WORKING WITH FIBERGLASS AND PLASTIC HULLS
Recently, these phone calls have frequently centered around the proper way to drill or cut holes into a fiberglass or plastic Hull. Several people were not sure what type of drill bit to use and others had experienced chipping and/or walking of the bit. Those of us that have been building for any length of time, know the answers to these problems. For those who are a bit newer to the hobby, let me share some tips and tricks I have learned, most of the time the hard way, from past projects.
The first tip will actually solve two (2) problems. 1. How to clearly see the location you need to drill. 2. How to keep the drill bit from walking across the Hull. The simple answer is
“Masking Tape”. Before laying out the exact position to be drilled, cover the general area with masking tape. The go ahead and lay out the location of the hole on the masking tape. Use a ball point pen or ultra fine tip sharpie marker to draw the cross hairs which will locate the hole. The marks are much easier to see on the tape than they would be on the bare Hull. Once the location is marked on the tape, the next step is to drill a small pilot hole. A good size to start with is 1/16”. If you place the tip of the bit on the cross hairs and then push slightly before starting the drill, the tape will grab hold of the point and keep it from moving. You now have eliminated the walking problem.
Another point to mention is the type of bit to be used. A common, ordinary twist drill bit works very well, is easy to find and is rather inexpensive. No need for a carbide tipped drill or one with any special coatings, just your every day bit purchased from the local Home Depot. Also, if you have a variable speed drill, it would be a big help, but it is not required. Carefully drill the 1/16” pilot hole with slow steady pressure on the drill. The best way to prevent chipping is to increase the size of the hole in 1/32” increments up to about 3/16” or so. Beyond this size, I rarely use a drill as it is very hard to keep fiberglass from chipping, or plastic from grabbing and tearing. For holes larger than 3/16” diameter I use a small round file and slowly file the hole to the size needed. Once the hole is enlarged to the final size the masking tape can be removed. For holes that are some shape other than round, just piece together a number of small round holes and then connect them with a small keyhole saw and file. (i.e. I grind mine from worn out hacksaw blades.) It is a bit like playing connect the dots. An example of this would be an oval scupper or hawse hole. Drill the proper size hole at each end (and possible some in between depending on the length of the oval), and then connect the holes with the saw. Finally, clean up the edges and file to the final size and shape with a set of needle files.
Armed with the above information, there should now be no fear related to the various openings you will have to make in your Hull, I hope this article has been of help.
Until next month – Good Luck.