How good is good enough, DAPO? Options

[930cabman]

Given this former Cali car is coming up on 50 years and probably not always taken good care of, I am lucky to have this level or rusting. I went after it with Ospho, wire brush and clean rinse.



Will be applying POR 15 to this area.

Question: my gut tells me the well adhered tar is sound and is not hiding any rusting.

[barefoot]

Agree, looks good (IMG:style_emoticons/default/beerchug.gif) (IMG:style_emoticons/default/beerchug.gif)

[Superhawk996]

Looks pretty good but playing devils advocate - an oscillating multi-tool with a scraper blade takes the tar off pretty easily. (IMG:style_emoticons/default/stirthepot.gif)

[JeffBowlsby]

Or dry ice.

That remnant tar looks pretty ratty, just remove it and replace it.

AA has an original floor tar looking kit, there are other solutions.

[mb911]

Por 15 is trash.

You’re on the right track but once it’s all clean then epoxy primer then body color. Por 15 is well marketed junk just like k&n air filters which is another rabbit hole.

[930cabman]

Por 15 is trash.

You’re on the right track but once it’s all clean then epoxy primer then body color. Por 15 is well marketed junk just like k&n air filters which is another rabbit hole.

I have wondered that for years. A year or so ago I bought a couple pint containers and go between POR or basic oil based DTM from the corner hardware store. Funny how us Americans are easily sold a bill of goods by the marketing folks. I have some epoxy primer that I am using on the entire body after paint removal.

Does anything stop the rust in it's tracks, my thought is to keep it sealed and dry.

[rhodyguy]

Mar-Hyde is a first rate rust conversion product. Mar-Hyde can be sanded and painted. Apply the MH with a cheap disposable foam brush. Wear disp gloves when using this product. It will leave dark purple stains if you get it on your hands.

[dr914@autoatlanta.com]

and definitely replace the original factory floor pan tar and paint the car's color

[SirAndy]

Por 15 is trash.

(IMG:style_emoticons/default/agree.gif)

Been there, done that, won't ever do it again ...
(IMG:style_emoticons/default/dry.gif)

[Superhawk996]

Por 15 is trash.

You’re on the right track but once it’s all clean then epoxy primer then body color.

Here’s my preferred epoxy primer solution - no mixing (other than puncture the 2nd chamber), no spray gun to clean. Lasts 3-4 days in can after activated. Available in multiple colors (grey, beige, black).

Great for small areas like you’re dealing with.

[Superhawk996]

More devils advocate:

IMHO POR 15 has its uses.

Low buck, low quality, heavily rusted stuff you don’t care about too much but where you are wanting it painted is where I tend to use it.

POR15 is a moisture cure urethane product largely for Paint Over Rust (POR) as the name implies. It depends on the adhesion of the rust to iron to form its bond to metal while sealing the rust underneath. It does not stop rust under that coating despite what is implied.

When used on bare metal, it doesn’t form as strong of a bond as epoxy primer. The instances of POR15 peeling off in sheets from bare metal (smooth or sandblasted) are well documented. This always gets blamed on prep, but is the nature of the beast (moisture cure) paint which was not designed to be used as “primer”. Likewise, once cured, other paints don’t like to bond to POR15. And per the POR literature, POR15 isn’t UV stable so it needs to be topcoated if exposed to UV. But . . . Other paint doesn’t stick well to it . . . So there’s that little problem.

I don’t think highly of POR15, but have used it on occasion, I thought I’d outline why it isn’t the right product to use for OP’s proposed purpose.

[930cabman]

Looks pretty good but playing devils advocate - an oscillating multi-tool with a scraper blade takes the tar off pretty easily. (IMG:style_emoticons/default/stirthepot.gif)

About 10 minutes and yes there is rust under what appeared to be well adhered tar.

[Superhawk996]

. . . yes there is rust under what appeared to be well adhered tar.

Yup!

In a plain steel, pre galvaneal, pre e-coat world, whatever humidity was in the plant is what got trapped between the tar, and paint.

This is why there is no such thing as a rust free 914 and why it is said that 914’s came from factory with rust.

Well on your way to not being DAPO. (IMG:style_emoticons/default/smilie_pokal.gif) Now back away from the hardware store DTM. (IMG:style_emoticons/default/poke.gif) (IMG:style_emoticons/default/laugh.gif)

[burton73]

You need to use an Awl and push in the areas that have some rust. On my 1969 build factory 6, when I removed the tar from the top of the pan and it looked OK but was not at all in the lower parts( recessed areas) of the pan under the seats. Southern California car garaged most of its life and in a garage for sure from 1986 on. There was no rust anyplace on the rest of car that we could find but I am happy that I changed out the pans so it would be perfect. I put factory tar on from George at AA, but PMB Performance wanted to put a different kind of modern mat on with better sound dreading.

I thought it was going to be great right there on the pan but no. We had to go into it for the clutch tube fix so new pans. I am going to show you a picture of the hell hole (not) so you can see just how not screwed my car was.

Best Bob B

[930cabman]

I will go after all of the rusted areas tomorrow with an awl

Is there any 914 in existence that is really rust free? my $5. is NO

thanks all

[friethmiller]

Por 15 is trash.

You’re on the right track but once it’s all clean then epoxy primer then body color.

Here’s my preferred epoxy primer solution - no mixing (other than puncture the 2nd chamber), no spray gun to clean. Lasts 3-4 days in can after activated. Available in multiple colors (grey, beige, black).

Great for small areas like you’re dealing with.

I just ordered a few cans to try. My main problem with my restoration is keeping the exposed metal rust free till I can get a large enough area to make it worth my while with the spray gun and the 2k epoxy. I'd like to be able to do smaller areas when they are ready with epoxy once, and not have to strip off temporary, and expensive, etch primer. This might be the solution I've been looking for. Thanks @Superhawk996 .

[Superhawk996]

I think you’ll like it. @friethmiller

I struggled with same problems when working in Midwest humidity. Seems expensive but the convenience and not having to mix, clean gun, etc. offset all that.

It holds up to nearby heat very well when welding near it.

[friethmiller]

I think you’ll like it. @friethmiller

I struggled with same problems when working in Midwest humidity. Seems expensive but the convenience and not having to mix, clean gun, etc. offset all that.

It holds up to nearby heat very well when welding near it.

Good to know! I'll post about it in my build thread next time whenever it decides to warm up again here in Texas.

[930cabman]

Almost passed the awl test, one small (less than 1/4" dia.) is all that I could get. Also, the poorly adhered POR is gone. It gripped to the rusted areas, but not at all to the clean surfaces.

[Olympic 914]

Another option to the POR 15 is Rust Bullet.

Used it on my car, on the undersides and inside floor. But did not paint it over rust. cleaned , sanded or blasted the areas first then two coats of rust bullet followed by two coats of epoxy primer and finally two coast of PPG single stage color.

Have not experienced any lifting.

Check post #22 in my build thread below.