Prepping frame for rattle-canning

[brockers]

Do I tip Nitromors over it, or spend yonks rubbing down with abrasive before I give up and get it done by a professional?

While I'm here, can anybody give advice or provide links on good sprays to use and technique?

This was meant to be a cheapy project. I bought an old frame and it's already taken a couple of hours to separate the forks as the stem was welded in to the steerer (tried coke, PlusGas, Herculean force and swearing. Nada. Ended up hack-sawing through the stem). As I'll now probably have to splash out on new forks, I'm trying to keep the costs down. Wish I'd bought a Pompetamine frame now!

 

[Ian H]

I did one years ago. Nitromors, Jenolite, red lead base, wet & dry, 2nd undercoat, wet &dry, top coat (car paint), wet & dry, top coat again. It looked okay and lasted well, even after I wrecked the frame and it sat in a damp shed for years.

 

[gbb]

You can achieve an acceptable finish, the hardest thing is getting rid of the old paint. It may be that Nitromoors won't work, it didnt even touch the paint on a cheapie project i was doing, perhaps the wrong kind of paint or nitromoors.
Getting into the details on the BB etc is nearly impossible, i just took the worst off and left the difficult detail stuff and smoothed the edges between the two.
Acid Etching Primer is good stuff, it gives a really good base. Make sure you give the frame a really really good clean and degrease before applying paint.

 

[smokeysmoo]

I used Nitro Mors on an 80's alu Peugeot earlier this year. It worked pretty well on the bulk of the paint, but it did take a few applications and then I still had a fair bit of rubbng down to do as well.

A sanding wheel on my drill made light work of anything that was left, and I used a wire wheel on the drill to get into the nooks and crannies.

 

[bobg]

Tried all the options and even just taking the cost of paint removing products into account, £10 at a local shotblasters is for me the best and most cost effective method to prepare for painting. Unless you really want the satisfaction of spraying it youself, ( and I can weel understand that ) ,to buy a couple of tins of primer surfacer, some filler putty, top coat and lacquer, is going to cost the thick end of £30 and a backstreet shotblaster/powder coater will do the whole job pretty well for £30... at least they do round here.

 

[brockers]

Tried all the options and even just taking the cost of paint removing products into account, £10 at a local shotblasters is for me the best and most cost effective method to prepare for painting. Unless you really want the satisfaction of spraying it youself, ( and I can weel understand that ) ,to buy a couple of tins of primer surfacer, some filler putty, top coat and lacquer, is going to cost the thick end of £30 and a backstreet shotblaster/powder coater will do the whole job pretty well for £30... at least they do round here.

I think you're right and therein lies the rub! Do I really want to fork out for sprays and stuff and spend hours breathing in fumes and getting sore arms when I can get a single colour finish by Mario Vaz in South London, or glass blasted and lacquered at Armourtex in Hackney for around £50 (or powdercoated for £60)? I'm sure if I ask around I might find a car body shop who can blast and do a basic colour for less. Suddenly, that frame isn't quite the bargain it was meant to be though! *facepalm*

 

[tyred]

Nitromers made zero impression on the paint on my Raleigh Twenty. Sandpaper and a small electric drill driven wire brush for the awkward bits between the lugs.

 

[bobg]

I think you're right and therein lies the rub! Do I really want to fork out for sprays and stuff and spend hours breathing in fumes and getting sore arms when I can get a single colour finish by Mario Vaz in South London, or glass blasted and lacquered at Armourtex in Hackney for around £50 (or powdercoated for £60)? I'm sure if I ask around I might find a car body shop who can blast and do a basic colour for less. Suddenly, that frame isn't quite the bargain it was meant to be though! *facepalm*

Mind you, if you're set on a rattlecan job then you really don't need a total strip to bare metal. Providing the frame is abraded and surface rust taken back to bare metal then 3 coats of primer surfacer with a light rub down with fine emery paper rubbed with soap then about 3 coats ( 15minutes between coats ) of the finished colour will be ok. Although paint from those car spray tins does chip easily. About 3 months ago I did a quick job using 3 coats of the original black hammerite spray and left if for a couple of weeks to harden. ( no primer, no nothing, just the Hammerite) Remarkably it looks pretty nice even over the rusty chrome forks which were roughened up with a file before painting.

If you do go for a basic colour powdercoat then there's no reason not to smarten it up by picking out the lugwork using signwriters paint and a 0 grade water colour brush or a rigger, its easier than you might think and if you make a balls of it the just wipe it off using white spirit and try again.

Sorry for rambling on... bike restoration is my passion, I love it!!

 

[brockers]

Thanks for that bobg. I think you've persuaded me to give it a shot with hammerite. Gios Blue I reckon. If it ends up looking awful, then I'll admit defeat and take it to a pro.

Do you have any tips for extracting cold-welded alloy stems from steerer tubes? I'm wondering if heating the forks on the hob will work (reminiscent of Eugene Christophe in the early TdF who repaired his own forks in the forge so that he could finish the stage!), to take advantage of the differing expansion rates of alloy and steel? Failing that it could be a long (two day) immersion in PlusGas and then a few sound thwacks from below. If that doesn't work, then I'd guess the forks are junk.

 

[tyred]

Turn the bike upside down and fill the steerer with diesel and let it sit for a few days. Then fit an old front wheel that you don't care about, wedge the wheel into something so it cannot move, stand astride the frame and twist and pull. I've used this for steel stems but not sure how it would work with an alloy stem but it costs little to find out.

I wouldn't apply too much heat to a bike frame. As alloy expands and contracts faster than steel, there is a valid argument for popping it in the freezer overnight if you have a large freezer. If not, Tescos have large freezers

 

[brockers]

Just thought I'd let you know that I got the forks out!!! I soaked the steerer in PlusGas for two days, turned the forks upside down and whacked the stem from below with a masonry bolster.

I AM A GOD OF BIKE TINKERING !!

Now to remove the crown race....

 

[brockers]

Ta Daaa!!

I had a good week moneywise so decided to let Mario do it in the end! He had it shotblasted for me for pennies, and on going round to pick it up, I saw some of the other frames in the workshop and thought they looked beautiful, so after a few days of going through RAL colour charts, changed my mind about twenty times and ended up with a 'Benotto' silvery gold metallic with a classic white seat and head-tube.

I'm so glad I didn't try to do it myself! Well maybe the next frame...

 

[tyred]

Nice job