32 replies to this topic

[RutgerHauer]

As some of you might know it can be a bit of a hassle to work with glass petris, especially when stacking them and pouring. This is worse when the petris are wet, but the problem remains even when they are dry.

What I do now is pour them one by one and then move them over to make a stack, can't get higher than five per stack without risking messing it all up, which doesn't help with condensation, and sometimes I mess up a plate by moving it after pouring, or a stack might fall over completely. It's also hard to stack them straight up and keep them from sliding around.

This means I am using up more space in my SAB and there's extra steps that I would like to eliminate.

I see videos of people stacking the empty dishes first and then pouring from the bottom up, while lifting the whole stack. I can't do this with my glass dishes for sure. They are not perfectly formed as some are a bit off so this makes the problem worse.

I was thinking of applying something to the bottom of every dish, but am unsure what materials would be useful here. I googled and got to shroomery someone talking about glueing sanding paper to the bottom. This doesn't seem like a good idea to me, sanding paper to glass will eventually mess up the glass. Not only eastethically, but they would also become harder to sanitize if the glass is sanded.

I was more thinking in the lines of some silicone or rubber, maybe all I need is 3 little points placed in a triangular shape that will give it grip and makes them more easily stackable. Or, a small piece of some sort of thin rubber right in the middle would suffice. Maybe they will stay slippery when using these materials, I wouldn't know! And will it hold up in the PC, is another question.

Any advice, recommendations or ideas are welcome here.

Thanks in advance!

Edited by RutgerHauer, 22 November 2019 - 04:23 AM.

[RutgerHauer]

Wasn't sure how to look for these, but found these button thingies used as glass door stops, made of silicone. I could apply three of these per plate.

Would relatively expensive to prep 50 dishes, 15 Euros, but might be worth it. Will just have to try them out.

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Edited by RutgerHauer, 22 November 2019 - 05:45 AM.

[RutgerHauer]

Any alternatives that might be cheaper are welcome!

Also realized just now that it will most likely not help with condensation to use this, since there would be a pocket of air between all dishes, but the effect might be negligible.

Okay this was a very useful topic of mine, helped myself to an answer, LOL.

Edited by RutgerHauer, 22 November 2019 - 06:08 AM.

[coorsmikey]

What about some Flex Seal? You have that too in Europe I am guessing.

 Spray Rubber Sealant Coating, 14-oz, Clear (2 Pack) (Home Improvement Product)

[pharmer]

maybe silicone house caulking?  IIRC it survives pastuerizing

 

RTV silicone definitely survives. It's used to make air ports in jars for PF tek. maybe for small dots per dish would let them stack without leaning. find it at auto repair stores

Edited by pharmer, 22 November 2019 - 09:00 AM.

[RutgerHauer]

@Mikey:

 

Thanks man! Had never thought of something like that. Easy enough to find similar products over here if I search for rubber spray.. Might come in handy for my leaking tap in the kitchen as well.  :) Sterilization temperatures might be an issue though.

 

@Pharmer:

 

Had definitely thought about RTV silicone, three dots would be more stable in fact. But I would rather not use the stuff,  easy to mess up. I pretty much don't like it. I foresee some trouble in applying similar amounts of the stuff so that things will keep stable.

 

Don't know about the other stuff,  house caulking? This stuff never translates well..

Edited by RutgerHauer, 22 November 2019 - 09:30 AM.

[DrepsiLocybe]

ive been using parchment in between dished, that seemed to help my case (but i work in fornt of a flow hood). also my dishes are 60mm and 90mm. the parchment also helps to prevent the parafilm from sticking dishes together. and to sterilize i just stack them up on a myco bag and pc for 45mins.

[RutgerHauer]

I'm now looking into ready to use gasket materials... sometimes you can get those in a shape of a ring. Flange gaskets. Also expensive..

Edited by RutgerHauer, 22 November 2019 - 10:17 AM.

[pharmer]

yup regular silicone caulk, colored or clear, that you'd use around the bathtub/shower

 

not saying I'm sure about this but if it survives multiple passes through your pasteurizer it would be cheap and easy

 

three dabs per dish, let dry for 15 minutes or whatever it takes to cure enought to steam, and you should be good for a few runs before something or other makes them fall off

 

the parchment sounds a whole lot easier though

 

speaking of ready to use gaskets - would a mason jar lid do the job?

Edited by pharmer, 22 November 2019 - 10:25 AM.

[RutgerHauer]

Hey thanks for thinking along here guys, really appreciate it.

 

Mason jar rings problably should do the trick, mason jars are not so popular around here unfortunately.

 

I have found a solution if i want to use silicone - you can order black sheets of it on aliexpress as well as cheap ass heat resistant black silicone I could use as glue, it would also double as a nice background to check the growth. I am afraid to mess up the dishes if I would go for that. It's not the most elegant solution.

 

Might as well just try a few of those silicone door stops I previously posted, run a few cycles in my PC to check if it sticks. If it comes loose, no harm done. Will give it a shot next week and let you know if it worked. :)

Edited by RutgerHauer, 22 November 2019 - 12:16 PM.

[ElrikEriksson]

I sure am glad my hands are steady. I pour stacks of 6 glass petris from the bottom by default, 8 if I'm feeling brave and I stack them 8-10 while they grow.

I sterilize mine in foil covered bread pans at 250°C so attaching things to the petris wouldn't be much of an option.

If I wanted spacers between the dishes, large rubber O-rings would be on my short list of things to try.

[RutgerHauer]

Yeah I saw those o-rings passing by just now, still a bit on the pricey side and unhandy to apply.

 

You must have better produced dishes then I guess. I have pretty steady hands - though I have been doing my agar work mostly stoned and late at night so that doesnt help with that - weed makes me more clumsy and impatient than I would like to admit. My dishes are definitely unable to stay stacked when I move them around so definitely need to fix that. Also recognize the parafilm problem, which makes the plates stick, dropped one on the ground recently.

 

Have also been using a very bulky pyrex pitcher to pour the agar, which takes a lot of my attention because it is just unhandy working in a relatively small SAB.. Have ordered some media bottles so the pouring will go a bit smoother.

 

Trying to streamline the process on all sides.

Edited by RutgerHauer, 22 November 2019 - 02:36 PM.

[MsBehavin420]

Hot glue? You can make dots directly on the petri or on another surface and glue them on

[TVCasualty]

I'd try putting a little glob of 100% silicone (I like the clear stuff) in the middle of the base and the lid of each dish and then squish them down (slowly and gently) on to wax paper (or something silicone won't stick to when it's cured) until it covers the whole base or lid. It should be a fraction of a millimeter thick by then so shouldn't affect the balance of a tall stack as the lids and bases will still be flat, but the silicone will be thick enough to create the friction needed for taller stacks. Let it cure before removing them from the wax paper.

 

Being so thin, the silicone will probably peel off at some point but one tube of it would cover a lot of dishes so reapplying it as needed shouldn't cost too much. This would also probably work around the edge for better grip when holding them. I'd put a glob on a gloved finger and just smear a thin layer around it and let it cure.

 

I'm not sure this will work, but it's what I'd try.

Edited by TVCasualty, 29 November 2019 - 12:52 AM.

[RutgerHauer]

I have tried the silicone drops I posted earlier on, they stuck beautifully but melted in my PC and they'll stick to any surface then. I think the only permanent solution would be gasket silicone like we use for self healing injection ports. I'm now doubtful any other silicone will hold up in the long run.

 

Like I said I'm a bit reluctant at applying the stuff directly to the dishes because it'll be easily messed up and end up with a lot of crooked dishes that will result in a leaning stack. I'm an bit of a perfectionist, I like to see things do right so before I go that route I will really have to think about it.

 

I'm still more into the idea of buying a sheet of black silicone and cutting that into nice circles that cover the bottom, and glue that with RTV silicone. But I am uncertain if silicone will stick to glass at all, so would maybe have to go for some heat resistant glue. I would have to experiment on of of my spare parts.

 

 

@MsBehavin & TVCasualty: Thanks for the tips on how to apply silicone/glue with more precision. I will think about my strategy! Hadn't thought about using materials that won't stick to silicone to help the process, as an over thinker such things sometimes slip my mind. ( how to make my mind anti-slip? )

Edited by RutgerHauer, 29 November 2019 - 02:04 AM.

[MsBehavin420]

Yes they make high temp silicone for cars....

And thank you TV, for the full explanation of what i was meaning by dots of glue and great idea on the wax paper (could use parchment paper also)

[CatsAndBats]

"Glass etching cream is also widely known as acid cream and is one of the easiest ways to personalize your glass. It is fairly inexpensive, but a jar doesn’t go a long way since you have to coat your glass with a thick layer to etch it correctly. The cream has a diluted mixture of chemicals which eats or etches the surface of the glass very lightly. The mixture is comprised of the hazardous chemicals: Barium Sulfate, Sulfuric Acid, Sodium Bifluoride, and Ammonium Bifluoride."

 

https://www.glassetc....com/cream.html

 

The above is a much gentler way to etch glass than the traditional hydrofluoric acid. We use both for graffiti.  ;)

 

[MsBehavin420]

They also make a spray etcher - home depot - spray paint aisle

[RutgerHauer]

I am finding out about new things here, thanks Cats. Great tip! I like it!

 

Im not sure about the spray version - it seems to add some material to the glass of which i am insure it will hold up in high temperatures. It isn't sold over here anyway besides vendors who import it and aren't able to give info on what it actually is they are selling besides 'etching spray'.

 

As far as I can tell by watching videos the spray gives the same effect but actually etching the glass with a cream seems to make more sense in this case. It will be somewhat labor intensive, but i think it might be the best solution so far, since it doesnt add anything to the glass which can come off later on. I suspect the effect will be subtle enough to have no big impact on the glass but still do the trick. I can think of different ways to apply it.

 

 

I was actually browsing aliexpress again yesterday and found pre-made silicone discs with double sided tissue tape already attached. 50 pieces would costs me about 35 euros, but the application would be real easy. The silicone and tissue tape should hold up in my PC but of course I'm never sure until I try.

 

I am glad Cats And Bats shared this etching thing. Might save me some cash!

 

 

Just found out the etching cream officially isn't sold here in NL either, it is prohibited. Must have something to do with the chemical composition. I still can get my hands on it through smaller vendors, fortunately.

Edited by RutgerHauer, 30 November 2019 - 01:30 AM.

[TVCasualty]

I have tried the silicone drops I posted earlier on, they stuck beautifully but melted in my PC and they'll stick to any surface then. I think the only permanent solution would be gasket silicone like we use for self healing injection ports. I'm now doubtful any other silicone will hold up in the long run.

 

Like I said I'm a bit reluctant at applying the stuff directly to the dishes because it'll be easily messed up and end up with a lot of crooked dishes that will result in a leaning stack.

 

I use the regular 100% clear silicone sold in the U.S. for kitchens and bathrooms (usually the GE brand). I have some stuck to blender lids and other tools that I've been using so long (over ten years in some cases) that I can't even count how many times they've been PC'd and the silicone is still stuck to almost all of it and is good as new (and the few that it peeled off of were easily fixed back up). This also includes some lids with self-healing injection ports.

 

A razor blade would remove it from the glass very easily, and I was suggesting a layer so thin (~0.1mm or less, if possible) that you would not notice any difference in how they stack, and if it covered the whole surface equally then the stack would not lean one way or another. And I also realized there's no point in treating both the lids and the bases like I initially wrote. Just treating the bases is adequate since they'll be stacked, obviously (duhh...).

 

 

 

Regarding etching it (the truly permanent solution) wouldn't a strong solution of sodium hydroxide/lye work to etch it, if you can't get the other chemicals?

 

We're warned about not using glass containers for lye solutions when extracting stuff because it basically weakens the glass through etching it, but it takes a much longer time to do so than with the mix of strong acids normally used. So a lye solution might work, and if so would just require a bit of patience.