Isopropanyl - UK Vintage Radio Repair and Restoration Discussion Forum

Paul Stenning · 26th Feb 2006, 10:45 pm

As a warning, do not use Isopropanyl on Perspex and other clear accrylic - especially shaped items (tubes etc). It causes the material to crack for some reason. This was something that was always avoided where I used to work (we made X-Ray sources and used a lot of Perspex in the high voltage bits).

I was reminded of it yesterday because my partner bought one of those light things with a long Perspex tube that is filled with water, has bubbles blown through it and a varying colour light underneath, from a car boot sale. It was only £2 because it leaked. He tried using isopropanyl to clean off the residue of silicone sealant from the tube (which it wouldn't do), and after an hour the whole area he cleaned had a load of cracks and had become very brittle.

The effect is quite surprising since isopropanyl is usually fairly mild stuff and doesn't hurt most things. Seeing it destroy apparently rigid plastic this way is most odd!

mikelect · 26th Feb 2006, 10:54 pm

For future ref acetic acid or vinegar cleans silicon sealer off

Mike

YC-156 · 26th Feb 2006, 11:34 pm

Quote:

Originally Posted by mikelect

For future ref acetic acid or vinegar cleans silicon sealer off

Mike, does that work for dry silicone sealer as well

I just tried it on some dry sealer here, and the result was not encouraging. Hot water apparently worked just as well, which is to say not very. Is there a trick to it, please?

Regards

Frank N.

ppppenguin · 27th Feb 2006, 8:29 am

Quote:

Originally Posted by YC-156

Mike, does that work for dry silicone sealer as well

I just tried it on some dry sealer here, and the result was not encouraging. Hot water apparently worked just as well, which is to say not very. Is there a trick to it, please?.

AFAIK, there's nothing that you can readily buy that will clean off silicone sealant easily. Mechanically remove as much as you can. Then try one of the silicone removers sold by Screwfix etc. The one I tried worked up to a point - it made it easier to scrape away the residues.

There may be a good solvent for silicone but I suspect it will be something highly hazardous like carbon disulphide or worse.

Sean Williams · 27th Feb 2006, 8:54 am

Simple answer to the silicone problem - Petrol!

It softens the silicone quite well, and makes it easier to remove....

Cheers
Sean

GMB · 27th Feb 2006, 10:59 am

It is not specifically isopropanol that can cause stressed plastics to crack - I have seen this happen with white spirit too. I suspect that anything that can work into the cracks to reduce the energy required to propagate them will do it.

Mike Phelan · 27th Feb 2006, 2:28 pm

We used to use IPA (isopropyl alcohol, not the Greene King sort of alcohol

) at TVVC to clean video tape path stuff, and discovered that some of the plastic cabinet parts, especially the clear stuff that must have been acrylic, suffered what Paul's lamp did.

Paul Stenning · 27th Feb 2006, 8:07 pm

I wonder whether the rapid evaporation (which causes it to feel cold on your hand) somehow causes additional stresses to the surface that cause it to crack? Perspex tube in particular is permanently stressed unless it has been annealed, and even that doesn't get rid of all the stresses.

Certainly where I used to work the problem would occur more on Perspex tubes than Perspex sheets, though it happened to some extent with all Perspex sometimes, so we had a policy of not using it on or near Perspex at all. Our normal degreasing method was washing in warm water with washing-up liquid then drying in a warm oven (about 60C).

Biggles · 28th Feb 2006, 4:32 pm

We had an unfortunate experience at work with some kind of solvent cleaner (can't remember which one now) where someone tried to clean a control head from a radio with it and promptly melted all the switch keys. After this I always test a very small non conspicuous bit with the cleaner before going the whole hog. It isn't always immediately obvious which chemicals will attack which plastics. Tread with caution, or is that proceed carefully?

Biggles

Nickthedentist · 28th Feb 2006, 11:38 pm

And while we're at it, foam cleanser sprays and DAC90A diffusers don't get on with each other very well

pmmunro · 1st Mar 2006, 6:55 pm

Industrial solvents specially formulated for "digesting" silicon rubber are available - one of these is called Digesil - information is available at

http://www.chela.co.uk/products.php

This can be bought is small quatities, though with quite big prices, of the order of £15 for 100ml, from local chemical suppliers.

As similar product, readily available but probably in more dilute form is sold for cleaning sanitary sealer by stores such as B & Q.

Digesil can be used to "unpot" electronic assemblies, although this may take several days. Some component casings may suffer but if you really want to know what's inside...

PMM

igranic · 25th Mar 2006, 11:39 am

Three products are available from Screwfix for removal of silicone sealant, they are:
17175 Sealant Remover 100ml @2.19
18504 Silicone Eater 150ml @£3.99
50102 Silicone Sealant Remover 300ml @£7.99

I have seen similar products in some of the DIY sheds, notably B&Q & Wickes.

zak · 26th Mar 2006, 8:21 pm

Plastic to be very carefull with are Perspex,and Polystyrene with isopropyll alcohol,I find petrol one of the finest for cleaning all sorts of things and thinning paint,however the smell annoys the wife!

Brian R Pateman · 26th Mar 2006, 9:14 pm

Quote:

Originally Posted by zak

Plastic to be very carefull with are Perspex,and Polystyrene with isopropyll alcohol,I find petrol one of the finest for cleaning all sorts of things and thinning paint,however the smell annoys the wife!

Well,

Every cloud has its silver lining

Seriously though, petrol is very good as a general solvent. I use lighter fuel as it is clean, leaves no deposits, evaporates very quickly and doesn't smell quite as bad as 95 octane.

Regards,

Mike Phelan · 27th Mar 2006, 8:15 am

Quote:

Originally Posted by Brian R Pateman

Well,

Every cloud has its silver lining

Seriously though, petrol is very good as a general solvent. I use lighter fuel as it is clean, leaves no deposits, evaporates very quickly and doesn't smell quite as bad as 95 octane.

Regards,

All my clock cleaning, including some parts made of various plastics, including Perspex and SRBP (Tufnol) is done using petrol. Outside, or in the garage, of course.

GMB · 27th Mar 2006, 11:50 am

White Spirit is more appropriate than petrol. It has more or less similar properties - except the huge risk of the inflammable vapour.

XTC · 27th Mar 2006, 12:31 pm

I've found White Spirit a good, non aggressive solvent. I've found it's good for removing felt tip writing and the remains of adhesive from labels etc. Turps Substitute is the same stuff but is a wider cut.

White Spirit, but not Turps Subsitute, should be used for thinning paint. I don't think using petrol to thin paint is a very good idea especially when there's a less flammable product intended for the job.

With all of these solvents, it's as well to go carefully before pitching in and risking damage to the thing you are trying to clean.

Isopropanol was the recommended solvent for cleaning computer tape drive heads after the freon cleaner was banned and remaining bottles were supposed to be surrendered. Some people hung onto little bottles of the freon cleaner for hard cases, because it did the job better.

Of course, warm soapy water, and rinsing down with rainwater, can be an amazingly effective and cheap way of cleaning things.

Pete.

mikelect · 27th Mar 2006, 3:45 pm

Quote:

Originally Posted by XTC

White Spirit, but not Turps Subsitute, should be used for thinning paint. I don't think using petrol to thin paint is a very good idea especially when there's a less flammable product intended for the job.
Pete.

If you thin paint with petrol you create rubber paint

I've just made some for restoring the grommets on my Mohican it worked extremely well. It was a trick I learned from the motor trade ove 30 years ago when tyre paint wasn't available commercially

vince · 30th Mar 2006, 3:01 am

Did you know that hospital wipes containing 70% isopropyl alchohol. can wipe the decal smile from a radio tuning glass, it will also remove stubborn sticky labels, also factory printed commands on vtrs/tv's like rew/f/f/stop/eject. even the brand name, the tv you bought second hand for a song even though you had momentry doubts about the brand name 'IBA' was really TOSHIBA. the isopropyl can be kind to other parts though like vtr heads, the tape path, head drum (upper & lower) rabbit, roller guides, rec/erase heads, tracking head, pinch roller with care, removing old grease from tape guide slots, idler wheels, brake pads, play/rew reels, metal carriages, the VHS/NHS combined to make a good format.

GMB · 30th Mar 2006, 9:32 am

A warning about using medical solvents for degreasing - they often contain grease! When I was a kid I used to distill such solvents to remove the grease for my electronic enthusiast friends.

26th Feb 2006, 10:45 pm	#1
Paul Stenning Administrator Join Date: Dec 2002 Location: Cardiff Posts: 9,071	Isopropanyl As a warning, do not use Isopropanyl on Perspex and other clear accrylic - especially shaped items (tubes etc). It causes the material to crack for some reason. This was something that was always avoided where I used to work (we made X-Ray sources and used a lot of Perspex in the high voltage bits). I was reminded of it yesterday because my partner bought one of those light things with a long Perspex tube that is filled with water, has bubbles blown through it and a varying colour light underneath, from a car boot sale. It was only £2 because it leaked. He tried using isopropanyl to clean off the residue of silicone sealant from the tube (which it wouldn't do), and after an hour the whole area he cleaned had a load of cracks and had become very brittle. The effect is quite surprising since isopropanyl is usually fairly mild stuff and doesn't hurt most things. Seeing it destroy apparently rigid plastic this way is most odd! __________________ Paul Stenning Forum Admin/Owner and BVWS Webmaster

26th Feb 2006, 10:54 pm	#2
mikelect Retired Dormant Member Join Date: Sep 2003 Location: Wrexham, North Wales, UK. Posts: 799	Re: Isopropanyl For future ref acetic acid or vinegar cleans silicon sealer off Mike

27th Feb 2006, 8:54 am	#5
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,517	Re: Isopropanyl Simple answer to the silicone problem - Petrol! It softens the silicone quite well, and makes it easier to remove.... Cheers Sean __________________ Engineers make things work and have spare bits when finished

27th Feb 2006, 10:59 am	#6
GMB Dekatron Join Date: Aug 2003 Location: near Reading (and sometimes Torquay) Posts: 3,094	Re: Isopropanyl It is not specifically isopropanol that can cause stressed plastics to crack - I have seen this happen with white spirit too. I suspect that anything that can work into the cracks to reduce the energy required to propagate them will do it.

27th Feb 2006, 2:28 pm	#7
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Re: Isopropanyl We used to use IPA (isopropyl alcohol, not the Greene King sort of alcohol ) at TVVC to clean video tape path stuff, and discovered that some of the plastic cabinet parts, especially the clear stuff that must have been acrylic, suffered what Paul's lamp did. __________________ Mike.

27th Feb 2006, 8:07 pm	#8
Paul Stenning Administrator Join Date: Dec 2002 Location: Cardiff Posts: 9,071	Re: Isopropanyl I wonder whether the rapid evaporation (which causes it to feel cold on your hand) somehow causes additional stresses to the surface that cause it to crack? Perspex tube in particular is permanently stressed unless it has been annealed, and even that doesn't get rid of all the stresses. Certainly where I used to work the problem would occur more on Perspex tubes than Perspex sheets, though it happened to some extent with all Perspex sometimes, so we had a policy of not using it on or near Perspex at all. Our normal degreasing method was washing in warm water with washing-up liquid then drying in a warm oven (about 60C). __________________ Paul Stenning Forum Admin/Owner and BVWS Webmaster

28th Feb 2006, 4:32 pm	#9
Biggles Rest in Peace Join Date: Feb 2004 Location: Hexham, Northumberland, UK. Posts: 2,234	Re: Isopropanyl We had an unfortunate experience at work with some kind of solvent cleaner (can't remember which one now) where someone tried to clean a control head from a radio with it and promptly melted all the switch keys. After this I always test a very small non conspicuous bit with the cleaner before going the whole hog. It isn't always immediately obvious which chemicals will attack which plastics. Tread with caution, or is that proceed carefully? Biggles

28th Feb 2006, 11:38 pm	#10
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,843	Re: Isopropanyl And while we're at it, foam cleanser sprays and DAC90A diffusers don't get on with each other very well

1st Mar 2006, 6:55 pm	#11
pmmunro Octode Join Date: Jul 2004 Location: Dundee, UK. Posts: 1,813	Re: Isopropanyl Industrial solvents specially formulated for "digesting" silicon rubber are available - one of these is called Digesil - information is available at http://www.chela.co.uk/products.php This can be bought is small quatities, though with quite big prices, of the order of £15 for 100ml, from local chemical suppliers. As similar product, readily available but probably in more dilute form is sold for cleaning sanitary sealer by stores such as B & Q. Digesil can be used to "unpot" electronic assemblies, although this may take several days. Some component casings may suffer but if you really want to know what's inside... PMM

25th Mar 2006, 11:39 am	#12
igranic Rest in Peace Join Date: Jan 2005 Location: North Bedfordshire, UK. Posts: 395	Re: Isopropanyl Three products are available from Screwfix for removal of silicone sealant, they are: 17175 Sealant Remover 100ml @2.19 18504 Silicone Eater 150ml @£3.99 50102 Silicone Sealant Remover 300ml @£7.99 I have seen similar products in some of the DIY sheds, notably B&Q & Wickes.

26th Mar 2006, 8:21 pm	#13
zak Retired Dormant Member Join Date: Feb 2005 Location: Monmouthshire,on South Wales border Posts: 85	Re: Isopropanyl Plastic to be very carefull with are Perspex,and Polystyrene with isopropyll alcohol,I find petrol one of the finest for cleaning all sorts of things and thinning paint,however the smell annoys the wife!

27th Mar 2006, 11:50 am	#16
GMB Dekatron Join Date: Aug 2003 Location: near Reading (and sometimes Torquay) Posts: 3,094	Re: Isopropanyl White Spirit is more appropriate than petrol. It has more or less similar properties - except the huge risk of the inflammable vapour.

27th Mar 2006, 12:31 pm	#17
XTC Retired Dormant Member Join Date: Oct 2004 Location: Bristol, UK. Posts: 837	Re: Isopropanyl I've found White Spirit a good, non aggressive solvent. I've found it's good for removing felt tip writing and the remains of adhesive from labels etc. Turps Substitute is the same stuff but is a wider cut. White Spirit, but not Turps Subsitute, should be used for thinning paint. I don't think using petrol to thin paint is a very good idea especially when there's a less flammable product intended for the job. With all of these solvents, it's as well to go carefully before pitching in and risking damage to the thing you are trying to clean. Isopropanol was the recommended solvent for cleaning computer tape drive heads after the freon cleaner was banned and remaining bottles were supposed to be surrendered. Some people hung onto little bottles of the freon cleaner for hard cases, because it did the job better. Of course, warm soapy water, and rinsing down with rainwater, can be an amazingly effective and cheap way of cleaning things. Pete.

30th Mar 2006, 3:01 am	#19
vince Retired Dormant Member Join Date: Sep 2005 Location: Tayside Dundee. Posts: 24	Re: Isopropanyl Did you know that hospital wipes containing 70% isopropyl alchohol. can wipe the decal smile from a radio tuning glass, it will also remove stubborn sticky labels, also factory printed commands on vtrs/tv's like rew/f/f/stop/eject. even the brand name, the tv you bought second hand for a song even though you had momentry doubts about the brand name 'IBA' was really TOSHIBA. the isopropyl can be kind to other parts though like vtr heads, the tape path, head drum (upper & lower) rabbit, roller guides, rec/erase heads, tracking head, pinch roller with care, removing old grease from tape guide slots, idler wheels, brake pads, play/rew reels, metal carriages, the VHS/NHS combined to make a good format.

30th Mar 2006, 9:32 am	#20
GMB Dekatron Join Date: Aug 2003 Location: near Reading (and sometimes Torquay) Posts: 3,094	Re: Isopropanyl A warning about using medical solvents for degreasing - they often contain grease! When I was a kid I used to distill such solvents to remove the grease for my electronic enthusiast friends.