# Vintage Crescent rebuild - frame rust



## Z'mer (Oct 28, 2013)

I'm in the middle of restoring my 1975 (bought it new) Crescent 531 Reynolds frame and wondering what to do about the rust. It's pretty spotted on the top tube, but appears to be surface type only. Some areas the size of a quarter, most smaller. 
What are people doing to restore these frames properly? I'd like to address inside the tubes (arrest any surface rust there plus preserve) as well as outside. 
The frame is currently 100% stripped down. I just have the BB re-tapped by my very cool local shop (Downtube in Albany) that still actually had a 35 x 1 French tap. A Phil Wood outboard BB is going in there. 
I'm thinking of making an acid dip tank for one section of the frame at a time from narrow cardboard box lined with a heavy garbage bag. And using phospheric acid to dip the frame and soak it / rinse it inside and out. Then Boeshield t-9 inside the tubes, strip and re-paint outside. 
Any hints on what paint color to use that matches would also be helpful. The bike is a blue Crescent 90320 or just 320, and was apparently sold in Europe as a Monark 90319, and the frame looks just like the one in the link below, blue with red accents around lugs, and stickers saying Reynolds 531 DB tubes, forks stays - 
Monark racercykel
Mine has Crescent seat tube decals instead of Monark.

A nice poster from the mid 70's. This was the orange model, the Pepita, with all Campagnola components.


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## Z'mer (Oct 28, 2013)

OK, found this stuff for bike frames - J.P. Weigles Bicycle Frame Saver Rust Inhibitor
Amazon.com: J.P. Weigles Bicycle Frame Saver Rust Inhibitor 4.75 oz: Sports & Outdoors

Also bought this at Lowe's Jasco Prep and Primer - it was recommended on a machine tool forum
Welcom to JASCO.com

Project is moving forward...


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## Gregory Taylor (Mar 29, 2002)

A couple of thoughts - 

- The dip tank that you are thinking of making sounds like it will be more trouble than its worth. Messy and a pain in the butt. Either get it dipped and stripped professionally, or just do what I do: after the paint is stripped, clean the metal with Lysol toilet bowl cleaner. If you can't find Lysol, look for one with hydrochloric acid. And make sure to use gloves.

Eight Tubes, Part 9: Finger Rippin? Good | The Wrecking Crew (Scroll down)

- I've used J.P. Weigle, and it is pretty good. It comes with all sorts of health warnings, etc., that are scary enough to lead me to conclude that I would contract cancer just holding the can, so I don't use it any more. I've taken to using boiled linseed oil. Works well, and it is so cheap that you don't have to scrimp when you dump it in. (Tip - I rustproof my frames AFTER they are painted. There are fewer issues with drippy framesaver contaminating a finish).

- I use acid-etch primer. Believe it or not, Rustoleum makes a dandy one. About $7 a can. I don't know about that JASCO stuff. You really don't need a rust "converter" if you take the rusty spot down to shiny metal via dipping or mechanical means. I'd also worry about it being compatible with my paint. If you are worried about the metal being pitted after you strip it, use a high-solid primer or spot putty and block sand it. This is simple - spray on a coat or two of primer, and then sand it smooth using fine grit sandpaper (start with 600) wrapped around a block of wood. If you still see pits from the rust spot, shoot another coat of primer and hit it again with the sandpaper. The concept here is that you fill in the craters with primer. If the pits are big, get a tube of spot putty, fill the spot, let it dry, and then block sand.


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## paredown (Oct 18, 2006)

Gregory Taylor said:


> A couple of thoughts -
> 
> - The dip tank that you are thinking of making sounds like it will be more trouble than its worth. Messy and a pain in the butt. Either get it dipped and stripped professionally, or just do what I do: after the paint is stripped, clean the metal with Lysol toilet bowl cleaner. If you can't find Lysol, look for one with hydrochloric acid. And make sure to use gloves.
> 
> ...


What GT said! (although I still use Weigle framesaver sprayed outside with a mask just for convenience...) Some people swear by T9 Boshield--originally an aerospace product although I have not used it.

I remember that poster!!!

We had a local Volvo dealer in Vancouver BITD who decided to jump on the bike boom and started importing Crescents, and sponsored a racing team that included some of the best Vancouver riders, including Bill Wild (who won the Nevada City race among others)...

We all had that poster up, and we all wanted to marry that Swedish girl!


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## Z'mer (Oct 28, 2013)

Thanks for the comments, tips, and local Crescent history. I also had this Crescent Swedish girl poster on my wall in 1975, but lost it somewhere over time. 
I worked for Riff's Cycle Center, a motorcycle dealer in PA who also decided to get in on the bicycle craze about 1974. They did so briefly, then backed out just as quick. They had maybe 20 or so bikes in storage and offered them to employees at cost, so I grabbed the biggest frame that fit me, a 25" (center BB to top seat tube) blue Crescent. It was pretty cheap by today's standards, maybe $150. or so.

Way back in 1975, I had fast riding aspirations, so promptly replaced the Stronglight steel crankset with a drilled out Sugino Mighty Comp unit, then Dia-Compe brakes, and SunTour Superb Cyclone F&R derailleurs, shifters. New handlebars and wheels with tubular tires completed the bike. It rode like a dream equipped like that for 38 years, and now I'm re-building it again. 

I think I pretty much got my money's worth out of this bike. Still love to ride it, but the new Felt Z4 is also fun, and my Raliegh M-60 churns through the really bad weather with fat tires.


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## headloss (Mar 3, 2013)

Consider what I said in another thread, if you want to take the anal approach... http://forums.roadbikereview.com/bi...-frame-help-rust-dirt-314750.html#post4508024

Jasco is good stuff, but only on surface rust. You can convert a top layer of rust to iron phosphate with a primer coating and still have active rust beneath it so you have to be careful that you aren't just basically painting over the rust with Jasco (or any other "rust converter"). The rustoleum rusty-metal primers are good, in that they have zinc in the mix which will help stop the rust cycle, but you're still better off removing the rust altogether if possible.


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## Scooper (Mar 4, 2007)

In the seventies, Crescent made a stainless steel bike in three component levels, the Mark XX, Mark XI, and Mark IX. They are classics.


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## Z'mer (Oct 28, 2013)

Thanks for the tips on steel rust, inside the frame and out. I've done a lot of rust repair and painting / body work on my old 1960's MG and 1970's BMW cars, so this topic is not totally new to me. I own a big compressor w/ dryer and Binks type paint spray gun, and typically shoot both lacquer and acrylic enamel. So not a novice to the refinish of steel. I've used DuPont steel etch products in the past, and all these boil down to be mostly phosphoric acid. 
I know Zinc Chromate primer used the be the best you could do, but not sure if they still allow one to use it. 

I usually sandblast to remove rust, but in the case of Reynolds 531 DB bike frames, I want to chemically remove the rust, so as not to weaken the frame, if possible. 

I'll post photos as I go forward, so hopefully others may get an idea of what is involved.


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