Some do
Krown rust proofing question for people using it
- Thread starter Johnny248
- Start date
I drove my Honda off the lot straight to a Krown applicator. I don't like it- too low viscosity and if you get it on rubber it swells it (I think they all do this) they slathered it all over the engine bay. I use a spray on product that gells up and has graphite so you see easily where it is applied.
Two other things to consider.
1) you want a product that creeps. It will tend to creep over an area should a rock scrape some off.
2) NH Coatings sells a brush on product in addition to spray on products. The brush on is for areas where road spray might wash off a sprayed on product.
1) you want a product that creeps. It will tend to creep over an area should a rock scrape some off.
2) NH Coatings sells a brush on product in addition to spray on products. The brush on is for areas where road spray might wash off a sprayed on product.
I would go with Krown only if you have a local franchise that will do it every year, because it is needed to be re-applied annually for at least several years to build up some layers.
Drilling is not a problem if the guy does it correctly, meaning he will grease the opening and then plug it with a plastic plug. My 06 Mazda had no issues when I got rid of it during Covid. I inspected the holes over several years and there was zero rust on the bare metal.
Drilling is not a problem if the guy does it correctly, meaning he will grease the opening and then plug it with a plastic plug. My 06 Mazda had no issues when I got rid of it during Covid. I inspected the holes over several years and there was zero rust on the bare metal.
I woolwax my vehicles and take them thru the car wash throughout the winters w very little washing away. The only real places that kinda wash are directly behind the tires. I would not worry about it washing away and keep the salt off the undercarriage by using the car wash. Or use a hose with a shower feature and do it yourself if really worried about it, either way I'd get it off of the vehicle.
- Joined
- Dec 7, 2022
- Messages
- 264
You just posted something that didn't answer the OP question so how are we different? My post at least is on the topic of rust. I was only making small talk. It's not like I'm able to get out in public and talk to people anymore so I talk with people on forums to pass the time.
I have used Woolwax, FluidFilm and Surface shield on 6 vehicles and do them every year. I buy them in the 1 gallon or 5 gallon containers Here are my observations.
1.) Woolwax: Very Thick, hard to spray at lower temps (without heating and costant shaking), Does not creep much, sticks and stay on, mild smell, seems to have the best coverage yield.
2.) Fluid Film: Much thinner viscosity compared to woolwax, Sprays at lower temps, creeps well, does not last, Stinks the worst, poor coverage yield.
3.) Surface Shield, low viscosity like fluid film, no scent, may be petroleum based, creeps, cant tell on durability as this is first year using it. TBH, poor coverage yield, I was expecting surface shield to be thick like woolwax but it is quite low viscosity. We will see if it holds up or if it swells any rubber.
My Recommendations
Use Fluid film or Surface shield for the crevices or if it is the first application so it creeps into crevices. If car has rust use all over for the first time to establish a base layer then use Woolwax after. In areas that do not get wheel spray I still have the original woolwax. As far as car washes, I wash car weekly in winter but only get under-body flush every other wash
1.) Woolwax: Very Thick, hard to spray at lower temps (without heating and costant shaking), Does not creep much, sticks and stay on, mild smell, seems to have the best coverage yield.
2.) Fluid Film: Much thinner viscosity compared to woolwax, Sprays at lower temps, creeps well, does not last, Stinks the worst, poor coverage yield.
3.) Surface Shield, low viscosity like fluid film, no scent, may be petroleum based, creeps, cant tell on durability as this is first year using it. TBH, poor coverage yield, I was expecting surface shield to be thick like woolwax but it is quite low viscosity. We will see if it holds up or if it swells any rubber.
My Recommendations
Use Fluid film or Surface shield for the crevices or if it is the first application so it creeps into crevices. If car has rust use all over for the first time to establish a base layer then use Woolwax after. In areas that do not get wheel spray I still have the original woolwax. As far as car washes, I wash car weekly in winter but only get under-body flush every other wash
Carlostrece
$100 Site Donor 2025
I don't know anything about Krown, but I have had my cousin DIY it for me on a Jeep underbody and diff/axle housings and brake drums using POR15.
POR15 is a rust barrier paint that is amazingly good. It's that black paint you see on ocean going ships that makes them black below the waterline. The ships have 3 coats of it below the waterline and it stands up to salt water just fine, but it doesn't stand up to UV very well, but there's no UV below the waterline of a ship just like there's no UV under your car.
Above the water line, the ships use 1 coat of POR15 as a very good rust preventing primer, then paint whatever pretty color of marine oil base paint over the POR15.
I figured if it's good enough for ocean going steel ships, it was good enough for a car or Jeep underbody coating. Boy was I correct!
POR15 website recommends applying 1 coat to underside of a car as underbody protection. My cousin applied 2 coats just because why not? We had enough to do 2 coats. The extra would have gone to waste if we didn't use it up.
Fully cured POR15 is so tough that you can beat on it with a hammer and it won't mar, chip, or scratch. It's very tough. Wash your car as often as you want to (to protect areas that don't have POR15 on them).
POR15 does not make any claims about heat resistance or heat tolerance, but I painted my brake drums with it and they get hot driving in mountains, but POR15 held up perfectly.
It can be applied to rusty metal (as long as you first wire brush off any loose rust and dirt), then wash with Dawn dish soap and water. You can use regular autobody soap, but I think Dawn is better for degreasing for paint prep. Let dry. Then use a hand pump spray bottle to spray/mist (the areas to be painted) with the surface prep acid (provided by POR15 company). Let acid sit on underbody for however long instructions say. I don't recall if it was 15, 20, or 30 min. Then use a garden hose to wash off all acid. Let it dry completely. Stir POR15 thoroughly, then begin brushing it on. Expect to throw away your brush when finished. Have a 2nd brush handy in case the 1st brush gets gummy.
Use a good oil base brush so you don't have bristles coming loose and drying in your paint job. This job would be easiest with a lift, but my cousin did it with jack stands. While it was up in the air couple feet, he replaced my stock springs with lift springs.
This has to be a DIY project because I don't know if any shops will do this for you. In my case, I hired my cousin to do it for me. He did a great job. My tire alignment guy was always super impressed everytime he put the Jeep on a lift. The underside always looked pristine. Never a hint of rust.
This is a summertime only type project IMO. It should be done outdoors, or at least with garage door wide open, so the fumes won't make you sick. Paint in the morning, late enough for all dew to be gone, but early enough that the temp is below 80F. Ideally between 65-75F. Above 75F it becomes difficult to brush on paint because it gets tacky too fast if above 75F and especially if above 80F.
Quit working and cleanup before temp rises to 76F, if possible. You must quit if temp rises to 80F. The summer afternoon and evening heat will dry and cure the POR15 very nicely in 1 day. Just to be extra sure that it was fully hard and durable, we waited 2 days before installing new springs and reinstalling the diff/axles housings (which were painted with POR15, as well as the underbody), but we probably only needed to wait 1 day.
I'd still recommend frequent car washes, including underbody wash, because there will be lots of parts that don't have POR15 on them (springs, control arms, steering components). Though you could (and probably should) paint POR15 on most of those things, but don't get any POR15 on grease nipples nor rubber boots. You can't paint springs with POR15 because AFAIK it's not a flexible paint.
Also, to be technically correct, POR15 is not a paint. It's a marine primer with zero UV prorection. So if you use it somewhere the sun will touch, then put a coat of paint over the POR15 in areas the sun will touch. Sun is POR15's kryptonite.
That's why for my Jeep's brake drums (which the sun could shine on through the 5 spoke wheels) we brushed on 2 coats of POR15 follow by spraying on 1 coat of black Duplicolor on top of the POR15. It held up well, but in hindsight we should have used black Rustoleum Enamel paint because it's more abrasion resistant than Duplicolor (after the Rustoleum enamel finally cures, but with hot afternoons and evenings Rustoleum enamel fully cures in 2-3 days).
POR15 is a rust barrier paint that is amazingly good. It's that black paint you see on ocean going ships that makes them black below the waterline. The ships have 3 coats of it below the waterline and it stands up to salt water just fine, but it doesn't stand up to UV very well, but there's no UV below the waterline of a ship just like there's no UV under your car.
Above the water line, the ships use 1 coat of POR15 as a very good rust preventing primer, then paint whatever pretty color of marine oil base paint over the POR15.
I figured if it's good enough for ocean going steel ships, it was good enough for a car or Jeep underbody coating. Boy was I correct!
POR15 website recommends applying 1 coat to underside of a car as underbody protection. My cousin applied 2 coats just because why not? We had enough to do 2 coats. The extra would have gone to waste if we didn't use it up.
Fully cured POR15 is so tough that you can beat on it with a hammer and it won't mar, chip, or scratch. It's very tough. Wash your car as often as you want to (to protect areas that don't have POR15 on them).
POR15 does not make any claims about heat resistance or heat tolerance, but I painted my brake drums with it and they get hot driving in mountains, but POR15 held up perfectly.
It can be applied to rusty metal (as long as you first wire brush off any loose rust and dirt), then wash with Dawn dish soap and water. You can use regular autobody soap, but I think Dawn is better for degreasing for paint prep. Let dry. Then use a hand pump spray bottle to spray/mist (the areas to be painted) with the surface prep acid (provided by POR15 company). Let acid sit on underbody for however long instructions say. I don't recall if it was 15, 20, or 30 min. Then use a garden hose to wash off all acid. Let it dry completely. Stir POR15 thoroughly, then begin brushing it on. Expect to throw away your brush when finished. Have a 2nd brush handy in case the 1st brush gets gummy.
Use a good oil base brush so you don't have bristles coming loose and drying in your paint job. This job would be easiest with a lift, but my cousin did it with jack stands. While it was up in the air couple feet, he replaced my stock springs with lift springs.
This has to be a DIY project because I don't know if any shops will do this for you. In my case, I hired my cousin to do it for me. He did a great job. My tire alignment guy was always super impressed everytime he put the Jeep on a lift. The underside always looked pristine. Never a hint of rust.
This is a summertime only type project IMO. It should be done outdoors, or at least with garage door wide open, so the fumes won't make you sick. Paint in the morning, late enough for all dew to be gone, but early enough that the temp is below 80F. Ideally between 65-75F. Above 75F it becomes difficult to brush on paint because it gets tacky too fast if above 75F and especially if above 80F.
Quit working and cleanup before temp rises to 76F, if possible. You must quit if temp rises to 80F. The summer afternoon and evening heat will dry and cure the POR15 very nicely in 1 day. Just to be extra sure that it was fully hard and durable, we waited 2 days before installing new springs and reinstalling the diff/axles housings (which were painted with POR15, as well as the underbody), but we probably only needed to wait 1 day.
I'd still recommend frequent car washes, including underbody wash, because there will be lots of parts that don't have POR15 on them (springs, control arms, steering components). Though you could (and probably should) paint POR15 on most of those things, but don't get any POR15 on grease nipples nor rubber boots. You can't paint springs with POR15 because AFAIK it's not a flexible paint.
Also, to be technically correct, POR15 is not a paint. It's a marine primer with zero UV prorection. So if you use it somewhere the sun will touch, then put a coat of paint over the POR15 in areas the sun will touch. Sun is POR15's kryptonite.
That's why for my Jeep's brake drums (which the sun could shine on through the 5 spoke wheels) we brushed on 2 coats of POR15 follow by spraying on 1 coat of black Duplicolor on top of the POR15. It held up well, but in hindsight we should have used black Rustoleum Enamel paint because it's more abrasion resistant than Duplicolor (after the Rustoleum enamel finally cures, but with hot afternoons and evenings Rustoleum enamel fully cures in 2-3 days).
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- Joined
- Jan 17, 2025
- Messages
- 47
I live in Metro Detroit and I've used Corrosion Free on our cars every other year 3x now. It works really well in the areas you can reach it in, I sprayed the pinch welds in the door jambs, under the hood the first time and haven't reapplied and those areas still have a nice coating. If you go on their website there are a couple of places in SE MI that do the work and a bigger presence in Ontario. Personally I chose this product as the Canadian army did a study and found it to be the most effective rust inhibitor that they tested. A lot of companies will say their products work great but seldom show you the study that supports that theory.
When you apply it (I buy a case of the aerosol cans and it does both of our cars plus some left over) you can see how it creeps and moves to cover the area. It is a bit messy, My Mechanics Place on Plymouth and Levan will rent you a bay with a lift for $30/hour, makes it an easy job.
Here's the link to the study:
https://corrosionfree.com/wp-conten...Wti1m36UXPxG34o4CAp5azl8G8Hpm9HhS_JqpEvhIig8n
When you apply it (I buy a case of the aerosol cans and it does both of our cars plus some left over) you can see how it creeps and moves to cover the area. It is a bit messy, My Mechanics Place on Plymouth and Levan will rent you a bay with a lift for $30/hour, makes it an easy job.
Here's the link to the study:
https://corrosionfree.com/wp-conten...Wti1m36UXPxG34o4CAp5azl8G8Hpm9HhS_JqpEvhIig8n
Carlostrece
$100 Site Donor 2025
P.S. - POR15 will last forever, or at least longer than the vehicle does. It's a do-it-once permanent solution, but is a lot of work that one time. Without a lift, it takes ⅔ of Saturday and ½ of Sunday. It's not expensive though, if you do it yourself.
It would be a lot faster and less labor intensive if you had a lift (which we did not).
Also it'd be faster for you than it was for us because we also replaced suspension.
It would be a lot faster and less labor intensive if you had a lift (which we did not).
Also it'd be faster for you than it was for us because we also replaced suspension.
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My 2005 Civic might be the ultimate advertisement for Krown. I purchased the car in 2010 from a gentleman who said he had it Krowned each year. I continued that routine for a couple of years but now get it done every other year. There is no rust on my vehicle at all despite Southwestern Ontario winters. These 7'th generation Civics are known for rear fender rust-outs. Mine is clean. The holes that they put in the car have not rusted at all and look the same as when I purchased it in 2010
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You will never get POR15 into all the areas a rust preventative productive needs to get into. Maybe for a flat area you can properly prep then POR15 might be OK. But that's not the case for the majority of the undercarriage area.
I did 3 cars total. Took me about 2 months per car. All with floor jacks and paint brushes. 1st was cleaning and prep. 2nd was priming. 3rd was painting with whatever I had around. Por 15, Caliper Paint, Chassis Paint. Let all that stuff cure , then hit it with spray undercoating in the rattle cans..Had to let that cure too. Even exhaust systems got 2000 degree paint..Let that cure...FINALLY, they are done. Just do a spring inspection and touch up work if needed..Then my back gave out, and went back in for # 2 surgery on another disc. 8 more years in the RUST BELT, then moving. I refuse to buy another car until we move and settle in to another state, NOT in the rust belt.
Carlostrece
$100 Site Donor 2025
Fair enough. How about POR15 on accessable areas (flat underbody areas and differential/axle housings) and one of the other products recommended in this thread on difficult to access areas? The advantage of POR15 is its permanence.
You can only reach so far using POR 15 and a brush. I've done it. Great for accessible areas and flat surfaces. Prepping the metal is key. I lived in the Salt Belt my whole life,,, and have been doing this to my cars for years. See 2 posts above. Sometimes I will tape a paint stick to a paint brush to access areas you can't get to by hand. It's a total messy job,,,get the stuff all over me.. I will not use enamel paint. That's garbage. All plastic or metal coverings/heatshield's must come off too. That's why it took me 2 months per car. Whatever I cannot reach with a brush, I'll use the undercoating rattle cans. The top coat over POR 15 is the rattle cans of spray undercoating. Fender wells need to be removed, bumpers. Quite the ordeal. Need a lot of patience and time. But, in the end, it saved me from buying new cars. I can't afford them anyway. So, I gotta do what I gotta do to save what I have. I even paint the coil springs on the struts and every other suspension part. 8 more years and the wife and I are moving out of the Salt Belt. The best I've used is POR 15 or Brake Caliper Paint. Chip resistant.