How to Polish Sink Interior

[Glenn Randle]

Do any of you know how the stone sink manufacturers are grinding & polishing the interiors? I've been thinking about casting sinks and understand the hot/warm part of it, but wouldn't know what to do after it cools down.:rolleyes:

I'd love to see what kind of wheel or head and the machine that is used if anyone has a photo or link.

thanks,
Glenn

[Wes Hunting]

We have one of these,
http://www.protoolsexpress.com/mk-diamond-polishers-grinders.html
works great on curved areas. The pads are flexable.

[Glenn Randle]

Thanks Wes,

I guess that would be the best tool to try first. I have a Makita poisher, but figured it wouldn't produce a smooth enough finish. You're probably right though, it would be the first thing to try. Probably mounting the sink onto a slowly rotating turntable would help produce a more even polish.

Sometimes I "over think" a project and it just gets me bogged down before it even gets off the ground.

[Wes Hunting]

These grinders do take a long time to produce a good quality polish.
Use a 60 grit pad, 100,220,440,800,1000 then cerium.
whew!

[Rosanna Gusler]

can you consider kiln forming your blank? you will get a fire polished interior that way. rosanna

[Glenn Randle]

Originally posted by Rosanna Gusler
can you consider kiln forming your blank? you will get a fire polished interior that way. rosanna



I do plan to try making some that way, but it seems like a thick cast sink would be an impressive & unique design. Somebody's probably already making them, but I haven't seen any yet. I'm just looking for a niche to fill.


Glenn

[Garner Britt]

Glenn,

If the casting has the smoothest possible finish to begin with, skipping the early grits would really help to avoid distortion.

Here the website for the company that makes those wheels I showed you yesterday.

http://www.polpur.cz/

They seem to flex enough as to remove 220grit scratches without altering the shape. They are also really easy to profile. I think the optics of a perfect hemisphere would be really cool.

Then again, we could probably build a robot.....

garner

[Brian Blanthorn]

Ur probably better acepting some polished texture n designing it arround that

So think of

Good as comes out of casting

Or


Work on it so smooth n mayb slump a bit n get fire polish

Unless ur realy crazed n rich I would avoid polishing

A nice textured fire polish can look realy good

Even if U do get a good polish can B a bit boring

As I assume ur a glass blower U could combine the technolgies mayB sand cast then work on it a bit cold then fire polish / slump

U will need a smmoth high gloss fire polish

Brian

[Mike Aurelius]

Contour shapes (ridges for example) are really cool, but be sure they run towards the drain, not in a circle around the drain as they would catch debris (like toothpaste for example)...

KISS of course!!!

[Glenn Randle]

Garner,

Those dense foam abrasive wheels are impressive. I look forward to trying yours out.

I think Brian & Rosanna make a very good point that it would be best to figure out how to avoid polishing, as much a possible.

I don't think I'd be capable of pushing a blown bowl into a mold full of hot ladled glass. Mainly because the size involved, but also I'd think the mass of molten glass would deform the blown shape anyway. Maybe I'm wrong?


So, assuming I want to cast/pour over an interior mold of a sink, what mold material would produce the highest surface quality?

Any other ideas...I'm just brainstorming.


thanks,

[Rosanna Gusler]

you could hot cast some blanks, in sand or whatever, coldwork any edges as needed and kilnform to shape. the vessels in the pics are sink worthy, 6/8" thick float. you can shape with texture in or out. rosanna http://wanchese-art.blogspot.com/

[Glenn Randle]

Rosanna,

I like that technique, those are beautiful. How much relief can you get in the exterior surface before causing problems in the slump process? I'd assume the slower you go, the better the results?

[Rosanna Gusler]

for a simple drape like those candle shields, 1/2" but those are formed on fiber over ss so are more forgiving. the bowl shapes are more difficult because there is sliding and compressing into the mold. smooth kilnwash and low and slow is the keu. heavy glass forms pretty easy though. gravity is your friend. 1240f for a top soak of 1 hour. keep in mind these are float and so a stiff glass. not too hard to dial in though. 1280f for instance is too hot with the same sched. i might tweak it cooler next firing. rosanna oh yea in a 4'x8' bell fiber top, brick and sand bottom top elements.

[John Riepma]

I've seen people spin casting into a sand mold that is mounted on a potter's wheel. The mold was made in the bottom half of an old 20# propane bottle, hot glass ladled in and the wheel turned on and when it set up enough to be lifted out it was placed in the annealer. I saw the finished product(s) and they were pretty cool - rough sandcast texture on the outside and smooth glassy surface on the inside. For a big'un you'd have to ladle pretty quick, then turn the wheel on to desired RPM to get the glass to "flow" up the walls, which have to have some slope to them.

[Brian Blanthorn]

Originally posted by Rosanna Gusler
for a simple drape like those candle shields, 1/2" but those are formed on fiber over ss so are more forgiving. the bowl shapes are more difficult because there is sliding and compressing into the mold. smooth kilnwash and low and slow is the keu. heavy glass forms pretty easy though. gravity is your friend. 1240f for a top soak of 1 hour. keep in mind these are float and so a stiff glass. not too hard to dial in though. 1280f for instance is too hot with the same sched. i might tweak it cooler next firing. rosanna oh yea in a 4'x8' bell fiber top, brick and sand bottom top elements.

A further refinement on this technology is a fast, then slow creap up

A radical alternitive is

Zap n Blastem tm

Above aneal mayb soak there a bit if thick / uneven
turn on full a only look through bung hole using a beam light checking 4 fire polish then immidiatly crash cool

If side elements baffle the mould

U will get cold glass but a flash fire polish on top reducing the mould marks

Related technology is

Skeleton Mould tm

This is where rather than a "mould" U have contact areas mayB just at rim or in round points arround rim which could then B polished out

Interesting methodology with car windows is a sophisticated counter weight system where glass is forced 2 bend at relativly low temps really cunning is this one

If U wanna bit more info on some of my Cheetin Technology try a search over warm glass on

Skeleton Mould tm

Zap n Blastem tm

Fiber Dizer n Wash tm

There is more

U could sand cast ( or watever flavour U prefer ) with hot glass technology mayB flame the top so smooth

Then possobly flat grind top to 220 then sandblast to 280 then slump this wil give a very silky surface

Brian

[Sandy Dukeshire]

we made one by casting into a ring on graphite, when it cooled enough we played pull the rug out with the graphite and let the pancake rest on the waiting drop ring to sag, and used a torch at the same time to smooth things up/ help control the falling glass then boxed up. coldwork only to make drain hole. they were never "perfect" but were very cool. featured on the tv show Find! installed in a newport mansion. no credit for the artist, only the designer of the kitchen.