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Message |
    
Dave Rivera
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 18, 2004 - 10:10 am: | 
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Hi,
I have a Tokina 100-300mm zoom that appears to have fungus(?) in the rear element (looks streaked
like a poorly mopped floor).
I was able to remove the rear lens assembly without any problems, but the 3 rear elements are encased in a single barrel(looks like an angle finder w/o the angle) with the two rear elements threaded/fitted together and sealed with an adhesive or locktite(?) on the outside.
I tried a couple of available solvents but had no luck. I did some research,in case this is "locktite",and came up with these possible solvents.
1.) Methylene chloride
2.) Methyl alcohol/Methanol (wood alcohol)
3.) Lacquer thinner(toluene) & model airplane gas (nitromethane) mixed together.
Has anyone had any experience with a similar problem and whether this is "locktite" or another adhesive/sealant?
Also, are most front elements on zooms removed by removing the lens barrel from under the focusing/zoom ring?
Any info,tips,suggestions,donations(?) would be helpful. I'm really stumped.
Thanks for your time,
Dave |
Stuart Willis
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 19, 2004 - 07:42 am: |
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Dave ....
If it is possible, use the finely honed tip of an Exato blade to break the surface of any visible shellac or sealant. Trickle a little Acetone into the joint. (As in several successive small drops picked up on the tip a screwdriver). Then leave it a while. Overnight is fine.
If it is a manufacturer's shellec / sealing agent, Acetone will nearly always do the trick.
If the root problem is corrosion (particularly galvanic corrosion) - then that's a whole new ballgame.
Stuart |
Dave Rivera
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 19, 2004 - 01:12 pm: |
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Stuart,
Thanks for the reply and suggestions. I tried some nail polish remover(acetone base) but I'll probably have to try acetone itself. I doubt this is a corrosion problem since the threads are completely sealed and dry. Lacquer thinner might be a try since it will dissolve both shellac and lacquer.
If I have no luck then I'll have to resort to the 3 solvents and hope for the best.
Thanks again,
Dave |
R COLLETT
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 11, 2004 - 03:50 pm: |
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HI,
NEED TO DIMANTLE AN EDIXA ISCOTAR
50mm LENS.
ANY IDEAS?
REGARDS, ROY. |
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