SchRadler

After reading these forums for several months, I'm ready to attempt my first significant restoration of a C&V bike: a Trek 720 that I was surprised to win with a bid of $75 in an online estate auction in Dec.
I had only seen a couple of photos, but I was mostly excited to land what I've learned is a coveted touring frame. I knew the bike would need work, was a bit disappointed when it arrived that there was pretty significant rust on both the top and bottom sides of the top tube, and down around the bottom bracket. This much rust wasn't obvious against the burgundy paint in the auction photos.
So, my first question for your collective wisdom: is there any chance that this amount of rust has compromised the integrity of the frame making it unsafe? And, if not, is there any hope for touching up this amount of surface area, or would you sand/soda blast this whole frameset and repaint it? Here's what it looks like after my initial attempt to remove the rust and flaking paint. Thanks in advance for your input.

niliraga 

Nice!!! If it were me with an '84 720 in my size, I would press on regardless of the obstacles... not an easy bike to find. How are the visible interiors compared to these outside shots? I've seen plenty that bad around the BB shell, and just remediate and continue as long as the interiors didnt suffer similarly.

I will leave it to the more experienced folks here to comment on that top tube... all I know is that my winter beater looked way worst before I treated it, and to this day the bare metal sits there and I oil it from time to time.

If it were me, I'd neutralize the rot with rust converter and simply let it be for now - spend a season or three riding it, determining if I loved it enough to invest in a full bare-metal rehab.

SchRadler

Thanks, @niliraga. I'm new enough at all this that I don't yet have the tool to remove the bottom bracket, but the other places that I can see the interior look fairly good to me (but are hard to get a decent pic of!). The seatpost came out just fine as well, so that seems good.



I also tried to measure the difference between the diameters of the rusted out and not rusted areas of the top tube, and they were only about 0.1mm less which seems like mostly the difference of the paint. Not sure if that's really meaningful, but it doesn't seem bad. It seems like most of this TT rust may have just been from the PO's (may he rest in peace!) failure to clean the sweat off the bike after a hard ride.

bark_eater 

This is a nice frame that needs new paint and is valuable enough to make it "worth" the effort. because of the rust pitting, personally I would at least chemically strip the rust compromised areas and carefully smooth the pitting out with sandpaper, then soak it in oxcylic acid and after that, have it media blasted and painted. Some sort of rust inhibiting primer would be a good idea if its possible with the coating system. Going over the frame by hand first will let get a good feeling for the condition, before deciding how much more to invest.

bark_eater 

If your really concerned about the structural integrity, start scratching around with an ice pick, don't push, just scratch at the rust bubbles to make sure their not coming from the inside out.

jPrichard10 

Inside of the tubes don't look too bad. And the seat post came out easy? Probably a good sign about the inside of the top tube.

Classtime 

How does it look inside the bottom bracket? I'd say that is a good candidate for the OA (wood bleach) bath. Re-evaluate from there. Some folks would be concerned about the amount of pitting on the tubes and some folks are of the opinion that "these" bikes are over built so no worries. I'm of the latter if the bike is in my possession. What a super first restoration project. I loved how my '85 620 rode.

Mr. 66

Around and through the front tunnel guide is the most concerning area to me. I'd check the worst with a pick. I wouldn't sand it smooth, perhaps primer sand, repeat. If all is sound.

SchRadler

Thanks, everyone. I probed and scratched quite a bit with a pick on the top tube. Scratched away some more rust that was built up inside the tunnel guides, but didn't find any spots on the tube itself that seemed soft like they were rusted through or from the inside.

Next step is probably a soak in OA--seems like there are PLENTY of threads here already about that. And, obtain a bottom bracket tool.

Likely more questions to come. Is it better to just ask something else in this same thread or start a new one with a specific question and title?

sd5782 

Far from an expert here, but I see you are from the Midwest as I am. Yes we get rust, especially when bikes sit outside a lot. I haven’t really seen lots here with real structural rot as we aren’t humid all year as some areas are. I suspect that the many members here from the pacific NW see it more often and yours would be fine apart from cosmetics.

bark_eater 

As far as edicate, I'd say ask specific questions, but keep this thread going with your progress. You've got some great "before" pictures.

I've got a couple project frames that I want to treat with OA some time. One has "rust worms" and I'm not sure OA is the way to go with rust under paint, but I haven't seen any other solution's presented.

badger_biker 

Nice find for the price! I had an 85 Trek 620 in very similar or slightly worse shape on the TT. I had it blasted and powder coated. The pitting was still visible under the PC if you looked close. I don’t know if it would have been possible or wise to do so but I regret not trying a little bondo or filler over those spots between the blasting and coating. I’ve never done it to a bike but those suggesting an OA bath are probably correct even with blasting since it would neutralize any oxidation inside the frame.
Good luck with the restoration. Definitely a bike worthy of a make over.

homelessjoe

I think the 720 Trek is one of very finest vintage bikes you can find......or ride........I would paint it up and drive it.........from the pictures it doesent look to bad.....there wont be any catastrophic failures anyway...........thats 531 Reynolds tubing ...just about the strongest steel there is........that frame is worth having it professionally painted.......if you paint it yourself sand the rusty areas until its shiny steel then prime it good........if you decide against restoring it let me know.....I live in Ann Arbor

gugie 

I've seen much worse rust paint up just fine. Media blasting will remove rust quite readily.

Example:

Before


After:



My powder coater gets down to bare metal. Media blasting removes rust at a much higher rate than bare metal, so it's fairly easy to remove without damaging the frame.

SchRadler

Definitely a beautiful result, gugie. I'll do some looking to find someone who does this kind of work in my area. I'm sure it varies by region, but can anyone suggest a ballpark figure that is reasonable to pay for media blasting and repainting a frameset? Is powder coating more expensive?

ctak

+1 for media blast and powdercoat, plus an internal coating of Boeshield T-9. I once took an 853 Reynolds Lemond, with similar pitting, through this process and rode it for years without any structural issues... though in hindsight, I also would have applied a bit of filler between blasting and coating to smooth out any leftover "surface dimpling", as badger_biker suggested

gugie 

Wet paint from a reputable bicycle painter is easily 3X powder coat, many think it's worth it.

Here's a powder coat thread. Costs for a media blast and one color, no masking of chrome is typically in the $100-$200 range. It's important to choose someone that knows bicycle frames, however!

If you want a nice wet paint job, @Doug Fattic is a forum member down in Niles, Michigan.