Remove residual paint before POR-15 in rusty floor

Aaand here is a post about everyone's fav topic - rust .

I found a bunch in my 2005 Dodge Sprinter, hiding under the floor panels.

I am planning on treating the whole floor with POR-15 and fiberglass cloth for a few wholes I found/created by tapping with the hammer.

I did 1/5th of the floor so far following the 3-step instructions (degreasing-etching-por15) and results seem good (no peeling; although I don't know how else to assess results?).

Now the remaining 4/5th await. Question is, what do I do with the parts where paint isn't fully removed? Should I wire-brush all the areas where I see paint that isn't in pristine conditions, and apply por15? What material/tools would you use?

Here are a few photos of the more rusty, and less rusty areas.

Open to any of your suggestions/experience on this delicate matter..

I did the same recently and I bribed two friends and my girlfriend with cold beer, to fire up a few angle grinders and drills with those wirey wheel things to knock it out in a day. It wasn’t fun or easy but the extra hands really really helped. I had only screw holes and some tiny little soft spots that I used JB weld to fill and a little (a lot..) of flex seal on the outside of the floor underneath to spot treat areas for added water proofing

joeDiHare said:

Aaand here is a post about everyone's fav topic - rust .

I found a bunch in my 2005 Dodge Sprinter, hiding under the floor panels.

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This makes me want to check under mine. How difficult was it to remove the wood floor paneling? Did you do so in a way to re-install it, or are you just leaving it out and putting something else in and thus destroyed it to remove? I kinda like the wood floor. Not sure how much new wood floor panels are either.

in the cargo van, the wood (and composite?) floor is 1/4 in thick and riveted (with probably 15-20 rivets--rough guess) to the real floor. The ones in the front can be very difficult to access from the bottom due to the fuel tank, transmission, etc.

The edge of the wood floor looks thicker than 1/4 in at the cargo door, but it's got a lip that makes it look falsely thicker than it is. Let's say my discovery of this resulted in use of many curse words and bondo... =)

I'd say get the metal as clean as you can if you see any rust. I was doing the area around my windshield this summer, and found an abrasive disk (the ones that look like a pot scrubber from hell) worked better than the wire wheels i had used previously.

In your 4th pic (1715), the discoloration on the paint looks like leftover adhesive from the cloth that's below the wood.

Did the same process and took an angle grinder (real cheap one) and some sanding discs and went after it. Tried to remove as much rust and old paint as possible before hitting with the 3 step POR-15 process. Turned out great too. Write up on it for mine is here.

Spent a ton of time removing rust and paint though. Also had to weld up/epoxy some holes in my floor left over from seats.



Finished with POR15:

doug022984 said:

This makes me want to check under mine. How difficult was it to remove the wood floor paneling? Did you do so in a way to re-install it, or are you just leaving it out and putting something else in and thus destroyed it to remove? I kinda like the wood floor. Not sure how much new wood floor panels are either.

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A California born and bred sprinter, with no sign of rust on the outside and only 60k miles...and yet, under the floor it looks like a scene from the Titanic. My guess is that water must have leaked from the top (maybe liquid cargo), and certainly also from the holes used to pin the floor panels.

Removing it not easy because the previous owner had sprayed several coats of lizard skin (which, however, did not prevent at least one leak). Removing the floor panels per se was not difficult, but I agree with @quillaja the rivets were annoying and I ended up cutting them from the top.

alexk243 said:

Did the same process and took an angle grinder (real cheap one) and some sanding discs and went after it. Tried to remove as much rust and old paint as possible before hitting with the 3 step POR-15 process. Turned out great too. Write up on it for mine is here.

Spent a ton of time removing rust and paint though. Also had to weld up/epoxy some holes in my floor left over from seats.

Finished with POR15:

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Hey, this is a great write up. Thanks, and there are a lot of other interesting posts on the same blog.

What do you think about using fiberglass+por15 instead of welding? For the largest hole (maybe 3.in x 2 in.) I am planning on using reinforced bondo patches (together with fiberglass and por15). What do you think?
I don't own a welding machine, and I'd rather not having to pay a welder.

Thanks! I try to update that blog as much as I can. I recieved so much help from other people's blogs and on here, felt I needed to post what I did to help out others also.

Honestly that welder was junk and didn't really work well at all. I ended up taking 18/22 gauge sheet metal (seen in the pictures) cutting it to size (larger than hole) with airline snips and then epoxying it over the holes. Once it dried I epoxied the bottom from underneath the vehicle and covered with rubberized spray. Seemed to work well and should be watertight seal. Once everything was sealed I painted it all with por-15.

I really don't know much about fiberglass, but I would not want to use Bondo... Not a big fan and especially not in an area that I don't get to keep an eye on (covered by wood floor now).

alexk243 said:

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I really don't know much about fiberglass, but I would not want to use Bondo... Not a big fan and especially not in an area that I don't get to keep an eye on (covered by wood floor now).

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Yep. Basic Bondo type filler is not waterproof.

There are polyester fiberglass reinforced fillers which are fine for repairs that will see water. Off the top of my head Marglas, Duraglas, Gorilla Hair are some brand names.

Epoxy for metal panels can be effective, but flexing can break the bond. For metal patch panels my preference is pop rivets combined with a good quality adhesive sealant eg. - polyurethane. Many people dismiss pop rivets for such work. Pop rivets and adhesive can be very effective for repairs where "real" body paint/finish work isn't needed. Different fasteners exist for a reason and can be applied as appropriate for the work.

vic

Aqua Puttana said:

Yep. Basic Bondo type filler is not waterproof.

There are polyester fiberglass reinforced fillers which are fine for repairs that will see water. Off the top of my head Marglas, Duraglas, Gorilla Hair are some brand names.

Epoxy for metal panels can be effective, but flexing can break the bond. For metal patch panels my preference is pop rivets combined with a good quality adhesive sealant eg. - polyurethane. Many people dismiss pop rivets for such work. Pop rivets and adhesive can be very effective for repairs where "real" body paint/finish work isn't needed. Different fasteners exist for a reason and can be applied as appropriate for the work.

vic

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Makes sense... Didn't think about the body flex with epoxy. Ill keep an eye on them from underneath.

Mistake alert:
I recently did this. My por 15 started bubbling/blistering after 2 weeks. I called por and they said to weight a day to make sure the metal is really dry. It was 75 when I painted too. So I did the whole thing twice yay! I used an angle grinder, a drill with a brush bit, and a dermal.

What did you folks replace the fabric with under the floor?