"Tony Hayes" wrote in message
...
My neighbour is laying the floor in his new bungalow - 4 inch thick
polystyrene insulation sheets covered with chipboard tongue and groove.
He
intends running plastic central heating pipes under the floor and is
looking
for the best way of cutting channels in the insulation to take the piping.

Any ideas gratefully received and passed on.

Thanks,
Tony

A circular saw will cut a groove to the depth required and a few passes will
provide the desired width.

Richard.

"Tony Hayes" wrote in message
...
My neighbour is laying the floor in his new bungalow - 4 inch thick
polystyrene insulation sheets covered with chipboard tongue and groove.
He
intends running plastic central heating pipes under the floor and is
looking
for the best way of cutting channels in the insulation to take the piping.



why on earth use 4" of polystyrene ? .... you can use polyurethane, it is
much better for use with underfloor heating.
It is more dense, and much higher insulating value than polystyrene .


But if you want to cut it ... you could use a soldewering iron, but simpler
to use a stanley knife set to correct depth of cut - cut left & right side
then use a fork to scrape out the waste.


Rick

Rick Hughes wrote:

why on earth use 4" of polystyrene ? .... you can use polyurethane, it is
much better for use with underfloor heating.
It is more dense, and much higher insulating value than polystyrene .


Thanks for your reply. It's not underfloor heating - he's just running the
pipework to the rads under the floor.
Tony

On Fri, 25 Jul 2003 20:39:02 +0100, Tony Hayes
wrote:


Any ideas gratefully received and passed on.

He needs to make a polystyrene cutter
(http://www.techlib.com/hobby/hotwire_foam_cutter.htm) for which he
will need Nichrome wire. The fact I still have a few km of Nichrome
wire is entirely immaterial.

If you need a few yards of the stuff it's sort of free (you are
requested to post what its worth to you in the next RAF Benevolent
fund box you come across). Get in touch if you need some.


--
Peter Parry.
http://www.wpp.ltd.uk/

In article , Peter Parry
writes
He needs to make a polystyrene cutter
(http://www.techlib.com/hobby/hotwire_foam_cutter.htm) for which he
will need Nichrome wire. The fact I still have a few km of Nichrome
wire is entirely immaterial.
Similarly but different, the pistol grip 100/200W instant heat soldering irons
that seem to be getting sold cheap all over these days have, *I think*,
copper wire elements which just get hot by passing a huge current through
the wire. Strip wire from some T&E and shape a new 'element' to the
desired cutting profile - bingo . . . .

Flaws anyone?, are those elements really just copper?
--
fred

"Rick Hughes" wrote
Q:
why on earth use 4" of polystyrene ? .... you can use polyurethane, it is
A:
cost

--
Toby.

NTL: Bringing you yesterday's news today, and a bit of last week's. Maybe.

In message , Rick Hughes
writes

"Tony Hayes" wrote in message
.. .
My neighbour is laying the floor in his new bungalow - 4 inch thick
polystyrene insulation sheets covered with chipboard tongue and groove.
He
intends running plastic central heating pipes under the floor and is
looking
for the best way of cutting channels in the insulation to take the piping.



why on earth use 4" of polystyrene ? .... you can use polyurethane, it is
much better for use with underfloor heating.
It is more dense, and much higher insulating value than polystyrene .


But if you want to cut it ... you could use a soldewering iron, but simpler
to use a stanley knife set to correct depth of cut - cut left & right side
then use a fork to scrape out the waste.

I think a craft knife at full extension might work a little better
--
geoff

In article , Steve Firth
writes
Peter Parry wrote:

He needs to make a polystyrene cutter
(http://www.techlib.com/hobby/hotwire_foam_cutter.htm) for which he
will need Nichrome wire.

Errm, you don't need nichrome, unwinding one strand from a steel bicycle
brake cable works perfectly. If it is clamped into a fretsaw frame
(suitably insulated) and fed with current from a 12V source via a
rheostat it works very, very well.

Constantan wire from Maplins also works well.

For straight cuts I suspend a piece from a batten fixed near the garage
ceiling tensioned with a weight. Croc clips supply the power (6V or
12V), and you slide them closer or further apart to get the required
temp. 18" is about right for 6V, IIRC.

I guess for troughs you could make a "U" shape, but it wouldn't be very
rigid.


Regards,

Simonm.

--
simonm|at|muircom|dot|demon|.|c|oh|dot|u|kay
SIMON MUIR, UK INDEPENDENCE PARTY, BRISTOL www.ukip.org
EUROPEANS AGAINST THE EU www.members.aol.com/eurofaq
GT250A'76 R80/RT '86 www.kc3ltd.co.uk/profile/eurofollie/

Thanks for all the very helpful replies - I'm sure my neighbour will be able
to choose a method he can cope with from all the suggestions.

Many thanks,
Tony

Rick Hughes wrote:

"Tony Hayes" wrote in message
...

My neighbour is laying the floor in his new bungalow - 4 inch thick
polystyrene insulation sheets covered with chipboard tongue and groove.

He

intends running plastic central heating pipes under the floor and is

looking

for the best way of cutting channels in the insulation to take the piping.




why on earth use 4" of polystyrene ? .... you can use polyurethane, it is
much better for use with underfloor heating.
It is more dense, and much higher insulating value than polystyrene .



and 4 times as expensive...



But if you want to cut it ... you could use a soldewering iron, but simpler
to use a stanley knife set to correct depth of cut - cut left & right side
then use a fork to scrape out the waste.


Rick

Steve Firth wrote:

Peter Parry wrote:


He needs to make a polystyrene cutter
(http://www.techlib.com/hobby/hotwire_foam_cutter.htm) for which he
will need Nichrome wire.


Errm, you don't need nichrome, unwinding one strand from a steel bicycle
brake cable works perfectly. If it is clamped into a fretsaw frame
(suitably insulated) and fed with current from a 12V source via a
rheostat it works very, very well.



So do guitar strings, stainless steel fishing trace or just about anything.

"Toby" wrote in message
...

"Rick Hughes" wrote
Q:
why on earth use 4" of polystyrene ? .... you can use polyurethane, it
is
A:
cost

Not if you buy form Seconds & Co. ... you can buy any size, thickness and
style of foam - getting polyurethane for the price of polystyrene.

They have 2 outlets - but I think they are now unrelated.


I bought more than 60 sheets of foam, 50mm and 100mm ... saved a packet
compared to builders merchants.

Rick

why on earth use 4" of polystyrene ? .... you can use polyurethane, it
is
much better for use with underfloor heating.
It is more dense, and much higher insulating value than polystyrene .



and 4 times as expensive...


not so ... see my subsequent post on seconds & Co.

Rick Hughes wrote:
"Toby" wrote
"Rick Hughes" wrote
Q:
why on earth use 4" of polystyrene ? .... you can use
polyurethane, it is
A:
cost

Not if you buy form Seconds & Co. ... you can buy any size,
thickness and style of foam - getting polyurethane for the price of
polystyrene.

They have 2 outlets - but I think they are now unrelated.

Looks good. I see Seconds (Southern) Ltd. in Kent & Seconds and Co. in
Wales, shame there isn't a third branch further north. Looks like they both
do deliveries - should be worth a call.
Was just about to buy a floor load of polystyrene.

Toby.

In message , Peter Parry
writes
On Fri, 25 Jul 2003 23:48:40 +0100, (Steve
Firth) wrote:

Peter Parry wrote:

He needs to make a polystyrene cutter
(http://www.techlib.com/hobby/hotwire_foam_cutter.htm) for which he
will need Nichrome wire.

Errm, you don't need nichrome, unwinding one strand from a steel bicycle
brake cable works perfectly.

Yes but think of the nuisance, first you have to buy a bicycle, then
dismantle the thing, then having extracted one strand of brake cable
you have to go and buy a replacement brake cable. I mean it's a
right hassle compared with my free offer :-).

G'wan then Peter, I'll have a km off you
--
geoff

Richard wrote:

"Tony Hayes" wrote in message
...
My neighbour is laying the floor in his new bungalow - 4 inch thick
polystyrene insulation sheets covered with chipboard tongue and groove.
He
intends running plastic central heating pipes under the floor and is
looking
for the best way of cutting channels in the insulation to take the piping.

Any ideas gratefully received and passed on.

Thanks,
Tony

A circular saw will cut a groove to the depth required and a few passes will
provide the desired width.

Richard.

Could you 'wobble' a circular or bench saw blade to cut a
groove/slot in the foam?
I've done this to cut shallow slots in the uprights for a book
case, in which to fit the horizontal shelves.
To wobble the saw, washers etc. were clamped in the bench saw
arbor, on both sides of the blade to tilt it 'off centre'. A few
experimental cuts with adjustments and it worked fine to a depth
of between a quarter to half inch, in plywood cutting a three
quarter inch wide slot. (So the outer edge of the blade had to be
wobbling about three eighths off centre line.)
In a soft material such as foam probably no trouble cutting say,
20 mm wide to a depth of say 40 mm?
Idea. Terry.

Rick Hughes wrote:

"Peter Parry" wrote in message
...

On Fri, 25 Jul 2003 20:39:02 +0100, Tony Hayes
wrote:



Any ideas gratefully received and passed on.

He needs to make a polystyrene cutter
(http://www.techlib.com/hobby/hotwire_foam_cutter.htm) for which he
will need Nichrome wire. The fact I still have a few km of Nichrome
wire is entirely immaterial.



Will polyurethane foam cut this way as well ??



No. it chars, doesn't melt.