Virgin 26m

[Hurley]

Take delivery of my new Mac this weekend and will commence fitting radios etc. Easily said!! However, am concerned about hacking into the gell coat with drills, hole saws etc.
Any advice from those that have travelled this path previously gratefully recieved. Am particulary concerned about about what tools to use when having cut rectangles.

Richard

[midget]

Congrats on your new boat, Hurley. I haven't cut any rectangular holes yet, but I wouldn't trade my Dremel tool for anything!!! They even have a sabre saw type attachment for it I'll probley get, if I do have to cut a rectangular hole. I already have used the circle cutter and the router attachments!! Get yourself one!!

[Hinesy]

I am winding down on my first season in our new M used primarily in Boston Harbor and vicinity. As gas here in the States jumped to over $3.00 a gallon, I was very happy I decided to start out with2-6 gallon tanks for our Merc BF 50. I chould shop for the best prices in the area, I could carry the tanks without stuggling (toomuch),and everytime I passed the fuel dock and looked at their prices on my way out of the Marina, I knew I made the right decision. We are sailors more than long distance motor cruisers however, best of luck with the M down under.
(Hope you choose the beautiful blue hull it is soooo much faster than the white hull under sail or power !!!)

[baldbaby2000]

I ending up putting a lot of holes in our new boat. Look in the mods and search the discussion board for hints. I've heard that putting masking tape over the area to be cut helps keep the gel coat from cracking. When threading screws into the gelcoat, I always drill the hole first, then use a larger bit to remove the gelcoat from the edge of the hole otherwise the gelcoat will crack when putting in the screw. I mounted a lot of things in the interior and it's always best to try to get something other than threading into the liner as a way to hold the screw. In other words use a nut and bolt if possible or a piece of wood as a backing. A lot of times I was able to use a nut by putting it on the end of my finger with double backed tape and reaching up under the liner to thread it on the bolt as I turned the bolt with a screw driver.

[Chip Hindes]

Hole saws for round holes. Drill the pilot hole, then run the hole saw in reverse for a few seconds until you're through the gelcoat. This scores the gelcoat and keeps it from cracking when you run it in the right direction.

Use a Dremel (or the B&D equivalent I have) for odd shaped holes or round ones too big for a hole saw. Sabre saws will work but will crack the gelcoat around the cut; I have not found tape to prevent this. I always use a circle cutter or some sort of guide if possible, it is surprisingly difficult to follow a line while freehanding. If you can't do that, make the cut inside the line and clean it up with sanding drums and discs.

The Mac fiberglass is very abrasive, trashing bits supposedly designed for fiberglass after only a few small cuts, and then you are burning through the fiberglass rather than cutting it which makes a terrible mess of the cut. The extra $$ invested in a carbide bit designed for tile cutting will pay for itself in no time.

[Graham Carr]

I use the following: Hole saw for cutting round holes, Jig saw for square holes, Roto tool for tight places and grinding.
I agree with Chip. Use a Hole saw to cut holes. They cut a clean, perfect hole. Hole saws come in two set-ups; a removable arbor and a fixed arbor.
The removable is a two piece system consisting of the saw and the arbor. The arbor has a pilot drill and the whole unit screws into the saw. Once the arbor is attached you turn a ring which pushes two pins down into the saw. This prevents the saw from cinching tight onto the arbor. With this system you can change to different size saws. When the pilot bit becomes dull you just install a new one. You can expect to pay about $25.00 for a 4 saw and $12.00 for the arbor (as of 5/05).
The fixed arbor is as the name implies. The arbor is not removable. You can not inter change the saws. This is the least expensive way to go. This is the best why to go if you will only be making a few cuts.

If you use a Jig saw The best blade to use is the blades that have no teeth but are carbide coated grit. They cut with a filing action. They are great for straight or curved cuts. Tight circles would be tough because the blades are stiff. The shank is about wide. They are made by Bosch, part # T130rf3 (30 grit) or T150RF3 (50 grit). The style of blade is a T-shank and will work with Bosch, AEG, Dewalt, ELU, Hitachi, Makita, Metabo, Milwaukee and others. The blades cut exceptionally well. The quality of you cut will depend on how well you can control the tool. If you have a lot of blade play the line will be on the rough side. It is better to use a variable speed jig saw. I use blue masking tape to highlight my cut line, placing it on the finished side. Next I put tape on the base of the saw so it will not scratch the surface. Then I run the saw at a slow speed and proceed slowly. I have used this type of blade a lot for the boat and construction and have never had any chipping.

Roto tools are great. I have the flexible cable attachment. This makes it nice to get into tight areas. Be careful when using this tool with out a guide, because it is easy for the bit to grab and go out of your lines.

If you are cutting a square hole, use a drill bit in each corner. Then you cut from hole to hole with the Jig saw or Roto tool.

You always want a round corner; this spreads the stress out and prevents creaks from developing. A 90 deg will creak.

Graham

[Richard O'Brien]

In the event that you need to sabresaw something, try to borrow or "good Grief" buy a Bosch sabre saw with a 14 tooth metal blade, and chip reducer (a little plastic gizmo on the front). It is the only saw that I've found does the job, but 139 bucks at home depot now? not cheap! the dremels and roto tools can do most of it.

[Richard O'Brien]

In the event that you need to sabresaw something, try to borrow or "good Grief" buy a Bosch sabre saw with a 14 tooth metal blade, and chip reducer (a little plastic gizmo on the front). It is the only saw that I've found does the job, but 139 bucks at home depot now? not cheap! the dremels and roto tools can do most of it.