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What Glue Do You Use To Attach Valves?


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#19 Don Taylor

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Posted 28 July 2016 - 07:26 AM

It is reversible, Place fresh PVA over the top and mix it into the old PVA which will easily soften and become removable. It is surprisingly fast.  I use a small screwdriver as it serves as a scraper as well as mixer.
 
One caveat, it works with the brands of PVA I use, other brands may have different chemistry.


Chris

Thanks for this, I have not heard of this technique - good to know.

Don.

#20 Patrick McMahon

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Posted 29 July 2016 - 06:38 AM

If that doesn't work, I would think that acetone would soften it. 

So long as you can get it to where the glue is. More difficult in a wood joint.



#21 Discord

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Posted 20 August 2016 - 06:26 AM

I have read about shellac becoming brittle with age and having a small shelf life..    This was also noticed by microscopists many years ago.   

 

  In preparing microscope slides the glass cover slip  above the specimen is sometimes given a protective ring of shellac.   This is painted on top of the sealing ring that holds the glass cover slip in place and seals any liquids around the specimen from leaking out.

The shellac can have dyes mixed in to give an attractive and practical hard coat to protect the sealing ring.

 

Microscopists  noted that after long periods of time the shellac could become brittle and chip and flake off.

An English preparer of microscope slides named Ernie Ives recommended the addition of a few drops of Castor Oil be added to the mix of Methylated Spirits and Shellac.     This acts as a plasticiser, allowing a little more flexibility to the mix.

I mixed up about quarter of a pint with roughly a third of a teaspoon of castor oil, six or seven years ago. It still works fine and the slides that I prepared then look fine.

I checked the contents of the jar a fortnight ago. Tested it by gluing glass, paper, leather and wood.   All worked fine and held within the limitations to be expected from an adhesive like this.

 

So after going all around the houses, the message is mix a little castor oil into your shellac and meths  varnish/glue and it could very well last a lot longer on the joint and on the shelf.

 

Cheers.

 

 

 

Sadly Ernie Ives who was also well known for his marquetry skills  passed away a couple of years ago. 






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