averyvm

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Hello Guys,

I have a '93 Honda Civic Hatchback DX. I have been driving around for a while without fender liners. Now is the time to put them back on but I want to paint the underbody a little bit before I install the liners. Which product would you guys recommend?

These are the different products I was thinking...
1. POR-15 rust preventive paint
2. 3M Rubberized undercoating
3. Hammerite paint (Kinda random) but I've heard good things about it.

I will be painting the area behind the fender liners and also the reverse side of the fenders. Thanks.

conor97hx

I don't have personal experience, but I've heard a lot of good things about por15.

MisereNoire

Por-15 is a decent ENCAPSULATOR, it works best on bare, slightly oxidized metal, but can be used over some coatings as long as theyre clean and scuffed. I use caliper paint on my suspension/underbody as it's less overall work, and my car isnt for show.

the POR will probably last longer and give better protection, but you'll be doing some serious prep to properly use it.

Ohmega

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I've heard great things about POR-15 as well. Also Lizard Skin, not sure if that's what you're looking for for your application, but its tough as hell!

averyvm

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Thanks guys for your responses. I'm leaning towards the POR-15.

tony_2018

I've seen build threads where members, not in this forum, use POR-15 with success. I base my decision on that. It does get messy so cover your floor before even thinking of using this stuff.

MisereNoire

I can vouch for the floor mess personally...you might also consider long sleeves and gloves.

joey1320

POR15 is a great product. I've used it on my EM1 resto and it is crazy durable and strong after it dries - almost like a porcelain.

Now there are some issues with it you may want to consider:

It's extremely toxic for your lungs, so apply in a well ventilated area and preferably with a good mask.

It does not have uv protection - I know this is not an issue under the fenders, but it wouldn't hurt to paint over it.

It needs to go over bare metal and preferably slightly rusted one at that. The name is "Pour Over Rust", so that's going to be a big time consuming process to do correct.

The pint/gallon of paint will go to **** if even a single drop of water/sweat falls in it, so best pour into a smaller cup and cover the rest for safety.


With all that said, if you only plan on covering the inner fenders, I would just clean them as best possible with a pressure washer and degreaser, then apply 3-4 good coats of any good spray paint and then a good coat of 3M undercoating.

TomCat39

With all this information on under coatings....

What closest resembles the under coating material used on the older (92-95) civics?

I know it's pretty thick, and it's flexible. My Jack stands have tore into it a bit and now I see the primer in the hole on the inside part of the under body at the front jack points. From that I can see the under coating is about 5 mm thick or better. And it crumpled back indicating flexibility.

I was wondering if any of the above products is like the OEM undercoating material.I believe that information can be handy to many even if it's not the direction the OP wishes to go.

tony_2018

tomcat, good question because this was something i want to know as well. just wish we had someone here who works at one the factories.

MisereNoire

TomCat and tony...none of the above products comes close to the oem coating. Eastwood sells a rubberized rust encapsulating undercoating (epoxy additives) that has a better adhesion and wear resistance than 3M coatings, but are still not as good as oem.

What I have found to be closer to oem in terms of adhesion, wear resistance, and flexibility is Noxudol UM-1600 for underbody coatings and the lighter noxudol 750 for hidden external body (behind fenders and such). These products are good, but still don't carry the same thickness/elasticity/coloration of the oe coatings, but may in-fact be superior in performance.

tony_2018

So what did Honda/Acura use?

TomCat39

Thank you, that is very good to know. Darn close is better than not at all.

And hey, if there is a chance it performs better.... Even better.

Also, it's possible the OE coating was more than one coat, or maybe a dip style. I don't mind double coating to get a little extra thick and seeing how that holds.

MisereNoire

I guess I missed mentioning that bit...whoops.
What little I DO know about the oe coat is that it was called "formula Q" and is a black, mineral-based rubberized coat. It seems that it is supplied to the manufacturer/dealer through Ziebart/Uniglass (or the vehicles were sent to them for the service), you can find some small info on it here. It was and is still used as the standard rustproofing coat on more than just Hondas.

I hope that satisfies your questions about it, as I don't know anymore than that. My experience with it is simply car ownership level hands-on repair and removal...and comparing it against the other products I listed to see what qualifies as a substitute.

tony_2018

I was thinking the same thing, double coat to give it that new durable look. I'm sure we might have to scrape off the old stuff in order for the new stuff to bond properly. All that dirt and debri will be hard to clean off in order to have the new layer stick properly.

TomCat39

I always wondered if the asphalt based rubber undercoating was similar.

Like this:
Dominion Sure Seal Brushable Undercoating | Canadian Tire

averyvm

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Very informative conversation going on here. It surpasses my expectation.