Torch a 531 frame?
 

I recently picked up a ladies Falcon Westminster. Without looking harder the date codes on both hubs, Maillard, indicate 1987. Happy 30th. The frame is butted 531 and the forks are 531. The paintwork is plagued with rust but none of it looks structurally bad. Previously on 18-23 frames I have been quite happy to burn the paint off with a meaty Blow Torch prior to a respray but AFAIK 531 undergoes some sort of heat treatment. I might be worrying too much but if I do go and Torch it am I likely to mess with the properties of the steel?

I would reccomend chemical stripping in this case. My opinion only, of course.

Media blasting is done with softer material like ground walnut shells. (than Sand)

Keep it below 1200 degrees. Better yet if there is a machine shop in your area they may have a sand blasting booth for this job.

@FBOATSB If in doubt probably does apply. I did use paint stripper, Tetrion, on the first bike I refurbished. Hours if not Days of fun getting into all the nooks and crannies.

@fietsbob That would be good if I had the equipment to hand. Otherwise I would have to outsource and at that stage may as well get it powder coated. The bike cost £12 and I can burn and rattle can it for £15, primer, colour and clearcoat. Miss out the burn and add paint stripper for a total of £20. Obviously I am going to overspend in order to bring it back to life but...

1200°F -> 650°C which sounds like brazing temperature? I do not expect to hit that in terms of burning off paint.

Reynolds Technology

Perhaps I should ask.

I'd be more concerned about toxic fumes from the burning paint than the heat adversely affecting the steel. What's wrong with media blasting?

I've never seen paint really clean up enough for paint prep with a torch. I think you'll end up sanding/blasting anyway. I always use a powerful chemical stripper, ZipStrip. I use it in an open garage when the temp is above 70*F and give it time to work. I use a wire brush to remove the stripper/paint, takes me a few hours to remove all the paint completely.

Here's what I always see after torching the paint, this is silver solder brazing temp, lots of burned paint hanging on real tight:

Nothing apart from the possible cost. Looking locally...

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It's not Apples and Pears but guess at £15-£30 then add on transport costs and I still have to paint it. £30 is new spokes, rim tape and inner tubes.

Point taken about toxicity. Ignoring the environment I burn at arms length and stand up wind.

Understood. However you were not really trying to burn the paint off. That was just collateral damage. If you set out to purposely burn paint off it goes through about three stages. Melts, Blackens, turns to Ash. Much of the ash drops off without provocation and the remainder gives up when attacked with a Dish Cloth soaked in White Spirit.

Some fettling is still required but apart from that it takes about 30 minutes to burn it down to bare steel.

I would not have a non bike experienced shop do any sand blasting on a nice lightweight steel frame. It is very east to remove significant wall thickness if the blaster dwells in one spot for too long. A lot of fab shops are not experienced with thin wall/gage products and often let their least costly (as in youngest usually) employee do the dirty work with little supervision. I would leave the sand blasting to the painter, they know about this stuff.


I would suggest using chemical methods to remove as much of the paint as possible first. This is far less harmful to the steel and reduced the amount of sand blasting done later. It is rather bad for one's brain, skin and eyes if you don't take proper precautions.


I have also burned off paint but the results still need further sanding or blasting. It can be real bad for the brain. I don't suggest it. Andy

531 is not heat treated so, within reason burning off the paint won't change it's properties. Reynolds made a heat treated premium version of 531 known as 753 and it did have to be protected from excess heat. Reynolds spec'ed silver brazing for it to keep the temperature exposure within it's limits.

No. It's steel sandblast it.

I would talk to an automotive machine shop. They often have chemical "hot tanks" for removing grease from large automotive parts. A few minutes in there will dissolve any paint without damaging the tubing.

It takes a lot longer than two minutes to dissolve paint.

Thanks for the replies. It looks like I am going to be investing in a bottle of goop, rubber gloves and brillo pads. Rather than asking Reynolds via the web form I've done so via an e-mail to what appears to be their technical support. If the request gets lost in the system I'll phone them. If I do get a response I'll add it to the thread.... Now I have to pick a colour. Stick to something close to the original or something off the wall. Decisions Decisions.

TI Reynolds is a Tube mill they really don't interact with end users, bicycle owners..

just factories and companies selling frame making parts to custom frame builder's shops..





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I had success with paint stripper years ago.

I live in hope but that's fairly powerful unless PR is low on the list. Assuming things do not go to plan can I quote you?

Bicycle shops are the closest service entry to the customer , the manufacturer is the furthest..

Generally the best customer service flows back up stream thru the bike shop.

Now if you want an 8x8x20 foot maritime container or truck full .

then you are the size of buyer manufacturers are usually shipping to ,
that is a distributor's niche, pallets full of cases on shelves in warehouses.



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Response from Reynolds... Sorry if it is a bit small.

Too many risks with flame and heat. You probably still need to invest in a pair of stout real leather gloves to protect yourself. Plus a respirator for the fumes.

For the frames I have stripped, I have always used paint stripper. Yeah, a bit more work, and there are still fumes to consider, but I would rather take the extra time than spend it in hospital with respiratory issues from burnt paint.

There are places that dip strip larger items such as window frames and furniture. I don't know if they exist around you, but it might be worth considering. You do have to ensure the inside of the frame is well washed out.

Is paint removal with a torch considered typical in the bike world? My first thought when stripping paint is chemically with paint stripper. Aircraft paint stripper works great on cars. The gung-ho restorer's way is to have the car dipped in a chemical bath.

No, it's not. Therefore all of the above posts recommending against it.

impressive! :thumb:

i can't even get my stock broker to reply to my emails. :)