my bow for an anchor rope hold. Cut cleanly through 1/4" fiberglass backed with 3/4" plywood just like cutting through butter. No need to scribe the circle. Just drill a small hole at the center. Adjustments can then be made to the tool to get the hole size you need.<br /><br />If you decide to use a jigsaw be sure to put masking tape on top of your cut line. This helps to prevent chipping out of the gel coat along the cut line.
"If you decide to use a jigsaw be sure to put masking tape on top of your cut line. This helps to prevent chipping out of the gel coat along the cut line."<br /><br />Also put tape or some kind of protection on ANY part of the surrounding surface which the base of the sabre saw will contact - vibration from the saw will easily mar gelcoat or any other finished surface.
