boomer

I am currently building a large wooden "box" to place over the cold water and central heating header tanks in my loft. I want to line this box with polystyrene (two times 50mm blocks), but i am not sure of the best way to cut the stuff, or stick it!

What is the best way to cut polystyrene - at the moment i am considering using a hacksaw blade, but is there a better way? When i wuz a kid, i used a "heated wire" to cut poly tiles - can you buy/hire such a device thesedays?

Also, what is the best way of fixing poly blocks? At the moment i am considering "coving adhesive" - but is there a better way?

This is "Blue Peter Badge" stuff!!!!

Cheers,

mb

Neil Smalley

Don't use a saw, you'll blunt it and get bits everywhere.
I'm sure i've seen a heated wire cutter in do it all, or check your local builders merchants.

WRXBOB

A mate did a similar thing

He used a large(sharp)bread knife to cut it with and held it together with gaffa tape...I suggested that method in the pub one night after a few beers

simple and easy, and as its in the loft, who's gonna see it?
Still going strong AFAIK

BOB

Mufasa

Talking of blue peter!
You can make a hot wire cutter easily from some thick copper wire (earth strand from twin flat & earth ideal) wrap around a couple of broom handles stretched and clamped in a work mate. Sort of a Rugby post 'H' arrangement. Hook up a battery charger, flick it on to 6v trickle see if it get hot enough, if not 6v high, 12v trickle, 12v high etc. The wire does stretch as it gets hot so wrap a bungee round the bottom of the broom handles to keep tension on.

I used to cut loads of the stuff like this when I was a kid trying to make surfboards, aeroplane wings and all sorts never even blew a fuse

Stick it with PVA or Copydex (smells like it's made from dead fish!!) anything like Evostick will melt it.

Edited to say:

I just remembered! The battery charger I was using wasn't up to getting my thick earth wire hot enough, so I ended up using an arc welder turned right down to about 30amps.... I hope I never have a kid like me


[Edited by Mufasa - 3/31/2002 1:12:25 PM]

fast bloke

Mufasa - COuld you not just have cut it with the welder?

Boomer - as above - use PVA to stick it. ANy solvent base adhesive will leave you with a sticky mess.

C h a z

Why don't you build the box, leaving a small hole in the top. Put it over the tank. Then fill it through the hole with expanding foam. When this has set you could remove the box and cut away the excess foam at the corners. Just a Thought. (Chaz gets dragged away to the room with the soft walls)

Mufasa

What I really need is a plasma cutter HOO HOO BABY!

David_Wallis

Id love to see you cut it with a plasma cutter!

Plasma cutter passes current through the workpiece and then blows the molten metal out with compressed air.

Blow torch and heat a long ruler or strip of metal if you cant make your own hot wire... I would use something like an old electric fire element or something similar though...


David

boomer

Thanks to everyone for your ideas.

Neil, how will Polystyrene "blunt" a saw??

I managed to find a web-site selling proper "hot blades" but at GBP200 a pop, i think that i will improvise

WRXBOB,

Nice one - i have purchased a new bread knife (GBP3-99 on offer in Sainsburys) and initial testing is good. Oh, and some duck tape for the edges to stop it all "fraying".

Mufasa and fast bloke,

i will be using diluted PVA to "prime" the inside of my box (hardboard) to help the poly blocks stick. I will probably still stick to coving adhesive to allow a little more play with the poly.

Chaz,

that is very nearly a good idea, but i still want access to the tanks afterwards. However, one option is to fill the box with polystyrene chips instead, which are removable.



Next time i think that i will just stick to the fibre-glass wrap!!!

Cheers,

mb

Mufasa

Thanks Dave, I was never seriously suggesting attempting to use a plasma cutter on polystyrene!

Basic plasma cutters use electricity to superheat air into plasma, which is then blown through the metal to be cut. And yes (at the moment...) they're only good for metal.

David_Wallis

thought you might have been joking... and your description is better than mine!

David