Split 746 case Repair Tips. - UK Vintage Radio Repair and Restoration Discussion Forum

richwk1 · 17th Apr 2010, 1:35 pm

Can i just say a big thank you to everyone for there useful comments and advice in the past, it is much appreciated. Now to my question:

I have had many split 706 and 746 cases and have never really found a satisfactory was of repairing them.

I would be interested in everybody's tips and how they have repaired them in the past, as far as type of glue and procedure and if any ex GPO engineers have any tips or tricks i would be grateful for any help or advice.

I have used super glue with limited success ( plastic tends to go white ) bostik type glue tends to leave to much build up. I have even melted the split from behind to stabilize with a old solering iron and filled the split from the front with either colored wax or melted old 700 series parts of the same color ( bit of a bodge but not to bad results)

Thanks guys Rich

Darren-UK · 17th Apr 2010, 2:54 pm

Solvent cement, liquid, will do it but let it run into the crack from inside the case, don't apply from outside. Once applied, leave the case somewhere ventilated and where it won't get touched or moved for several hours. Don't try to push the crack together once applied either, or a horrid sticky mess of melted plastic will ooze out.

That's fine if the crack is hairline though. If it's opened out then close it up using a couple of tiny drops of Superglue, then use the Solvent cement.

Millay_2010 · 17th Apr 2010, 3:09 pm

Solvent cement, is that the stuff that i used fduring my childhood to put model planes together?

richwk1 · 17th Apr 2010, 3:53 pm

Darren would it be possible to use solvent weld for water pvcu water pipes.
( just asking as i already have some of this)

Rich

Darren-UK · 17th Apr 2010, 4:15 pm

This is the stuff I use (scroll page to see a picture of the bottle), it's liquid whereas that used for model aircraft kits was/is a 'squeeze from the tube' glue.

It's intended primarily for Polystyrene but yes, it will work on uPVC although to be honest I wouldn't trust it with water pipes under mains pressure.

Whatever you use it on, it's a lot slower curing than publicity material may suggest. That's why I said above about leaving the 700 case a good few hours.

richwk1 · 17th Apr 2010, 4:42 pm

Sorry Darren i will rephrase my question correctly, i have a tube of pipe joining cement left over from a plumbing job i did. would that work on a 700 case.
It will join upvc and abs water pipes so i assume as it holds under mains water pressure it would be strong enough to join a split in my phone case.

Rich

Darren-UK · 17th Apr 2010, 4:46 pm

Ah sorry, misread #4. Yes it will work on 700 cases, which I think are ABS anyway.

richwk1 · 18th Apr 2010, 12:02 am

Thanks Darren , i will try some pipe weld on an old case i have with a split and see how it goes. I will post later with progress report.

Rich

mickash · 18th Apr 2010, 1:37 am

At work we used to have a big bottle of some kind of solvent that we used to repair damaged plastic. It was very useful for repairing cracked VCR fronts, damaged TV control flaps etc.
To add extra strength it was possible to melt a piece of plastic to the inside of a crack to brace it..
The best way to apply it was to dip the end of a switch cleaner extension pipe into the solvent which would then creep into the pipe by capillary action. The end of the pipe was than applied to the closed crack allowing the solvent to empty out of the pipe and then seep into the crack. Care had to be taken not to allow too much solvent into the crack.
I can't remember what this solvent was called, di or tri someting. It would have been ideal for repairing cracked phones. It might have been similar to pipe welding solvent. I'd love to get hold of some more.

Michael.

russell_w_b · 18th Apr 2010, 9:35 am

Quote:

Originally Posted by mickash

I can't remember what this solvent was called, di or tri someting.

trichloroethylene?

We once used a degreasing solvent that would instantly start dissolving certain types of thermosetting plastic. It made a good 'unofficial' adhesive!

richwk1 · 18th Apr 2010, 12:22 pm

I remember when i was young my next door neighbor had cans of trichloroethylene and we used it for cleaning motorbike parts and car parts.
I f i remember correctly he got it from his work (he painted the bridges and gantries across the motorways)
As i remember it was a great degreaser but as far as plastic melting properties i can't say. I know we all got a bit woozy on the fumes.
I have tried my pipe weld and it seems to do the trick although care is needed this stuff marks if you get it on the front of the case.
I have placed a piece of masking tape over the split and applied the weld from the back. Will leave a few hours before messing with the case.
Rich

17th Apr 2010, 1:35 pm	#1
richwk1 Retired Dormant Member Join Date: Aug 2009 Location: Birmingham, West Midlands, UK. Posts: 80	Split 746 case Repair Tips. Can i just say a big thank you to everyone for there useful comments and advice in the past, it is much appreciated. Now to my question: I have had many split 706 and 746 cases and have never really found a satisfactory was of repairing them. I would be interested in everybody's tips and how they have repaired them in the past, as far as type of glue and procedure and if any ex GPO engineers have any tips or tricks i would be grateful for any help or advice. I have used super glue with limited success ( plastic tends to go white ) bostik type glue tends to leave to much build up. I have even melted the split from behind to stabilize with a old solering iron and filled the split from the front with either colored wax or melted old 700 series parts of the same color ( bit of a bodge but not to bad results) Thanks guys Rich

17th Apr 2010, 2:54 pm	#2
Darren-UK Retired Dormant Member Join Date: Apr 2003 Location: Blackpool, Lancashire, UK. Posts: 4,061	Re: Split 746 case Repair Tips !!! Solvent cement, liquid, will do it but let it run into the crack from inside the case, don't apply from outside. Once applied, leave the case somewhere ventilated and where it won't get touched or moved for several hours. Don't try to push the crack together once applied either, or a horrid sticky mess of melted plastic will ooze out. That's fine if the crack is hairline though. If it's opened out then close it up using a couple of tiny drops of Superglue, then use the Solvent cement.

17th Apr 2010, 3:09 pm	#3
Millay_2010 Hexode Join Date: Feb 2010 Location: Hull, East Riding of Yorkshire, UK. Posts: 315	Re: Split 746 case Repair Tips !!! Solvent cement, is that the stuff that i used fduring my childhood to put model planes together?

17th Apr 2010, 4:15 pm	#5
Darren-UK Retired Dormant Member Join Date: Apr 2003 Location: Blackpool, Lancashire, UK. Posts: 4,061	Re: Split 746 case Repair Tips !!! This is the stuff I use (scroll page to see a picture of the bottle), it's liquid whereas that used for model aircraft kits was/is a 'squeeze from the tube' glue. It's intended primarily for Polystyrene but yes, it will work on uPVC although to be honest I wouldn't trust it with water pipes under mains pressure. Whatever you use it on, it's a lot slower curing than publicity material may suggest. That's why I said above about leaving the 700 case a good few hours.

17th Apr 2010, 4:42 pm	#6
richwk1 Retired Dormant Member Join Date: Aug 2009 Location: Birmingham, West Midlands, UK. Posts: 80	Re: Split 746 case Repair Tips !!! Sorry Darren i will rephrase my question correctly, i have a tube of pipe joining cement left over from a plumbing job i did. would that work on a 700 case. It will join upvc and abs water pipes so i assume as it holds under mains water pressure it would be strong enough to join a split in my phone case. Rich

17th Apr 2010, 3:53 pm	#4
richwk1 Retired Dormant Member Join Date: Aug 2009 Location: Birmingham, West Midlands, UK. Posts: 80	Re: Split 746 case Repair Tips !!! Darren would it be possible to use solvent weld for water pvcu water pipes. ( just asking as i already have some of this) Rich

17th Apr 2010, 4:46 pm	#7
Darren-UK Retired Dormant Member Join Date: Apr 2003 Location: Blackpool, Lancashire, UK. Posts: 4,061	Re: Split 746 case Repair Tips !!! Ah sorry, misread #4. Yes it will work on 700 cases, which I think are ABS anyway.

18th Apr 2010, 12:02 am	#8
richwk1 Retired Dormant Member Join Date: Aug 2009 Location: Birmingham, West Midlands, UK. Posts: 80	Re: Split 746 case Repair Tips !!! Thanks Darren , i will try some pipe weld on an old case i have with a split and see how it goes. I will post later with progress report. Rich

18th Apr 2010, 1:37 am	#9
mickash Hexode Join Date: Sep 2007 Location: Derbyshire, UK. Posts: 289	Re: Split 746 case Repair Tips !!! At work we used to have a big bottle of some kind of solvent that we used to repair damaged plastic. It was very useful for repairing cracked VCR fronts, damaged TV control flaps etc. To add extra strength it was possible to melt a piece of plastic to the inside of a crack to brace it.. The best way to apply it was to dip the end of a switch cleaner extension pipe into the solvent which would then creep into the pipe by capillary action. The end of the pipe was than applied to the closed crack allowing the solvent to empty out of the pipe and then seep into the crack. Care had to be taken not to allow too much solvent into the crack. I can't remember what this solvent was called, di or tri someting. It would have been ideal for repairing cracked phones. It might have been similar to pipe welding solvent. I'd love to get hold of some more. Michael.

18th Apr 2010, 12:22 pm	#11
richwk1 Retired Dormant Member Join Date: Aug 2009 Location: Birmingham, West Midlands, UK. Posts: 80	Re: Split 746 case Repair Tips !!! I remember when i was young my next door neighbor had cans of trichloroethylene and we used it for cleaning motorbike parts and car parts. I f i remember correctly he got it from his work (he painted the bridges and gantries across the motorways) As i remember it was a great degreaser but as far as plastic melting properties i can't say. I know we all got a bit woozy on the fumes. I have tried my pipe weld and it seems to do the trick although care is needed this stuff marks if you get it on the front of the case. I have placed a piece of masking tape over the split and applied the weld from the back. Will leave a few hours before messing with the case. Rich