Cutting grp

[billyfish]

I want to cut a hole big enough for a new gas locker in a rear bulkhead but I know from previous experience that a angle grinder is the weapon of choice but the dust...is there a alternative, jig saw maybe. I'm always surprised the strength of grp. Also is there a off the shelf gas locker to fit in the hole.

 

[Gixer]

I keep seeing people use a oscillating saw for cutting fiberglass.

 

[geem]

I want to cut a hole big enough for a new gas locker in a rear bulkhead but I know from previous experience that a angle grinder is the weapon of choice but the dust...is there a alternative, jig saw maybe. I'm always surprised the strength of grp. Also is there a off the shelf gas locker to fit in the hole.

Angle grinder with a steel, diamond tipped wheel as used for cutting tiles works well. It gives a narrow cut. Use in conjunction with a vacuum cleaner heald by a helper.

 

[Boathook]

Multi tool and a vacuum cleaner. If possible, have the vacuum cleaner outside to reduce dust inside. The finestuff always finds its way through the filters unless it is designed for the stuff.

 

[Ribtecer]

Yes an angle grinder for straight lines, and a jigsaw for the radius cuts. Although get some spare blades, grp wrecks jigsaw blades very quickly. (Tile cutting blades is interesting, I've never tried them on fibreglass)

And yes you can buy a preformed gas bottle lockers, be aware there are strict regulations for gas installations that must be followed.

Force 4 Gas Bottle Locker | Force 4 Chandlery

 

[geem]

Yes an angle grinder for straight lines, and a jigsaw for the radius cuts. Although get some spare blades, grp wrecks jigsaw blades very quickly. (Tile cutting blades is interesting, I've never tried them on fibreglass)

And yes you can buy a preformed gas bottle lockers, be aware there are strict regulations for gas installations that must be followed.

Force 4 Gas Bottle Locker | Force 4 Chandlery

The tile cutting blade was a tip from a grp pro. It's what they use. They never use normal discs on grp

 

[Dellquay13]

Ear defenders! The high frequency noise from any of these tools is surprisingly loud and very damaging.

 

[AngusMcDoon]

Since getting an oscillating multitool I've never gone back to jigsaws and angle grinders.

Oscillating multitools have these advantages...

They distribute the dust less
They are much safer - you can put your finger on the end of an oscillating blade without injury
You can use a guide to get a perpendicular cut
You can get a square end cut unlike a disc cut
You can get tiny blades for cutting short lengths - not possible with a disc and shorter than a jigsaw cut
They won't skid across the surface like a disc can on starting the cut
They don't mark the surface alongside the cut like jigsaws sometimes do
With a sander pad they work as a detail sander as well so one less tool to carry
Speed control
More controllable
No blade penetrating through the cut surface like a jigsaw
No starting hole needed like a jigsaw

Disadvantages...

Slower
Risk of RSI and numbness if used long term
Curves and corners not possible, but I use a hole saw for corners
Noisy

 

[bluerm166]

I posted previously on cutting out a grp floor locker ,originally intended for an inflatable.
Cutting Fibreglass
You will see in the last post that the reciprocating chisel blade proved by far the best ,especially for its ability to get into tight corners which you may have to deal with.
I also gaze at my gas locker ,based on a 907, and wish dearly that I could enlarge it.

 

[geem]

I posted previously on cutting out a grp floor locker ,originally intended for an inflatable.
Cutting Fibreglass
You will see in the last post that the reciprocating chisel blade proved by far the best ,especially for its ability to get into tight corners which you may have to deal with.
I also gaze at my gas locker ,based on a 907, and wish dearly that I could enlarge it.

When we had gas onboard, I had a s/s cradle made for a grp, refillable 8kg gas bottle. The Mrs made an acrylic canvas cover for the cradle. The gas bottle cradle was fixed to the pushpit. It worked well and minimised the risk of gas leaks. The copper pipe was continuous with no joints, all the way to the cooker.

 

[Neeves]

Angle grinder, tile cutting blade.

If you need to cut curves, plan ahead, use a hole saw (having different sizes helps), and then join up the holes

Jonathan

 

[harvey38]

I had to cut the end out of one of the seat mouldings to create better access, the aperture was approx 16" x 12", the GRP was about 3/8 thick.

The job was started with a jigsaw but it was awkward, dusty and killed three blades in quick succession. I tried a Milwaulkee battery multi tool with a flat blade and It made the job quick, easy, not much dust and surprisingly quite and reduced vibration compared to my 240v Bosch multi tool.

I was wearing a cartridge respirator, eye protection and gloves, probably sensible precautions but not really necessary.

 

[Blueboatman]

I want to cut a hole big enough for a new gas locker in a rear bulkhead but I know from previous experience that a angle grinder is the weapon of choice but the dust...is there a alternative, jig saw maybe. I'm always surprised the strength of grp. Also is there an off the shelf gas locker to fit in the hole.

Are you thinking of buying a ready made lid assembly or door?
For less dust and restricted access near adjacent panels I would use multi tool then jigsaw then if needs must the dreaded angle grinder with vacuum cleaner duct taped to it.. and then fit the pre-made trim and lid

 

[Wansworth]

Drill holes and use a keyhole saw

 

[PCUK]

As said, a multitool is the correct tool for this job. Minimum dust and maximum accuracy.

 

[Trident]

Having done this for a living for several years .. grinder is great BUT you have noted that you want to keep dust down and no amount of dust extractor / vacuum cleaner will do that with a disc and the special covers for extraction for these means it simply wont cut so..

For quicker cutting use a jig saw with a metal blade (though any will cut it but blunt more quickly) - you can set up a guide so it's straight if that matters or finish up the edge afterwards. For slower but more refined cutting an oscillating multitool will cut straight and neat with practice and makes sucking up the dust as you go easier . It will also cut nice curves with some practice - so much so that when cutting some radiuses on wood corners the other day I did the first one (slowly but very neatly) with the multitool before I remembered I had a nice jig saw which cut the next 7 fast and neat .

You can buy off the shelf lockers depending 0n the size you want - most are small. Also don't forget to work out where the gas drain will go overboard

 

[billyfish]

I posted previously on cutting out a grp floor locker ,originally intended for an inflatable.
Cutting Fibreglass
You will see in the last post that the reciprocating chisel blade proved by far the best ,especially for its ability to get into tight corners which you may have to deal with.
I also gaze at my gas locker ,based on a 907, and wish dearly that I could enlarge it.

That's why I'm doing it . Fed up with calor at £50 for a silly little bottle. Need a new cooker as well . The only thing not perfect with the Degero 28 the gas is in the anchor locker rubbish idea in this country probably fine in scandinavian waters