Arduino Forum

Using Arduino => General Electronics => Topic started by: liamorourke on Jun 18, 2016, 01:13 pm

Title: using surgical spirit to clean connections before desoldeirng?
Post by: liamorourke on Jun 18, 2016, 01:13 pm
Can i use ethanol and methanol based surgical spirit for cleaning connections prior to desoldering instead of isopropyl alcohol?
Thanks
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: aarg on Jun 18, 2016, 02:19 pm
Huh? I never bother to clean anything prior to desoldering. Sometimes I have to add some flux...
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: MarkT on Jun 18, 2016, 02:47 pm
You would normally use a flux-remover _after_ soldering or desoldering.  Make sure you use a
solvent that can dissolve rosin.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: Noobian on Jun 18, 2016, 04:30 pm
1) I do not know of any methanol based surgical spirit, since methanol is super Toxic :smiley-mr-green: . I don't think you should be playing around with methanol if you don't know how to properly handle it, since even inhaling it or topical contact is dangerous.

2) Ethanol or Isopropyl based surgical spirit are not 100% pure. They are diluted with water. So make sure you don't clean your contacts in such a way that you might short them.

3) Do not use it if the contacts are not at room temperature, since these alcohols are flammable and have a low flashpoint (autoignition ). Also keep it away from your soldering Iron, unless danger is your middle name.  :smiley-twist:

4) Why do you wanna clean the solder which you are going to remove anyway???  people usually clean the contacts before they solder something on to it, and not before taking it off. That is unless your connections were exposed and accumulated a lot of dirt/muck, in that case rubbing alcohol is not your best solution. :D





Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: raschemmel on Jun 18, 2016, 04:37 pm
IPA (IsoPropyl Alchohol) can be used to clean PCBs or remove flux.

That is NOT rubbing Alchohol which is dfferent. I don't know which you are referring to .

The bottle of IPA that I have says only "Isopropyl Alchohol".

It says nothing about ethanol so the answer to your question is NO.

Use IPA only. (Not ethanol)
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: Noobian on Jun 18, 2016, 05:00 pm
That is NOT rubbing Alchohol which is dfferent. I don't know which you are referring to .

The bottle of IPA that I have says only "Isopropyl Alchohol".

It says nothing about ethanol so the answer to your question is NO.

Use IPA only. (Not ethanol)
Rubbing alcohol is nothing but diluted IPA with some additives. It is also called surgical spirit because it is used to cleanse the skin.

If your bottle say only "Isopropyl Alchohol" then it is 99% IPA. You can use it to clean but must do so in a well-ventilated area since it is toxic (not as toxic as methanol which is NSFW anyway). Rubbing alcohol is relatively the best choice for cleaning when it comes to safety.

In some countries they use ethanol instead of IPA in rubbing alcohol.

Actually you an use ethanol based solution to clean. I use Vodka to clean my screen. (not pure ethanol)
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: raschemmel on Jun 18, 2016, 07:07 pm
Quote
I use Vodka to clean my screen
Not the good stuff I hope !  ;D
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: MarkT on Jun 18, 2016, 07:18 pm
Rubbing alcohol is nothing but diluted IPA with some additives. It is also called surgical spirit because it is used to cleanse the skin.

If your bottle say only "Isopropyl Alchohol" then it is 99% IPA. You can use it to clean but must do so in a well-ventilated area since it is toxic (not as toxic as methanol which is NSFW anyway). Rubbing alcohol is relatively the best choice for cleaning when it comes to safety.

In some countries they use ethanol instead of IPA in rubbing alcohol.

Actually you an use ethanol based solution to clean. I use Vodka to clean my screen. (not pure ethanol)
Surgical spirit is ethanol and some additives.  It won't contain IPA since that's not safe for medical use.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: Whandall on Jun 18, 2016, 07:24 pm
It won't contain IPA since that's not safe for medical use.
Ethanol would be to expensive (taxes) and IPA is safe for medical use (at least it is used there heavily).

Quote
Medical

Rubbing alcohol, hand sanitizer, and disinfecting pads typically contain a 60-70% solution of isopropyl alcohol in water. Water is required to open up membrane pores of bacteria, which acts as a gateway inside for isopropyl. A 75% v/v solution in water may be used as a hand sanitizer.[18] Isopropyl alcohol is used as a water-drying aid for the prevention of otitis externa, better known as swimmer's ear.[19]
https://en.wikipedia.org/wiki/Isopropyl_alcohol (https://en.wikipedia.org/wiki/Isopropyl_alcohol)

Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: larryd on Jun 18, 2016, 07:49 pm
I use a bit of liquid flux on component leads prior to desoldering them.



I use: Tabasco and Worcestershire sauce, a good Vodka and Clamato juice to rinse the inside of my esophagus.



.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: raschemmel on Jun 18, 2016, 08:13 pm
Quote
I use: Tabasco and Worcestershire sauce, a good Vodka and Clamato juice to rinse the inside of my esophagus.
I recommend Tito's Vodka.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: larryd on Jun 18, 2016, 08:38 pm
I forgot the Celery.
I'll look for Tito.

(http://clubzone.com/content/uploads/2015/04/classic-caesar660.jpg)
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: raschemmel on Jun 18, 2016, 08:46 pm
Tito's Handmade Vodka (http://www.titosvodka.com/)



(http://forum.arduino.cc/index.php?action=dlattach;topic=407789.0;attach=171130)
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: Paul__B on Jun 18, 2016, 11:54 pm
1) I do not know of any methanol based surgical spirit, since methanol is super Toxic :smiley-mr-green: . I don't think you should be playing around with methanol if you don't know how to properly handle it, since even inhaling it or topical contact is dangerous.
What a load of bollocks! :smiley-roll:

It turns out that "surgical spirit (https://www.medicines.org.uk/emc/medicine/25473)" is by definition, "methylated spirit (https://en.wikipedia.org/wiki/Methylated_spirit)" which is 10% methanol, so rubbing it on the skin (and possibly introducing it into cuts) is exactly its intended application.

Calling methanol "super toxic" is quite an exaggeration.  The body has limited capacity (https://en.wikipedia.org/wiki/Methanol#Toxicity) for tolerating it so the small amounts involved in the reasonable use of surgical spirit - on the skin - or as a cleaning agent, are not dangerous.

The only concern might be the oily residue - or perhaps this might even be an advantage.

Ethanol would be to expensive (taxes) and IPA is safe for medical use (at least it is used there heavily).
"Denatured" alcohol avoids the taxes since it is simply not practical to remove the methanol.  IPA is certainly the standard for medical use in skin "prep" swabs and cleaning cloths, so the vapour is not considered a significant problem.

Mind you, it is generally prohibited for use in the operating theatre as a skin "prep" due to accidents where this has pooled on sheets and ignited during surgery.  On the other hand (or hands), ethanol - denatured with acetone (whose awful smell means no-one would even dream of drinking it) - is now used as an alternative to water-based surgical (hand) scrubbing.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: larryd on Jun 19, 2016, 12:52 am
Quote
"super toxic"
If you are really worried wear protection:

(https://images-na.ssl-images-amazon.com/images/I/41HDi4QagrL._SX342_.jpg)
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: larryd on Jun 19, 2016, 12:53 am
I buy them by the gross:
(http://thumbs2.ebaystatic.com/d/l225/m/mKNo26VvP74oJ0uvyMQyCDw.jpg)

(http://www.sanitopia.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/g/r/grafco_finger_144_1_1000_1.jpg)
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: ChrisTenone on Jun 19, 2016, 06:27 am
Quit bragging Larry ... ;)

Methanol, ethanol and isopropyl alcohol are the three most common and lightest alcohols. They contain 1, 2 and 3 carbon atoms respectively. They are all flammable, volatile and toxic. Ethanol is the least toxic, and isopropyl alcohol the least volatile. Methanol is the most toxic and the most corrosive. Isopropyl alcohol is the best to use for cleaning flux residue, but ethanol evaporates faster. Methanol can cause micro-pitting on iron (or below in the activity series) surfaces, so should not be used.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: larryd on Jun 19, 2016, 07:18 am
I use Isopropyl alcohol to remove the residue, before the alcohol evaporates wash the PCB in distilled water, then use an air compressor to blow off the water.
Things like switches, relays etc. that can be damaged by water, are soldered after.
.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: Noobian on Jun 19, 2016, 07:20 am
What a load of bollocks! :smiley-roll:

It turns out that "surgical spirit (https://www.medicines.org.uk/emc/medicine/25473)" is by definition, "methylated spirit (https://en.wikipedia.org/wiki/Methylated_spirit)" which is 10% methanol, so rubbing it on the skin (and possibly introducing it into cuts) is exactly its intended application.

Calling methanol "super toxic" is quite an exaggeration.  The body has limited capacity (https://en.wikipedia.org/wiki/Methanol#Toxicity) for tolerating it so the small amounts involved in the reasonable use of surgical spirit - on the skin - or as a cleaning agent, are not dangerous.

The only concern might be the oily residue - or perhaps this might even be an advantage.
Mother of sweet bejeezus :smiley-eek:

It turns out that the methylated spirit "aka denatured alcohol" by definition is nothing but ethanol with 10% methanol additive. So basically the Surgical spirit which you mentioned is Ethanol based, and NOT methanol based. But that's B.P's version of surgical spirit, others use IsoPro with no methanol, instead of denatured alcohol.

Here's what your wiki page says about Methanol.
Quote
Methanol has a high toxicity in humans. As little as 10 mL of pure methanol, ingested, is metabolized into formic acid, which can cause permanent blindness by destruction of the optic nerve. 30 mL is potentially fatal,[16] although the median lethal dose is typically 100 mL

Methanol (whether it enters the body by ingestion, inhalation, or absorption through the skin) can be fatal due to its CNS depressant properties
The amount of methanol in Surgical spirit is of a considerably small amount, that is after the methylated spirit has been diluted with 30% Water.
But opening a bottle of pure methanol in a non ventilated room is by no means "small amounts" or safe.

and does any of these signs look like an exaggeration to you?

(http://images.mysafetylabels.com/img/lg/G/methanol-ghs-label-small-ghs-013-c.png)

(http://images.mysafetylabels.com/img/lg/L/Methanol-ANSI-Chemical-Label-LB-1584-81.gif)




If you are really worried wear protection:
No, you must wear real full body protection :D
(http://g02.a.alicdn.com/kf/HTB1Ih.pKpXXXXXsXFXXq6xXFXXXv/TOMSUIT-Spandex-Open-Face-Full-Bodysuit-Pink-Guy-Suit.jpg)
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: raschemmel on Jun 19, 2016, 10:01 am
This is the only place in the world where a simple question can start WWIII...
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: Paul__B on Jun 19, 2016, 10:45 am
It turns out that the methylated spirit "aka denatured alcohol" by definition is nothing but ethanol with 10% methanol additive. So basically the Surgical spirit which you mentioned is Ethanol based, and NOT methanol based.
And that is what I said.  No-one ever suggested there was a version of "Surgical spirit" based on methanol.  If nothing else, it would probably be more expensive.

But that's B.P's version of surgical spirit, others use IsoPro with no methanol, instead of denatured alcohol.
No problem.

The amount of methanol in Surgical spirit is of a considerably small amount, that is after the methylated spirit has been diluted with 30% Water.
It is as stated, about 10%.  Dilution with water, if performed (rather unclear from these sources), would arguably reduce this to 7%.  Whether you consider this "a considerably small amount" is clearly relative.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: Boardburner2 on Jun 19, 2016, 05:32 pm
Surgical spirit traditionally was ethanol +water.
It has been largely superseded by isopropyl alcohol.

Methanol additives are only used for methylated spirit.
Industrial if you can get it is better than the store stuff as it can be had without water and the various chemicals added to prevent consumption.

All are acceptable cleaning agents but be aware that rubbing alcohols can contain lanolin or similar.
That stuff must be avoided.

EDIT

I prefer industrial meths as it leaves no residue and in smaller quantities is half the price of ispropyl.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: gpsmikey on Jun 19, 2016, 05:52 pm
I use Isopropyl alcohol to remove the residue, before the alcohol evaporates wash the PCB in distilled water, then use an air compressor to blow off the water.
Things like switches, relays etc. that can be damaged by water, are soldered after.
.
I usually use a cotton swab with Isopropyl Alcohol to clean up after soldering etc. with rosin core solder (or before soldering to make sure I get any grease/oil etc.).  Be careful with the air compressor - many of them will have some oil in the air and end up contaminating the work area with oily air (that is why you can buy all those oil/water separators).  A diaphram type compressor is usually pretty clean, but if yours is like mine (2hp piston type), there is some oil in the air (blow it on your hand for a bit then rub your hands and notice the slight oil film).  Another issue with high pressure air if you are not careful - things like O-rings seal by pressure on them and while they can withstand quite a bit of pressure, fast moving air etc. does not give them a chance to seal and will sneak under to get inside (used to have that problem with diving watches where they were good to 200+ feet, but would flood in the shower where high speed water drops hit the seal and went under it.  They changed the design of the buttons so it can't do that, but it used to be an issue.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: Boardburner2 on Jun 19, 2016, 06:04 pm
As an aside , i have used methanol in my helicopter for many years.
Never seen anyone at my club with protective gear on and no one has gone blind yet.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: Noobian on Jun 19, 2016, 06:19 pm
no one has gone blind yet.
yet   :smiley-mr-green:
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: Boardburner2 on Jun 19, 2016, 06:27 pm
 :)
I just knew.....

The main risks are fire and prolonged exposure as with any hydrocarbon.
The odd splash should not be an issue.

If you are silly enough to drink it that very effectivley removes yourself from the gene pool.
Certainly wont be able to fly a model if blind.

Sensible precautions, do not use indoors, empty fuel tank before putting in car or workshop.

"median lethal dose is typically 100 mL"

I cant help but wonder how they arrived at that figure.

The double blind test takes on a whole new meaning.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: raschemmel on Jun 19, 2016, 06:45 pm
Quote
I cant help but wonder how they arrived at that figure.
Autopsy report ?
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: Noobian on Jun 19, 2016, 08:56 pm
Autopsy report ?
Naah!  Frankenstein "trial and error" :smiley-lol:


(https://upload.wikimedia.org/wikipedia/commons/thumb/a/ae/Mad_scientist.svg/257px-Mad_scientist.svg.png)

Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: raschemmel on Jun 19, 2016, 09:54 pm
Quote
Naah!  Frankenstein "trial and error" 
I'm not sure if the Toxology Dept of a hospital is required to notify the FDA in fatal overdose cases but I doubt it. Even if they did they likely could not link it to a particular manufacturer but it could wind up in a database field under fatal overdose /methanol. The manufacturer may be required to request that information when they submit their application for product approval since the manufacturer's labeling department would need that to design their label. Their must be a national database for overdose data that the manufacturer can access using their license.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: ChrisTenone on Jun 19, 2016, 10:47 pm
I overheard a couple technicians in the stockroom, while drinking the wood alcohol. "Better hurry and drink up, it's getting dark."

Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: larryd on Jun 19, 2016, 10:48 pm
Bad!
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: raschemmel on Jun 20, 2016, 12:21 am
Methanol (http://www.fishersci.com/shop/products/methanol-certified-acs-fisher-chemical/p-216156?campaign=GblChem-US_FC-Solvents&adwordskeyword=methanol&adgroup=Methanol&ppc_id=GC_goog_81689838_4321462638_methanol_p_69923407878_12531729921876649352&gclid=CMuMs-2Ptc0CFReUfgodJNANKA#tab2)

Quote
Flammable liquid and vapor. Cannot be made non-poisonous. Vapor harmful. Toxic by inhalation, in contact with skin and if swallowed. Irritating to eyes and skin. May cause irritation of respiratory tract. Toxic: danger of very serious irreversible effects through inhalation, in contact with skin and if s. Explosive. Use personal protective equipment. Keep away from open flames, hot surfaces and sources of ignition. Use only under a chemical fume hood. Wash off immediately with plenty of water for at least 15 minutes. Wash off immediately with plenty of water for at least 15 minutes. Immediate medical attention is required.  
CLICK "View more specs..." at the bottom.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: Boardburner2 on Jun 20, 2016, 12:53 am
<Rant on>

I used to use industrial meths for dissolving shellac for varnish.
A now passed on friend used to swear by it for lacquering  guitars and Japanese finish furniture.

Then i ran out.
I used pure methanol after that until it ran out also.
Commercial meths is ok for most stuff but not for light wood particularly balsa, the purple stain is a menace.
Also as a solvent it leaves a residue.
IPA can work if pure but takes longer to evaporate it is also twice the price.
Also difficult to dissolve shellac in ipa without heat, i do not want to put alcohol on my stove for obvious reasons.
There are  proprietary answers to this but they cost.

It is possible to get a licence from HMRC for hobby use provided you can supply a document from a supplier showing that meths is required.
Shellac supplier used to recommend this but since HMRC made the ruling they seem not to.  
They just say alcohol without specifying type.
I can point HMRC at threads where this is discussed but thy want to see documents.

Very very annoying.
<rant off>
EDIT
<Rant off>
syntax error.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: raschemmel on Jun 20, 2016, 09:00 am
Have you ever heard of Dichlorodifloromethane ? (AKA "OH NO !" gas ?)
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: Noobian on Jun 20, 2016, 12:15 pm
aka Ozone buster?
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: raschemmel on Jun 20, 2016, 03:51 pm
Quote
aka Ozone buster? 
Not familiar with that name but probably the same thing. Not a chemist but I guess a methane is very different than a methanol.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: gpsmikey on Jun 20, 2016, 04:26 pm
Not familiar with that name but probably the same thing. Not a chemist but I guess a methane is very different than a methanol.
Yep - totally different critters - methane is CH4 while Methanol is CH3OH

Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: Boardburner2 on Jun 20, 2016, 05:07 pm
Methane gas is the precursor to liquid methanol, first step to synthetic fuel.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: ChrisTenone on Jun 21, 2016, 03:33 am
Methane gas is the precursor to liquid methanol, first step to synthetic fuel.
Well, it could be, but in fact methanol is commercially made by reacting carbon monoxide with hydrogen. The traditional way is to distill rotting wood.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: Boardburner2 on Jun 21, 2016, 11:50 am
Well, it could be, but in fact methanol is commercially made by reacting carbon monoxide with hydrogen. The traditional way is to distill rotting wood.
Large scale pilot plants are now operating.
Some gas fields are uneconomic for pipelines to the plan is to convert to liquid at the rigs.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: raschemmel on Jun 21, 2016, 03:42 pm
Quote
Large scale pilot plants are now operating.
Some gas fields are uneconomic for pipelines to the plan is to convert to liquid at the rigs.
 
there is a slight chance we might be drifting off topic... ;D
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: Noobian on Jun 21, 2016, 04:33 pm
there is a slight chance we might be drifting off topic... ;D
Just a slight chance?? :D


The topic was like "hey b0ss, can I habe methanol to clean my pcb plz"... and has now reached the point where various production methods of methanol are in discussion.
Title: Re: using surgical spirit to clean connections before desoldeirng?
Post by: Paul__B on Jun 21, 2016, 04:34 pm
there is a slight chance we might be drifting off topic...
So - what's new? :smiley-roll: