You should have laid some dynamat or its equivelant down.

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1985 CA 300D Turbo , 213K mi

I plan to use RAMmat in the future. Dynamat is overpriced.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

I did pull up the asphalt floor boards. Then cleaned and touched up the rust spots. I used B-Quiet. It was probably 1/2 of Dynamat and listed its sound deadening properties near Dynamats. I haven't seen the other makers list their sound deadening properties. I also did the fire wall. The ruber or plastic shell, I put 1/4 heat shield stuff. I should have used 1/8. I patched up the asphalt stuff and put some EVAP foam sheets to hold them together and to act as the faom layer it had. I cut the asphalt boards in sections. Once I got one section up with a scraper, the other sections were easier to pry up.
Tom

I may have been a bit premature with my praise of POR-15. When installing the seat today I scuffed the POR-15 coat with the seat track and it peeled up easily. I sent the following email to POR-15:

To whom it may concern-

I recently used the POR-15 series of products on my 1979 Mercedes and am quite dissatisfied with the results. The POR-15 was used on the car’s floor panels as part of a rust repair job following welding in some patch panels. The surface was a mixture of paint, surface rust and bare steel. I cleaned and prepped the areas using Marine Clean and Metal Ready following the instructions on the packaging, then applied three coats of black POR-15 using a brush after through stirring of the product. Several days later when reinstalling the seats in the car one of the seat tracks impacted the POR-15 coating causing it to chip and peel. Further investigation revealed that the POR-15 coat could easily be pealed off with a finger nail. I have attached a photograph of the area. The surface of the area that has peeled is a combination of wire wheeled surface rust and original paint. Unfortunately it seems that the POR-15 did a better job sticking to my skin than the floor panels. Because the POR-15 has formed a “skin” with poor adhesion to the panel it seems that it will provide worse rust protection than standard paint because it will trap water against the metal and hid the rust rather than bubbling up as paint would do. I selected POR-15 because I did not want to worry about these areas rusting ever again, but it seems that I was mistaken.



I'm torn on what to do now. The POR-15 seems to have stuck quite well to the lid, so it is possible it has adhered better in other areas of the floor. I could try removing it but I think it would be time consuming. My other choice is to leave it and keep an eye on it. I am sick of this rust repair job and want the car to be drivable again so I really don't want to spend another month of weekends pealing and re-coating the area.

Attached Thumbnails

 

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

Correct me if I am wrong but isn't the idea with POR 15 that it is to encapsulate the area that has rusted and create an anaerobic environment rendering the rust inactive.
I'm actually surprised that you could simply scrape it off with your fingernail. I've used it and I had a heck of a time getting it off areas I didn't intend to apply it to.
Something must have contaminated it.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

When I rebuilt my floor I deliberately didnt replace the asphalt. I also drilled several drain holes. For insulation I took those heavy rubber pads out of an old truck cut them to fit, but did not glue them down.....

Me too. You should see my hands and arms. I did seem to stick quite well to the can's metal lid. I think I will do a test and see how it sticks to the rusty area I cut out. I REALLY want to be done with this repair, but I want it to be done right.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

I've had mixed results with the product. The black on seat springs and an air cleaner cover worked great and stuck like paint should. I tried their silver on the lug bolts and just getting a coat to stick was an effort. Of course once a garage hit with an air hammer to change the tires it was all over. There was never any real adhesion to speak of.

I never complained about it since it was somewhat of a non-traditional use.

I think part of the problem is that POR-15 needs something to "stick" too. Smooth, clean metal doesn't seem like a good candidate for the product. In fact I think somewhere in their documentation it says it needs a bit of rust to stick. my 2 cents.

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1982 300TD 210K miles ("The Replacement" aka "The Anvil") - SOLD
1979 300SD 245K miles (never ending project)
2007 Pinarello F3:13
1995 Ducati 916 (SOLD, sniff)
1999 Ducati 900SSie (SOLD)

These floors were any thing but clean metal. I did hit the surface rust with a wire wheel before I applied it though.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine