When I want to glue to surfaces togther then I am advised to
roughen the surfaces first.

In this particular case I have two fairly soft hard plastics
(about as soft as styrene but not as soft as polyethylene) which i
wish to stick together.

----------------------

I have a choice of adhesive:
(1) "super glue" - cyanoacrylate adhesive
(2) Bostik or UHU - general purpose adhesive
(3) Evostik - contact adhesive
(4) Araldite - epoxy resin
(5) hot melt adhesive from glue gun - various formulations

The cyanoacrylate super glues should be good for this application
but too often I have tended to get disappointing results from
this type of glue. I find the hot melts too can be problematic.

So I will probably use either (a) a Bostik/UHU type of general
purpose adhesive or (b) a contact adhesive.

----------------------

The QUESTION is what sort of roughening is best to allow this sort
of glue to bond strongly with each plastic surface. Each surface
is currently smooth.

(ONE) Should the roughening be quite fine. Perhaps similar to
using 300 grit glasspaper?

(TWO) Or should the roughening be almost visibly "streaky" as one
might get using 40 grit glasspaper?

(THREE) Would you change your recommendation if I made a different
choice of adhesive fro the range above?

Thank you.

"Andy" wrote in message
...
When I want to glue to surfaces togther then I am advised to
roughen the surfaces first.

In this particular case I have two fairly soft hard plastics
(about as soft as styrene but not as soft as polyethylene) which i
wish to stick together.

----------------------

I have a choice of adhesive:
(1) "super glue" - cyanoacrylate adhesive
(2) Bostik or UHU - general purpose adhesive
(3) Evostik - contact adhesive
(4) Araldite - epoxy resin
(5) hot melt adhesive from glue gun - various formulations


you should use a glue for that plastic, all the above will not work that
well.
The plastic glue will dissolve the plastic some, and bond it.
Try pipe cement, for plastic piping, it is a great plastic glue.

You need to identify the plastic. Styrene is a liquid, not a solid, so
comparing hardnesses is not logical.

Marshall

Andy wrote:

When I want to glue to surfaces togther then I am advised to
roughen the surfaces first.

In this particular case I have two fairly soft hard plastics
(about as soft as styrene but not as soft as polyethylene) which i
wish to stick together.

----------------------

I have a choice of adhesive:
(1) "super glue" - cyanoacrylate adhesive
(2) Bostik or UHU - general purpose adhesive
(3) Evostik - contact adhesive
(4) Araldite - epoxy resin
(5) hot melt adhesive from glue gun - various formulations

The cyanoacrylate super glues should be good for this application
but too often I have tended to get disappointing results from
this type of glue. I find the hot melts too can be problematic.

So I will probably use either (a) a Bostik/UHU type of general
purpose adhesive or (b) a contact adhesive.

----------------------

The QUESTION is what sort of roughening is best to allow this sort
of glue to bond strongly with each plastic surface. Each surface
is currently smooth.

(ONE) Should the roughening be quite fine. Perhaps similar to
using 300 grit glasspaper?

(TWO) Or should the roughening be almost visibly "streaky" as one
might get using 40 grit glasspaper?

(THREE) Would you change your recommendation if I made a different
choice of adhesive fro the range above?

Thank you.

"Andy" wrote in message

When I want to glue to surfaces togther then I am advised to
roughen the surfaces first.

In this particular case I have two fairly soft hard plastics
(about as soft as styrene but not as soft as polyethylene)
which i wish to stick together.

----------------------

I have a choice of adhesive:
(1) "super glue" - cyanoacrylate adhesive
(2) Bostik or UHU - general purpose adhesive
(3) Evostik - contact adhesive
(4) Araldite - epoxy resin
(5) hot melt adhesive from glue gun - various formulations


On 14 Apr 2006, Kono wrote:

you should use a glue for that plastic, all the above will not
work that well.
The plastic glue will dissolve the plastic some, and bond it.
Try pipe cement, for plastic piping, it is a great plastic
glue.


Maybe drain pipe solvent cement could work. But different cement
is used for different drain pipe plastics (styrene, ABS, PVC, CPV)
and I can't identify what my surfaces are.

The two plastics I am joining do not dissolve even slightly with
acetone or with ethyl acetate (both as nail varnish removers).

On 14 Apr 2006, Marshall wrote:

You need to identify the plastic. Styrene is a liquid, not a
solid, so comparing hardnesses is not logical.

Marshall

--

Hi Marshall, was using a short form. Bit sloppy really.

Meant to refer to the plastics derived from styrene like ABS, SIS and
all that stuff.

Was speaking as a modeller where we nearly always refer to hard
plastic as "styrene plastic".

"Andy" wrote in message
...
"Andy" wrote in message

When I want to glue to surfaces togther then I am advised to
roughen the surfaces first.

In this particular case I have two fairly soft hard plastics
(about as soft as styrene but not as soft as polyethylene)
which i wish to stick together.

----------------------

I have a choice of adhesive:
(1) "super glue" - cyanoacrylate adhesive
(2) Bostik or UHU - general purpose adhesive
(3) Evostik - contact adhesive
(4) Araldite - epoxy resin
(5) hot melt adhesive from glue gun - various formulations


On 14 Apr 2006, Kono wrote:

you should use a glue for that plastic, all the above will not
work that well.
The plastic glue will dissolve the plastic some, and bond it.
Try pipe cement, for plastic piping, it is a great plastic
glue.


Maybe drain pipe solvent cement could work. But different cement
is used for different drain pipe plastics (styrene, ABS, PVC, CPV)
and I can't identify what my surfaces are.

The two plastics I am joining do not dissolve even slightly with
acetone or with ethyl acetate (both as nail varnish removers).

try the plastic pipe cement, very cheap, works with many plastics, but not
polycarbonate I think

On Fri, 14 Apr 2006 22:57:20 +0100, Andy Gave us:

"Andy" wrote in message

When I want to glue to surfaces togther then I am advised to
roughen the surfaces first.

In this particular case I have two fairly soft hard plastics
(about as soft as styrene but not as soft as polyethylene)
which i wish to stick together.

----------------------

I have a choice of adhesive:
(1) "super glue" - cyanoacrylate adhesive
(2) Bostik or UHU - general purpose adhesive
(3) Evostik - contact adhesive
(4) Araldite - epoxy resin
(5) hot melt adhesive from glue gun - various formulations


On 14 Apr 2006, Kono wrote:

you should use a glue for that plastic, all the above will not
work that well.
The plastic glue will dissolve the plastic some, and bond it.
Try pipe cement, for plastic piping, it is a great plastic
glue.


Maybe drain pipe solvent cement could work. But different cement
is used for different drain pipe plastics (styrene, ABS, PVC, CPV)
and I can't identify what my surfaces are.

The two plastics I am joining do not dissolve even slightly with
acetone or with ethyl acetate (both as nail varnish removers).

Liquid nails construction adhesive from home depot or the like. No
surface pre-prep required.

Kono imo! wrote:
"Andy" wrote in message
...
When I want to glue to surfaces togther then I am advised to
roughen the surfaces first.

In this particular case I have two fairly soft hard plastics
(about as soft as styrene but not as soft as polyethylene) which i
wish to stick together.

----------------------

I have a choice of adhesive:
(1) "super glue" - cyanoacrylate adhesive
(2) Bostik or UHU - general purpose adhesive
(3) Evostik - contact adhesive
(4) Araldite - epoxy resin
(5) hot melt adhesive from glue gun - various formulations


you should use a glue for that plastic, all the above will not work that
well.
The plastic glue will dissolve the plastic some, and bond it.
Try pipe cement, for plastic piping, it is a great plastic glue.


This is good advice. CA and epoxy do not bond well to MOST plastics.
Solvent based contact adhesive is good.

But it all depend on the type of joint, and the exact plastic.

Styrene and PVC solvent weld very well indeed. Polythene is almost
impossible to glue to anything with anything - its just to greasy.

Thermoset plastics work well with epoxy and polyester glues.

Reasonable glue joints can be made to MANY but not ALL plastics with
hot melt or no more nails type glues...

It would hep if you said exactly what you are trying to do.

Andy wrote:
"Andy" wrote in message
When I want to glue to surfaces togther then I am advised to
roughen the surfaces first.

In this particular case I have two fairly soft hard plastics
(about as soft as styrene but not as soft as polyethylene)
which i wish to stick together.

----------------------

I have a choice of adhesive:
(1) "super glue" - cyanoacrylate adhesive
(2) Bostik or UHU - general purpose adhesive
(3) Evostik - contact adhesive
(4) Araldite - epoxy resin
(5) hot melt adhesive from glue gun - various formulations


On 14 Apr 2006, Kono wrote:
you should use a glue for that plastic, all the above will not
work that well.
The plastic glue will dissolve the plastic some, and bond it.
Try pipe cement, for plastic piping, it is a great plastic
glue.


Maybe drain pipe solvent cement could work. But different cement
is used for different drain pipe plastics (styrene, ABS, PVC, CPV)
and I can't identify what my surfaces are.

The two plastics I am joining do not dissolve even slightly with
acetone or with ethyl acetate (both as nail varnish removers).

Bad news. TRy petrol =- that may dissolve them.

There are lots of styrene based plastics. I think that Bondo is based
on styrene, as well as the resin used for making fiberglass composite.
It's some type of polyester -


Well, if you live in the US, there is a new type of glue on the market
callet "Gorilla Glue". I think it's made in Norway or somewhere, and
you can also get it from their website. It is a polyurethane, and would
probably stick pretty good.

You could also try %100 silicone from hardware store.

But for this app, I think that a hot glue gun might work pretty good
too. I think that the glue sticks these days are made from some kind of
polypropylene formulation.

You might also consider welding somehow, most thermoplasts can be
welded.

If I were you I'd hit it with various sandpapers, and then scrape it up
a little with a razor blade.

Cyanocrylate will dissolve expanded polystyrene. If cyano softens your
plastic, you may not need to rough it at all. I think that hobby models
are made of styrene, and the glue is basically styrene dissolved in
toluene.

I'd test the cyano - it wont cure at all on some substrates.


What is it you are building ? Where'd you find the plastic ?