POR-15 is junk

[70-500-SE-EXPORT]

I bought two gallons of this stuff three years ago. I have used in on about 20 different rusty areas including inside the frame rails of my charger before I put trunk and floor pans in.. I also used it on the entire underside of my 64 polara and on my rockers before I wielded the quarters on my charger. I have used it on rusty floors and over a dozen different things. Within a year the rust was coming through the por 15 on everything I ever used it on. The most unbelievable thing is my charger has never left my temperature controlled garage or seen any moisture in my garage. The rust just eats right through the paint and it can be pealed off on some surfaces in sheets. I used it on brand new primed floors in my charger and my cat pissed on the floor. The piss ate the por-15 and it pealed off in sheets and I found rust underneath. Everything I used it on was properly wire brushed and cleaned before painting and 2-3 coats applied. I have been using rust-oleum paint for 20 years and thought this was better. Im disgusted this company charges $100+ a gallon for liquid s*it. My car is rusting worse from the inside of my frame out and I can do nothing about it because them, not to mention the other things I used it on like my power wagon. Getting the stuff off is impossible unless I sandblast it.  Now I use ospho rust converter and rust-oleum.

[daytonalo]

I have always said that stuff is Armature hour

[Silver R/T]

I used it on brand new primed floors in my charger and my cat pissed on the floor.

POR-15 should not be applied over other paints.
Here's more directions, I hope you follow them before you bash a product. 
http://www.terebinthpaints.com/page/17610196

[resq302]

I have to agree, the stuff does suck!  The company is right down the road from where my job is and I have gone there on numerous occasions when I have had problems.  Specifically their exhaust manifold treatments.  They said that even though I media blasted the manifolds, that got moisture into them and caused them to peel the paint off.  I then had to buy their marine clean and metal ready prep.  More money out of my pocket.  The stuff did the exact same thing.  Brought them back again, this time prior to blasting them again.  They claimed it was cause I had oil or grease on my hands.  Nice try since I wore latex gloves as to not get the POR 15 on myself.  Last time I will ever use that stuff or stuff by that company.

[Mike DC]

 
The substance itself doesn't seem half bad, basically a liquid pour-able urethane.  But getting it to stick to anything is a b*tch (no matter how well you follow their directions) and it goes from black to purple if it sees any sunlight. 


The modern epoxy primers are a better option IMHO. 

[69*F5*SE]

I've had it stick to my garage floor for several years after some spilled, but it won't save a car from rust.  I think it would be a better garage floor coating than something to waste on our cars. POR 15 pisses me off.  There's much better products out there now to help in restoration.  Don't believe the hype that POR 15 will solve your rust problems.  It won't.  I followed every instruction to the T with the other components and it still sucked.  I wish I could get the message out to others before they waste their money on it.  Maybe this will help. Those who defend it haven't experienced the reality of it yet.  But, they will eventually find out the hard way. 

[Silver R/T]

 
The substance itself doesn't seem half bad, basically a liquid pour-able urethane.  But getting it to stick to anything is a b*tch (no matter how well you follow their directions) and it goes from black to purple if it sees any sunlight. 


The modern epoxy primers are a better option IMHO. 

If you read directions it does say it must be topcoated. Also epoxy is not ment to go over rust.

[maxwellwedge]

I have always said that stuff is Armature hour

I agree....It goes well with 3" thick bondo and worm hole metal work.

[devilgear]

Well good thing  saw this...I was about to buy some soon...By the way I am an amature...haha

[mopar_nut_440_6]

I am a bit disappointed since I used some on my car. Not much but a bit inside the frame rails and trans x member before I put the new floor pan in. I had read soem write ups on it and it seemed OK, oh well. What about the Eastwood product? I have read some excellent write ups on that stuff.

[daytonalo]

DO IT ONCE , DO IT RIGHT OR GET ANOTHER HOBBY !!! SANDBLAST OR ANY TYPE OF MEDIA , REPLACE METAL ,WITH WELDER , NOT GLUE OR TAPE OR EPOXY , EPOXY PRIME  OR ETCH PRIME !! ANY QUESTIONS IF SO IT TRULY IS AMATEUR    HOUR

[mopar_nut_440_6]

DO IT ONCE , DO IT RIGHT OR GET ANOTHER HOBBY !!! SANDBLAST OR ANY TYPE OF MEDIA , REPLACE METAL ,WITH WELDER , NOT GLUE OR TAPE OR EPOXY , EPOXY PRIME  OR ETCH PRIME !! ANY QUESTIONS IF SO IT TRULY IS AMATEUR    HOUR

I was just curious how the Eastwood product compared!

FYI, I am an amateur and have used advice on this forum to do the best job I can. I had used the POR 15 after sandblasting and metal etch as it was suggested to me by a few sources prior to suggestions made on this site. I will not do that again but like anything else in life, you learn as you go along. I also live by the same philosophy you do and like to do things the right way first time! Of course if you get the wrong info then....

[daytonalo]

Sorry for outburst , I think I need to work on my approach !!

[Brock Samson]

Oh yeah,.. 'n what approch is that?.. 

[daytonalo]

F4-F ?

[mopar_nut_440_6]

Sorry for outburst , I think I need to work on my approach !!

No worries! I thought maybe you were a Vancouver Canucks fan watching the game tonight!!  

[Brock Samson]

   

[71charger_fan]

I've had excellent results with POR-15 over the years. I've got a patch in my trunk that's fiberglass cloth and POR that went in during the late '80s and it's still strong and solid. I had it peel off a master cylinder in sheets though. Great luck with it on floors though.

[TexasStroker]

I never saw anything bad about POR15 till after I had used it 

Obviously I used it bc the sources I followed led me to believe it was a good product when used correctly...Those same ple contine to use it with good results.

Mine is currently limited to rear frame rails and has held up great...I did do all the prep per their directions though.  I sure as heck hope it holds up well for the sake it is on there.  I'll likely finish using it on my trunk floor as I have done (if it does blow up in my face I'd have had to re-do it anyway).

This could turn out to be like when I defended the 94-01 Ram dash issues and then had mine crack, hopefully not.

[daytonalo]

ASK SANTA EARLY FOR A MIG WELDER !!!!

[bull]

I bought a quart of the stuff about a year ago to coat the inner roof and firewall of my car but I could never bring myself to use it because the idea has always bothered me for some reason. It just seems like you're putting a candy coating on the metal instead of working with it. Over the past few months I decided I'd rather try a rust inhibiting primer. Can't point to any facts or figures to support my "feelings" but sometimes you've got to go with your gut.


Sooo.... anyone want to buy an unopened quart of POR-15?

[daytonalo]

BOTTOM LINE , "MARKETING " THAT IS IT , IF BILLY MAZE SAID MIGHT PUTTY WAS THE BEST FOR  RUST  9 OUT TEN ON HERE WOULD BUY IT

[devilgear]

I see what you all are saying about working wit the metal to get it where it needs to be, but will POR15 or something else help stop the spread of rust before you can finally get to dealing with the metal? Or is it good just to leave it alone?

[Ghoste]

The theory is that the POR stuff will completely seal the rust and prevent further oxidizing by not allowing access to the oxygen.  The reality is a little different, there is a reason it's sometimes referred to as "cancer".

BTW, who the hell is Billy Maze??

[694spdRT]

BTW, who the hell is Billy Maze??

He's probably most known as the OXY Clean pitchman on TV, but he sells other stuff. 

Not to be confused with Vince the Sham Wow guy. 

[Ghoste]

Ah yes, I remember now.  Is he the one that Mike Meyers was doing the parody of in "The Cat in the Hat"?
I guess I'd fall into the non-buying category by default (you have to see Billy in order to know which is the best product). 

[roger440]

I see what you all are saying about working wit the metal to get it where it needs to be, but will POR15 or something else help stop the spread of rust before you can finally get to dealing with the metal? Or is it good just to leave it alone?

Wax or oil to stop it getting worse. To get rid of it, as already suggested, either blast or cut it out. You cant stop rust by painting over it.

[Silver R/T]

I never saw anything bad about POR15 till after I had used it 

Obviously I used it bc the sources I followed led me to believe it was a good product when used correctly...Those same ple contine to use it with good results.

Mine is currently limited to rear frame rails and has held up great...I did do all the prep per their directions though.  I sure as heck hope it holds up well for the sake it is on there.  I'll likely finish using it on my trunk floor as I have done (if it does blow up in my face I'd have had to re-do it anyway).

This could turn out to be like when I defended the 94-01 Ram dash issues and then had mine crack, hopefully not.

I did my trunk floor back in 2002 (when I got Charger). Years later it still looks like new and no peeling. It will be topcoated as per directions as it doesn't have UV protection.

[Tilar]

BTW, who the hell is Billy Maze??

The single most annoying person I know of... Next to my second wife.  http://www.asseenontvvideo.com/511847/Quick-Chop.html

[lexxman]

ok I was planning on using por-15 on the inside of my charger.On the roof supports were you can't sandblast,you know those tight spots.I have a mig welder and a small sandblaster and I'm replacing what I can,but there still will be tight spot you can't get too.

[74Rallye]

I had one big disaster with POR-15. It was due to my sorry preparation work. I've also had many successes with the stuff. It's all in the prep work and being able to completely coat the item. If edges are left unpainted, that's where the rust will lift it.
One trick that's worked well on lawn furniture for me is to spray rattle can paint over the POR-15 before it completely dries. Another thing I've done is to lightly spray etch primer onto clean steel to get it to stick.
It's not a fixer, it's a paint. It's wicked tough when properly applied.

[superbirdtom]

I live in the rainiest place on earth, ketchikan alaska. and i use hammerite it is the toughest stuff on earth. i used it on a rusty oil tank outside and it is still holding up 20 years later. I would use it on inside of frame rails. most people are looking for a 1 shot solution and por-15 is not it. or use the rustoleum hammered finish paint.  this is for all the people who want to go over slightly rusted metal. I would only use it inside frame rails . not on exterior of car as an undercoat.

[TexasStroker]

I never saw anything bad about POR15 till after I had used it 

Obviously I used it bc the sources I followed led me to believe it was a good product when used correctly...Those same ple contine to use it with good results.

Mine is currently limited to rear frame rails and has held up great...I did do all the prep per their directions though.  I sure as heck hope it holds up well for the sake it is on there.  I'll likely finish using it on my trunk floor as I have done (if it does blow up in my face I'd have had to re-do it anyway).

This could turn out to be like when I defended the 94-01 Ram dash issues and then had mine crack, hopefully not.

I did my trunk floor back in 2002 (when I got Charger). Years later it still looks like new and no peeling. It will be topcoated as per directions as it doesn't have UV protection.

Good to hear!  I'm not just one of those guys slapping it over swiss cheesed metal and hoping it works magic.  I'm just using it to hopefully PREVENT rust and it does provide a nice finish on interior areas of the trunk.  I'll probably finish the trunk floor out with it and then apply a top coat as you plan to do.  I've only had the rails and dutchman etc done since January, but it has held up great and is rock solid.

[Silver R/T]

This is phosporic acid (as far as I know) so all it does is it converts rust in another form. You have to be chemist to fully understand how it works. They also call it conversion coating. Rust Mort is the same deal, probably a little less expensive.

[superbirdtom]

I never saw anything bad about POR15 till after I had used it 

Obviously I used it bc the sources I followed led me to believe it was a good product when used correctly...Those same ple contine to use it with good results.

Mine is currently limited to rear frame rails and has held up great...I did do all the prep per their directions though.  I sure as heck hope it holds up well for the sake it is on there.  I'll likely finish using it on my trunk floor as I have done (if it does blow up in my face I'd have had to re-do it anyway).

This could turn out to be like when I defended the 94-01 Ram dash issues and then had mine crack, hopefully not.

I did my trunk floor back in 2002 (when I got Charger). Years later it still looks like new and no peeling. It will be topcoated as per directions as it doesn't have UV protection.

Good to hear!  I'm not just one of those guys slapping it over swiss cheesed metal and hoping it works magic.  I'm just using it to hopefully PREVENT rust and it does provide a nice finish on interior areas of the trunk.  I'll probably finish the trunk floor out with it and then apply a top coat as you plan to do.  I've only had the rails and dutchman etc done since January, but it has held up great and is rock solid.

ALSO THERE IS AN EQUIVELLENT IN EASTWOOD THAT A GUY USED OVER A RUST BOMB OF A CAR. AND THAT WAS 25 YEARS AGO HE TOPCOATED IT AND IT IS STILL HOLDING UP AMAZING.

[69*F5*SE]

A great product for converting rust to a non-living animal is something called Picklex 20. It was originally developed for welding but was found to convert rust and kill it.  It produces welds with up to 65% more strength than without also.  It will prevent sparks when welded.  I've used this stuff for sometime now and it amazes me that if you treat bare metal with it it will keep the metal from rusting for several years if kept inside and kept from getting wet.  Use epoxy primer to coat it, as an etch process has taken place (NO ETCH PRIMER).  It can be coated with many things just not etch primer.  It is a geen waterlike liquid. 

ZeroRust is a product that can be applied over Picklex 20 or clean bare metal. But, it can also be applied over straight rust and keep it at bay and last, unlike POR 15.  It won't peel either.  These products are gaining more popularity in the restoration world but, many out there have not discovered it yet.  It's much cheaper than POR 15 also.  It's probably very similar to Eastwoods Rust Encapsulater but is still a different product of its own.  It comes in many different colors.

As far as POR 15 goes.  Yes, it is hard when it dries to its self leveling shine. Makes you feel warm inside cause you think it is a miracle coating. But, it's just old technology that can fail even when following every instruction and using every product that they call for before using POR 15.  I have wasted some money on it with POR lasting results.  The rust came back. Enough said.

[Silver R/T]

I wonder if you put it on very thin, that way rust came back through it?

[69*F5*SE]

Actually, I applied it liberally after using their degreaser Marine Clean and the Metal Ready.  I even used it on an old shovel treated with all the above and the rust came through eventually.  I hardly use the shovel.  All my experience is with the black POR15.  Maybe the silver POR 15 is a better potion, I don't know. I guess it's just not for me.  No real offense to those who have had luck with it.   I've found products that I've had tremendous results with that I'm happy with and will use them when needed.  I have a sandblaster that will take care of most of my rust issues anyway so a cover up product just isn't needed.  But, I will use the Picklex 20 to keep my clean bare metal from forming even micro-rust after it's blasted if I can't get to having it epoxy primed right away.    Ted

Here's a link to Autobodystore's website that shows the products I mentioned in my prior post. Worth checking into:

http://autobodystore.net/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=6RCC

[Silver R/T]

just wondering if you have top coated it afterwards.

[69*F5*SE]

You got me there.  I didn't have a top coat on it at all.  Even though, it should've still held up better.   

[Silver R/T]

Point being is that it does need to be topcoated to withstand UV rays, says so on instructions. I wouldn't blame it if I were you. If you don't follow instructions and product doesn't hold up as you expected it to it's not products fault. That's why I always read application data for every product I use, base/clears, etc.

[69*F5*SE]

I hear what your saying but, this was originally in my trunk area that saw very little light. It held up for a while until I found it starting to show rust through it.  I could then peel it off in little sheets here and there that exposed the underlying rust that was already there originally.  It doesn't bother me now as I removed my trunk pan but, the rust that came back is what got me to remove the trunk pan.  It really needed a new trunk anyways.  The POR 15 was something I expected to prevent removing it originally.  Nevertheless,  I don't feel comfortable just covering up rust with something before it's been converted at least these days.  The Picklex 20 I mentioned earlier is a great product to kill the rust first but, I just remove the rust all together and go from there.  I do hope that the POR 15 holds out for you in your car.  I don't like to see anyone else have to redo something that they already done with the expectations of being a permanent fix.  By the way, your car does look sweet in your avatar pic.     I hope to get mine there some day eventually.

[Silver R/T]

If someone wants to save money they can try Rust Mort. It's SEM product and I've used it before with success. It's been around a while so this product has proven itself and not something that just came out.

[69*F5*SE]

Picklex has actually been around for quite awhile in industrial usage under the original name Rasonil.  I believe they changed the name just as it became apparent that it had a following in the auto restoration market.  Checkout the link for info.  http://picklex20.com/  I'm not denouncing Rustmort or anything but, just getting a useful product awareness out there.  It's a more advanced product.

[rapom]

Another vote for Zero rust.  Works excellent and is a lot more user friendly.

Below is a Pro/con list that Restro Rick from the Moparts board wrote.

Here's a pro/con list I wrote to compare these different products.
There are others, such as Master Series & Rust Bullet which are similar to
POR-15.
My personal choice in all situations is to have clean unrusted bare metal whenever
possible, however in hidden or pocket areas, that isn't always feasible depending on
the job at hand.  Obviously I'm biased because I sell the Zero-Rust,  but I do so because I
think it's best product of its kind.  My observations listed below are based on my personal experiences...
Rick

Pros & Cons....
Corrosion Control Coatings

POR15
Pros:
1. Tough, hard, glossy finish when dried.
2. Flows well when applied with a brush.

Cons:
1. Has isocyanates.
2. If sprayed the overspray sticks to everything and is impossible to remove.
3. Difficult to remove from skin & clothing.
4. Leftover contents of can will harden and also seal can closed.
5. Initial dry time is 3-4 hours.
6. Questionable rust control.  Coating tends to act like a sheet of plastic and
   retain moisture and allows creeping.
7. Adheres best to rust.  Adhesion to clean bare steel is marginal.
8. Fades with UV exposure.



EASTWOOD RUST ENCAPSULATOR
Pros:
1. Good rust control
2. Dries quickly
3. Reasonable cleanup characteristics.
4. Leftover material stores well.

Cons:
1. Relatively expensive
2. Limited color selection
3. Adheres best to rust.  Not recommended for clean bare steel ref: Eastwood
   Customer Service Rep

ZERO-RUST
Pros:
1. Excellent corrosion control.
2. Lab tested for 2000 hr. salt spray rating
3. Dries out of dust quickly.
4. Available in aerosols, quarts & gallons.
5. Available in 10 different colors.
6. Easily recoated with proper precautions.
7. Sprays very well. (Applies very much like PPG DP epoxy
   and has similar gloss.)
8. Reasonable cleanup characteristics.
9. Reasonably priced.
10. Is safer to use... has NO isocyanates.
11. Has exceptional bare metal adhesion as well as over tightly adhered rust.
12. Leftover material stores well.
13. Can be thinned and poured into seams, etc. and drained off material
   reused.

Cons:
1. Paint film stays soft until fully cured.
2. Has limited UV exposure qualities.  Will fade after 3-4 months of direct exposure, but
   this will not affect corrosion control.
3. Can be brushed, but works best when sprayed.

[TexasStroker]

In the future, particularly if I have any issues with this batch of POR15 I will try picklex and ZeroRust.  I can continue to say the POR15 is holding up fine in the confines of the garage, lol.  The RestoRick bit was nice!

Just curious...Is there any need to top coat it if it is on the frame rails and underside of the trunk pan.  It looks great imo and I could prob live with it fading.  However while the car is down would be the time to go ahead and spend more time on my back sanding...I guess    Most of the guys I referenced were going full tilt and painting the undercarriage body color etc.  One or two were leaving it as is, but I never got to follow update threads regarding how well the POR15 had held up etc.

[69*F5*SE]

Since you've already got it applied to the underbody, topcoating it would probably be a plus.  A lot of people forget that POR 15 was designed to P-aint O-ver R-ust and not for bare metal.  It seems everyones experience is different with this stuff.  Some like and some don't.  It failed for me and was a waste of time and money.  I followed all the instructions, used their cleaning and etching products beforehand and over time the rust started showing through.  It was used in my trunk area which saw no sunlight.  I never topcoated it.  But, it didn't fade or anything.   I will agree, this stuff dries hard and is tough but, it just isn't the correct fix for me.  At least with my application. 

Picklex 20 and ZeroRust are better products in my experience.  Like I mentioned above, I'd rather remove the rust altogether by sandblasting or grinding etc..  I used Picklex 20 to keep my sandblasted bare metal from rusting over a long period of time (kept dry and inclosed) until I could get it primed.  It can be used for this application although, I suggest getting bare metal primed as fast as possible.  But, it can also be used for welding (which is what is was originally designed for).  It is supposed to increase the strength of the welds by up to 65%.  But, it will also kill rust altogether.  It's a versitile product.  Weld sparks are eliminated using Picklex 20 which is a good thing.

ZeroRust was designed to be applied directly over rust like POR 15 but, it didn't fail me in my experience.  It comes in several colors and is less expensive.  Hope all this helps without 

[TexasStroker]

As of right now it is just on the frame rails (inside and outside) but I intended to do the entire pan to hopefully rust proof it...However, the sanding of the friggin underside of the trunk floor with POR15 on it would be a complete pita.

Would it be better to just prime it and spray rust proof paint or something?  I believe I saw that ZeroRust was available as an aeresol    As much as I like body colored trunks, I'm keeping it black bc I just like the contrast.  Heck back in the day I used Rustoleum Flat Black on the front wheel wells and that stuff still looks good    I just really wanted to do everything I could to prevent the trunk floor from rusting out during my tenure as owner/operator of the Charger.  Granted removing the late 70s era carpet and getting solid weatherstrip should help 

I don't take offense to any of this stuff...I used POR15 based on advice from guys I consider to be top notch bodyworkers.  So far I haven't had any problems with it, but it has only been on in limited areas for about 5 months and hasn't seen much natural light (I have it on the frame rails, the rear seat brace, and the underside of the dutchman panel etc etc).  That area had surface rust and I addressed it as per instructions and as of Sunday night it still has an amazing finish on it (although no one will ever see it but me, lol).  I'm just here to learn stuff and do the best I can for the car!

[69*F5*SE]

 Read up on the ZeroRust and go from there to see what you would like to do. 


Here's the link for ZeroRust  http://zero-rust.com/

[acelondon]

Anybody here use Chassis Saver? at 24$/pint, i hope its a little better!

[SeattleCharger]

 

[yeahitsgotahemi!]

I thought I'd chime in with my experiences with POR-15.

I've used it for several different things. I painted the bottom, as well as the interior and trunk of  my charger with it. I then top coated it with Raptor truck bed liner. I also used it to paint the bottom of my 65 Mustang several years ago. I have been neglecting that car, but last I remember it was holding up well.

The only reason I use POR 15 in particular is that its available locally. I've heard good things about Rust Bullet, but ordering and waiting for a product when I need it immediately is a hassle.  In general, I have had decent results so far with a few exceptions. My experience has been that the surface needs to be rough. I media blast surfaces and parts to be painted with it and it seems to work fine as it gives the substrate some tooth. I think top-coating it is also a good idea that helps the longevity of the product. I've used their chassis coat black as a top coat on some parts and was satisfied with the results.

To be honest, powder coating and epoxy primer is probably the better way to go. The thing I like about POR-15 is that I don't have to spray it. I can pop open the can and brush it on and be done with it, especially in areas that are not exposed, like inside frame rails, the interior, trunk ect. There are a lot of times when I want to get something coated or protected that is a small area that is not exposed and it is a huge pain in the ass to mix up something like an epoxy primer, mask off adjacent areas, put on a respirator, spray it, wait, spray again, clean the gun, ect. With product like POR-15 or any similar paint, it alleviates that hassle of using a spray gun when it really isn't necessary or cost/time effective.

I guess if I could mix up some epoxy primer and just brush it on when it isn't worth the time/effort and expense of shooting it, I would do that, but I have never heard of that being done before, and imagine that would be frowned upon. I would much rather use the rust paint then experiment with brushing epoxy on, as my experience has been that,as long as the surface has some tooth it will hold up fine. Anyone ever try this?     

[69B3RT]

I can attest to how well SEM Rust Mort and Rust Seal work. The vinyl top was removed on my Charger before I bought it, and was only primed with surface rust showing. I sanded down the roof and still had the black rust specks showing. I primed roof again and had surface rust showing through the primer couple months later again. I was only 17 years old at the time. still learning how to fix cars. I put Rust Mort and Rust seal on roof thinking I would work on the roof again later. 23 years later I finally get around to sanding the roof again. The Rust Mort was some tough stuff to sand and the roof was just like i left it 23 years ago. The car was stored outside all that time. 

[scatpack69]

what would be good for a floor pan the is solid but just has surface rust?

[69*F5*SE]

Removing as much rust as you can would be good.  You can kill the rest with Picklex 20. Picklex will also help remove the surface rust and treat the metal for epoxy primer or ZeroRust.  Spray the Picklex 20 on and scrub with a Scotch Brite pad and the surface rust will come off while killing the residual rust left behind in the pits.  Wipe off any rusty soot you can.  Once the metal is "completely dry" then you can coat with epoxy primer or the ZeroRust.  Next to sandblasting to bare metal and then epoxy priming the above will work for you.  The rust will be dead and the coating will protect against anymore rust from forming. 

http://picklex20.com/

http://zero-rust.com/

[TylerCharger69]

I've used it and...I haven't had any trouble with it.  You really can't just apply it. (kinda like set it and forget it) You still need to sand it down or wire brush it a bit in order for it to penetrate the rust properly. It also requires a top coat over that.  I use an adhesion promoter afterwards, then a sealer, then paint.  I wouldn't recommend it on rusted out cancer, but stuff like surface rust and other minor issues.  The biggest misconception some people get from this product is you can just apply it over the rust and it's done.  I wish it were that easy.   I too had to learn that one the hard way.  Just my experience though.