distorted Jenaval DIK filter

[Changhee]

Dear all,

I have a jenaval microscope.
I guess my drum filter is distorted between glasses.
I can't find solutions and spare parts.
please, help me

[Changhee]

dear  everyone,

I separated the DIK(jeneval) filter using heat gun( BOSCH GHG20-63 with digital temp. control), which has a balsam issue.
So far, it seems to have been a successful separation.
However, there is one concern issue. It's how to attach it.
I can't get balsam fluid and I don't have equipment and technology to attach it with a high transparent urethane resin.

I'm asking you which of the two methods should I dig into to solve it.

[Changhee]

dear  everyone,

I separated the DIK(jeneval) filter using heat gun( BOSCH GHG20-63 with digital temp. control), which has a balsam issue.
So far, it seems to have been a successful separation.
However, there is one concern issue. It's how to attach it.
I can't get balsam fluid and I don't have equipment and technology to attach it with a high transparent urethane resin.

I'm asking you which of the two methods should I dig into to solve it.
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[Michael L.]

Hi,

why not using UV bonding resin from Loctite or similar, hardenig with blue light or sun light.

Best

Michael

[Changhee]

Dear Michael,

As a result of inquiring with a resin company, I heard that there is no Yellow mutation from UV light
when air bubbles are removed with a vacuum chamber and urethane resin is used.

I found it, but it's too expensive.

Crystal Clear 204 (0.86kg)

Best
Changhee

[Changhee]

Dear Michael,

I have no experience using resin.
Can you recommend a more specific resin product?

Best
Changhee.

[olaf.med]

Hi Changhee,

In my opinion, the perfect way to repair your DIK-component is to use a thermoplastic resin such as Canada-Balsam (not as fluid, but in solid state) or a similar substance. These resins melt at about 100°C and are easy to apply. The great advantage is that you can separate the parts easily and without any risk if something went wrong. I would never ever use a UV-light hardening substance for such an issue.

If you have problems with the procedure, I can offer my help.

Best,

Olaf

[Changhee]

Dear Olaf,

Thank you for your comment.
I agree with you.
According to your advice, I purchased Canadian balsam.

http://swscience.net/product/detail.html?product_no=9081&cate_no=129&display_group=1&cafe_mkt=naver_ks&mkt_in=Y&ghost_mall_id=naver&ref=naver_open&NaPm=ct%3Dkzs7fr6w%7Cci%3D3b1078776b04045054f8fce8e06679f52ff8d407%7Ctr%3Dslsc%7Csn%3D270836%7Chk%3D50608bd938980ec2170e72cea0751cbe3a2e0369

How long does it take for the filter to stick on?

Best,
Changhee

[olaf.med]

Hi Changhee,

Unfortunately I'm not able to read the description of this product written in Chinese. I hope this is the original hard and brittle resin and not any solution in xylene or other solvents. If it is the pure substance, it will get soft by heating and finally melts at about 100°C. It will be hard again immediately after cooling down. You need some experience with that stuff. Heating too far above the melting point will produce small bubbles which are hard to remove.

The solution of Canada balsam will not work for this application!!!

Best, Olaf

[Changhee]

Dear Olaf,

Can you tell me what Balsam products you know?
I can purchase through Amazon or eBay.com web site.
And, I live in Korea. ^^

I found this product on eBay.
https://www.ebay.com/itm/162580633469?var=463887248728&hash=item25da8f977d:g:9pIAAOSwKOZcReBb

Best,
Changhee

[Michael L.]

Hi Changhee,

the argument with balsam make sense as it will be removable. I would use Conloc UV-665 and a LED light source with around 368nm. The argument for this is that jou can adjust the optical elements as long as you are operating with low light intensity. With vacum you can remove bubbles and if ok than apply the light, ready within a few seconds but not removable.

Best,

Michael

[Michael L.]

Hi Changhee,

As Olav mentioned you need the dry resin, it is hard to find. The product you are showing us here is fluid.I could send you a smal amount: Cana Balsam extra pure, dried to glas hardness for microscopy Riedel De Haen. I guess the issue will be shipment of obscure material to your country.

Best

Michael

[Rene]

Hallo Olav, Michael, verzeihen Sie mir meine Unwissenheit, aber was ist der Unterschied, wenn Sie den aufgelösten Kanadabalsam bei 100oC trocknen lassen?

Danke,
René

BTW, ich verwende UV-Kleber (Methacrylat) für Deckgläser auf Kunststoffzylindern. Wenn sie brechen, lege ich sie in 50-70%igem Ethanol mit etwas Spülmittel ein. Nach ein paar Wochen lassen sie sich dann zur Reparatur ablösen.
Der Brechungsindex von UV-Kleber könnte natürlich nicht ideal sein.

[Changhee]

Dear Michael,

Thank you for your help.
I want to experiment with it myself, and I'm going to dry Canadian balsam using a hot plate machine with stir function.
If the experiment continues to fail, please give me advice.

Best,
Changhee

[Apochromat]

Hello Changee,

also from my side, please only use Canada Balsam "Glashart" here as Olaf Medenbach recommended! Why?

Two reasons: It is a reversible process and the Canada Balsam "Glashart" hardens fairly immediately after cooling. If Canada Balsam "Liquidum" (= Canada Balsam dissolved in xylene) as sold  e.g. by ROTH for histology, is used, the hardening process can take months (in an oven at 60° 2-3 weeks). The glueing must be done between crossed polars (heat sensitive!), so You have to make your own simple vertical assembly system here, consisting of a light source, the polarizer (in JENAVAL, the vibration direction of the polarizer is not W-E as conventionally, but SW- NE) and analyzer with the then corresponding perpendicular NW- SE vibration direction. The DIK- prism is under 45° between both vibration directions of the polars. An intact prism helps here to figure out the location and starting point of the dark/ black interference stripe which can also assist as alignment tool here. Please also note, that if the polars are parallel other interference stripes (no black stripe but a blueish- brownish stripe according to the parallel polarization colours)  are produced. Whatever alignment is used, an intact JENAVAL contrast prism must serve as reference. The fine- alignment of the prism halfs can be done with bamboo sticks or similar as long as the glue is not hard. Also the glue film should be a thin as possible. The two prism halfs must, when glued together, again produce the stripe system in the approx. same positions as the other intact prisms do. Otherwise the de SENARMONT contrast modulation will be off from your other prisms (you would then have to rotate the de SENARMONT plate in between to retain a similar contrast, which is a hassle).

The other reason for using Canada Balsam is, that for the correct crystallographic functionality of the DIK prism, of those freely- acessible optical matters for glueing optical components, only Canada Balsam has the fairly correct refractive index of nD= 1.5225 (the used optical quartz Quartz was absolutely strain- free (< 15 nm/ 2 cm) in the JENA 250-CF systems with n e = 1.55337  and n o = 1.54426 as usually). A wrong glue with a wrong dispersion will change the way how the upper DIK- prism half will reunify the two rays.

When mounting the refurbished prism back in its JENAVAL contrast prism housing, the edged wedge helps to mount it in the correct wedge direction (the wedge of the condenser DIK prism and that of the objective sided DIK prism must be the same in the JENAVAL- otherwise no DIK is produced). That is also, why in the normal "non- contrast version" of the JENAVAL, the objective- sided DIK prisms can be fully rotated by 360° in their intermediate ring mounts.

If You accidentially "flip" the prism up-side-down, also no DIK will be produced (luckily that cannot happen here, due to the alignment edge). Also, the original tilting angle must be kept, by glueing in the prism as accurately as possible (not too much glue!- for that also Canada Balsman can serve well), otherwise the DIK will also not be produced, as the c- axis tilt will change then (if the mounted prism has a different angle against the mount as in the original alignment), resulting in a wrong prism shear.

A decent JENAVAL DIK image looks like the one I have attached below, taken with an oil immersion GF- PA 50x type (no "Photoshop result", no sharpening, no contrast enhancement, nor disruptive setting of the display curve etc. -just as it is- when visually enjoying the phantastic JENA- 250 CF optics!).

The slide is from a non- public ZEISS-talk, I made, to illustrate the specialities of our JENAVAL DIK.



Take Care
Michael