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Opppps - Hasselblad Focus Screen


abintraphoto

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I was hesitant to post this on the forum due to the tone of recent

feedbacks but decided I was big enough to admit ignorance and someone

else might learn from my mistake - let those who have led a mistake

free life cast the first stone ..... In CAREFULLY cleaning my

Accumatte split-prism focus screen the "stuff" from inside the can of

compressed air came out on the screen (I was holding the can upright).

I've tried warm soapy water but can't get it off .... If the screen

is ruined anyway, perhaps WE could all use it to experiment with

different cleaning agents to see if anything works (i.e.

Alcohol ? ... Bourbon ? ... Lens cleaning solution ? ... Dom

Perigon ? ... Brake fluid ? - just kidding) I envision soaking it in

something vs. rubbing it in any way. Your suggestions are

appreciated. It would seem I have nothing to lose .... I have the

original screen so it's not a total loss but close.

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Try Swafegaer, Petrol or Bleech, or soak in hot soapy water - at what temperature does the crud or the screen soften?

 

If chemical attack fails try getting physical - scrape with a sharp implement or polish with car paint cutting compound.

 

I advise you to take the screen out of the camera first, and initially test each technique on a small area at the edge!

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as you now know, you really shouldn't ever clean the underside -- the part with raised whorls (if the compresses air grunge was on the smooth side it would have just wiped off). my advice is to soak the screen in soapy water overnite. the next morning, if all is not clear, you mite try stroking with a camel hair brush dipped in the same water. brush gently.
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Oh by the way .... Sorry if I sounded a little stuffy with my opening.

I kicked myself enough last nite and I'm over it now ... ready to move on. This would be a great thread to interject some humor so please fire away - probably the best medicine anyway !! So let's have fun with this. One stipulation - let me know if your not serious by saying "just kidding" .... otherwise I may end up running this thing thru the washing machine with the whites and delicates if you tell me its worked for you !! .......... (-;

Going out to the car now - think I may still have some corn liquor stashed out there.

 

Ken,

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Why not ask Hasselblad? They sell and service the thing. As I recall, there is someplace on the www.hasselbladusa.com web site where you can email the technical support folks. Gives you a link to their service department. My guess is that they have seen it all, possibly even this condition and can tell you if there is a magic solution....
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One more note - the chemical listed on the can is - Tetrafluoroethane - if there is a chemist in the group maybe this will help.

 

I'm also reading the First Aid notes .... "Move to fresh air.Give artifical respiration if necessary.Flush with water.Induce vomoitng."

 

My wife tried all these things but I'm still kicking myself ... (-;

 

Ken,

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Update - I have sent an opppsmail to HB New Jersey and am hoping to hear from then soon ...I also had a lengthy phone discussion with Bill Maxwell in Georgia - very interesting fellow - about a 40 minute call ... He said a lot of things but one item was that the 2-piece construction is a glass layer = .030" thick & plastic layer = .050"

thick - point being the glass is very fragile. He never uses canned air (NOR DO I ANY LONGER) so had no experience removing the gunk ...

It appeares the gunk was blown inside the 2 layers ....

 

As a side note I have located the largest bulb blower known to exist !! You take a deep breathe ... place your palms over both ears ..... and push in sharply ........ the less gray matter you have, the more effective the blower - obviously mine is VERY effective........ [-;]

 

Also, as an alternate use for the canned air - it seems to annoy the cat a great deal .... hang on here he comes - Pssssttttttttt

 

Ken,

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The Fresnel lens of the focussing screen is usually made of plastic; hence the sandwich construction mentioned by a previous poster. If you have managed to get propellant (which will be a fluorinated hydrocarbon) from the compressed air can on the plastic underside of the screen then I am sorry to say that you probably have ruined it. This may well have acted as a solvent for the plastic and at least etched the surface. It may still be usable but I don't think you will get rid of the blemish. At least it is a user replaceable part.
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UPDATE #2 ...

Initially soaked the screen in warm soapy water - used the plastic case it came in - for about 12 hours with no change .... Pretty much gave up and let it sit out in the dryed out case after that .... It seems the Hasselblad Gods have smiled on me and after 48-72 hours it has almost completely cleared up on its own !! .... Except for the spec of dust that compelled me to clean it in the 1st place !! I've made peace with this spec of dust now and I've grown accustomed to its face .... Still like the ultrasound idea though.

Never heard back from HB in New Jersey so I'll try Sweden next time - Thanks Piotr ......

 

Ken,

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Ken,

 

It�s easy to disassemble and to clean the screen of the sandwich design. There are two steel frames: the outer and the inner one, the first has bent springing edges that hold the inner frame. Press slightly on the plane of the top screen near its corners and you�ll get both frames and screen plates apart with a click. Then you can reach and clean both inner surfaces with a pure spirit, just drink 2-3 ounces and exhale on a surface :?), then wipe it in direction from around the center to the edges with a cotton wool tampon or special napkin for cleaning optics. The bottom plastic plate of screen looking up has very fine matte structure and Dohden�s wedges, don�t touch it with fingers and wipe very slightly and carefully. Use cotton gloves when working. If your screen is one-peace made clean its surfaces same way. Good luck. Victor

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Ken, give the NJ guys a chance, the reply from Sweden didn't come immediately either!

 

You're so impatient. Remember, you got that Hassy to do what? TO SLOW YOU DOWN!!!!

 

Enjoyed your story. I feel lowly and unimportant using just simple methods to clean dust from my screen, and I could apply so many great techniques.

 

:o)))))))))

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Update - Epilog .....

Tha NJ Hasselblad guys must read the forum - They contacted me right after my posting and we have had 3 email exchanges since. They tell me (after double checking internally) that alcohol WILL NOT damage either the glass or plastic layer. That I should gently apply it sparingly to either side of the screen but not to soak it in anything as the liquid could get between the layers. Unfortunately, I believe the 'propellant' was blown between the layers by the compressed air. They also suggested I send it in for evaluation .... They've been very responsive.

 

I'm now considering a combination of the suggestions from Victor and HB New Jersey ....... Try the 2-3 ounces per Victor's post and send myself in to New Jersey for evaluation (Hic).

 

Thanks Guys ....... Ken

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  • 3 weeks later...
  • 11 months later...

Hello

 

I too completely stuffed my focus screen trying to clean it so don't feel bad about it, here is a cautionary tale though.

Having tried warm soapy water, compressed air, blower brush and all other benign methods I too moved to chemical attack.

Purely by chance I figured out how to delaminate the focus screen parts and proceded to soak the plastic part in Isopropanol Alchohol.

After a few moments a white deposit formed on the frensel surface and by the time I had rinsed the component in warm water irreversible damage had occured.

This leads me to think the plastic part is an acrylic so when I use the term CHEMICAL ATTACK that is exactly what happens.

If there was an upside to this tale? it is that I am now the proud owner of a small square NINJA DEATH SCREEN which I throw around the house during moments of frustration.

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