Naval Jelly Removes Auto Paint?

JHZR2

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My accord seems to be more rust prone than any vehicle I've owned. There are a few rock chips to the primer on my hood, sesame seed sized to maybe the size of a small popcorn kernel. On one or two the primer is starting to brown, indicating that there's probably some porosity and surface rust.

I tried ospho but didn't really get much of an outcome. I need something with a bit more staying power. I went to the parts store to get some Naval Jelly, but hit a pause because it says to not let it touch paint.

Not sure what kinds of paint it might remove, and how much it is contingent upon rust being under the paint.

I'm not really keen on trying it, even in an inconspicuous spot, let alone the front edge of my hood. So I'm curious about if this stuff will affect modern automotive paints.
 
Honda's paint is terrible
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Are you near any of these shops?
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Not a matter of getting it sprayed. It's a matter of prepping these little spots before putting touch up paint.
 
Thanks, I may have some.

I was hesitant to scratch it, as at least some (more like most) of the primer is there. It's just starting to turn brown, so I take that as it's porous. Do I really want to make it more porous?

Newspaper is a great idea. I'll top it with Saran Wrap to prevent evaporation.

The real intent of a jelly was to get it to stay in place. That should work!
 
It would be good to see quality pictures of these spots, but the odds are that you don't need this level of work for tiny beginnings of rust spots.

I'd try putting a cotton swab in a cordless drill, with rubbing compound on the tip. Buff the rust out with it, wash off any debris.

This will not be enough if the paint around the spot has lifted because the rust has spread under it. Nothing will fix that except removing all lifted paint and rust under it, though sealing the hole with touch up paint would temporarily slow that down.
 
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Originally Posted by Dave9
It would be good to see quality pictures of these spots, but the odds are that you don't need this level of work for tiny beginnings of rust spots.

I'd try putting a cotton swab in a cordless drill, with rubbing compound on the tip. Buff the rust out with it, wash off any debris.

This will not be enough if the paint around the spot has lifted because the rust has spread under it. Nothing will fix that except removing all lifted paint and rust under it, though sealing the hole with touch up paint would temporarily slow that down.


I'll try to do this tomorrow. Definitely not under the paint. No bubbles, no lift. Tiny spots, but left unchecked Im sure it could get worse.
 
Originally Posted by JHZR2
So I'm curious about if this stuff will affect modern automotive paints.


Here is some of my experience with phosphoric acid ( and muriatic) which I believe may be close to your inquiry.

Never done car paint but have done all types of industrial coating and I imagine the effects are similar.

Naval jelly doesn't chemically destroy and or remove paint like muriatic acid ( except latex types or coats on improperly prepared surfaces) but it does get in the pores and makes it soft or otherwise changes properties in some ways ( you can visibly see the changes)

We use it for prep ( it etches very well) but has to have residue cleaned then a protective coating PDQ.

I have noticed ( based on surface finish of the substrate) that on a smooth prepped surface it softens paint but it still mostly sticks ( except if there is a crack then it makes it peel)- that said the remaining exposed paint clearly no longer has the qualities of the original so t has been 'affected' in some way and I would recommend removing it.

I have also seen on rougher castings where it doesn't seem to soak in the cracks and damage the paint at all.

I would ask someone in auto body for specifics, surely they would know
 
Ospho and naval jelly are both phosphoric acid. If anything, I would think the Ospho is higher concentrated phosporic acid compared to the naval jelly. It's hard to compare the SDS's. Ospho shows 45% acid by weight, Naval Jelly shows 10-30% (weight or volume???).

Maybe the gel part of naval jelly is more hazardous to paint? Still, I would not expect better results from naval jelly vs. Ospho since they both are based on the same type of acid.

On new tight chips, the factory applied metal treatment should mitigate rust creep. Having said that, on old paint chips I have enlarged them to find rust "veins" creeping underneath the paint on vehicles with poor paint systems.

All you can do is try. Sometimes I just prime and paint (toothpick) on tight new chips. Other times I abrade to clean metal, metal prep, prime, paint. Again, with homemade micro tooling (spot sanding tool)
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Have been so swamped... here are some pics. The screw is a #8 spax iirc.

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Don't mind the horrible pollen mess we have around here.
 
Paying the stupid tax.

Had ospho, figured since it is also a detergent, I'd use it before evaporust and after scratching with the fiberglass.

Because it's hot, I made little paper towel squares and we them, then applied them to the spots. Note I had tested that there wasn't damage before in an inconspicuous spot.

Well, I guess the paper towel on it with more contact wasn't the best. It lifted the paint on clear coat sections, and the paint wipes to primer on the Underhood areas.

I made the paper spots too big. I thought I was ok because I had tested it before. I figured more chemical in there would be better, because ospho seems to work slow. I also left it longer than 30 minutes because again, it works slow.

I should have used it for detergent only, if that, and gone straight to the evaporust or the paint. Very annoyed.

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The biggest problem I have found with Naval Jelly, and products similar to it, is the parts cleaned with it will immediately rust once the product is rinsed off. Faster than brake rotors after you rinse your wheels after a car wash.

If you use these type of products, have a can of WD-40 available, and spray the treated area immediately after rinsing.
 
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