Cold working cast glass

Sandera · January 14, 2012, 08:53:45 AM

Oh - I'm in such a quandry! I want to coldwork a pyramid (about 7 x 7 x 7 cms) which has come out of the mould very rough. However I also have a couple of pieces of cast glass that are contoured that I also want to polish up without losing the detail.

I don't want to waste my money by buying something that can't handle both jobs or that will be too small to handle bigger pieces. Can anyone recommend a good all round grinder and polisher that has this much flexibility but won't break the bank?

I've looked at the Swap Top flat grinder/polisher but I think I've ruled flat lap grinders out as being too expensive or too small. My eye has now been caught by the electric handheld grinders/polishers.

www.hisglassworks.com/cart/Flex_LE_12_3_100WET_Variable_Speed_Grinder_Polisher_p854.html

It's pretty reasonable as far as pricing goes. Has anyone opted for something similar?

Thanks

Sandera

Pat from Canvey · January 14, 2012, 09:30:10 AM

Don't forget that Customs and VAT costs will bump up that price.

Sandera · January 14, 2012, 09:39:22 AM

Quote from: Pat from Canvey on January 14, 2012, 09:30:10 AM
Don't forget that Customs and VAT costs will bump up that price.

Thanks Pat - I've found that to my cost before

However I'd probably also look at UK suppliers if it looks like a promising bit of equipment.

Zeldazog · January 14, 2012, 10:41:41 AM

If you're wanting to cold work something up to a polish, be prepared for literally hours and hours and hours of work....

And as well as customs, you might need to buy a power conversion unit thingy (I am sure it has a proper name) - as it doesn't show an option, I presume its only going to be 110v...I know sometimes the savings on importing something, even with all those costs are worth it but its probably something extra you will need to consider

As for the tool itself, looks interesting!!

Flyingcheesetoastie · January 14, 2012, 11:17:48 AM

This tool is meant for much bigger pieces that you can't hold on a bench machine, I think you will really struggle to use this on a 7cm piece as you would need to clamp it down yet still leave an area exposed to polish. Coldworking is one of these aspects that you just can't really do cheaply or without hours of hand grinding! Personally from what your describing you want to do, I would look into a lathe which uses wheels or drums to grind and polish, what you can get is a brush wheel that will polish but not remove surface detail.

Sandera · January 16, 2012, 08:15:19 PM

Okay - so i'm still trying to find the best bit of equipment and suddenly, like a light bulb, the solution seems to be getting closer and I can't think why I didn't think of it first - a wet belt sander/polisher!!! Now must find the best size for the right price!

Flyingcheesetoastie · January 16, 2012, 10:37:38 PM

They are sometimes called linishers if that helps. I think Gryphon so a benchtop one.

Glyn Burton · January 16, 2012, 11:00:36 PM

I have a Gryphon belt linisher, its OK but not great. I also have a Makita polisher 110v water cooled which is fantastic for bigger bits which can be held down firmly, I wouldn't fancy trying to hold the 7cm pyramid to polish it.
I agree with the other post, cold working is expensive or time consuming or both, in the end I bought a lap which was expensive but does the job really well saves time and effort. Tools are tax deductable so you could lay it off against your tax bill if you are working professionally but for a hobby worker its a big outlay.
You also have to consider if it takes you 3 hours to polish something it puts 3 hours of wages on the piece even if you pay yourself the minimum wage its still going to put £20+ on the cost of the final piece, are you going to recoup that cost in the final price? if so then it will be worth doing if not you may be better off leaving it alone and doing something else.

Flyingcheesetoastie · January 17, 2012, 12:05:13 AM

Hence, why I have a 12inch flat lap grinder and also design cast pieces to only require the minimum amount of coldworking, usually the reservoir and the opposite end only. My lap was £2000 including discs, shipping and tax back in 2009 and have since bought two replacement discs as a couple get more used than others and I also work with more soda glass on it now than the crystal.

What width are the belts on your Gryphon, Glyn?

Glyn Burton · January 17, 2012, 11:19:23 AM

I fully agree with you, design to minimise the amount of cold working, its a pain in the bum and eats your time. I have the 12 inch lap its a great tool but better if you don't have to use it I got mine from Minereaux et Machine in Paris who have a fantastic range of cutting drilling and polishing equipment.
The belts on the Gryphon are 4inches wide, the machine can be tricky to set up but will do the job if slowly. I think I will have to buy a set of polishing wheels at some point, I saw a cracker the last time I was at MetM (the chap there will let you have a play before you buy) but I have no pressing need at the moment.

Sandera · January 17, 2012, 12:54:48 PM

Thank you for your replies. You've given me a lot of really good advice and I appreciate the time you've taken to respond. I think what you've said may very well affect what I try to achieve in the future. So far I've managed to avoid too much coldworking and will continue to do so.

I would like to find a way of grinding and polishing the 7x7x7cm pyramid though. Do you think the Swap top (8" version) would be able to cope?

If not - it's back to the drawing board

Moreton · January 17, 2012, 06:00:09 PM

Hi Sandera, Yes the 8" Swop Top should be fine ...just. The 6" version won't have enough free grinding area due to the centre bolt. They both only use the outer band of grit. If you can afford the Glastar B41 8" flat lap life would be considerably easier as there is no centre bolt but the costs are considerable. £1650 from Warm Glass compared to the Inland Swop Top complete for £466 or £326 for the flat lap only.

Pete

eta Warm Glass now stock the Flex water cooled angle grinder at £466. Without disks. Similar to the HISS Glassworks one.
It is also possible to use a bench disk sander, the disk is vertical, but you would have to arrange water feed to the vertical surface. It has been done but the risk is that water can enter the motor if adequate protection is not arranged. Not for the amateur to risk

Moreton · January 17, 2012, 08:23:31 PM

Hi again I've just found this tut. looks good ,free but Miriam would appreciate a donation. I sent her €3 for a "beer". Well worth downloading as she does explain the lapping process with clear pictures. All in English.

http://www.miriamsteger.com/blog/tutorials/lapping-beads-kralen-slijpen-tutorial

Pete

Flyingcheesetoastie · January 17, 2012, 10:47:57 PM

I've gotten diamond tools and drills from DK Holdings here in the UK too. Great guys who will also alter anything you need from them in a different shank etc.

Personally if you have 1 pyramid to polish and are not planning on doing anymore, I would get a quote for someone to do it for you! Or see if there's someone with a decent flat bed polisher near you who would hire it out. What's it made from as that will make the difference in terms of time. Also be aware that any polishing will take away material so it will never be 7cm x 7cm x 7cm again!