Thanks in advance for any wisdom or tips!

I have this frame and fork I picked up for free off of Craigslist. It's an older Trek frame w Ishiwata 022 tubing.

When I first brought it home it was very ugly. I started sanding and before I knew it I was determined to clean the bike of all of it's old paint. I pulled out my belt sander for some of the heavy lifting and used whatever sandpaper I had on hand. Some of the sandpaper I used was pretty course, maybe 80.

The finished product looks really nice but now I've done some of the online research I should have done before I started the project and I'm concerned that in my haste to sand the frame I might have ruined the integrity of the steel.

Is this project no longer safe? Should I throw the frame out?

It still looks fine but so far my investment is only time and safety is very important to me.

Bump!

Is this too vague of a question? Maybe I should be asking how I could tell if I compromised the steel.

Only once or twice did I see a pattern left in the steel by my sander and each time it easily buffed out. My feeling is that I didn't take off much if any metal when sanding, so maybe I'm just being paranoid.

I think you're just paranoid. Unless you seriously went into the tubing I suspect you're fine. Bikes are way easier to strip either by bead blasting or chemically rather than hand sanding.

Pictures might help.

I think you're being paranoid, but it's impossible for me to make this diangnosis properly over the internet.

There exist out in the world metal thickness testers - you could find a metal shop in your town and pick a few places on your frame where you have the most concern.

Unless you seriously gouged it near the ends of the tubes trying to work around the curves and joints you're fine.

In any case steel is very forgiving and not prone to sudden catastrophic failure. You've gotten this far, I'd build it and ride it. Maybe if I were concerned I'd relegate it to local use, and not take long tours with it. It may crack eventually, but is unlikely to part without plenty of warning, such as cracks visible through the paint before it lets go.

Thank you! and everyone else. I'm prone to paranoia. lol!

Then, based on some other posts here, you're in the right forum.

If you sanded with something as rough as 80-grit, I would make sure you remove all the big scratches. Notch-failure is the most type of failure in tubing and starts at a surface scratch and expands from there. The highest load areas are under the downtube about 2-3" away from the head-tube. And on the seatstays about 2-3" behind the bottom-bracket. As long as those areas are clean and smooth, you should be OK.

You can get sandpaper on cloth rolls, like tape. I prefer the 1" wide ones for bike tubing. Cut off 12" strips and wrap it around the tubing at about 45-degree angle. This gives you complete 360-degree coverage of the tubing. Then floss it back and forth and move it up and down the tubing. This ensures you remove a uniform layer of paint (and metal if any). Much better than using something like belt-sander which takes material off in flat strips. Use 220-grit, 320-grit, 400-grit and 600-grit before you prime for paint. Then wet-sand between coats with 800-grit wet-n-dry paper. Then 1000-grit before final clear-coat. After clear-coat has had 2-weeks to fully dry and harden, wet-sand with 2000-grit before polishing.

Funny you should mention the area on the chainstays behind the bottom bracket. There is damage in this area from where a kickstand had been mounted. You can see a crease in the top and bottom of both chainstays from the kickstand clamp. Is this an issue? I can and will post some pictures when I get the time but I assume this is a common area for this kind of damage.

Thankfully, there are no real scratches in the metal from sanding and everything buffed out smooth.