InterL
Aluminum
- Joined
- Nov 28, 2014
- Location
- Wisconsin, USA
I’m pretty new around here and have no reputation to worry about, so . . . .
Seems like the subject of WD40 tends to raise the blood pressure of a few folks. I’ve seen some goods points made about it - and a lot of bogus folklore as well - so I thought I’d chime in with something that will REALLY get some people’s panties in a bunch: Science!
I run a company that makes scientific research equipment. Some of our manufacturing processes require parts to be meticulously clean. We therefore work hard to understand the chemistry of everything we use - especially stuff in a spray can that can spread itself around and contaminate everything in the shop. Everyday products you wouldn’t even suspect of causing problems can create major headaches for some of our operations. One can of Pledge getting lose in the clean room can bugger the ceramic coating process on $100K worth of parts. We once had to completely rebuild a $200K machine because the end user tried to clean it with a not-sure-pure batch of xylene. It’s a real problem for us and we pay close attention to anything that comes with a spray nozzle.
Because of this we’ve taken a hard look at what’s inside a can of WD40. I thought I’d share what we know so people can decide for themselves what’s real and what’s legend. As you’ll see, for the most part everybody is at least a little bit right in there opinion of the stuff with the learned and respected Forrest Addy coming as close as one could to the perfect answer through his own process of experimentation.
HOW DO WE KNOW WHAT’S IN IT?
WD40 is supposed to be a “secret formula”. But as most of you know we live in the age of the Safety Data Sheet for all the chemicals we use. We therefore have a general idea of what’s in WD40 from the SDS, especially the SDS’s from countries where the disclosure requirements are stricter than they are in the USA. WD40 has also been analyzed by a couple of different laboratories using a very sensitive technique called Gas Chromatography-Mass Spectroscopy (GC-MS) . This has given us a really good picture of exactly what the major ingredients are.
SO WHAT’S IN IT THEN?
In technical speak it’s a mixture of C9-C11 aliphatic n-, iso-, and cyclic-alkanes with a small amount of a mixed polycyclic aromatics and some solvent-refined dewaxed heavy paraffinic distillate.
In layman’s terms it’s 2 cups mineral spirits, 1 cup mineral oil, half a cup of naptha, and two or three candles from your last birthday cake.
That’s obviously not the exact formula but if you mixed that up you’d have something so close to WD40 that you probably couldn’t tell the difference. There is certainly some other stuff in it as well. We can see from the GC-MS analysis that there’s other ingredients but the concentrations are so minor that it’s probably just residual contaminates from the manufacturing process and nothing of any importance.
So, in a nutshell, WD40 is pretty much what it says it is. It’s a mixture of common solvents that dissolve oil, grease, and other gunk. Those same solvents also chase off any water and then evaporate. What’s left is a small amount of waxy mineral oil that stays behind to provide some lubrication and corrosion protection.
IS THERE REALLY A SECRET INGREDIENT?
Maybe - and this is actually an interesting story.
Before about 2010 the SDS for WD40 listed a surfactant (basically a detergent) as part of the ingredients. The surfactant was listed as a proprietary trade secret by the company so we couldn’t tell what it was. However, it would make sense from a chemistry point of view that any “secret ingredient” in WD40 would be a unique surfactant that would help get rid of water and keep the other ingredients in a consistent mixture. Everybody assumed that the surfactant was the big secret.
Then, sometime after 2010, the secret surfactant disappeared from the SDS.
We don’t really know why that happened. Does it means that there was a secret ingredient and it’s no longer in there? Was it just something unimportant that they used to put in and now think is unnecessary? Was it really the secret ingredient and they were forced to drop it because of increasing environmental/health regulations? Was it just some useless gunk they threw in to trick people into thinking there was a really a magic formula? Unfortunately, nobody’s got answer to this one except the folks at WD40, Inc..
So as of today there’s no ingredient listed on the WD40 SDS that you can’t go and look up by its Chemical Abstract registry number and know exactly what it is. There’s no longer any major ingredient that’s protected by trade secret rules. All we know from the GC-MS analysis is that any secret ingredient would have to be non-hazardous and included at very, very low concentrations. If they do have some sort of magic pixie dust it would have to be damn powerful stuff to work in such small quantities.
SO WHAT’S IT GOOD FOR THEN?
I think Forrest Addy’s numerous posts on this subject pretty much sum it up.
It’s good for getting gunk off of stuff. It’s good for chasing away water. It’s OK as a light lubricant on things like door hinges and sharpening stones. It does provide a decent amount of light corrosion protection for short periods. It’s also pretty safe for most paints and plastics.
In the end, though, it’s a consumer product and not generally intended for heavy-duty industrial applications. It’s not gonna keep your ways from wearing. It’s not gonna resist 300 hours of salt spray. It’s not gonna get you in good with the ladies. Use it for what it’s good for and it’s a fine product. Overuse it and you deserve what you get for not buying the right gunk for the job.
(Note: I have no personal experience with using it as an insect killer as JST has suggested in another thread. It’s probably awesome for that, though. We use light oils in the laboratory to kill things like fruit flies. The oil blocks the small tubes insects use to breathe through. Hitting them with WD40 should basically choke them to death in a long and agonizing manner. If you’ve got a vendetta against bees and wasps this is probably your weapon of choice.)
One thing I will say is that you’re probably overpaying if you’re using it as a lube for aluminum. All you’re really doing is spraying mineral oil on your part. The other ingredients aren’t going to do anything for you except stink up the shop and get you a little high if you inhale enough of them. You could probably get just as much benefit from wiping on a thin layer of light oil at about 10% of the cost. I agree that there’s a convenience factor to the spray can and it’s not like shops are going through 55gal drums of this stuff every day. Just bear in mind that you’re paying for the ease of that spray nozzle. There’s no magic finishing goop in WD40 that’ll make your aluminum parts any shinier than other methods.
As for me, I actually like the stuff. It’s banned from the “clean” areas of the shop as it does leave that oily/waxy coating that contaminates everything within ten feet of the spray can. We do use it in the tool room, though, and it actually makes a nice short-term corrosion inhibitor for parts waiting to be finished and coated. It’s a lot easier to clean off than other stuff we’ve tried. One wash in a water-based detergent at 165oF followed by a hot water rinse and a dip in acetone and the stuff is long gone. It’s a very useful product if you understand its limitations.
As always YMMV.
Cheers,
Dan.
Seems like the subject of WD40 tends to raise the blood pressure of a few folks. I’ve seen some goods points made about it - and a lot of bogus folklore as well - so I thought I’d chime in with something that will REALLY get some people’s panties in a bunch: Science!
I run a company that makes scientific research equipment. Some of our manufacturing processes require parts to be meticulously clean. We therefore work hard to understand the chemistry of everything we use - especially stuff in a spray can that can spread itself around and contaminate everything in the shop. Everyday products you wouldn’t even suspect of causing problems can create major headaches for some of our operations. One can of Pledge getting lose in the clean room can bugger the ceramic coating process on $100K worth of parts. We once had to completely rebuild a $200K machine because the end user tried to clean it with a not-sure-pure batch of xylene. It’s a real problem for us and we pay close attention to anything that comes with a spray nozzle.
Because of this we’ve taken a hard look at what’s inside a can of WD40. I thought I’d share what we know so people can decide for themselves what’s real and what’s legend. As you’ll see, for the most part everybody is at least a little bit right in there opinion of the stuff with the learned and respected Forrest Addy coming as close as one could to the perfect answer through his own process of experimentation.
HOW DO WE KNOW WHAT’S IN IT?
WD40 is supposed to be a “secret formula”. But as most of you know we live in the age of the Safety Data Sheet for all the chemicals we use. We therefore have a general idea of what’s in WD40 from the SDS, especially the SDS’s from countries where the disclosure requirements are stricter than they are in the USA. WD40 has also been analyzed by a couple of different laboratories using a very sensitive technique called Gas Chromatography-Mass Spectroscopy (GC-MS) . This has given us a really good picture of exactly what the major ingredients are.
SO WHAT’S IN IT THEN?
In technical speak it’s a mixture of C9-C11 aliphatic n-, iso-, and cyclic-alkanes with a small amount of a mixed polycyclic aromatics and some solvent-refined dewaxed heavy paraffinic distillate.
In layman’s terms it’s 2 cups mineral spirits, 1 cup mineral oil, half a cup of naptha, and two or three candles from your last birthday cake.
That’s obviously not the exact formula but if you mixed that up you’d have something so close to WD40 that you probably couldn’t tell the difference. There is certainly some other stuff in it as well. We can see from the GC-MS analysis that there’s other ingredients but the concentrations are so minor that it’s probably just residual contaminates from the manufacturing process and nothing of any importance.
So, in a nutshell, WD40 is pretty much what it says it is. It’s a mixture of common solvents that dissolve oil, grease, and other gunk. Those same solvents also chase off any water and then evaporate. What’s left is a small amount of waxy mineral oil that stays behind to provide some lubrication and corrosion protection.
IS THERE REALLY A SECRET INGREDIENT?
Maybe - and this is actually an interesting story.
Before about 2010 the SDS for WD40 listed a surfactant (basically a detergent) as part of the ingredients. The surfactant was listed as a proprietary trade secret by the company so we couldn’t tell what it was. However, it would make sense from a chemistry point of view that any “secret ingredient” in WD40 would be a unique surfactant that would help get rid of water and keep the other ingredients in a consistent mixture. Everybody assumed that the surfactant was the big secret.
Then, sometime after 2010, the secret surfactant disappeared from the SDS.
We don’t really know why that happened. Does it means that there was a secret ingredient and it’s no longer in there? Was it just something unimportant that they used to put in and now think is unnecessary? Was it really the secret ingredient and they were forced to drop it because of increasing environmental/health regulations? Was it just some useless gunk they threw in to trick people into thinking there was a really a magic formula? Unfortunately, nobody’s got answer to this one except the folks at WD40, Inc..
So as of today there’s no ingredient listed on the WD40 SDS that you can’t go and look up by its Chemical Abstract registry number and know exactly what it is. There’s no longer any major ingredient that’s protected by trade secret rules. All we know from the GC-MS analysis is that any secret ingredient would have to be non-hazardous and included at very, very low concentrations. If they do have some sort of magic pixie dust it would have to be damn powerful stuff to work in such small quantities.
SO WHAT’S IT GOOD FOR THEN?
I think Forrest Addy’s numerous posts on this subject pretty much sum it up.
It’s good for getting gunk off of stuff. It’s good for chasing away water. It’s OK as a light lubricant on things like door hinges and sharpening stones. It does provide a decent amount of light corrosion protection for short periods. It’s also pretty safe for most paints and plastics.
In the end, though, it’s a consumer product and not generally intended for heavy-duty industrial applications. It’s not gonna keep your ways from wearing. It’s not gonna resist 300 hours of salt spray. It’s not gonna get you in good with the ladies. Use it for what it’s good for and it’s a fine product. Overuse it and you deserve what you get for not buying the right gunk for the job.
(Note: I have no personal experience with using it as an insect killer as JST has suggested in another thread. It’s probably awesome for that, though. We use light oils in the laboratory to kill things like fruit flies. The oil blocks the small tubes insects use to breathe through. Hitting them with WD40 should basically choke them to death in a long and agonizing manner. If you’ve got a vendetta against bees and wasps this is probably your weapon of choice.)
One thing I will say is that you’re probably overpaying if you’re using it as a lube for aluminum. All you’re really doing is spraying mineral oil on your part. The other ingredients aren’t going to do anything for you except stink up the shop and get you a little high if you inhale enough of them. You could probably get just as much benefit from wiping on a thin layer of light oil at about 10% of the cost. I agree that there’s a convenience factor to the spray can and it’s not like shops are going through 55gal drums of this stuff every day. Just bear in mind that you’re paying for the ease of that spray nozzle. There’s no magic finishing goop in WD40 that’ll make your aluminum parts any shinier than other methods.
As for me, I actually like the stuff. It’s banned from the “clean” areas of the shop as it does leave that oily/waxy coating that contaminates everything within ten feet of the spray can. We do use it in the tool room, though, and it actually makes a nice short-term corrosion inhibitor for parts waiting to be finished and coated. It’s a lot easier to clean off than other stuff we’ve tried. One wash in a water-based detergent at 165oF followed by a hot water rinse and a dip in acetone and the stuff is long gone. It’s a very useful product if you understand its limitations.
As always YMMV.
Cheers,
Dan.
