Ultimate oil undercoating guide (DIY Waxoyl)

jbtvt

New member
Rust kills more of our trucks than any other cause. This ~$100 investment (depending what you own already) can save thousands in body and frame rot and struggling with seized bolts, and keep more of the cars and trucks we love on the road. I've used bar and chain oil for years and a knowledgeable friend has used B&C and Fluid Film and has said they're comparable. Both work OK but need annual reapplication and anything that is exposed to constant road spray like the A arms is bare in a matter of weeks. This treatment will not wash off easily, or maybe ever. For most of the vehicle areas it seems like this will be a lifetime coating. It's a PITA, but worth it.

Ingredients -
2 gallons name brand bar and chain oil ( all season, or 1 gal winter, 1 summer)
16 oz paraffin wax
Spray gun with wands ( I like PMT's - https://www.amazon.com/Undercoating-Gun-Spray-Wand-Kit/dp/B018RI373S/ )
Air compressor, 4CFM or higher, 8+ is ideal
Metal paint can
Propane/MAP torch
Scale
Hatchet
Hot plate
Old shirt
Duct tape

Optional:
Infrared thermometer ($17 @ https://www.amazon.com/gp/product/B00837ZGRY/ )
Spray suit (the heavy duty plastic lined one from Home Depot paint section works very well)
Spray sock (for hair, paint section)

Truck/car should be clean and dry underneath.

The ratio of wax to oil makes a big difference. You don't want to go above 2 ounces per quart or the oil will harden at very high temperatures, making spraying difficult, as well as possible chipping at cold temperatures. I put various concentrations on wax paper and put it in the freezer, at 0* anything much above 2oz/qt would separate from the paper rather than bending with it. 2oz/qt begins to harden around 150*. Much below 1 oz/qt would make the mixture more fluid than ideal, this mixture hardens around 100*. I used 2 oz/qt on high splash areas like A arms and low crossmembers, as well as anything I could access easily without a wand. With a wand 2oz concentration tends to harden by the time it reaches the end, but can still work with enough heat.

Wrap spray gun base with an old shirt and duct tape to keep the oil warm, like this:


Put paint can on hotplate, add oil, and turn on high. Oil will begin to lightly smoke around 150* and heavy smoke around 200*, this is too hot for the washer in the spray gun so keep it under 200*. Chip up wax into quicker melting flakes, if you don't have a fine scale weigh a large block and divy it up, then chip it. Add to oil at desired ratio, probably start with 2 oz/qt. When mix hits about 175* and wax is all melted add to gun. Beware the vent hole, don't spill this on yourself! You will have to jump start the top of the gun or wax will harden when it hits this, apply heat from torch to top of gun, from base to tip, both sides, then spray away. The threaded nozzles affect flow rate so play around with that till you find one that works for you.

Anytime you stop spraying long enough for the gun to cool down you will have to reapply heat from the torch to it, especially with the higher wax mix. When using nozzles, especially the long one, you will have to heat them with the torch as well, going quickly and careful not to melt them of course. This is an extra PITA but is an important step to get inside of the frame. Take your time and get inside all holes you can find, in A arms, crossmembers, top of the shocks, etc. I dropped all front skid plates, gas tank skid plate, and spare tire to spray everything. Try not to get anything on the exhaust, especially the catalytic converters. It's a good idea to keep a fire extinguisher in your vehicle at all times, but especially for the first few trips after undercoating.

I applied inside of the doors (salt spray will run down the windows and inside in the winter and rust them from inside) by drilling a 1/2" hole at latch side, spraying with the lower wax mixture, and plugging with these - https://www.amazon.com/gp/product/B0040CWV5G/ . I also did inside the rockers.

This is what my GX A arms look like two months after spraying and constantly subjected to NH salt and slush.:


Fully waterproof. You can still see runs on the crossmembers.
 
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jbtvt - very impressive write-up and your DOE (design of experiment) on the wax ratio is clever...:thumb:.

How much a gallon, is your base oil costing?...and thanks.
https://www.waxoyl-usa.com/?gclid=CMnjsrKssdECFce6wAoduBgEIA

Decades ago,

I was mixing Hydraulic Oil & Bearing Rust Inhibitor packaging Oil (from Manuf. process, scrapped on small dirt count).
- I didn't know it at the time, but Hyd. Oil causes too much oil fog
- leaving huge visibility problems, during application
I had heard of the red Chainsaw bar oil or Trans-fluid, but already had to much Hyd. on hand.

The Krown & Rust Check I experimented with, washed off quickly.
- I believe these products are water soluble / not ideal
- and not as good as claimed, in advertisements

Like how your testing solved your coated formula, from cracking...very important.
Coating cracking was the #1 failure mode, with Zeibart tar based spray.
- I once sprayed with heated oil warmed up on a kerosene heater
- but our heated way-oil solidified in 25 ft. of our supply hose...LOL
More info. Post #6: http://www.toyota-4runner.org/3rd-gen-t4rs/231102-frame-rust-anonymous.html

The following photo, was my 1989 Nissan Pathfinder that I sprayed annually.
- bought used and owned another 14 years
- still captured good resale value, and old body metal was rust free
- after 17 years of driving in winter (on Hwys. applied with rock salt) and SUV never garaged

PS - back in the mid 1970's / used motor oil undercoating, was the ticket.
- but dirty oil contains engine acid, on the pH scale...just saying / acid does not stop rust, in its tracks
 

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Great write up. I've been using grease, fluid film, and used motor oil. I'll give this a go. A liquid coating is the only way to go in the winter IMO. You can paint and power coat all you want but it still chips and rusts.
 
I bought a fluid film gun with a gallon of fluid film and sprayed away with air compressor.

Seems a lot easier than all the steps here but I do appreciate your in depth write-up.
 
Great write up. I've been using grease, fluid film, and used motor oil. I'll give this a go. A liquid coating is the only way to go in the winter IMO. You can paint and power coat all you want but it still chips and rusts.

FF is like a liquid application.
 
jbtvt - very impressive write-up and your DOE (design of experiment) on the wax ratio is clever...:thumb:.

How much a gallon, is your base oil costing?...and thanks.
https://www.waxoyl-usa.com/?gclid=CMnjsrKssdECFce6wAoduBgEIA

Decades ago,

I was mixing Hydraulic Oil & Bearing Rust Inhibitor packaging Oil (from Manuf. process, scrapped on small dirt count).
- I didn't know it at the time, but Hyd. Oil causes too much oil fog
- leaving huge visibility problems, during application
I had heard of the red Chainsaw bar oil or Trans-fluid, but already had to much Hyd. on hand.

The Krown & Rust Check I experimented with, washed off quickly.
- I believe these products are water soluble / not ideal
- and not as good as claimed, in advertisements

Like how your testing solved your coated formula, from cracking...very important.
Coating cracking was the #1 failure mode, with Zeibart tar based spray.
- I once sprayed with heated oil warmed up on a kerosene heater
- but our heated way-oil solidified in 25 ft. of our supply hose...LOL
More info. Post #6: http://www.toyota-4runner.org/3rd-gen-t4rs/231102-frame-rust-anonymous.html

The following photo, was my 1989 Nissan Pathfinder that I sprayed annually.
- bought used and owned another 14 years
- still captured good resale value, and old body metal was rust free
- after 17 years of driving in winter (on Hwys. applied with rock salt) and SUV never garaged

PS - back in the mid 1970's / used motor oil undercoating, was the ticket.
- but dirty oil contains engine acid, on the pH scale...just saying / acid does not stop rust, in its tracks

Interesting (and speaking of Nicopp in the other post, you can see half a roll in the pic above, good stuff). This year I used Echo oil, it was $11-$12/qt. I wish the manufacturers would give more info on their ingredients, some of the stuff has more phosphoric acid in it which really stops rust. I had a gallon of something years ago that worked incredibly well, turned all existing rust black and hard, but can't remember what brand it was. I think the phosphoric acid is red (all the rust stoppers like naval jelly seem to be anyway), as you mention, but a lot of brands add red dye anyway for visibility so can't really count on it.

I ilke how clean the actor is on the Waxoyl page, in a button up shirt :D

I bought a fluid film gun with a gallon of fluid film and sprayed away with air compressor.

Seems a lot easier than all the steps here but I do appreciate your in depth write-up.

Definitely much easier, I was just sick of doing it every year, and my A arms etc still getting rusty.
 
..............
I like how clean the actor is on the Waxoyl page, in a button up shirt :D

^^ The undercoat shop businesses (up here), tend to us a pneumatic 50:1 pump, to transfer wax-oils / using air pressure without the oil fog.
- this keeps T-shirt, eye glasses, vehicle interiors clean & oil out of employee lungs / vehicle windows & bay cleanup, is also minimized

Many Commercial transfer-wax oil spray systems, cost upward of $3,000.
- improves yield of oil formula (reduced waste), better hidden coverage & uniform mil thickness results

Graco Fire Ball pump: https://www.youtube.com/watch?v=ywaD4wT3hus
Spray equipment: Lemmer rust proofing spray equipment | corrosion control | corrosion inhibitor | rust inhibitor | undercoating | sound barrier
 

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3 winter update on this - these pics were from mid-winter, you can still see solid waxy-oil runs on the frame
3BLFxk4.jpg


More of a waxy grime on the crossmember and trans lines but still 100% waterproof and rust-free
D7c4jsK.jpg


Replaced this CV, I believe after I undercoated, or maybe it just flung the oil off, can't remember time frame. Either way, you can see what the whole undercarriage would look like without being sprayed for comparison
DuDTDPL.jpg


By the end of this winter there are a coule bare spots that are just starting to get some surface rust on the bottom of my front diff, so going to touch that and a few areas that I can see I missed in the engine bay as well. Still lloking better after 3 winters than Fluid Film or plain B&C did after 3 weeks, worth it to me.
 
I've always used Fluid film on all my vehicles here in MI. The salt and sodium chloride that we put on the roads here is terrible for rust. Not to mention the freeze/thaw cycles in the spring mixed with humidity and rain. Most of the Canadians swear by Krown and Ontario (40 miles down the road) is littered with Krown shops.

Based on my experience, using anything other than an oil application (Krown, Fluid film, rust check etc) you're asking for issues. The hard undercoating type stuff from Zeibart and others is terrible. It locks in moisture and then flakes off. The waxy stuff doesn't creep into pinch welds like the oil applications. The only issue with an oil spray that I have come to find is most undercarrige nuts, bolts and fastners are easy to remove yet the underside of the vehicle is a PITA to work on without getting covered in oil and grime.
 
I've always used Fluid film on all my vehicles here in MI. The salt and sodium chloride that we put on the roads here is terrible for rust. Not to mention the freeze/thaw cycles in the spring mixed with humidity and rain. Most of the Canadians swear by Krown and Ontario (40 miles down the road) is littered with Krown shops.

Based on my experience, using anything other than an oil application (Krown, Fluid film, rust check etc) you're asking for issues. The hard undercoating type stuff from Zeibart and others is terrible. It locks in moisture and then flakes off. The waxy stuff doesn't creep into pinch welds like the oil applications. The only issue with an oil spray that I have come to find is most undercarrige nuts, bolts and fastners are easy to remove yet the underside of the vehicle is a PITA to work on without getting covered in oil and grime.

How often do you Fluid Film?

I got mine Ziebarted, but didn't know any better. I just saturate everything with Fluid Film and am hoping for the best.
 
I've always used Fluid film on all my vehicles here in MI. The salt and sodium chloride that we put on the roads here is terrible for rust. Not to mention the freeze/thaw cycles in the spring mixed with humidity and rain. Most of the Canadians swear by Krown and Ontario (40 miles down the road) is littered with Krown shops.

Based on my experience, using anything other than an oil application (Krown, Fluid film, rust check etc) you're asking for issues. The hard undercoating type stuff from Zeibart and others is terrible. It locks in moisture and then flakes off. The waxy stuff doesn't creep into pinch welds like the oil applications. The only issue with an oil spray that I have come to find is most undercarrige nuts, bolts and fastners are easy to remove yet the underside of the vehicle is a PITA to work on without getting covered in oil and grime.

It's funny that Mass, where I drive often, puts more salt down per mile than any other state but has very few shops that specialize in undercoating. Must be enough money coming out of Boston where they just throw 'em away and buy a new one every 5-10 years.

The good thing about the method here is that when heated, the mix applies and penetrates like oil, but when cool resists wash-off like wax, and doesn't chip. Definitely get coated in grime working on it though, was covered after upgrading my hitch today.

How often do you Fluid Film?

I got mine Ziebarted, but didn't know any better. I just saturate everything with Fluid Film and am hoping for the best.

I don't know what Zeibart is but my friend, who still uses Fluid Film although he swears he's going to do this method one of these years, applied it twice last winter. There will generally be bare spots on low areas of your chassis after a month, depending on weather and miles driven.
 
I’ve never been more grateful to have a garage and live in a place where true winter weather is rare. Seems the oil-based treatments would smell awful. Is there an issue with that?
 
I’ve never been more grateful to have a garage and live in a place where true winter weather is rare. Seems the oil-based treatments would smell awful. Is there an issue with that?

Yup, sucks to have rust and to have to prevent it, which is why I was looking to minimize the time spent doing so. If you get oil on your exhaust, which always happens, the truck will smoke a little for a few days. You only smell it when stopped, of course. Bar oil itself has no smell so when that burns off there is no odor. Fluid film smells like sheep/lanolin at first and also smokes but both fade as it soaks up road grime.
 
How often do you Fluid Film?

I got mine Ziebarted, but didn't know any better. I just saturate everything with Fluid Film and am hoping for the best.

I do mine annually for the first few years and then every other year. Early spring here in MI is the worst for rust.
 
I’ve never been more grateful to have a garage and live in a place where true winter weather is rare. Seems the oil-based treatments would smell awful. Is there an issue with that?

Fluid film smells like a wet sheep when its applied. Not kidding, it lanolin based. Some people hate the small. I actually dont mind it. Completely goes away after a few days.
 
It's funny that Mass, where I drive often, puts more salt down per mile than any other state but has very few shops that specialize in undercoating. Must be enough money coming out of Boston where they just throw 'em away and buy a new one every 5-10 years.

The good thing about the method here is that when heated, the mix applies and penetrates like oil, but when cool resists wash-off like wax, and doesn't chip. Definitely get coated in grime working on it though, was covered after upgrading my hitch today.



I don't know what Zeibart is but my friend, who still uses Fluid Film although he swears he's going to do this method one of these years, applied it twice last winter. There will generally be bare spots on low areas of your chassis after a month, depending on weather and miles driven.


I'm going to give your mix a try. Seems like it would work well and like the idea of the wax and oil combo.

Ziebart is a hard time under coating that is sprayed on. It has the consistency and texture of spray on bedliner. It makes the vehicle impossible to work on. Unless the applicator literally caps or protect ever nut and bolt under the vehicle. It was very popular in the 80s and then people started figuring out that after time, it chips off, allows moisture and dirt to get under it, the causes worse rust issues.
 
Fluid film smells like a wet sheep when its applied. Not kidding, it lanolin based. Some people hate the small. I actually dont mind it. Completely goes away after a few days.

I’ve used the rattle-can version but can imagine the odor is a lot stronger when it’s being slathered on the frame.
 
Like Fluid Film, Wool Wax is a lanolin based undercoating/rustproofing/ lubricant. The installer says the odor from Wool Wax is much less offensive than Fluid Film. He said it is thicker and needs touched up every 2-3 years vs. every year for FF. It also comes in black. Like FF it never dries and continues to “creep” into the nooks and crannies. Mine has been on 2 weeks and is as wet as the day it was applied. It doesn’t encapsulate the existing rust like Zeibart rubberized “coating” it adheres to it and inhibits any further rust development. I am very impressed with this product and I am certain it will prolong the structural integrity of my beloved ‘07 V8 Limited.
 

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