Removing stubborn knob brights - UK Vintage Radio Repair and Restoration Discussion Forum

telstar · 10th Sep 2012, 3:41 pm

Hi. On my Murphy A574 radio, I noticed that on one plastic control knob, one of the brights was reversed (with the "dimple" pointing inwards). Is there anything that I can remove this bright from the knob (without damage) with, as it is well stuck down? In the present state, the set looks a bit odd in appearance.
Cheers
Mike

Nickthedentist · 10th Sep 2012, 4:01 pm

Hi Mike,

A soak in warm water, then a sharp tug using a piece of "Duck" tape or similar might do the trick.

Nick.

60 oldjohn · 10th Sep 2012, 4:38 pm

Failing Nicks idea try putting it in freezer overnight, if any water has got behind the bright it may expand and help you. I would also recommend the Duck tape but after a night in the freezer condensation is a real problem but it is possible.
Good luck, John.
Ps. Brights only come loose when you are not looking and get lost!

Nickthedentist · 10th Sep 2012, 9:06 pm

Quote:

Originally Posted by 60 oldjohn

Brights only come loose when you are not looking and get lost!

Yes, put it in a cupboard and they'll all be off (and down the cracks between the floorboards) by the time you get it out.

Refugee · 10th Sep 2012, 10:43 pm

The freezer method can be enhanced.
Get an old pickle jar and fit a connector that will take a tube from an old pushbike pump with the washer turned over. This will suck the air from under the bright. With the knob covered with water this will fill the gap behind it. Put it in the freezer for a couple of hours and it should be out or at least ready for another go. You will if you have seen bubbles while drawing the air out be able to see that it is part of the way out or better. Dry it for a couple of days before you continue restoration.

PaulE27 · 11th Sep 2012, 12:43 am

What about freezer spray? It would be much quicker.

Paul

Refugee · 11th Sep 2012, 1:59 am

Cost but the important bit is getting some water behind it.

petertheorgan · 11th Oct 2012, 9:27 am

There is a way that has always worked for me and I have used it for other things that are stuck fast too . In fact I used it last night to remove two knob brights as I wanted to clean them up and use them in different knobs .

Place the offending knob in a mug or glass and 3/4 fill with water , place in microwave and " cook" untill the water is boiling , normally you will then find the bright is on the bottom of the mug / glass.

I believer this to be the combination of the heat and the microwaves softening the glue
I hope this is helpful

Peter

10th Sep 2012, 3:41 pm	#1
telstar Octode Join Date: Dec 2003 Location: Leeds, West Yorkshire, UK. Posts: 1,592	Removing stubborn knob brights Hi. On my Murphy A574 radio, I noticed that on one plastic control knob, one of the brights was reversed (with the "dimple" pointing inwards). Is there anything that I can remove this bright from the knob (without damage) with, as it is well stuck down? In the present state, the set looks a bit odd in appearance. Cheers Mike

10th Sep 2012, 4:01 pm	#2
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,846	Re: Removing stubborn knob brights Hi Mike, A soak in warm water, then a sharp tug using a piece of "Duck" tape or similar might do the trick. Nick.

10th Sep 2012, 4:38 pm	#3
60 oldjohn Dekatron Join Date: Dec 2004 Location: East Yorkshire, UK. Posts: 3,987	Re: Removing stubborn knob brights Failing Nicks idea try putting it in freezer overnight, if any water has got behind the bright it may expand and help you. I would also recommend the Duck tape but after a night in the freezer condensation is a real problem but it is possible. Good luck, John. Ps. Brights only come loose when you are not looking and get lost!

10th Sep 2012, 10:43 pm	#5
Refugee Dekatron Join Date: Apr 2012 Location: Worksop, Nottinghamshire, UK. Posts: 5,553	Re: Removing stubborn knob brights The freezer method can be enhanced. Get an old pickle jar and fit a connector that will take a tube from an old pushbike pump with the washer turned over. This will suck the air from under the bright. With the knob covered with water this will fill the gap behind it. Put it in the freezer for a couple of hours and it should be out or at least ready for another go. You will if you have seen bubbles while drawing the air out be able to see that it is part of the way out or better. Dry it for a couple of days before you continue restoration.

11th Sep 2012, 12:43 am	#6
PaulE27 Pentode Join Date: Jul 2010 Location: London, UK. Posts: 222	Re: Removing stubborn knob brights What about freezer spray? It would be much quicker. Paul

11th Sep 2012, 1:59 am	#7
Refugee Dekatron Join Date: Apr 2012 Location: Worksop, Nottinghamshire, UK. Posts: 5,553	Re: Removing stubborn knob brights Cost but the important bit is getting some water behind it.

11th Oct 2012, 9:27 am	#8
petertheorgan Hexode Join Date: Dec 2006 Location: Bromley, Kent, UK. Posts: 332	Re: Removing stubborn knob brights There is a way that has always worked for me and I have used it for other things that are stuck fast too . In fact I used it last night to remove two knob brights as I wanted to clean them up and use them in different knobs . Place the offending knob in a mug or glass and 3/4 fill with water , place in microwave and " cook" untill the water is boiling , normally you will then find the bright is on the bottom of the mug / glass. I believer this to be the combination of the heat and the microwaves softening the glue I hope this is helpful Peter