DAC10 white bezel? What's it made of? - UK Vintage Radio Repair and Restoration Discussion Forum

Nicko · 21st Jan 2013, 6:09 pm

Title says it all: What's the white bezel round the buttons and scale on a DAC10 made of - is it the same as an ivory DAC90A, i.e. Urea Formaldehyde, or is it a form of white Bakelite?

Whatever its made of, will the usual T-cut/Paste #5 + beeswax do the trick or can it be "whitened" by further processing?

Thanks

Nickthedentist · 21st Jan 2013, 9:37 pm

I'm not sure "white Bakelite" exists, I think it's UF as you suggest.

I've heard of people using bleach although others say this can cause long-term damage.

See https://www.vintage-radio.net/forum/...ad.php?t=45900 and https://www.vintage-radio.net/forum/...ad.php?t=60915 etc.

Nick.

Tim · 24th Jan 2013, 2:06 am

Whatever it's made from, I wonder if it has a different expansion co-efficient from the surrounding Bakelite case, accounting for the usual cracks one sees in the corners.

telstar · 24th Jan 2013, 5:21 pm

Hi,

I once worked in an amplifier factory in Leeds, that made guitar and keyboard amplifiers. They had a Bush DAC10 radio in their factory (not working), but the cabinet had been damaged at some time, and the white bezel too. Some bright spark had painted the whole lot in Dulux gloss paint (can't remember the colour).

What a mess it looked, they might have been able to remove the paint from the bakelite cabinet (if required), but not the bezel. Not sure what the bezel was made from, could it be cellulose?

Cheers,
Mike

Nicko · 1st Feb 2013, 4:02 pm

Coming round to it being made of Catalin.

Fits the bill - the oxidisation mode of it turning from white to cream, the shrinkage (which Catalin has a habit of doing) and tendency to crack etc.

I believe that the DAC10 also cracks round the screws due to a design flaw - the escutcheon doesn't mate fully with the main Bakelite body of the case; over-tightening of the escutcheon fixing screws would result in stressing the area around the fixing points, leading to the development of hairline cracks. To prevent this, insertion of suitable washers/shims may be a good plan.

Nickthedentist · 1st Feb 2013, 5:11 pm

Quote:

Originally Posted by Nicko

I believe that the DAC10 also cracks round the screws due to a design flaw - the escutcheon doesn't mate fully with the main Bakelite body of the case; over-tightening of the escutcheon fixing screws would result in stressing the area around the fixing points, leading to the development of hairline cracks. To prevent this, insertion of suitable washers/shims may be a good plan.

I've had a couple of DAC90As where the chassis lugs haven't quite met the two threaded bosses in the Bakelite case. To my surprise, even fairly careful tightening of the two screws caused one of the bosses and its surrounding Bakelite to crack away from the rest of the moulding. Again, shims (plus an Araldite repair) were the answer.

Nick.

vinrads · 2nd Feb 2013, 8:55 pm

I doubt very much if it is made of Catalin. I don't know any British radio that uses this material unless you know different! It's a hard plastic that cannot be reformed once set. Jonathan Hill lists the small white Alba model C112 as being made of plastic, so it's made of hard plastic.

Mick.

vinrads · 2nd Feb 2013, 9:58 pm

Forgot to say Jonathan also states the tuning scale surround on the DAC10 is made of white plastic!

Nicko · 6th Feb 2013, 6:47 pm

Quote:

Originally Posted by vinrads

Forgot to say Jonathan also states the tuning scale surround on the DAC10 is made of white plastic!

Bakelite and Catalin are both plastics! There are 100s of plastics, but only a few that were around at that time. It's the type of plastic that the bezel/escutcheon is made of that I'm after, and currently, Catalin is the best option I've heard of.

I'm sending a few scrapings to a friend who has access to an analytical chemistry lab. We shall see...

History/timeline of plastics: http://inventors.about.com/od/pstart...a/plastics.htm

vinrads · 6th Feb 2013, 7:54 pm

I have repaired many catalin radios exclusively made in the U.S.A. It is a very different material to the hard plastic which the Bush DAC10 bezel is made of.

Mick.

Paul_RK · 7th Feb 2013, 4:09 pm

Agreed. As I understand it, catalin that was originally white is a butterscotch yellow by now. It's a very recognisable plastic to anyone who's met it, with a marble-like smoothness and a tendency to some of its discolouration being so very superficial that cleaning with metal polish often produces quite a drastic change of colour in the direction of what it originally was. I think at least two different materials have been used for DAC10 bezels, a coarser ivory-coloured plastic and another that's more of a cream colour and more smooth or waxy in appearance. Neither resembles catalin.

Paul

21st Jan 2013, 6:09 pm	#1
Nicko Pentode Join Date: Jan 2006 Location: Goudhurst, Kent, UK. Posts: 136	DAC10 white bezel? What's it made of? Title says it all: What's the white bezel round the buttons and scale on a DAC10 made of - is it the same as an ivory DAC90A, i.e. Urea Formaldehyde, or is it a form of white Bakelite? Whatever its made of, will the usual T-cut/Paste #5 + beeswax do the trick or can it be "whitened" by further processing? Thanks __________________ Nicko

21st Jan 2013, 9:37 pm	#2
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,861	Re: DAC10 white bezel? What's it made of? I'm not sure "white Bakelite" exists, I think it's UF as you suggest. I've heard of people using bleach although others say this can cause long-term damage. See https://www.vintage-radio.net/forum/...ad.php?t=45900 and https://www.vintage-radio.net/forum/...ad.php?t=60915 etc. Nick.

24th Jan 2013, 2:06 am	#3
Tim Dekatron Join Date: Jan 2003 Location: Bradford on Avon, Wiltshire, UK. Posts: 3,310	Re: DAC10 white bezel? What's it made of? Whatever it's made from, I wonder if it has a different expansion co-efficient from the surrounding Bakelite case, accounting for the usual cracks one sees in the corners. __________________ "Nothing is as dangerous as being too modern;one is apt to grow old fashioned quite suddenly."

24th Jan 2013, 5:21 pm	#4
telstar Octode Join Date: Dec 2003 Location: Leeds, West Yorkshire, UK. Posts: 1,592	Re: DAC10 white bezel? What's it made of? Hi, I once worked in an amplifier factory in Leeds, that made guitar and keyboard amplifiers. They had a Bush DAC10 radio in their factory (not working), but the cabinet had been damaged at some time, and the white bezel too. Some bright spark had painted the whole lot in Dulux gloss paint (can't remember the colour). What a mess it looked, they might have been able to remove the paint from the bakelite cabinet (if required), but not the bezel. Not sure what the bezel was made from, could it be cellulose? Cheers, Mike

2nd Feb 2013, 8:55 pm	#7
vinrads Dekatron Join Date: Feb 2009 Location: Chesterfield, Derbyshire, UK. Posts: 3,764	Re: DAC10 white bezel? What's it made of? I doubt very much if it is made of Catalin. I don't know any British radio that uses this material unless you know different! It's a hard plastic that cannot be reformed once set. Jonathan Hill lists the small white Alba model C112 as being made of plastic, so it's made of hard plastic. Mick. Last edited by vinrads; 2nd Feb 2013 at 9:18 pm.

1st Feb 2013, 4:02 pm	#5
Nicko Pentode Join Date: Jan 2006 Location: Goudhurst, Kent, UK. Posts: 136	Re: DAC10 white bezel? What's it made of? Coming round to it being made of Catalin. Fits the bill - the oxidisation mode of it turning from white to cream, the shrinkage (which Catalin has a habit of doing) and tendency to crack etc. I believe that the DAC10 also cracks round the screws due to a design flaw - the escutcheon doesn't mate fully with the main Bakelite body of the case; over-tightening of the escutcheon fixing screws would result in stressing the area around the fixing points, leading to the development of hairline cracks. To prevent this, insertion of suitable washers/shims may be a good plan. __________________ Nicko

2nd Feb 2013, 9:58 pm	#8
vinrads Dekatron Join Date: Feb 2009 Location: Chesterfield, Derbyshire, UK. Posts: 3,764	Re: DAC10 white bezel? What's it made of? Forgot to say Jonathan also states the tuning scale surround on the DAC10 is made of white plastic!

6th Feb 2013, 7:54 pm	#10
vinrads Dekatron Join Date: Feb 2009 Location: Chesterfield, Derbyshire, UK. Posts: 3,764	Re: DAC10 white bezel? What's it made of? I have repaired many catalin radios exclusively made in the U.S.A. It is a very different material to the hard plastic which the Bush DAC10 bezel is made of. Mick.

7th Feb 2013, 4:09 pm	#11
Paul_RK Dekatron Join Date: Nov 2003 Location: Fakenham, Norfolk, UK. Posts: 4,259	Re: DAC10 white bezel? What's it made of? Agreed. As I understand it, catalin that was originally white is a butterscotch yellow by now. It's a very recognisable plastic to anyone who's met it, with a marble-like smoothness and a tendency to some of its discolouration being so very superficial that cleaning with metal polish often produces quite a drastic change of colour in the direction of what it originally was. I think at least two different materials have been used for DAC10 bezels, a coarser ivory-coloured plastic and another that's more of a cream colour and more smooth or waxy in appearance. Neither resembles catalin. Paul