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Question about dichromate

Posted: Thu Jul 21, 2016 6:19 am
by RBMenz
I am new to holography and and looking into making some DCG holograms. I have seen videos of people wearing respirators and even working in a glovebox when handling either ammonium dichromate or potassium dichromate. I also read online elsewhere that this is not necessary. I was wondering if anyone had input on this topic. How do you handle dichromate?

Re: Question about dichromate

Posted: Thu Jul 21, 2016 1:05 pm
by Din
I think it's overkill. We don't use respirators, or even lab coats. One of us actually draws the gel over the plate, and she wears gloves because she has direct contact with the dichromate. I simply pour the gel onto the plate, so I have minimal contact and so don't wear gloves. Generally, we coat 9 plates every week, but, in past, we have coated 40 plates at a single coating session.

As far as developing is concerned, I don't wear gloves.

Having said this, it really is your own decision. I know all too well how people are nervous about chemicals, so if it makes you feel better, wear all that stuff.

Re: Question about dichromate

Posted: Sat Jul 23, 2016 5:04 am
by lobaz
It is like wearing safety glasses when working with a chainsaw. It is your own decision. Dichromates are highly toxic.
I know that my skin is quite sensitive to chemicals so I prefer to wear gloves. (I don't work with DCG, so I cannot tell anything about respirators and fume hoods.)


Re: Question about dichromate

Posted: Sat Jul 23, 2016 8:38 am
by admin_jsfisher
As Lobaz indicated, it is a personal decision.

Chemicals should always be treated with respect, but a full-face respirator seems way over the top. If you have concerns of inhaling dichromate dust during the measuring and mixing process, a simple paints mask I'd think sufficient. Skin contact can be avoided with ordinary vinyl or latex gloves (and they can be had for under $5.00(USD) per hundred).

There are other reasons to wear gloves when handling the plates, so I'd recommend them regardless of your concerns for the chemistry. Skin oils and such can easily contaminate and ruin your plates, so why not invest a few cents for a bit of vinyl. Also, when coating plates, the gelatin mixture is (1) sticky and (2) hot. Anyone who has mishandled a glue gun knows the danger of those two attributes in combination.

Re: Question about dichromate

Posted: Wed Jul 27, 2016 9:46 pm
by Steven
Personally I think the biggest risk to health is the accidental inhalation when handling the powdered form of AmDi or KDi.
However, both compounds are reasonably heavy and unless you are careless you are unlikely to have problems with airborne chemicals.
The key is to be gentle when handling such chemicals, pretend that you are handling gold dust.

I do dip and shoot, so my exposure risk is mostly limited to accidental inhalation when making up a sensitizing solution.
I wear a simple cheap nose/mouth mask when handling/weighing the powder over a suitable, easy to neutralize/clean work surface.
All utensils used are neutralized after use in either Ascorbic acid or Sodium Metabisulphite solutions, which are made up
prior to working with AmDi.

I only wear a surgical glove on the hand that I use to dip the plates in the sensitizing solution, I don't bother with a face mask when
working with the solution. The used glove is soaked for a few minutes in one of the above neutralizing solutions prior to disposal.

I usually dip my fingers in a neutralizing solution after handling dried sensitized plates, unless I'm putting the plate in rapid fix, as that
does the same job.

I agree with Dinesh. I think using such things as a glove box is overkill.
DCG has enough hurdles to overcome for a beginner, without having to make and use a glove box.


Re: Question about dichromate

Posted: Tue Aug 02, 2016 11:49 am
by Grayham

If it's OK I would like to ask a related question please.

What do you do with the water used to wash away the Dichromate?
Everything I have read on the subject says you can't put this down the drain.


Re: Question about dichromate

Posted: Wed Aug 03, 2016 9:07 pm
by holomaker
neutralized with either Ascorbic acid or Sodium Metabisulphite solutions, which are made up
prior to working with AmDi.


Re: Question about dichromate

Posted: Fri Aug 05, 2016 4:41 am
by Grayham
Thank you