Topics

Bonding Glass to Metal


Darren Conway
 

Hi

That special adhesive is probably the stuff used to bond rear view mirrors to car windscreen glass.


Regards

Darren Conway
36 Orr Crescent
Lower Hutt
New Zealand
ph +64  (0)4 569 1963

On 12.04.20 9:17 pm, John Haine wrote:
Neil, further to your question, I was leafing through my copy of "Woodward on Time" to chase another reference and it includes a short description by David Walter of how he went about the construction, giving more detail than his website.  It wasn't published separately alas (I think).  But he specifically refers to "...using a special Loctite adhesive designed to bond metal and glass."  That might help?

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neil
 

Hi Darren,
                  Coincidental that you post this. I have spent the last few hours tonite pondering the fixing of my pendulum to the suspension, and what happens when the temperature changes. I dont think the type of epoxy/locktite etc will matter too much. They all should be strong enough, and im not worried about the adhesive properties. According to a table of linear TC that i am looking at, most resins and epoxies have quite high TC, but looking at the physics at the molecular level, i am thinking that a temp change will not result in a length change. ( if you look at a molecule of glue ...those below the dentre of pressure will move down towards the bob, and those above the C of P will move upwards towards the sudpensio. Net result =  no pendulum length change. Just my random thoughts)
But what may be more critical is a change in viscosity of the glue  with temperature. This would allow the glue to "relax" lengthwise under load and cause the effective pendulum length to increase. 
Still ..if this is a linear change then i should still be able to compensate with an under bob compensator.
Im doing a video on an experimental glass pendulum and should have it up in a few days  ..the video that is.

On Sun, 12 Apr 2020, 9:27 PM Darren Conway <darren.conway@...> wrote:

Hi

That special adhesive is probably the stuff used to bond rear view mirrors to car windscreen glass.


Regards

Darren Conway
36 Orr Crescent
Lower Hutt
New Zealand
ph +64  (0)4 569 1963

On 12.04.20 9:17 pm, John Haine wrote:
Neil, further to your question, I was leafing through my copy of "Woodward on Time" to chase another reference and it includes a short description by David Walter of how he went about the construction, giving more detail than his website.  It wasn't published separately alas (I think).  But he specifically refers to "...using a special Loctite adhesive designed to bond metal and glass."  That might help?

Virus-free. www.avast.com


Darren Conway
 

Hi

I have read that the right combination carbon fibre in resin can have near zero thermal coefficient of expansion.

Your concerns could be addressed by increasing the vertical surface area of the bonds.  It sounds like some experimental measurement would be required to determine if it is a significant effect. 


Regards

Darren Conway
36 Orr Crescent
Lower Hutt
New Zealand
ph +64  (0)4 569 1963

On 12.04.20 9:57 pm, neil wrote:
Hi Darren,
                  Coincidental that you post this. I have spent the last few hours tonite pondering the fixing of my pendulum to the suspension, and what happens when the temperature changes. I dont think the type of epoxy/locktite etc will matter too much. They all should be strong enough, and im not worried about the adhesive properties. According to a table of linear TC that i am looking at, most resins and epoxies have quite high TC, but looking at the physics at the molecular level, i am thinking that a temp change will not result in a length change. ( if you look at a molecule of glue ...those below the dentre of pressure will move down towards the bob, and those above the C of P will move upwards towards the sudpensio. Net result =  no pendulum length change. Just my random thoughts)
But what may be more critical is a change in viscosity of the glue  with temperature. This would allow the glue to "relax" lengthwise under load and cause the effective pendulum length to increase. 
Still ..if this is a linear change then i should still be able to compensate with an under bob compensator.
Im doing a video on an experimental glass pendulum and should have it up in a few days  ..the video that is.

On Sun, 12 Apr 2020, 9:27 PM Darren Conway <darren.conway@...> wrote:

Hi

That special adhesive is probably the stuff used to bond rear view mirrors to car windscreen glass.


Regards

Darren Conway
36 Orr Crescent
Lower Hutt
New Zealand
ph +64  (0)4 569 1963

On 12.04.20 9:17 pm, John Haine wrote:
Neil, further to your question, I was leafing through my copy of "Woodward on Time" to chase another reference and it includes a short description by David Walter of how he went about the construction, giving more detail than his website.  It wasn't published separately alas (I think).  But he specifically refers to "...using a special Loctite adhesive designed to bond metal and glass."  That might help?

Virus-free. www.avast.com


John Haine
 

I've recently seen recommended Gorilla Glue Clear for doing this too.  I use this for wood joining and it is fantastic stuff, join remains flexible for quite a long time, but sets hard in a day and at least between wood (actually an engineering wood substitute) is incredibly strong.


Harvey Moseley
 

Hi Neil,

When we needed to match the coefficient of the epoxy to the material being bonded, we would get quartz-filled versions, that match typical material coefficients near room temp.  There must be some info on line on how to choose the type and amount of fill since it may not be possible to buy small volumes of the filled exoxy(We typically used Stycast 2850 FT).

Harvey


On Sun, Apr 12, 2020 at 5:57 AM neil <njepsen@...> wrote:
Hi Darren,
                  Coincidental that you post this. I have spent the last few hours tonite pondering the fixing of my pendulum to the suspension, and what happens when the temperature changes. I dont think the type of epoxy/locktite etc will matter too much. They all should be strong enough, and im not worried about the adhesive properties. According to a table of linear TC that i am looking at, most resins and epoxies have quite high TC, but looking at the physics at the molecular level, i am thinking that a temp change will not result in a length change. ( if you look at a molecule of glue ...those below the dentre of pressure will move down towards the bob, and those above the C of P will move upwards towards the sudpensio. Net result =  no pendulum length change. Just my random thoughts)
But what may be more critical is a change in viscosity of the glue  with temperature. This would allow the glue to "relax" lengthwise under load and cause the effective pendulum length to increase. 
Still ..if this is a linear change then i should still be able to compensate with an under bob compensator.
Im doing a video on an experimental glass pendulum and should have it up in a few days  ..the video that is.

On Sun, 12 Apr 2020, 9:27 PM Darren Conway <darren.conway@...> wrote:

Hi

That special adhesive is probably the stuff used to bond rear view mirrors to car windscreen glass.


Regards

Darren Conway
36 Orr Crescent
Lower Hutt
New Zealand
ph +64  (0)4 569 1963

On 12.04.20 9:17 pm, John Haine wrote:
Neil, further to your question, I was leafing through my copy of "Woodward on Time" to chase another reference and it includes a short description by David Walter of how he went about the construction, giving more detail than his website.  It wasn't published separately alas (I think).  But he specifically refers to "...using a special Loctite adhesive designed to bond metal and glass."  That might help?

Virus-free. www.avast.com