Under Coating ...

Ndx

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1,875
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IL
Hi Guys, Any good stuff to get some permanent under coating ? my 2004 Mazda 3 is almost red under the car .. Im thinking about sanding it ... and using something to protect it .. Should it be sanded to bare metal ? or those under coatings have rusts inhibitors ? Something not toxic would be grate :) Any ideas ps.. My car is sprayed with Krown/Rustcheck on inside ...
 
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15,056
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Canada
Those coating would be runst protection - I wouldn't sand off the bottom of the car to bare metal! What do you mean your car is sprayed with Krown on 'the inside' - those are rust protectors for the outside, and will treat all over the car - floors, doors...etc....
 

JHZR2

Staff member
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44,842
Location
New Jersey
What about the black spray protector that Eastwood sells? It is self healing and rust inhibiting. Amsoil MP is another variety that may be good, but i dont think they sell a black variety. Ive heard that spray undercoating tends to allow water to get entrapped in its pores and cause rust, if not done right. I wonder if spray-in truck bedliner would be a good option???
 

Ndx

Thread starter
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IL
addyguy.. Inside i mean ... Inside doors etc ;D I will look in to Eastwood ... :) And Amsoil MP :) Thx Guys PS. you got me worried on those pores .. I heard that before :> I don't think MP is resistant enough - i think its like wd40 spray ?
 
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9,568
Location
Ontario, Canada
If you go to a Crown or rustcheck place they also spray the bottom of your car. It wears off the exposed surfaces fast but atleast it keeps fastners from rusting solid, or tight areas that hold moisture. I think once the rust has started its too late to put a rubberized undercoating on, it just holds the salty water longer and doesn't let it get washed out... I've been thinking about just using tremclad under my cars everywhere I can reach easily and seeing if that helps slow the rust down and start doing the crown sprays again. Anyone try just using rust paint? Ian
 

Kestas

Staff member
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13,822
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The Motor City
Some spray coatings are better than others in adhering to the metal. Some waxy coatings get hard easily and start delaminating from the surface rather quickly. Others, like Krown and Texaco Rustproof compound, stay greasy. It takes a number of years before they get hard and delaminate. These compounds are appropriate to apply over dry rust. They seep in and seal the surface from further rusting. It's odd that your car was only sprayed on the inside. Regardless of what was done, after five years it should definitely be resprayed.
 

Ndx

Thread starter
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Location
IL
So I Guess Amsoil MP Heavy Duty is the way to goo ... And I will change Krwon store .. They didn't lift my car for sure to have it sprayed under Will see how wast it will wash off its pretty cheap ... :) So I guess I should go under and spray everything beside exhaust pipes ?
 
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JHZR2

Staff member
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44,842
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New Jersey
 Originally Posted By: Ndx
I don't think MP is resistant enough - i think its like wd40 spray ?
The HD MP that I have is nothing like WD-40. It is a thick, brown waxy substance that self-heals. The only thing that is similar is the fact that it is in a spray can :)
 

Ndx

Thread starter
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o I see :) So should i spray it or its to late ? POR-15 looks like good product
 
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CA.
Another vote for Amsoil HD Metal Protector. Make sure it is the HD Metal Protector and not the Metal Protector. HD version is nothing at all like WD-40. It will also slow rust down on surfaces that have started to rust. Best to get it on before it starts though. AD
 
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25,045
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ON, Canada eh?
 Originally Posted By: Ndx
Hi Guys, Any good stuff to get some permanent under coating ? my 2004 Mazda 3 is almost red under the car .. Im thinking about sanding it ... and using something to protect it .. Should it be sanded to bare metal ? or those under coatings have rusts inhibitors ? Something not toxic would be grate :) Any ideas ps.. My car is sprayed with Krown/Rustcheck on inside ...
Hey, you live by me... Go to the Krown guys on Rymal just west of Nebo on the South side. They are great and they do my Santa Fe. It looks like new all over after 3 harsh winters and 170K KM I always buy them coffee because they do such a thorough job. They always spray the underneath so well it drips for 2-3 weeks afterward! (Non toxic, environmentally friendly and doesn't harm the driveway because it contains no dyes or solvents.)
 

Ndx

Thread starter
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1,875
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IL
 Originally Posted By: StevieC
 Originally Posted By: Ndx
Hi Guys, Any good stuff to get some permanent under coating ? my 2004 Mazda 3 is almost red under the car .. Im thinking about sanding it ... and using something to protect it .. Should it be sanded to bare metal ? or those under coatings have rusts inhibitors ? Something not toxic would be grate :) Any ideas ps.. My car is sprayed with Krown/Rustcheck on inside ...
Hey, you live by me... Go to the Krown guys on Rymal just west of Nebo on the South side. They are great and they do my Santa Fe. It looks like new all over after 3 harsh winters and 170K KM I always buy them coffee because they do such a thorough job. They always spray the underneath so well it drips for 2-3 weeks afterward! (Non toxic, environmentally friendly and doesn't harm the driveway because it contains no dyes or solvents.)
Hey, Steve do they lift the car ? I know the place :) There is my Buddy who owns Body Shop ..
 
Messages
682
Location
ontario canada
Fluid Film is gr8 stuff - used by sea tankers to protect the hold, used by NASA to protect space craft from oxidizing away from the rocket fumes, etc. Fluid Film was developed for US military to protect amphibious vehicles from rusting away in salt water. I get my mechanic to spray fluid film on my car, and it forms a greasy coating that stops rust, and prevents rust. Also, bonus! it's an American product It's a mixture of lanolin (wool wax) and oil. You can buy it by the 55 gallon drum, 5 gallon pail, one gallon pail, or spray cans. My mechanic heats it up in a big pot, mixes it with oil, and then sprays it with a Wagner spray gun. It goes all over, and six months later it's still making a 3 mm. thick layer on my car bottom. Amsoil is also good stuff, but I don't know if U can get it by the 5 gallon pail. Krown is very superior, but it is a much thinner product. It is good for seeping into seams, getting through rust to the metal part, etc. If U already have rust, it is good to have one treatment of Krown, followed by a treatment of one of the wax/oil products like Fluid Film, and my mechanic has a similar greasy product, I don't know what it's called, but he sprayed some of that stuff on for me, and it's good too. Just look through the yellow pages, and phone up various places, ask them to describe what they use.
 
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Messages
355
Location
Ontario, Canada
Originally Posted By: dwendt44
IF the underside is already rusty, forget it, it's too late. Undercoating when rust is already present will only make it worse. My 2¢
I disagree, my 16 yr old maxima is rusting in the wheel wells and rocker panels. It never got rust proofing for yrs. I started doing my own home made spraying with oil & grease mix 2 yrs ago and the rust, although there is alot, practically halted in it's advance. Next spring i'm going to cut it out and MIG the nasty areas. Luckily no structural stuff is rusting bad, and none of the suspension. Once the chassis gets attacked, I can bet that's the end of the car. Kestas, did you mention before in the summer, that one should heat up the rustproof before I apply it? I bought a cheap kettle from Walmart, and was planning on heating it up outside on my gas burner near the BBQ. Question though, does motor oil and grease ignite into flame at a certain point? Will the motor oil start to bubble/boil before it bursts into flame?
 
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3,577
Location
no. indiana
I agree with you 1993 VG30E GXE. rust can be stopped dead in it tracks if an oil or rustproofing is applied. Be VERY careful heating up motor oil or any kind of oil, when it starts to bubble is just before the flame up, the gases from the bursting bubbles are what ignite. Really I don't believe the oil needs to be heated, I know they didn't heat it up at the RustCheck I went to.
 
Messages
588
Location
Chicago, IL
Yeah, heating oils up will change their behavior. Just watch the yearly turkey fryer accident videos... The hotter the oil, the less extra heat it will take to vaporize. The trouble isn't that a boiling kettle of oil will burst into flame, it is that the vapors of the boiling oil can hit an open flame and go up. Like when you watch a cooking show, and they are pan frying a steak really hard and fast. When they pick up the pan and flip the steak, sometimes you can see the oil vapor from the pan ignite if it contacts the flame. (Or even farm silo explosions- just the dust from the grain can explode if the conditions are right.) But depending on the compound being used, I can see where heating it gently would be beneficial. Like the old mechanic's trick of using candle wax as a penetrant. If you get the metal nice and hot, the melting wax really wicks into the crevaces. I would think that if there was a way to heat the chassis before application, that would be the best way to do it. Maybe the best answer would be to do rust proofing during the height of summer- take the car out for a nice hot drive, let everything heat up from the sun and the reflected heat from the pavement, and apply the oil/wax. Do this a couple of times, and I'd bet you would be good to go for the winter. Especially if you can time the last application for the last hot day of the year.
 
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