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Floorpan surface rust - how much is too much?

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WidespreadPanic

WidespreadPanic

Jedi Hopeful
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I recently acquired a 74 TR6 w/a bit of rust in the floor pans, 1 or 2 pin holes are visible on each side....should I replace them? other options???

let me add that these pinholes became apparent after I pulled the seats & carpet and began roto brushing the surface rust out......it truly seems to be mainly surface rust, although these itty bitty pinholes (visible with a hi powered light source) are a bit disconcerting.

Don't shun the n00b. /ubbthreads/images/graemlins/nonono.gif

n00b appreciates your opinion. /ubbthreads/images/graemlins/cheers.gif
 
Personally, I wouldn't... Unless you're planning a full restoration. I'd scrape and brush as much of the rust as I could off, then paint them with POR-15. The pin holes could be sealed with JB Weld or a similar "steel" epoxy.
 
everything you'd ever want to know at https://www.por15.com/

rock-hard rust stopper... many people have been using it on frames to prevent rust in the future and encapsulate existing surface rust. Don't get it on your hands or you'll be wearing it for weeks.
 
Do a Google search, and you'll find more info than I can relay. It's essentially a rust encapsulating paint. Eastwood's makes a similar product that I've used in the past.
 
... depends on how many tiny pinholes you have and how widespread they are. As rust progresses, you will feel the metal getting thinner. I had 3-4 small areas with pinholes in location that suggested leaky or missing weatherstrip. I cleaned the are then spread tiger hair fiberglass/resin smoothed flat over the area; the resing dripped through and sealed the holes and the fiberglass hairs added strength to the floor. I stayed away from the edges of the floor so, down the road, I can more easily remove and replace with new floor. I sanded the tiger hair to a perfectly smooth and undetectable finish then applied por15 over the top.

People with more money than me are gasping at the horror of not replacing the entire floor but I'm talking about maybe 3 sq inches of repair spread out.

If yours is all over the floor, by all mean, replace the floor, don't cob it up. But for a small repair, patch is adviseable. But please no bowing down, OK?
 
I've detecetd about 3 or 4 pinholes per side. I suspect this is due to the car being left in a good rain once or twice with the top down. It doesnt seem too significnat, but I do like your idea of strengthening the floor with fiberglass. I have done boat repairs in the past so this is something I am comfortable with. Thanks.
 
I bought a TR3 project a few months ago and it has a covering of surface rust too. The floors seem pretty solid, if a little "oil-canny," but there are two or three holes, less than the size of a dime in them. I have thought about using the MIG to weld them all closed but I wondered what y'alls thoughts are on using only part of the replacement floor panel to fix the bad areas and not cut the whole floor out.

It seemed to me it might help in keeping it aligned and be a lot less work.
 
Hi,

I see no reason not to weld in a patch repair. It won't be seen and will give strong results. Larger holes might mean making a patch piece from a sheet of 18 gauge steel. Small holes can be filled by backing up the hole with a small, flat piece of copper. Welding rod won't stick to it. If oxy/acetylene is used, a hammer and dolly can be used to flatten the weld and make it nearly invisible.

The only tricky part of welding like that is be sure to check what's underneath before heating things up. A fuel line? Brake pipes? Flammable stuff! Be prepared to douse a fire on the opposite side from the work... it will likely be greasy, might be undercoated (remove that first!) and even if it's just painted, it will catch fire.

It's hard to tell the extent of rust without doing some media blasting or a chemical dip. Often that reveals more than there appears to be at first.

However, there are also "rust stopper" chemicals available at hardware stores. One brand name that sticks in my mind is "Rust Mort". There are others. It essentially changes the rust to a black, inert mass. I suppose it would get started again pretty quickly if left bare, which is where a sealing coat of a product like POR15 comes in. That's tough stuff and prevents any moisture intrusion. In fact, POR15 cures harder in the presence of moisture. There is also a thicker product called POR Putty that can be used to fill small holes. Same material as the paint, but thicker and useful for possibly up to 1/8, maybe even 1/4". Dry it is almost as strong as the surrounding metal. It is not easly sanded, though. This is mainly because it gets tiny air bubbles in it as it cures, that show up as pits if it's sanded.

The car won't win any awards with this sort of repair, but all these patch-type repairs are useful to keep a driver on the road for a few years longer, until you really want to dig into it and restore it properly, if that day ever comes.

/ubbthreads/images/graemlins/cheers.gif
 
i have found the only way to stop rust is to cut it out. patch it with good metal (welded). isolate the area after patching and media blast. epoxy prime to seal (this needs to be done within 5 minutes of blasting unless you live in arizona and it is 140 degrees out). the problem with rust is that it is intergranular in the metal. frankly, anything else is temporary. rust can be under the paint and not visible. blasting all around the area will expose this.
rob
 
I agree with rob, a patch is only a stopgap measure and will not stop the rust process. But if you don't have the $ or time right now, a patch will keep you driving until such time as you replace the rusted areas. Our cars don't see much water (or salt up here in the Northeast) so rust doesn't progress as quickly and if sealed off (with por15 or rust encapsulator), it will slow to a crawl.

My 3A floors are like new except for the small perforations where water has leaked under the carpets. So prompt removal and drying of wet carpets is important to be proactive in rust prevention.
 
Sometimes a person has to do with what they have. Many years ago I was a mechanic repairing military vehicles. One of the things was to clean and paint battery boxes. Often they were quite rusted and had heavy battery corrosion.
I used to use toilet bowl cleanser and water to clean them. Then I used baking soda to neutralize the clenser and acid. Then thourghly rinsed and dried them, sometimes using a torch to warm them or just placed them in the sun. After I was sure they were dry I painted them. This process ate away all the rust and gave me a very clean metal surface to work with. Over the years I had great results and it cut down the repeat problems when the vehicles came back through for scheduled maintenance.
 
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