Plastic insert in top of glue cans.

Plastic insert in top of glue cans.

Post by Herbert Wa » Thu, 20 Feb 2003 03:19:25


What is the purpose of the threaded plastic insert in the top of glue cans?

Other volatiles (for example, Bestine, naptha, and turpentine) have all-metal cans.

 
 
 

Plastic insert in top of glue cans.

Post by Scott L. Burso » Thu, 20 Feb 2003 11:42:09

Quote:

> What is the purpose of the threaded plastic insert in the top of glue cans?

> Other volatiles (for example, Bestine, naptha, and turpentine) have all-metal cans.

I would expect it's easier to get a good seal with plastic than with metal.

I think it's still possible with metal, though -- you just have to
tighten the cap really tight.

-- Scott

 
 
 

Plastic insert in top of glue cans.

Post by Peter Moo Youn » Thu, 20 Feb 2003 23:13:12

Because the contents are volatile, any distortion in either the cover or the
lip of the can could result in the contents vapourizing. We therfore use
plastic because of it's pliablity it will always make a good tight seal...


Quote:
> What is the purpose of the threaded plastic insert in the top of glue
cans?

> Other volatiles (for example, Bestine, naptha, and turpentine) have

all-metal cans.

 
 
 

Plastic insert in top of glue cans.

Post by Herbert Wa » Sat, 22 Feb 2003 01:17:43

Quote:
> Because the contents are volatile, any distortion in either the cover or the
> lip of the can could result in the contents vapourizing. We therfore use
> plastic because of it's pliablity it will always make a good tight seal...

Commercial jelly jars use a metal cover and a glass lip, and maintain
a hermetic seal for years (notice the "pop" when you open them).

I suspect that using plastic is cheaper than making a metal lip.

 
 
 

Plastic insert in top of glue cans.

Post by Scott L. Burso » Sat, 22 Feb 2003 06:58:55

Quote:

> > Because the contents are volatile, any distortion in either the cover or the
> > lip of the can could result in the contents vapourizing. We therfore use
> > plastic because of it's pliablity it will always make a good tight seal...

> Commercial jelly jars use a metal cover and a glass lip, and maintain
> a hermetic seal for years (notice the "pop" when you open them).

But a lot of jars these days have a soft plastic layer on the inside of
the metal where it meets the glass.

Quote:
> I suspect that using plastic is cheaper than making a metal lip.

I think that making a good metal-to-metal seal is possible but yes,
somewhat expensive.  It's easier if plastic is involved on one side or
the other.

-- Scott

 
 
 

Plastic insert in top of glue cans.

Post by Ke » Wed, 26 Feb 2003 03:51:59

My two cents worth - metal cap + metal thread = too tight seal for
hand to open.
This is my experience with the ASTI speed glue booster. It is
impossible to open the booster with bare fingers or even with ***
gloves on. I ended up using a vice-grip on the lid and still have to
apply a lot of efforts to open it. The second time is not any easier
either. Same thing happens to my Spinmax bottle. May be because the
highly flammable liquid builds up a lot of pressure thus making
opening very difficult.
Another thing - glue on the cap can bond it to the thread area and
seize the bottle, just like the caps on my epoxy glue.
Even the large one litre speed glue cans I've used todate all come
with plastice cap and tread.
Ken
 
 
 

Plastic insert in top of glue cans.

Post by Arno Stiene » Wed, 26 Feb 2003 18:10:46

I had the same problem with ASTI cans, but it was solved easily by using a
bit of edge-tape on the cap:

http://SportToday.org/~stienen/astican.jpg

No more problems after that.

Arno.


Quote:
> My two cents worth - metal cap + metal thread = too tight seal for
> hand to open.
> This is my experience with the ASTI speed glue booster. It is
> impossible to open the booster with bare fingers or even with ***
> gloves on. I ended up using a vice-grip on the lid and still have to
> apply a lot of efforts to open it. The second time is not any easier
> either. Same thing happens to my Spinmax bottle. May be because the
> highly flammable liquid builds up a lot of pressure thus making
> opening very difficult.
> Another thing - glue on the cap can bond it to the thread area and
> seize the bottle, just like the caps on my epoxy glue.
> Even the large one litre speed glue cans I've used todate all come
> with plastice cap and tread.
> Ken

 
 
 

Plastic insert in top of glue cans.

Post by Herbert Wa » Fri, 28 Feb 2003 07:29:17

Quote:
> May be because the
> highly flammable liquid builds up a lot of pressure thus making
> opening very difficult.

Pressure would create a hissing sound upon opening.

I bet they use plastic necks just because they're cheaper.  Anyone
could make a mold for threaded plastic necks.  But how do you
manufacture threaded metal necks?  Some expensive and complex stamping
machine I guess, which needs expert operation and maintenance.