UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Test Gear and Workshop Equipment

Notices

Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders.

Closed Thread
 
Thread Tools
Old 7th Jan 2022, 10:45 am   #1
avocollector
Heptode
 
Join Date: Jul 2010
Location: Wellington, New Zealand.
Posts: 653
Default AVO 8 case repair preferred filler.

I've just purchased a cheap Avo 8 and the reason it was cheap is there is some damage to the bakelite body case. Mostly it's cracks but there is at least one small piece missing.

I've had a look on this webiste search engine and people there seem to have used Isopon P38 filler for filling/restoring small missing bits.

Is it still the favoured reapir medium or is there anything better for bakelite??

Thanks folks.
avocollector is offline  
Old 7th Jan 2022, 1:02 pm   #2
ajgriff
Nonode
 
ajgriff's Avatar
 
Join Date: May 2004
Location: Halifax, West Yorkshire, UK.
Posts: 2,583
Default Re: Avo 8 case repair preferred filler.

I guess we all have our favourites for this kind of thing but for small repairs I use traditional slow setting araldite or original JB Weld. These two and Isopon are all two part epoxies of course but Isopon is essentially designed as a car body filler (epoxy with bulking material) and is probably best suited to larger repairs. Isopon also seems to be more susceptible to air bubble formation thus requiring extra applications.

My favourite at the moment is JB Weld as I find easier to handle and mold than araldite plus it has greater heat resistance. It's easy to file/sand and is slightly more flexible than araldite. The attached photos (before and after) show a recent repair to a cassette recorder case.

Colouring is another issue to consider. I used a black acrylic spray paint for the repair pictured but black enamel paint could have been mixed in with the epoxy as an alternative. There's a recent thread on the subject here:

https://www.vintage-radio.net/forum/...d.php?t=185154

Milliput is another option although its handling properties are rather different from the epoxies already mentioned. One advantage to Milliput is that it comes in a range of colours including black.

Alan
Attached Thumbnails
Click image for larger version

Name:	Corner Before.jpg
Views:	77
Size:	59.0 KB
ID:	249186   Click image for larger version

Name:	Corner After.jpg
Views:	71
Size:	39.6 KB
ID:	249187  
ajgriff is offline  
Old 7th Jan 2022, 2:05 pm   #3
Guest
Guest
 
Posts: n/a
Default Re: Avo 8 case repair preferred filler.

Isopon is a polyester resin not epoxy, this has the advantage that the catalyst amount is not critical, use a lot for a fast set, a little for a slower one. It is also much cheaper and smellier.
 
Old 7th Jan 2022, 2:36 pm   #4
ajgriff
Nonode
 
ajgriff's Avatar
 
Join Date: May 2004
Location: Halifax, West Yorkshire, UK.
Posts: 2,583
Default Re: Avo 8 case repair preferred filler.

Quote:
Originally Posted by merlinmaxwell View Post
Isopon is a polyester resin not epoxy ....
In terms of chemical action you're quite right of course. My apologies for the misleading and inaccurate statement but I hope my other comments still have some validity. Polyester resin also sets quickly and is more brittle than epoxies.

Alan
ajgriff is offline  
Old 7th Jan 2022, 3:10 pm   #5
ajgriff
Nonode
 
ajgriff's Avatar
 
Join Date: May 2004
Location: Halifax, West Yorkshire, UK.
Posts: 2,583
Default Re: Avo 8 case repair preferred filler.

Just for reference this link seems to provide a good overview of the practical differences between epoxies and polyester resins:

https://www.pcepoxy.com/what-is-the-...lyester-resin/

Alan
ajgriff is offline  
Old 7th Jan 2022, 3:46 pm   #6
The Philpott
Dekatron
 
The Philpott's Avatar
 
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 4,081
Default Re: AVO 8 case repair preferred filler.

Hi Peter,

As regards the cracks (if they are closed cracks) i would let some superglue wick into them then remove the white staining with acetone/nail varnish remover.

Personally i prefer Araldite (slow setting) to car body filler for replacing missing segments, it has more 'give' and enamel paint can be added.

Dave
The Philpott is offline  
Old 9th Jan 2022, 12:22 pm   #7
avocollector
Heptode
 
Join Date: Jul 2010
Location: Wellington, New Zealand.
Posts: 653
Default Re: AVO 8 case repair preferred filler.

Many thanks to all for your advice/suggestions - greatly appreciated. There are cracks which I think can be closed as Dave advises with superglue but also at least one small chunk missing. The instrument has not arrived yet so cannot supply decent pics.

Of course it may be beyond reapir when it arrives electrically speaking - I find it amusing how often an item was 'working well' when it left the seller but miraculously seems to become defunct by simply going through the post. The latest of these was a multimeter which was described as 'working'. When it arrived the two internal cartidge fuses (one on the +ve terminal and one on the -ve) were missing so there is no way it could have been 'working' when sent.

My favourite one though a few years back was a valve radio in 'excellent condition' - despite the fact the tar had clearly bubbled out of the mains transformer, all the valves were missing and it had been in the chickenhouse for a number of years where the occupants had covered it in chook poop. Whne I asked where the speaker (not seeing it in the picture) was I got told 'Oh that's missing too'. Obviously a real bargain!!

Happy New year to everybody!
avocollector is offline  
Old 10th Jan 2022, 1:37 pm   #8
pmmunro
Octode
 
Join Date: Jul 2004
Location: Dundee, UK.
Posts: 1,797
Default Re: AVO 8 case repair preferred filler.

When repairing a crack, rather than a break, it is often a good idea to drill a small hole at the end of the crack. This relieves stresses and stops the crack propagating.

To fill small holes, I have used Araldite mixed with Bakelite filings from scrap cases.

PMM
pmmunro is offline  
Old 10th Jan 2022, 7:26 pm   #9
Geoff Sherratt
Tetrode
 
Geoff Sherratt's Avatar
 
Join Date: May 2005
Location: Burton upon Trent
Posts: 75
Default Re: AVO 8 case repair preferred filler.

It might be worth trying QBond. It's available in black and grey and I have to say as far as adhesives go it's very good.
It is primarily an adhesive filler so would be ideally suited
Geoff Sherratt is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 2:01 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.