Isopropyl

[PavanYK]

Thinking of repasting my cpu. Trying to find isopropyl alcohol on amazon, but not sure what to % concentration or type is best.

Country/currency: UK/£

[Haswellx86]

You need 99.9%. small bottles are very cheap.

[Needfuldoer]

9 minutes ago, PavanYK said:

Thinking of repasting my cpu. Trying to find isopropyl alcohol on amazon, but not sure what to % concentration or type is best.

Get the highest concentration you can find at the drugstore. It will be fine.

 

No, you don't need the 99.9% industrial strength stuff.

 

"Surgical spirits" ethyl alcohol should also work.

 

[Haswellx86]

1 minute ago, Needfuldoer said:

No, you don't need industrial grade alcohol.

 

Plain old 91% from the drugstore is perfectly fine to use, readily available, and much less expensive.

Can't even find 91%. It's either 99.9 or something like 70.

 

99.9 is very cheap. There isn't even much of a price difference with 70%, and 99.9 works better and is safer.

[PavanYK]

Would something like this be fine: https://www.amazon.co.uk/gp/product/B0CCN1189S/ref=sw_img_1?smid=A3P5ROKL5A1OLE&th=1

[Poinkachu]

3 minutes ago, PavanYK said:

Would something like this be fine: https://www.amazon.co.uk/gp/product/B0CCN1189S/ref=sw_img_1?smid=A3P5ROKL5A1OLE&th=1

Yes

[Haswellx86]

6 minutes ago, PavanYK said:

Would something like this be fine: https://www.amazon.co.uk/gp/product/B0CCN1189S/ref=sw_img_1?smid=A3P5ROKL5A1OLE&th=1

Do you really want to buy a whole litre?

 

Also you need to quote or mention (@) people to get notified.

[porina]

3 minutes ago, Haswellx86 said:

Do you really want to buy a whole litre?

At that price, why not? It's a lifetime supply for general PC cleaning. I've probably used less than half the 1L tin I bought decades ago. Find a smaller secondary container for actual use to make it easier to handle.

[OhioYJ]

37 minutes ago, Haswellx86 said:

Can't even find 91%. It's either 99.9 or something like 70.

Odd, all my local general and drug stores carry 91 and 70. 91% tends to be cheap, the 99% stuff jumps in price considerably. 

[Dedayog]

1 hour ago, PavanYK said:

Thinking of repasting my cpu. Trying to find isopropyl alcohol on amazon, but not sure what to % concentration or type is best.

Country/currency: UK/£

I use paper towel.  All by itself.

 

Don't overthink.

[Blasty Blosty]

3 minutes ago, Dedayog said:

I use paper towel.  All by itself.

 

Don't overthink.

Same, never failed me

[porina]

1 hour ago, Dedayog said:

I use paper towel.  All by itself.

I have 3 tiers of application:

1, don't wipe it at all. Just add a bit more TIM to ensure coverage. When it just needs to work and I'm using cheaper paste.

2, wipe to prevent excess accumulation. Ok for reapplying similar paste, or not high performance system.

3, alcohol clean if fitting high performance cooler on high performance CPU using high end TIM, and want "the best".

[Haswellx86]

1 hour ago, Dedayog said:

I use paper towel.  All by itself.

 

1 hour ago, Blasty Blosty said:

Same, never failed me

Really though? Because I want to replace thermal paste as well. Does a microfiber cloth (like spectacle cleaning cloth) just work? How about making it a little damp (I mean the die itself is non-conductive right)? The paste applied is already quite new that I want to replace.

[porina]

14 minutes ago, Haswellx86 said:

Really though? Because I want to replace thermal paste as well. Does a microfiber cloth (like spectacle cleaning cloth) just work? How about making it a little damp (I mean the die itself is non-conductive right)? The paste applied is already quite new that I want to replace.

I just kitchen towel. Don't think a microfiber cloth will be much better, plus you have the extra step of cleaning that later if you want to reuse it, whereas kitchen towel is disposable. This is more a mechanical cleaning. If you use water too, that might help a bit more but wont help to shift any oils or other non-water-soluble items used in the paste. Isopropyl alcohol does help more there.

[Pusbucket]

4 hours ago, Needfuldoer said:

Get the highest concentration you can find at the drugstore. It will be fine.

 

No, you don't need the 99.9% industrial strength stuff.

 

"Surgical spirits" ethyl alcohol should also work.

 

 

4 hours ago, PavanYK said:

Thinking of repasting my cpu. Trying to find isopropyl alcohol on amazon, but not sure what to % concentration or type is best.

Country/currency: UK/£

 

4 hours ago, Haswellx86 said:

Can't even find 91%. It's either 99.9 or something like 70.

 

99.9 is very cheap. There isn't even much of a price difference with 70%, and 99.9 works better and is safer.

the thing to keep in mind with 70% Iso is that it's also 30% water which equals longer evaporation, possibility of residue and it simply doesn't work as well.

 

99.9% alcohol???

That's pretty hard to make and should be more expensive because it requires more processing to remove all the water.

Distillation at best yields about 95% pure.

 

Anything above 90% would be fine for cleaning electronics, but I would avoid the 70%.

[Haswellx86]

8 minutes ago, Pusbucket said:

99.9% alcohol???

That's pretty hard to make and should be more expensive because it requires more processing to remove all the water.

Distillation at best yields about 95% pure.

I think if you are looking for small spray bottles then it is relatively cheap in itself for 99.9% but if you add up with the quantity then the comparison does become much more expensive. Or that my local prices for 99.9 are quite lower than what I see on international.

[Pusbucket]

8 minutes ago, Haswellx86 said:

I think if you are looking for small spray bottles then it is relatively cheap in itself for 99.9% but if you add up with the quantity then the comparison does become much more expensive. Or that my local prices for 99.9 are quite lower than what I see on international.

honestly I doubt some of the ads I see for low priced 99% ISO. How would you even know or test if they sent you 90%?

It is more expensive to make because all the moisture has to be removed through special drying process'.

Further, just exposing high proof/percentage alcohol to air begins to dilute it because alcohol is so hydrophilic and will pull moisture out of the air.

Not really something we need to worry about in this instance, but does illustrate that high purity alcohol is not easy to make.

 

[Blasty Blosty]

2 hours ago, porina said:

I just kitchen towel

Yup, me too

[Blasty Blosty]

IMO, its a complete myth that you need IPA for cleaning thermal paste off

 

Unless the paste is like 1938249018321 years old and is COMPLETELY dried solid, a literal paper towel will be more than fine

[Pusbucket]

52 minutes ago, Blasty Blosty said:

IMO, its a complete myth that you need IPA for cleaning thermal paste off

 

Unless the paste is like 1938249018321 years old and is COMPLETELY dried solid, a literal paper towel will be more than fine

even then ISO won't work. I had to use a razor blade to scrape it off.

[Blasty Blosty]

1 hour ago, Pusbucket said:

even then ISO won't work. I had to use a razor blade to scrape it off.

mmm crusty

[freeagent]

99.9% is dirt cheap, unless you live in an area where people drink the shit, then yeah its gonna be harder to get lol.

 

I use it every time.. and my temps are awesome.

 

If you use that 71% bunk make sure you wipe off the residue.

 

 

[Mark Kaine]

On 11/28/2025 at 11:50 AM, Needfuldoer said:

Get the highest concentration you can find at the drugstore. It will be fine.

 

No, you don't need the 99.9% industrial strength stuff.

 

"Surgical spirits" ethyl alcohol should also work.

 

70% is supposed to be best (for consumer electronics and overall cleaning)

 

Just recently bought 1L, was pretty hard to find because most the stuff on Amazon is 99%....

 

My old bottle is also 99% it works, but tends to leave a residue and is really highly irritating if you get it on skin, would not recommend.

 

PS: also drugstores sell it here in Germany, the problem is you gonna pay like €40 per L instead of like €8-10 on Amazon.

 

[daygeckoart]

70% is fine. It's the only thing available ins tores in Hawai'i, maybe because shipping by boat results in evaporation of the higher %? I don't know.