Help: Need some #600 grit for making ground glass...

Discussion in 'Camera Building, Repairs & Modification' started by Denis P., Jan 22, 2013.

  1. Denis P.

    Denis P. Member

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    Hi,

    I'm trying to make a (better) ground glass for an old 4x5 reducing back I have, but I'm not quite happy with the results, compared to my other 4x5 camera (Horseman Woodman).
    It seems the grinding powder I have is too coarse...

    Now, I've checked locally for suitable silicon carbide (?), but all the suppliers I contacted sell minimum quantities which are waaaay too big (and expensive) for me. I've also checked online in USA and elsewhere, and managed to find a few sellers, but the shipping costs to Croatia are really expensive (orders of magnitude more expensive than the product itself...).

    So, I'm asking other DIY types here: perhaps someone has some #600 grit silicon carbide that they would be willing to ship to Croatia? I need a relatively small quantity (enough to make several GGs), which would most likely fit into a standard-size envelope (3-4 ounces, i.e. about 0.1 kg at the most should be more than enough, I guess...).

    Of course, I'm willing to pay for the material and shipping - and I suppose the shipping should be much less than the standard $45-$50 the online sellers are asking :smile:

    I'm not sure why they charge so much for shipping: perhaps the silicon carbide requires some special forms to be filled or something? It's not as if it's a hazardous substance, AFAIK....

    Thanks in advance,

    Denis
     
  2. E. von Hoegh

    E. von Hoegh Member

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  3. Denis P.

    Denis P. Member

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    Thanks, but I'm generally wary of web sites which require me to register just to be able to see what they offer.
    Even after registering, all I was able to see was a spinning circle....
    So, thanks, but that didn't help.
     
  4. jeffreyg

    jeffreyg Subscriber

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    Denis,

    I'm not sure how you intend to get an even abrasion but you might consider a dental supply or your dentist for pumice, carborunduim or aluminum oxide powders which should be available in different degrees of coarseness. There are airbrushes that are designed to spray abrasives as well. Glass can also be etched with hydrofluoric acid.

    http://www.jeffreyglasser.com/
     
  5. E. von Hoegh

    E. von Hoegh Member

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    Register? Something is wrong, there is no registration neccesary. McMaster Carr is an industrial supply company, I've been buying from them since the late 80s.
    Clicking on the link I posted should take you directly to the abrasives section of their online catalog.
     
  6. Denis P.

    Denis P. Member

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    Perhaps they have a different policy for overseas visitors?
    Besides, I'm using Linux, and my browser is definitely NOT IE... This sometimes poses problems with IE-optimized sites. Nevermind - thanks for the suggestion.

    Anyway, I've got some other suggestions, particularly from Ian, so I might be able to get some from ebay, after all - I managed to find some sellers who do not charge an arm and a leg for shipping :smile:
    My initial search was rather restricted somehow, chaning search terms on ebay yielded more results, so I might find something there, after all.

    Thanks everyone for the suggestions!
     
  7. mgb74

    mgb74 Subscriber

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    Try some rock polishing grit. Comes in various grit fineness.

    But loose powder in an envelope probably not a good idea, given biohazard concerns. A bit in a film canister or sealed plastic envelope shouldn't be an issue.
     
  8. NormanV

    NormanV Member

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    Try this supplier on Ebay item number 251208546401. I have bought from them, they supply worldwide.
     
  9. oldlincoln

    oldlincoln Subscriber

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    This is re-packaged Clover compound. the grease base helps the cutting and washes away with soap and water.
     
  10. Whiteymorange

    Whiteymorange Subscriber

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    Hi Denis,
    I've bought grit from Gotgrit.com and was quite pleased with the service. I don't know about overseas shipping.

    Good luck!
     
  11. E. von Hoegh

    E. von Hoegh Member

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    Denis,
    If you have an auto mechanic's supplier in the neighborhood, see if they have any fine valve grinding compound. There are two basic types, grease based and a water soluble base.

    I'd have mentioned this sooner but I was distracted.:redface:
     
  12. BMbikerider

    BMbikerider Member

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    Years ago I made a ground glass screen for a Medium format camera by getting two pieces of glass the right thickness and the same size and actually rubbing them together with fine white quarz sand between the sheets. A little water was added and the whole process only took 30 mins. The biggest problem is getting it even at the edges. This med format Rollie look-a-like still has one of the screens I made and it is working fine (although not very often now).
     
  13. Marek Warunkiewicz

    Marek Warunkiewicz Member

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  14. John Koehrer

    John Koehrer Subscriber

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    Any astronomy hobbyist site should be able to direct you to telescope making supplies.
     
  15. rorye

    rorye Subscriber

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    I'd be happy to send you some of mine, just PM me.
     
  16. Loren Sattler

    Loren Sattler Subscriber

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    Any motor rebuilding shop (or factory maintenance shop) will have a small can of lapping compound around which is a fine abrasive paste used to polish or lap valves and other finely machined mating pieces to improve the fit or whatever. Perhaps they would give you a little for your project. Clover Lapping Compound (mentioned above) is a popular brand in the US. It may be available everywhere?
     
  17. Loren Sattler

    Loren Sattler Subscriber

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    Dennis, another thought would be very fine 3M sandpaper used to repair auto paint. Any supplier that sells auto paint will carry sheets ranging from say 1000 grit up to about 2000 grit (at least in the US). Again, it is not an expensive product. Here you can buy 1 small sheet at a time for say $1.00.
     
  18. mjs

    mjs Member

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    If you can find a local amateur telescope maker who grinds their own mirrors they could probably help.

    Mike