Protect chrome from bead blast?

Quoted message said:

I have an old steel road frame with a chrome rear triangle, chrome
lugs, and a horrible spray-paint job. It's nice enough to repaint, but
not so nice to deserve a big investment.

A local guy offered to bead blast and paint it cheap. The price is
right, but I'm wondering: how do I protect the chrome from the bead
blasting? Will tape (electrical? duct?) be enough? Is there a better
trick?

There's a special type of tape made for this sort of application. It's
called "masking" tape, and you can get it at any hardware store, usually
in a range of widths. It won't leave as much gooey residue as
electrical or duct tape.

Sheldon "Masked Marvel" Brown
Newtonville, Massachusetts
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Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

On Wed, 19 Jan 2005 11:17:27 -0500, Sheldon Brown

may have said:

Quoted message said:

I have an old steel road frame with a chrome rear triangle, chrome
lugs, and a horrible spray-paint job. It's nice enough to repaint, but
not so nice to deserve a big investment.

A local guy offered to bead blast and paint it cheap. The price is
right, but I'm wondering: how do I protect the chrome from the bead
blasting? Will tape (electrical? duct?) be enough? Is there a better
trick?

There's a special type of tape made for this sort of application. It's
called "masking" tape, and you can get it at any hardware store, usually
in a range of widths. It won't leave as much gooey residue as
electrical or duct tape.

Masking tape needs to be double-layered at the edges when used for
protection against beadblasting, or else the paper backing gets torn
up and the adhesive stays behind in a gummy mess. With to layers,
though, it's usually going to work just fine. I've also used 3M
self-sealing electrical tape (the stuff that bonds to itself instead
of using an adhesive) for edge protection in such instances with very
good results. Duct tape will work, but it's much worse than any of
the others about the backing disintegrating at the edges, and getting
it off afterwards can be more of a career than a job.

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Quoted message said:

I have an old steel road frame with a chrome rear triangle, chrome
lugs, and a horrible spray-paint job. It's nice enough to repaint, but
not so nice to deserve a big investment.

A local guy offered to bead blast and paint it cheap. The price is
right, but I'm wondering: how do I protect the chrome from the bead
blasting? Will tape (electrical? duct?) be enough? Is there a better
trick?

Yes, rubber tape will do the job. Try 3M Scotch 23. See:
http://tinyurl.com/6ps9l

BTW, this stuff will even work with shot peening. :-)

jeverett3<AT>earthlink<DOT>net http://home.earthlink.net/~jeverett3

On Wed, 19 Jan 2005 16:52:09 GMT, John Everett

may have said:

Quoted message said:

I have an old steel road frame with a chrome rear triangle, chrome
lugs, and a horrible spray-paint job. It's nice enough to repaint, but
not so nice to deserve a big investment.

A local guy offered to bead blast and paint it cheap. The price is
right, but I'm wondering: how do I protect the chrome from the bead
blasting? Will tape (electrical? duct?) be enough? Is there a better
trick?

Yes, rubber tape will do the job. Try 3M Scotch 23. See:
http://tinyurl.com/6ps9l

BTW, this stuff will even work with shot peening. :-)

It has the singular advantage that since it uses no adhesive, it
leaves nothing behind if peeled wihin any reasonable period of time.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

Thank you to everyone who replied. This was the result:

I covered the lugs in two or three layers of masking tape then trimmed
with a razor blade. I wrapped the chromed tubes of the rear triangle
in a single, overlapping layer of masking tape, just like you would
wrap handlebars with cork.

Unfortunately, the bead blasting ate through the single layer of
masking tape and pitted the chrome on the rear triangle. The lugs
(which were covered in multiple layers) turned out fine, so I would
definitely recommend multiple layers of tape for anyone else trying
this! Luckily, it was not a frame with significant value, so I'm
calling this one a learning experience.

Sam

zamley said:

Thank you to everyone who replied. This was the result:

I covered the lugs in two or three layers of masking tape then trimmed
with a razor blade. I wrapped the chromed tubes of the rear triangle
in a single, overlapping layer of masking tape, just like you would
wrap handlebars with cork.

Unfortunately, the bead blasting ate through the single layer of
masking tape and pitted the chrome on the rear triangle. The lugs
(which were covered in multiple layers) turned out fine, so I would
definitely recommend multiple layers of tape for anyone else trying
this! Luckily, it was not a frame with significant value, so I'm
calling this one a learning experience.

Thanks for the update. Did you get a nice well defined line where you masked and
trimmed?

I have a plated frame that has gotten a bit tatty in spots and want to keep what
plating I can while painting the bad areas so nothing rusts or pits any worse
than it already has.

Ron

The definition came out okay, though I would do some pin striping if I
were restoring the frame. First I cleaned the lugs in alcohol and
applied the masking tape. Then I rubbed the tape for a few minutes
with my thumb to create a good bond, especially at the edges. This
made the trimming easier too, because there was a well-defined place
where the lug ended. Use a sharp blade.

The problem came where the cross section of the lug meets each tube. I
couldn't get the tape to bend and stick to such a small surface area,
so the cross section was left exposed to be painted. This crevice
collected paint unevenly--a bit lumpy. I imagine a razor blade and
some patience could remove the excess paint and then you could pin
stripe with model paint or nail polish to get a uniform appearance.

Someday I'll have to visit a restoration shop and see how the pros do
this. Now I'm curious. In retrospect, with a nice frame I would be
happy to pay someone to do it right.

Good luck,
Sam