What parts are safe to sandblast?

ParkRNDL · Nov 13, 2024

So I've got this X-53 boys' bike with horrible homebrew paint and lots of wrong parts, and I just stumbled upon a complete X-53 girls' bike with fair to good paint. At the moment my plan is to paint the boys frame and tank to match the two-tone blue paint scheme of the girls bike and switch the parts over. I know that the frame can be safely sandblasted, but what about the tank? I've read that sandblasting can be destructive to sheet metal and other thin parts. Can an old tank like this be safely sandblasted? Alternately, will aircraft stripper damage it?

KJV · Nov 14, 2024

I prefer to soda blast ; this takes all the paint off without messing up the metal.

Captain Awesome · Nov 14, 2024

KJV said:
I prefer to soda blast ; this takes all the pain off without messing up the metal.

+1 ^

Much less harsh option

ParkRNDL · Nov 14, 2024

now that you mention it, I have seen signs for a place near me that does soda blasting. I will look them up. Thanks!

Kevin B · Nov 14, 2024

Some blast with nut shell chips for a less harsh removal.
https://www.amazon.com/dp/B0CXPJ4SG...SLKJ1&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it_im

rickpaulos · Nov 14, 2024

That home brew paint should come off very easy. Even soap and hot water and a scotch brite pad will take it off.

Sand or shot blasting would destroy tins. Ice blasting would probably leave dents in that thin metal.

I bought a blaster and a box of walnut shell chips. Useless. I suspect my air home compressor wasn't powerful enough.

I've been using various non toxic orange type strippers with pretty good results. Very useful for small items. Not so great for full kitchen walls. There are some that you apply then wrap with plastic to keep the stripper from drying out. Others don't need the plastic. The claims of removing up to 7 layers of paint in 1 pass are bogus. A small tub will cost far less than any blasting service.

Kleen Strip with MTBE (the good stuff) is really hard to find anywhere anymore. Their less toxic version isn't so great.

Some Trek bikes are nearly impossible. I swear the finish is tougher than the aluminum frames. I've given up trying to strip those frames. Impervious to all chemicals. the rotostripper took chunks of metal out of the aluminum.

I used to use a ROTO-STRIPPER, as seen on TV. Fits in an electric drill so it only spins as fast as your drill goes. There are cheap knock offs that are prone to throwing wires so you have to very careful to hold it 90 degrees away from your head. Does a decent job on hard steel parts. Will go through tins. Won't get in to corners like most bike frames have. Will gouge mild steel. Will rip wood to shreds depending on the gauge of the wires.

Sanding. Not talking about old sheets of woodworking sand paper. Strips of emery cloth can take paint off pretty quick, including in tight corners. Not very good for flat surfaces. I recently bought a tiny hand held belt sander (1/2" wide belt) that's almost too aggressive.

Any time you have steel parts blasted, you need to prime them immediately, as in the same day. Don't touch the parts with your hands or greasy rags. I've had bike frames blasted and the blasters primed them minutes later. Primer isn't a sealer so you you need to paint your base coat the next day at the latest.

Kevin B · Nov 15, 2024

rickpaulos said:
That home brew paint should come off very easy. Even soap and hot water and a scotch brite pad will take it off.

Sand or shot blasting would destroy tins. Ice blasting would probably leave dents in that thin metal.

I bought a blaster and a box of walnut shell chips. Useless. I suspect my air home compressor wasn't powerful enough.

I've been using various non toxic orange type strippers with pretty good results. Very useful for small items. Not so great for full kitchen walls. There are some that you apply then wrap with plastic to keep the stripper from drying out. Others don't need the plastic. The claims of removing up to 7 layers of paint in 1 pass are bogus. A small tub will cost far less than any blasting service.

Kleen Strip with MTBE (the good stuff) is really hard to find anywhere anymore. Their less toxic version isn't so great.

Some Trek bikes are nearly impossible. I swear the finish is tougher than the aluminum frames. I've given up trying to strip those frames. Impervious to all chemicals. the rotostripper took chunks of metal out of the aluminum.

I used to use a ROTO-STRIPPER, as seen on TV. Fits in an electric drill so it only spins as fast as your drill goes. There are cheap knock offs that are prone to throwing wires so you have to very careful to hold it 90 degrees away from your head. Does a decent job on hard steel parts. Will go through tins. Won't get in to corners like most bike frames have. Will gouge mild steel. Will rip wood to shreds depending on the gauge of the wires.

Sanding. Not talking about old sheets of woodworking sand paper. Strips of emery cloth can take paint off pretty quick, including in tight corners. Not very good for flat surfaces. I recently bought a tiny hand held belt sander (1/2" wide belt) that's almost too aggressive.

Any time you have steel parts blasted, you need to prime them immediately, as in the same day. Don't touch the parts with your hands or greasy rags. I've had bike frames blasted and the blasters primed them minutes later. Primer isn't a sealer so you you need to paint your base coat the next day at the latest.

Very informative post. Thanks.

BMX Punks! · Nov 15, 2024

Not to highjack this thread but does anyone know what would be the best way to remove old chrome and get a frame down to bare metal, 100% ready for cold blueing? The softer material blasting sounds like it might be right but not sure if that leaves a sort of rougher finish like sand blasting does?

ParkRNDL · Nov 15, 2024

rickpaulos said:
That home brew paint should come off very easy. Even soap and hot water and a scotch brite pad will take it off.

Sand or shot blasting would destroy tins. Ice blasting would probably leave dents in that thin metal.

I bought a blaster and a box of walnut shell chips. Useless. I suspect my air home compressor wasn't powerful enough.

I've been using various non toxic orange type strippers with pretty good results. Very useful for small items. Not so great for full kitchen walls. There are some that you apply then wrap with plastic to keep the stripper from drying out. Others don't need the plastic. The claims of removing up to 7 layers of paint in 1 pass are bogus. A small tub will cost far less than any blasting service.

Kleen Strip with MTBE (the good stuff) is really hard to find anywhere anymore. Their less toxic version isn't so great.

Some Trek bikes are nearly impossible. I swear the finish is tougher than the aluminum frames. I've given up trying to strip those frames. Impervious to all chemicals. the rotostripper took chunks of metal out of the aluminum.

I used to use a ROTO-STRIPPER, as seen on TV. Fits in an electric drill so it only spins as fast as your drill goes. There are cheap knock offs that are prone to throwing wires so you have to very careful to hold it 90 degrees away from your head. Does a decent job on hard steel parts. Will go through tins. Won't get in to corners like most bike frames have. Will gouge mild steel. Will rip wood to shreds depending on the gauge of the wires.

Sanding. Not talking about old sheets of woodworking sand paper. Strips of emery cloth can take paint off pretty quick, including in tight corners. Not very good for flat surfaces. I recently bought a tiny hand held belt sander (1/2" wide belt) that's almost too aggressive.

Any time you have steel parts blasted, you need to prime them immediately, as in the same day. Don't touch the parts with your hands or greasy rags. I've had bike frames blasted and the blasters primed them minutes later. Primer isn't a sealer so you you need to paint your base coat the next day at the latest.

Thank you. Saving this for future reference.

rickpaulos · Nov 15, 2024

BMX Punks! said:
Not to highjack this thread but does anyone know what would be the best way to remove old chrome and get a frame down to bare metal, 100% ready for cold blueing? The softer material blasting sounds like it might be right but not sure if that leaves a sort of rougher finish like sand blasting does?

What kind of frame? There weren't many fully chrome frames (except in bmx). Many old school road bikes had chrome stays about 1/2 way up. Some Spaceliners were full chrome (poorly done) but have so many nooks it would very hard to remove.

Chrome over steel directly vs triple plate?

Triple plate is 3 layers: copper : nickel : chromium . Typical on many old Schwinns. The copper is meant to fill in the pits to make smooth surface. Good triple plate involves polishing each layer. When it starts to rust, it forms tiny pin holes and the rust erupts and spreads over the surface. 99% of what is visible is just sitting on the surface. Will often clean up well. The best chrome product was Chrome Glo but they stopped shipping a couple years ago. The wd-40 & aluminum foil will scratch the surface and leave countless mini scratches. Steel wool will leave bits of steel wool behind that will rust very vast. Brass or copper wool won't do that. Car wax as a final layer will seal the pin holes so the rust won't return. I've tried to clear coat chrome but it never comes out well. I you can see the clear, you used way too much.

The cheaper method of chrome directly on steel was used on cheaper bikes like AMF, Murray, etc. Tends to rust and flake off. I've used emery cloth to take much of it off. Beware that the small flakes of chrome are razor blade sharp so wear heavy gloves and face protection. I have a large bench grinder with a wire brush wheel (and cloth buffer) that I have taken poor chrome off with. Works for parts, not whole frames. A good face mask is needed to keep the tiny bits of chrome out of your eyes. A roto-stripper would take chrome off but not in the corners.

A car battery charger, the right solution and anodes may work to remove the chrome electrically. But some processes will remove brass used in frame construction so it depends on how the frame was built. I went to a pro plating company to have a Schwinn frame chrome plated but they said their prep process would remove the brass. Well there are only minimal brazed joints (seat stay to seat tube & top tube to seat tube) on a electro forged schwinn frame but they still wouldn't do it.

I think chrome is harder than steel so any blasting that can remove the chrome will surely affect the steel. A big plus of blasting is it can get into the tight corners.

ParkRNDL · Nov 15, 2024

rickpaulos said:
(snip)

Triple plate is 3 layers: copper : nickel : chromium . Typical on many old Schwinns. The copper is meant to fill in the pits to make smooth surface. Good triple plate involves polishing each layer. When it starts to rust, it forms tiny pin holes and the rust erupts and spreads over the surface. 99% of what is visible is just sitting on the surface. Will often clean up well. The best chrome product was Chrome Glo but they stopped shipping a couple years ago. The wd-40 & aluminum foil will scratch the surface and leave countless mini scratches. Steel wool will leave bits of steel wool behind that will rust very vast. Brass or copper wool won't do that. Car wax as a final layer will seal the pin holes so the rust won't return. I've tried to clear coat chrome but it never comes out well. I you can see the clear, you used way too much.

(snip)

This is all great too. I have some more chrome to clean up on this same bike project and will be trying brass/copper wool on some of it, and an oxalic acid bath on other parts. I did aluminum foil on the chrome part of the guard and it seemed to work well; I also sealed the chrome/paint on the guard with Turtle Wax.

I'm very happy that the paint on this bike, though worn/damaged in places, responds really well to the Turtle Wax. I'm picking away at the fenders and fork now.

BMX Punks! · Nov 18, 2024

rickpaulos said:
What kind of frame? There weren't many fully chrome frames (except in bmx). Many old school road bikes had chrome stays about 1/2 way up. Some Spaceliners were full chrome (poorly done) but have so many nooks it would very hard to remove.

Chrome over steel directly vs triple plate?

Triple plate is 3 layers: copper : nickel : chromium . Typical on many old Schwinns. The copper is meant to fill in the pits to make smooth surface. Good triple plate involves polishing each layer. When it starts to rust, it forms tiny pin holes and the rust erupts and spreads over the surface. 99% of what is visible is just sitting on the surface. Will often clean up well. The best chrome product was Chrome Glo but they stopped shipping a couple years ago. The wd-40 & aluminum foil will scratch the surface and leave countless mini scratches. Steel wool will leave bits of steel wool behind that will rust very vast. Brass or copper wool won't do that. Car wax as a final layer will seal the pin holes so the rust won't return. I've tried to clear coat chrome but it never comes out well. I you can see the clear, you used way too much.

The cheaper method of chrome directly on steel was used on cheaper bikes like AMF, Murray, etc. Tends to rust and flake off. I've used emery cloth to take much of it off. Beware that the small flakes of chrome are razor blade sharp so wear heavy gloves and face protection. I have a large bench grinder with a wire brush wheel (and cloth buffer) that I have taken poor chrome off with. Works for parts, not whole frames. A good face mask is needed to keep the tiny bits of chrome out of your eyes. A roto-stripper would take chrome off but not in the corners.

A car battery charger, the right solution and anodes may work to remove the chrome electrically. But some processes will remove brass used in frame construction so it depends on how the frame was built. I went to a pro plating company to have a Schwinn frame chrome plated but they said their prep process would remove the brass. Well there are only minimal brazed joints (seat stay to seat tube & top tube to seat tube) on a electro forged schwinn frame but they still wouldn't do it.

I think chrome is harder than steel so any blasting that can remove the chrome will surely affect the steel. A big plus of blasting is it can get into the tight corners.

I have an early 80s Japanese BMX frame.

us56456712 · Nov 26, 2024

I use phosphoric acid. Ph down in gallon. Diluted n a tank. If there’s any rust, even a tiny amount underneath the paint the paint will fall off with gentle hosing. This leaves a coat of iron phosphate that will result new rust from forming for a few days. I use a small homemade sand blaster to remove small areas of paint where there wasn’t any rust. If there’s paint is good then it will not remove it, just the rust. It I’ll badly discolor the paint.