cutting inspection hatch in holding tank

[pquinn]

Hi folks,

I am fitting a toilet waste holding tank and am gettuing one of those toilet tank packages from leesan. The tank will be a ''rotary molded tank' which i assume is some kind of plastic/fiberglass. what i would like to know is if it would be a good idea to use a jig saw to cut the inspection hatch as i need to buy at least five different holesaws for the installation and will have little or no use for these hole saws after i have installed the toilet and tank. the inspection hatch needs a 121 mm hole saw. Any ideas for cutting down on all these hole saws would be welcome. Thanks . Paul.

[lulu fish]

Why would you want to inspect the inside of a plastic poo tank?

[dor]

Rotary moulding probably means it is polypropylene.  You can cut a hole with a jigsaw (use a fairly fine blade, but not hacksaw-fine).

Rotationally moulded PP tends to be a bit more brittle than injection moulded, but should still cut easily enough.

[pquinn]

What else would i be doing on a saturday night after x factor?

[dor]

1 minute ago, pquinn said:

What else would i be doing on a saturday night after x factor?

I presume you are referring to investigating the content of your holding tank.   I think I would rather do that than watch X Factor!

[pquinn]

Just now, dor said:

I presume you are referring to investigating the content of your holding tank.   I think I would rather do that than watch X Factor!

[system 4-50]

Are you sure that it does not come with one in? I understand that rotary moulded tanks usually have a large lid because of the way they are made and this can serve as an inspection hatch. My RM tanks have 8" lids.

[pquinn]

1 minute ago, system 4-50 said:

Are you sure that it does not come with one in? I understand that rotary moulded tanks usually have a large lid because of the way they are made and this can serve as an inspection hatch. My RM tanks have 8" lids.

No, i dont think so as i asked leesan the best way to cut the hole and they said a hole saw.

[X Alan W]

121 mm is a roughish 5"dia hole you should be able to cut a hole with a jigsaw if you get some of the fine down as opposed to upward cutting blades it should pose no problem a varible speed jigsaw should make the task easier use a slower speed to avoid melting the plastic if that's what the tank material is

[stegra]

If you are only cutting through plastic, you'll hardly need to smash the piggy bank:

http://m.ebay.co.uk/itm/16PC-HOLE-SAW-CUTTING-SET-KIT-19-127MM-WOOD-METAL-ALLOYS-/192011730726?epid=1205420773&hash=item2cb4ca7f26%3Ag%3AmoAAAOSwcLxYEyt-&_trkparms=pageci%3Ac8532d2f-730e-11e7-aa97-74dbd1800c73%7Cparentrq%3A85dad93415d0a7f23456d370ffff2208%7Ciid%3A1

[Sea Dog]

My preference would be to leave the thing as sealed as it possibly can be, that is to say without an inspection hatch. Should you ever need to get inside the thing in the future, that's the time to.... get someone else to remove it and fit a new one, also without an inspection hatch!