I have a ring of expanded polystyrene foam, which has snapped. The
cross-section of the ring, i.e. the surface area of the break is small,
about 2cm square.

What's going to be the best adhesive to repair it?

Daniele

On 05/11/2013 15:50, D.M. Procida wrote:
I have a ring of expanded polystyrene foam, which has snapped. The
cross-section of the ring, i.e. the surface area of the break is small,
about 2cm square.

What's going to be the best adhesive to repair it?

PVA is probably as good as anything. You can't use anything with an
organic solvent or you will end up with a horrible gooey mess.

--
Regards,
Martin Brown

On 05/11/13 15:50, D.M. Procida wrote:
I have a ring of expanded polystyrene foam, which has snapped. The
cross-section of the ring, i.e. the surface area of the break is small,
about 2cm square.

What's going to be the best adhesive to repair it?

as an avid model plane man,. you have three or four options known to work.

1/. PVA. yes simple white glue. It will however take a week to dry
because polystyrene don't let the water out, so we genereally use it to
attach things like balsa to polystyrene, where its light and very strong.

2/. foam safe superglue. This is model specific as its a fast superglue
that does NOT turn poly into a soggy puddle as most superglues do. I
never found it very effective

3/. Epoxy. It doesn't bond that well but it bonds stronger than the
poly. It is however heavy and much harder than the poly, so we tend not
to use it that much.

4/. Hot glue. This is the best of all. 240v generator and a hot glue gun
gets a foam model back in the air in minutes, even if it looks like
Frankenstein's monster.

It has good flexibility fast grab and set and is not too heavy.

The finished joint is more less like a lighter and more flexible version
of epoxy, and like an epoxy repair, the next time it crashes it always
breaks somewhere else :-)

do not attempt any solvent based glues - they all attack the styrene, as
does Cyanoacrylate superglue and polyester resins (car body filler)

Glues based on PVA and other acrylic type stuff work, but take a long
time to get the water out of. So e.g you can use decorators caulk to
blend with poly, but it takes forever to turn rubbery.


Daniele



--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

The Natural Philosopher wrote:

On 05/11/13 15:50, D.M. Procida wrote:

I have a ring of expanded polystyrene foam, which has snapped. The
cross-section of the ring, i.e. the surface area of the break is small,
about 2cm square.

What's going to be the best adhesive to repair it?

as an avid model plane man,. you have three or four options known to work.

2/. foam safe superglue. This is model specific as its a fast superglue
that does NOT turn poly into a soggy puddle as most superglues do. I
never found it very effective

4/. Hot glue. This is the best of all. 240v generator and a hot glue gun
gets a foam model back in the air in minutes, even if it looks like
Frankenstein's monster.

Well I'm surprised, but I'll give that a try. The foam-safe CAs seem to
be very expensive.

Daniele

On Tue, 05 Nov 2013 17:32:08 +0000, The Natural Philosopher wrote:

as an avid model plane man,. you have three or four options known to
work.

1/. PVA.

2/. foam safe superglue.

3/. Epoxy.

4/. Hot glue.

Evo stick? Pretty sure I've seen that on the back of polysytrene
tiles. I'd do a test first though just incase the solvent does what
solvents do...

--
Cheers
Dave.

Trouble is it has no structural strength, so gluing seems not to work. Most
glues seem to be mild (or not so mild) solvents and then the fix looks messy
and ugly.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"D.M. Procida" wrote in
message
...
I have a ring of expanded polystyrene foam, which has snapped. The
cross-section of the ring, i.e. the surface area of the break is small,
about 2cm square.

What's going to be the best adhesive to repair it?

Daniele

On 06/11/13 08:36, Dave Liquorice wrote:
On Tue, 05 Nov 2013 17:32:08 +0000, The Natural Philosopher wrote:

as an avid model plane man,. you have three or four options known to
work.

1/. PVA.

2/. foam safe superglue.

3/. Epoxy.

4/. Hot glue.

Evo stick? Pretty sure I've seen that on the back of polysytrene
tiles. I'd do a test first though just incase the solvent does what
solvents do...

Be careful. some sort of petrol like solvents dint attack poly, but
glues with them in are well nigh impossible to source due to sniffing etc.

And the evostik on the back was a water based contact...


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

Dave Liquorice wrote:
On Tue, 05 Nov 2013 17:32:08 +0000, The Natural Philosopher wrote:

as an avid model plane man,. you have three or four options known to
work.

1/. PVA.

2/. foam safe superglue.

3/. Epoxy.

4/. Hot glue.

Evo stick? Pretty sure I've seen that on the back of polysytrene
tiles. I'd do a test first though just incase the solvent does what
solvents do...

Evode used to make a PVA based adhesive. The normal rubbery impact
adhesive uses organic solvents and will dissolve expanded polystyrene.

--
Tciao for Now!

John.

On Wednesday, 6 November 2013 08:36:30 UTC, Dave Liquorice wrote:

Evo stick? Pretty sure I've seen that on the back of polysytrene
tiles. I'd do a test first though just incase the solvent does what
solvents do...

I was thinking something like that.
I have never tried it and can't imagine having to but if you spread the glue on surface A and let it dry, as long as you keep off the dust, you can leave it indefinitely, the same with cyanates I believe. (That actually worked on a burglar for me.)

Can you spread some on a stretched skein of film such silk and then apply that to the broken piece "B"?

I imagine tape would do as well but I'm not sure what you requirements are.
No piccies?

On 06/11/13 13:05, Weatherlawyer wrote:
On Wednesday, 6 November 2013 08:36:30 UTC, Dave Liquorice wrote:

Evo stick? Pretty sure I've seen that on the back of polysytrene
tiles. I'd do a test first though just incase the solvent does what
solvents do...

I was thinking something like that.
I have never tried it and can't imagine having to but if you spread the glue on surface A and let it dry, as long as you keep off the dust, you can leave it indefinitely, the same with cyanates I believe. (That actually worked on a burglar for me.)

Can you spread some on a stretched skein of film such silk and then apply that to the broken piece "B"?

I imagine tape would do as well but I'm not sure what you requirements are.
No piccies?


largely polystyrene of the expanded kind fractures on the joints between
the bubbles. It is not suitable for tape repairs.

Neither is contact particularly good - you need a gap filler.

in my case hot glue is no 1, followed by lightweight polyfilla to make
good the fracture line at the surface, and then re-covering with
whatever you used to make a decen't finish in the first place. Tissue or
brown paper and pva plus an acrylic coat is then suitable for most paints.



--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

In article o.uk,
"Dave Liquorice" writes:
On Tue, 05 Nov 2013 17:32:08 +0000, The Natural Philosopher wrote:

as an avid model plane man,. you have three or four options known to
work.

1/. PVA.

2/. foam safe superglue.

3/. Epoxy.

4/. Hot glue.

Evo stick? Pretty sure I've seen that on the back of polysytrene
tiles. I'd do a test first though just incase the solvent does what
solvents do...

Evo Stick certainly used to do a polystyrene ceiling tile adhesive,
but it was nothing like regular Evo Stick. The ceiling tile adhesive
worked very well, but may have relied on drying through the ceiling.

I had an expanded polystyrene carving kit (hot wire, glue, etc) as a
child. That came with small tubes of glue which worked, but I've no
idea what it was.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 06/11/13 16:10, Andrew Gabriel wrote:
In article o.uk,
"Dave Liquorice" writes:
On Tue, 05 Nov 2013 17:32:08 +0000, The Natural Philosopher wrote:

as an avid model plane man,. you have three or four options known to
work.

1/. PVA.

2/. foam safe superglue.

3/. Epoxy.

4/. Hot glue.

Evo stick? Pretty sure I've seen that on the back of polysytrene
tiles. I'd do a test first though just incase the solvent does what
solvents do...

Evo Stick certainly used to do a polystyrene ceiling tile adhesive,
but it was nothing like regular Evo Stick. The ceiling tile adhesive
worked very well, but may have relied on drying through the ceiling.

I had an expanded polystyrene carving kit (hot wire, glue, etc) as a
child. That came with small tubes of glue which worked, but I've no
idea what it was.

one of the UHU derivatives works too..cant remember which.


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

D.M. Procida wrote:

The Natural Philosopher wrote:

On 05/11/13 15:50, D.M. Procida wrote:

I have a ring of expanded polystyrene foam, which has snapped. The
cross-section of the ring, i.e. the surface area of the break is small,
about 2cm square.

What's going to be the best adhesive to repair it?

as an avid model plane man,. you have three or four options known to work.

2/. foam safe superglue. This is model specific as its a fast superglue
that does NOT turn poly into a soggy puddle as most superglues do. I
never found it very effective

4/. Hot glue. This is the best of all. 240v generator and a hot glue gun
gets a foam model back in the air in minutes, even if it looks like
Frankenstein's monster.

Well I'm surprised, but I'll give that a try. The foam-safe CAs seem to
be very expensive.

I can confirm it worked very nicely, thanks! Not beautiful, but it seems
pretty strong.

Daniele

On 05/11/2013 17:32, The Natural Philosopher wrote:
On 05/11/13 15:50, D.M. Procida wrote:
I have a ring of expanded polystyrene foam, which has snapped. The
cross-section of the ring, i.e. the surface area of the break is small,
about 2cm square.

What's going to be the best adhesive to repair it?

as an avid model plane man,. you have three or four options known to work.

1/. PVA. yes simple white glue. It will however take a week to dry
because polystyrene don't let the water out, so we genereally use it to
attach things like balsa to polystyrene, where its light and very strong.

2/. foam safe superglue. This is model specific as its a fast superglue
that does NOT turn poly into a soggy puddle as most superglues do. I
never found it very effective

3/. Epoxy. It doesn't bond that well but it bonds stronger than the
poly. It is however heavy and much harder than the poly, so we tend not
to use it that much.

4/. Hot glue. This is the best of all. 240v generator and a hot glue gun
gets a foam model back in the air in minutes, even if it looks like
Frankenstein's monster.

Why the generator and 240V hot glue gun? Why not a lighter gas powered one?

SteveW

On Sun, 01 Dec 2013 23:34:49 +0000, SteveW wrote:

4/. Hot glue. This is the best of all. 240v generator and a hot glue
gun gets a foam model back in the air in minutes, even if it looks like
Frankenstein's monster.

Why the generator and 240V hot glue gun? Why not a lighter gas powered
one?

Or a 12v one. Or an internal battery one.