conflicted about rust repair

[xray]

Hey all:

I need some expert advice. I have been griding the rust off the floorpans over the weekend, fully expecting those "little holes" I noticed initially to end up taking over and making my decision to opt for new floorpans an easy one. But, after finishing up all I found were those pesky little pinholes and about 4 areas maybe 1 x 3 inches (2 on each side) in size...

Should I still get the floorpans whacked out and rewelded?

I was on the POR-15 website and they talk up their PorPatch product which sounds like a great option for wha I am dealing with. Has anyone used this stuff? Is this even a proper indication for that type of product?

Here are some pics.

Many thanks!

X

[Ed]

Using the POR-15 product would be an easy fix for your current rust problem. My only concern would be retaining the structural integrity of the floor pan. I wouldn't want to run over anything knowing that there is only a little bit of filler and paint with paper thin rusted sheet metal protecting my feet. If it was me (look in my gallery) I would cut out all the rusted metal weather it's in patches or the entire pan and replace it with new sheet metal. It's a pretty easy fix since you have access to both sides of the pannel. Once welded in place then use the POR-15 product and protect your new steel floor.

[EScanlon]

I might surprise a few people by this, but the kind of damage you exhibit is exactly what I had, and I used the POR and their Power Mesh product to repair it with.

The Power Mesh is basically a strengthened, single ply fiberglass sheeting that you apply along with POR to strengthen panels.

Is it the BEST way to repair this, no. Is it a BAD way? Not in my opinion.

The rust in your pictures is nasty, as the holes show. The "proper" way, is to cut it all out, and weld / braze replacement metal in. This can be a very tedious and expensive proposition, which is why the complete pan replacement would be the "best" and the most "proper". However, it doesn't necessarily get cheaper. Expect to pay about $1,000 US by the time you are done to replace the floor panels. That amount includes the purchase, shipping and welding of the floors. If that amount does not scare you, AND you can find a good welder who can do just that, then go that route.

While laying in patch panels may be a bit cheaper, it does have the unfortunate effect of looking unsightly when you are finished. (Unless you take a LOT of time and care to hide / blend in the repair, at which point you might have been better off replacing the whole pan.)

The POR method uses the Power Mesh fabric to reinforce the POR and the metal. I would not expect this to be as strong as the original metal, but having seen a "fake" panel actually made from the POR/Power Mesh and having had the opportunity to try to bend / break it, I was very impressed with the strength it DOES have. Having learned that, and knowing that down the road, I'll be taking the car apart and redoing that whole area (possibly years down the road), I decided to try it.

My results were exceptional. The floor has a noticeable strength to it, has no leaks, is noticeably quieter, and what's more, cost me less than $100 US for both floor pans, and I was able to do it rather quickly.

For those interested, here's what I did.

Once the tar paper had been removed and I was able to ascertain the extent of the problem, I wire brushed, and ground off as much of the "soft" rust as I could. Soft rust is the stuff that is already flaking or already permeated completely. Although this exposed a few more holes, I wasn't surprised. Then I sandblasted the floor, specifically those areas that still demonstrated that shiny black rust that you can see in a couple of your pictures.

At this point, the complete extent of the damage was evident. I decided to braze closed the more critical cracks and holes, as well as make a couple of metal patches for the really weakened and torn areas. The patches were migged for the most part, with only one or two being brazed in.

Now the floor was ready for the POR process. There were still a few areas that showed some of the holes, but the steel around the holes was still relatively strong.

I vacuumed and pressure blew the interior to remove the sandblast media, then I applied the Marine Clean product, and used a nylon and soft metal wire brush to thoroughly degrease the area. This was followed by a thorough water hose blasting to ensure that it was rinsed thoroughly. I then used my air hose to power dry as much of the metal and nooks and crannies as possible. The car was then allowed to dry (in summer).

The next step was the Metal Prep. Again, the floor was completely bathed, scrubbed and treated for at least an hour or more. I made it a special point to ensure that I also reached inside the rocker panels. In order to do that, I used a Cleaning Wand with my compressor and a pail of the Metal Prep. The Cleaning Wand has a hose attached to it that allows you to pick up a liquid and expel it out via air into tight nooks. (I had placed several of those wallpaper soaking tubs underneath the car to recover the Metal Prep so I could re-use it over and over again.)

Once finished, I allowed the Metal Prep to drain out of the car, recovering as much as possible in the wallpaper pans. That done, I rinsed the car again with the hose. Another force dry and air dry period.

Now the car is finally ready for the POR.

First, using duct tape, or some other liquid proof tape, I taped the bottoms of the holes from underneath the car. This was to prevent gobs of POR from dripping onto the driveway as well as reducing "scrap". Once satisfied that all the holes were "patched", I applied a good layer of the POR paint to the floor.

Then, I cut the Power Mesh material to conform to the areas I was repairing. Since I still wasn't completely sure of the material, I decided to cut TWO pieces for each area. My intent was to lay the second layer of material at a "cross" direction to the original. Although it is a fiberglass mat sheet, by rotating the nominal "direction" of the second layer of fabric, you add strength to the union (just as in the true fiberglass/ resin process).

I made what I consider a mistake then, immediately after coating the floor, I began to lay out the mesh. Looking back now, after the hazzles I encountered, I would recommend that you WAIT until the first coat of POR is just..almost..tacky. Meaning that the POR is still somewhat liquid, more of a real sticky tar, but not yet hard nor what the instructions refer to as "finger-drag" sticky. Depending on the humidity, this can be an hour or more to more than 4 hours. It is better to err on the side of wet than on the side of dry.

At this point, lay your mesh pieces in place. They'll stick MUCH better than what I had happen (don't ask). If the mesh doesn't stick to the POR, you waited too long, give it a quick re-coat to make it sticky. If on the other hand, the POR literally feels goopy, then you're early. You want the POR to be dry enough that it doesn't release the mesh once you've pushed it into it, and soft enough that you CAN push it into it.

Lay out all your pieces, and push them firmly INTO the POR you've painted. Once you have them firmly in place, start painting POR over them. Remember that the NEW paint over the old will activate the old to an extent, so don't get so over eager that the POR lifts the Power Mesh. (That's what happened to me. Geez, what a mess / nightmare.)

Add enough POR that the mesh is coated and somewhat wet, but don't go for saturation yet. Allow this coat to reach the same state as before, i.e. just before finger tacky.

Paint some more POR over the whole floor, this time taking the time to fully saturate and smooth out the mesh finish. Allow to dry.

After about 4 hours or so, you should be able to cut out any drain holes that SHOULD be in the floor pan. (It's up to you if you don't want to, but they are there to allow you to DRAIN any liquid from the floor.) This is a simple process with an X-Acto knife (hobbyist scalpel) if you catch it just before it turns rock hard. (If you've worked fiberglass, just as if you were trimming mat or cloth from a mold / repair.)

That was the repair of the floor. For those interested, I also used my blow gun sprayer to shoot POR into the rocker panels as deep and as thorough as I could. That way I could protect the INSIDE of the rocker panel.

Hope this helps someone.

Enrique

[Bambikiller240]

If you were to treat the area's pictured with POR's "Metal Ready" product, the holes would be enlarged considerably. Bearing that in mind, and what little of the rocker panels that can be seen, I'd opt for replacement of the entire floorpans, and rockers (if needed) AND treatment of the entire area with POR15. This is the kind of work that you only want to do once,............................ unless you have lots of money, and time to burn.

Just my $.02

[beandip]

I recently replaced one side of the pan and repaired the other . I bought my floor pans from Zedd Findings as they are the vary best in my openion. The passanger side of my Z was a real mess and beyound repairing in my view . It could have been treated and the POR systime used but it would have been a mickey mouse repair. I cut it all out and fitted in a new floor pan. Took the car to a certified welder and he TIG welded it in place . On the driver side there were holes like you show , one the size of a quarter and a couple smaller ones . Those I cut them out and the welder put in patches 3'' to 4'' long and 1 1/2 wide three total. there was an area that had some swis-cheese looking rusted out about the size of a dollor bill. This after using the sand blaster and all. Her I did as escanlon did and used the matting , I followed with using the POR to treat all exposed metal both on the up side and under the car. I also shot the POR into all the hidden spaces through out the whole car , a rolling shell at this time. I have found the repair to be vary strong and have no worries in this area . POR is vary vary tough stuff but flexable enough to allow movement and not crack just like the origional pannel. Gary As escanlon stated rust repair is not cheep , my repair all totaled was close to $900.00 and would have been $1100. + if the whole thing was replaced. I believe my fix is as strong as origional . Gary

[hls30.com]

The rust on my floors was a little bit worse than yours-3 or 4 quarter sized holes on the floors, I could have cut it out and welded in patches, but I chose to replace the floors and the seat mounts. I think Enrique is right that the POR15 repair will do the job quickly and efficiently, but I want to know my car is as structurally sound as when it was new when my foot gets heavy and my tires get hot!

I used Zedd Findings as well-excellent quallity, great price! Tig, Mig and Oxy-acet, my car is getting all three!

Will

[Truckin1972]

Speaking of rust has anyone hear used Rust Bullet? If so how did you like it?

[beandip]

wkarns used it and he liked the fact that he dident need to use the mariene clean and metal ready and that you could top coat over it . I dont know how well it seals the rust compaired to the POR15 . I think Z Tharpy sell it. There are several members and others I have talked to and seen the results of POR so rather than try a unknown product I have used POR . Gary

[xray]

Thanks for the advice, everyone. Enrique--great post! I will print it out and tape it up while I do my repairs...

MOst of the damage is in the middle of the floorpans near the drain holes, so I think I will POR those (unless the Metal Prep uncovers more extensive damage). There is some through-and-through rust along the welding line near the firewall (pic #3) which I would feel more comfortable having welded. The car is not going to be a 300hp hotrod, so the odds of it ripping in half from some rust like above is pretty slim.

I'll post some "after" pics when I get done...

Again, thanks!