The Stovebolt Site Forums The Shop Area General Truck Talk My PB Blaster vs. Kroil test

Friday I brought home a 1957 Corvette engine. When I took it apart, the right bank of pistons were all stuck. One of the worst ones had a pile of white and yellow crystalized corrosion filling the cylinder. It reminded me of a severely corroded battery terminal. I decided to test the PB Blaster and Kroil on the motor to find out which one actually worked the best.

For the sake of clarity I will number the cylinders 1-2-3-4.

The two outside cylinders (1 and 4) had the most corrosion, and I assumed they would be the toughest pistons to remove. The two center cylinders were stuck and not quite as bad.

Cylinders 1 and 4 seemed to be the worse of the four, and I decided that since the Kroil was the most expensive I would give it the task of the worse cylinder (#1). I also chose to use kroil in the number 2 cylinder. PB Blaster was used in 3 and 4, with 4 being the worse of those two.

First I took a 2" wire wheel on my die grinder and removed as much rust and corrosion from the tops of the pistons and I cleaned the tops of the cylinders too. I then propped the block so the right bank of pistons were level.

I then sprayed Kroil into cylinders 1 and 2 until the top of the piston was covered, then the same to 3 and 4 with the PB Blaster. I noticed the PB Blaster was bubbling a little around the edges of the piston. It reminded me of carbonated beverage when you pour it in a glass. I let them both sit for about 18 hours. All the cylinders looked like they had the same amounts of penetrant on top of the pistons when I returned.

First I took a wood 2 x 2 and hammered the two center pistons (2 and 3) down into the bore. Both came loose relatively easy. I pounded them from the bottom and they both came out of the cylinders fairly easy and with reletively equal force.

I pounded on the tops of the 1 and 4 pistons to see if they would loosen up. The number 1 cylinder with Kroil started to move so I continued to work on it. I got it far enough down the cylinder to see where the rings has set against the cylinders. I took my wire wheel and cleaned up the cylinder again and then pounded the piston from the bottom and it came out of the cylinder.

I then turned my attention to #4 with the PB Blaster. I pounded and pounded on the top and bottom of the piston and it would not move. I sprayed some more PB Blaster on top of the piston and waited about 15 minutes and pounded again. The piston did not move.

I decided that I had better prop the motor up again and let it soak another day. I was already leaning towards the Kroil as being the better of the two, and I sprayed some Kroil in the #4 cylinder.

After 10 minutes I took the 2 x 2 and hit it with the hammer. The piston moved on the first hit. After moving the piston down far enough, I again cleaned the cylinder with the wire brush. I pounded from the bottom and got the piston out.

Now you could say that all the pounding on the #4 PB Blaster piston helped loosen it up before switching to the Kroil, but I really believe that the Kroil did a better job of penetrating and loosening up the pistons. I also looked at the cylinders afterwards too. The PB blaster cylinder showed deeper scores in the cylinder walls from the hard deposits left behind.

I also noticed the lubrication of the kroil was much higher. The PB Blaster seemed dryer and less oil like.

My test finds Kroil superior to PB Blaster.

I always thought PB was the best but I will now try Kroil. I'm always willing to try new stuff.

Thanks for the report. Very thorough and easy to comprehend.

Started using Kroil after my F in Law recommended it. They used it at the Celanese plant in western Maryland all the time. Never been happier with a product.

Where can a guy buy Kroil? I have s stuck 350 in my 48 coupe. I have kept the cylinders full of PB for the last 3 or 4 weeks and tried to turn the engine with a bar on the flywheel but no luck. I was trying to get away without pulling the heads. It looks like I might have to pull it apart and use the wooden block. I have tried to find Kroil but no luck. Don

Where can a guy buy Kroil? I have s stuck 350 in my 48 coupe. I have kept the cylinders full of PB for the last 3 or 4 weeks and tried to turn the engine with a bar on the flywheel but no luck. I was trying to get away without pulling the heads. It looks like I might have to pull it apart and use the wooden block. I have tried to find Kroil but no luck. Don

I have been impressed with PB Blaster, looks like I will have to check out Kroil.

Thanks for the tip.

John

packrat, most industrial supplies carry it and "some" parts houses. I use to get it in a can like WD-40 but now I can only find it in a larger can and use my own squirt bottle. Its the best stuff around. The plant I worked at for many many years tried it all.....and ended up using Kroil to. I have a quart of it!!

sea foam
Test this stuff out. Its expensive but good. It even sprays upside down.
Sea foam, Deep Creep

I just bought some on eBay.

This subject keeps coming up, so, I dug it up and posted again.

KANOLABS.COM

It was posted here a while back when Kano ran a sale on Kroil. Two cans for the price of one and free shipping at that time.

I ordered two cans and since I'm on their "list" they send me a flyer with the specials ever so often. A six weeks ago I got a flyer advertizing Sili-Kroil, two cans for 18 bucks. I ordered me two.

The first I ordered is AERO Kroil which is STRAIGHT PENETRATING oil. I then ordered two cans of SILI Kroil which is the exact same formula but with and added ingredient(silcone) to also give it some Lubricating properties.

I bought a can of PBBLASTER and used/tried about 2/3 of it but it just don't do the job of the "Kroil". As I mentioned in a post above the plant I worked at did some "trials" on stuff and the conclusion was Kroil was THE best. I know we used it for over 15 years.
Most folks buy PB because they don't know about Kroil or they don't do the work to find it.
GOOD STUFF

I started using Kroil back in the 70's working in the shop on my uncles farm. Back then it was more commonly known as "Knock-R-Loose" made by Kroil..... Although I've tryed other products/brands (including PB), I always go back to the Kroil...... Costs a little bit more, but well worth it in the long run.

For those in the Puget Sound region of Wa. state you can get it at most any Tacoma Screw locations.

I like to keep a little of both around, but tend to gravitate towards the KROIL products. I mostly use the blaster to clean up my yard and garden tools.

I still use WD-40 for some things because it is cheap. It has its place. I do reach for a can of KROIL out of habit though.

Penetrating oil eats rust or is it just Smoke and Mirrors?.

Samples:
Rusted nut bolts, nuts washers.

Penetrating Products tested:
Kano Kroil 1939 (no history formula)
Liquid Wrench 1941 (originally contained Benzene)
WD40 1953 (retail 1958 no history of formula)
PB Blaster 1957 (no history of formula)

http://www.pbase.com/dennygraham/image/140204669/large
http://www.pbase.com/dennygraham/image/140204704/large

The formulas really aren’t a secret if you have access to a Gas Chromatograph mass
spectrometer. Many well equipped chemical labs have these today and even a small
chemical lab or you as an individual can send samples out to be analyzed, if you can
afford it. All the companies know the competitors secret formulas now days. You just
can’t market the formula as your own once you know what’s in it. There are a thousand
lubricants that you can choose that will perform the same job which is simply to reduce
the friction at the threads, and that many more solvents for thinning them down. So
there’s no magic involved in producing a thinned down penetrating lubricant, the magic is
in how you market your product.
The fact that most of these products don’t list the contents simply indicates to me that
they don’t want you to know that it’s simply some oil cut with some solvent so it will
seep into spaces with a very small amount of clearance. Oh, and there is always that dash
of something special that gives it its distinctive odor. The word clearance stands out in
my mind because none of these products will penetrate a metal seal. A close tolerance
thread that has been deformed from over tightening can form a metal seal to the inner
threads. There has to be a space for the lubricant to seep thru or it won’t do it’s job.

So far in the 1hour test I found that none of the products, “eats” rust as one of the
promotions boosted. I’ll take another look this afternoon and see how the samples look
after they’ve soaked for 8hours. The only thing in my experience that will do that is my
Phosphoric acid bath and even that takes a goodly amount of time to, “eat” rust. PB
Blaster has the most hilarious promotional video ad out of all of them. They take three
Styrofoam cups and squirt a sample of Liquid Wrench, WD40 and PB Blaster into each
cup. With in a minute or so the claim is “The PB Blaster eats its way thru the cup just like
it eats its way thru rust” Now maybe my “big old wife” would believe that, but have any
of you ever put a few drops of acetone in a Styrofoam cup????

I’ve removed bolts that had been soaked with all of the above products and in the end I
had to break them off with an impact. When they were autopsied by splitting the nut with
a hack saw there was no evidence of any of the products penetrating past the first or last
thread. I think the bottom line is that all the products are simply thinned down oil.

A couple of years ago I pulled a bed off a 1950 ½ ton Stovebolt and what I used was the
home brew formula of acetone and ATF in a mustard bottle, it worked just as good as any
of the commercial penetrating oils.

Bottom line is all you have to do is get a thin lubricant of your choice into most frozen
fasteners and they will come loose. So pick the one that fits your budget, your sense of
smell or which ever one you have on the shelf and you will in all likelihood get the same
results, none are going to “eat” or dissolve the rust.
Denny Graham
Sandwich, IL

Soaking 10 hours:
http://www.pbase.com/dennygraham/image/140212812/large

I have worked in the oil field all my career. An old guy I worked with years ago said to spray Aero Kroil on go take a break. When you come back the nuts or bolt will be laying on the ground. Its good stuff.

well if you get a bolt stuck in styrofoam you got it covered

For once in my life I'm speechless ...but I still spend the big bucks on Kroil.
Thanks for Oil Penetration 101 I knew it all the time and I gues the reason PB can afford their ads is they thinned down the oil the most and clear the most profit!!
(I guess its like the gas additives. Cost 7-21cent to make a bottle and folks pay 10 bucks for it.) Thats another topic later on.

The 24 hour soak:
http://www.pbase.com/dennygraham/image/140221991/large
Parts washed off with CRC brake cleaner after 24 hours soaking in solutions:
http://www.pbase.com/dennygraham/image/140221995/large

Conclusion:
None of the products “eat” rust or chemically alter the state of the fastener, they simply
seep in to the cracks where they can and lubricate the thread.
The product that works the best depends on which part of the country you were raised in
and which product was first introduced to you. Kroil-Tennessee (South Central), PB
Blaster-Ohio (mid-west), Liquid Wrench-North Carolina (East Coast), WD40-California
(West Coast). Those in between learned to use what ever the wagon train delivered to the
mercantile.
Since your inland and close to the Western border Alvin, you could swing either way!

Now as far as the lubricity of the samples tested, that would take a much more
sophisticated test setup using controlled weights and contact surfaces and accurate scale
measurements which I taint got time for……..right now that is!
Denny Graham
Sandwich, IL

I like Marvel Mystery Oil, 'cause it smells good! I mostly use oil, cut with kerosene though, 'cause I'm cheap. Or the blue wrench.

Oh no!!!!! You're not going to bring more snake oil into the picture are you Chris????
See now I didn't test any of the favorites north of the 49th parallel.

Denny Graham
Sandwich, IL

Don't worry Denny, you can't actually buy it up here anymore. I have my parents bring me up a gallon every spring.

Did I mention is smells good?

I do tend to burn it in the model T. Mostly because it smells good. And when people ask what you are putting in the tank, you get to be a smart [censored] and say, only the Shadow knows, its a mystery!

Well, the Shadow tells me it's 5wt oil, and stoddard solvent, plus the stuff that smells like wintergreen. That just doesn't sound as good as Mystery Oil though does it?

Just to be fair I should post this, it’s been floating around for a long time and don’t know
just how scientific the test was or how consistent the samples were.
But the Machinist Workshop magazine studied the most popular penetrating oils to see
what did the best job of removing rusted bolts by measuring the pounds of torque
required to loosen the bolt. I'm not sure just what flavor bolt they were using
that would take 516 pounds of torque but it must have been a monster.
These were the results they published:
Penetrating oil: Average load:
None...................................516 lbs.
WD-40.................................238 lbs.
PB Blaster.............................214 lbs.
Liquid Wrench........................127 lbs.
Kano Kroil..............................106 lbs.
ATF-Acetone mix......................53 lbs.
“The Auto Trans fluid- acetone mix was a "home-brew" mix of 50-50 ATF-acetone.
The home brew tested better than the commercial products in this test. Note that
Liquid Wrench is about as good as "Kroil" for about 20% of the price.”

Then there’s always these “best ever” penetrating oils.
Mouse Milk Penetrating Oil, Motion Penetrating Oil, The Blue Wrench, Knocker-Loose
by K-N, CRC 5-56, Castle Thrust Penetrating Oil, Calfonex, Gibbs Brand, Sea Foam
deep creep, Loctite Freeze & Release, Chrysler foaming rust penetrant with graphite,
Heat and wax, Mopar Rust Penetrant, P/N 04318039AB, Royal Purples Maxfilm.

Denny Graham
Sandwich, IL

Ahh, when I say blue wrench, I mean the oxy-torch. That loosens every thing up, or melts it.

Given all this it seems a nut buster, or a big wrench, maybe with a cheater bar, could be less messy, faster, as effective and easier on the wallet.

With the cost of AFT going up to 5 or 6 bucks a qt and not sure about acetone these days, Kroil isn't such a bad deal,eh?

Doesn't acetone evaporate quickly? I use to use it keeping my woodfiller "moist".

Interesting about the Liquid Wrench,Denny, as that is another one I have "favored" for years.

Sooo, I guess I need to use my Advance Auto discount and get me a quart of ATF, can of acetone, and a squirt bottle and add it to my collection! Since I like to "drown" what I'm soaking it may save me a lot of money!!

I know Chris, but there really was a penetrating oil called "Blue Wrench."
As I posted Alvin, I've used the ATF/Acetone mix and it works just as good as any of the
others, and as you can see, I've tried most of the popular ones. And yep the Acetone is
like lacquer thinner, gone in a flash. But it keeps the oil thinned out long enough to get it
into any open threads and that’s what counts. You do have to keep it in a sealed up
container, I use an old plastic Plochmans mustard squeeze bottle and even with it
capped it evaporates over time.

DG

Denny, you never cease to amaze me. You're always going the second mile to provide good info.

Thanks a lot!

Tks, I know that some think it's an over inflated ego but I really am curious about dang
near everything and I enjoy sharing what I find out. I taint got a junk yard in the back yard
so I don't have spare parts to offer like of the guys, but anything that's in my head I'm
more than willing to give away

DG

You're the kind of people that make me keep coming back to this site. Thanks again for all the detailed info you provide Stovebolt.com.

Keep it up!

I heard about Kroil 30 years ago from a mechanic at a coal fired power plant shortly after I started restoring old gas engines, (the single cylinder kind.) It is the best stuff I ever saw! Cast iron rusted to cast iron has always been a difficult problem to solve. I have a very rare Holland 1hp headless that was stuck badly. It took all one summer spraying, soaking, and tapping to get it unstuck but Kroil is the only thing I could find that would touch it! I didn't know about ATF/Acetone at the time, but it might have worked, too.

Best wishes,

Les

I call it the Flame Wrench....

kroil IS the best...used in refineries for years...and nuke plants......kev

Now there is true logic, "cause it smells good", yuk yuk.

When we ran the family race car on a Methanol/Hydrogen Peroxide mixture, we used Amyl Acetate as an additive to break down the surface tension and help the components mix. It had a pungent odor some people thought smelled like banannas, so it got the nickname "bananna oil". Just a couple of drops in an unattended cup of coffee would get a guy's attention in a hurry! Liquid Wrench has an odor very similar to it, so it's possible that might be part of the mix.
Jerry

Thank you for taking time to do some comparison testing between PB Blaster, which I've been using & Kroil.

I've just placed an order for Kroil on amazon.com; it's available in 3 different sray can sizes.

I also went to youtube.com & entered the search term: Kroil vs PB Blaster which came up with numerous videos all extolling the virtues of Kroil. The overwhelming FAVORABLE consensus on youtube satisfied my curiosity/question.

Why not go straight to the source and save the middleman markup? KROIL is made about 60 miles north of my place, in Nashville. I buy mine by the gallon.

www.kanolabs.com

Jerry

...and if you get on their mailing list they will send you advertisements. I don't buy it by the gallon like Jerry but when I get a "buy one get one"...or buy and get free shipping....or buy the BIG cans at a nice price I stocked up and have plenty on the shelve.
I have both Aero-Kroil and Sili-Kroil on my shelf.
Haven't seen a sale for a while so maybe some will come out shortly although they did increase the price a good while back.