Sciencemadness Discussion Board - Plastic lid creation

Plastic lid creation

Fantasma4500 - 25-4-2013 at 06:18

i remember on a video i saw on youtube with a guy running electrolysis, he mentioned he made his own lid for the purpose..
this is related to electrolysis cells but i think its more in reagents and apparatus as its not the actual chemistry behind the electrolysis

anyways.. is there anybody that knows how to make a good lid, as in chemical resistant, relatively heat resistant and that can be fitted pretty much airtight, still being all of the above?

glass is properly heat and chemical resistant, but you cannot make holes in it!

a preferred material would be PTFE, but well its kinda hard to make a whole lid of, and most of all i have no idea how to fit this to a container.. the problem with finding a container is that it needs a good lid aswell, preferably screw lid and good plastic (PET) PET is melting around 160*C or something.. just recently i found this plastic type, tho i havent heard of it before..

http://en.wikipedia.org/wiki/Polyetherimide

+200*C thermal stability..

i have also considered metal coated with plastic of some sort, but again thats just the container, i can coat the anode/cathode electrical wires with plastic to make it not be in contact with metal, but then we got the factor of chemical resistance being weakened as in handling chlorine gas

if you have any suggestions on any of the above mentioned please speak up! (:

edit: actually found it for sale, 8 litre jar with nice design but very pricey
http://www.coleparmer.com/buy/product/59032-thermo-scientifi...

[Edited on 25-4-2013 by Antiswat]

Organikum - 25-4-2013 at 10:33

Epoxy fits most of your demands and it is available for temperatures up to 260°C with tempering. You can bond PTFE foil to it. PTFE foil which is pretreated on one side so it can be glued with epoxide glue is available.

PTFE is actually pretty easy but annoying to work with. It is just to expensive in sizes useful for a lid and the structural stability is lousy. It is fucking weak.
The stability of epoxide/glassfibers and the resistance of PTFE seems like a good deal to me.

/ORG

chemcam - 25-4-2013 at 10:43

What about just using fiberglass? I remember when I was in high school I made a custom sub-woofer box out of fiberglass and it was easy to mold, you could use that as a rigid body (which is very strong) then coat in what you choose for added protection.

Organikum - 25-4-2013 at 10:52

Quote: Originally posted by chemcam

What about just using fiberglass? I remember when I was in high school I made a custom sub-woofer box out of fiberglass and it was easy to mold, you could use that as a rigid body (which is very strong) then coat in what you choose for added protection.

He talks about standing up against chlorine.
And Polyester has no noteable chemical resistance worth to mention IMHO.

/ORG

[Edited on 25-4-2013 by Organikum]

chemcam - 25-4-2013 at 11:32

I know that but what I am trying to say is make the lid out of fiberglass so it is sturdy and hard then coat it in whatever plastic he chooses to resist the actual chemicals.

Organikum - 25-4-2013 at 12:02

Quote: Originally posted by chemcam

I know that but what I am trying to say is make the lid out of fiberglass so it is sturdy and hard then coat it in whatever plastic he chooses to resist the actual chemicals.

You are funny kid, thats exactly what I suggested in my first post you know? Just a bit more detailed.

/ORG

chemcam - 25-4-2013 at 12:19

Hahaha, I guess I didn't read your post very well! That is my mistake.

I am slightly older than a kid, mid 20's, but that doesn't really matter. I have only been studying chemistry for a short time so my knowledge may be skattered still. However, building and designing things is my specialalty.

Fantasma4500 - 25-4-2013 at 13:50

Quote: Originally posted by Organikum

Epoxy fits most of your demands and it is available for temperatures up to 260°C with tempering. You can bond PTFE foil to it. PTFE foil which is pretreated on one side so it can be glued with epoxide glue is available.

PTFE is actually pretty easy but annoying to work with. It is just to expensive in sizes useful for a lid and the structural stability is lousy. It is fucking weak.
The stability of epoxide/glassfibers and the resistance of PTFE seems like a good deal to me.

/ORG

wweeeelll it seems to me that 2component epoxy goes slightly brown-yellowish after it has been run for some time with my cell, and i have used it almost all the time for my cells..

but if i were to use epoxy for creating a WHOLE LID... how would i be able to fit it properly without breaking it? i mean its not very flexible when it does harden..

actually i didnt realise PET's MP was at 265*C, which is somewhat readily available.. i have thought about throwing my steelplate on the stove and by slowly turning the heat up putting some PET plastic on there to slowly melt it to a fine dish form

but again im left with a problem.... how do i fit this to a cylindrical shape? and is it even possible to use a redhot glowing wire to melt holes through this material? (which is my preferred method for precision when it comes to plastics)

but PTFE foil.. ptfe foil.. very interesting, but it sounds costly and as you say very very stressing to work with.. its one of the most slick things after all (:

Fantasma4500 - 25-4-2013 at 13:54

Quote: Originally posted by chemcam

fiberglass.. i think i saw some persons creating a speakercube undervacuum or something alike with this using .. epoxy to seal it up.. not 100% sure tho
ill look it up, but do you know if this is readily possible to well.. fit to other plastic containers as in easy to take on and off? this is my main problem really :S

i mean you would need really good accuracy to make a 360* perfect circle at home

Fantasma4500 - 25-4-2013 at 14:01

sorry for tripple-posting..

''The basis of textile-grade glass fibers is silica, SiO2. In its pure form it exists as a polymer, (SiO2)n. It has no true melting point but softens up to 1200°C, where it starts to degrade. At 1713°C''

http://en.wikipedia.org/wiki/Glass_fiber#Melting

well it has potential as in speaking about heat resistance and as its composed of mainly SiO2, or well polymerized SiO2 then it should have the chemical resistance aswell
i know a few that has made high quality glassfiber for actual weaponsystems, dont know why i didnt think about this as a possibility before..? perhaps too advanced to get / shape?

sounds like a good idea, hope i will be able to figure out a way to shape it without noisy or expensive tools to be fitting well, if so then i have nearly unlimited possibilites when it comes to containers, even a chemistry beaker would be possible

edit: another problem; how do i make holes in this material when its hardened then?

[Edited on 25-4-2013 by Antiswat]

chemcam - 25-4-2013 at 14:29

If you already have a threaded container and just need a lid you mold the fiberglass around the top and threads, then when it gets almost hard unscrew it and it dries with the needed threads.

To make a container mold the fiberglass around something that is the right size. To get threads in it do the opposite of the above paragraph. Take a lid and screw it onto the wet fiberglass container then remove after it sits for a while.

Why not just get a large diameter steel pipe that is threaded and coat the inside with what you want?

watson.fawkes - 25-4-2013 at 17:50

Quote: Originally posted by Antiswat

glass is properly heat and chemical resistant, but you cannot make holes in it

Translation: "I don't know how to cut holes in glass." Did you search at all before making this claim?

Hint: Look for how to cut a hole, not just drill a hole.

Hint #2: You don't even have to build your own tools to do this any more.

chemcam - 25-4-2013 at 19:14

I have successfully drilled holes into glass using a diamond drill bit, they are not as expensive as they sound $10-$20. I was drilling holes into beer bottles for a project, however, for me 2 out of 5 break so I have never attempted it in nice glassware.

*EDIT*
I used a drill press, using a hand drill would be nearly impossible unless you build some sort of column to mount it to so it slides down perfectly level.
The diamond drill bits I use look like this:

[Edited on 4-26-2013 by chemcam]

Xenoid - 25-4-2013 at 19:33

I have made various types of lids over the years, both for chlorate/perchlorate cells and other chemical processes.

The procedure is very simple, and I have mentioned it several times on this forum.

I first scribe circles on 15mm thick grey PVC which are slightly larger than the outside diameter of the jar neck you are trying to fit it to.
Drill about a 5 or 6mm hole in the exact centre and then cut out the circle using a fret or coping saw (stay outside the scribed circle).
Fit the plastic circle onto a 5 or 6mm bolt or threaded rod using large washers, lock washers and nuts.
Place this assembly in a portable electric drill chuck and mount in a vice, so you can use it like a lathe (poor man's lathe).
For a cutting tool I used an old 5mm chisel, and for cutting the "O" ring grooves I used an old screwdriver blade which had been sharpened appropriately.
It would be best to try and provide a simple tool rest, but many of the lids in the pictures were done "free hand".

I now have a proper lathe which makes things somewhat easier, but I still use the same basic process. If you have set of appropriate sized "hole-saws" these can be an easier method of obtaining the original "blank".

The largest of the lids are about 11cm in diameter and fit 5 litre "pickle" jars.
One drawback of this method is that you always end up with a hole in the centre of the lid. In chlorate/perchlorate cells I use this for the venting tube, or a thermometer, etc. If you don't really want it, plug it with a bit of plastic rod. Some of my early lids were made from HDPE "chopping boards" and some were made in two parts with a bolt through the centre (Perspex upper with HDPE lower) - not recommended.

Fantasma4500 - 26-4-2013 at 08:19

Quote: Originally posted by chemcam

If you already have a threaded container and just need a lid you mold the fiberglass around the top and threads, then when it gets almost hard unscrew it and it dries with the needed threads.

To make a container mold the fiberglass around something that is the right size. To get threads in it do the opposite of the above paragraph. Take a lid and screw it onto the wet fiberglass container then remove after it sits for a while.

Why not just get a large diameter steel pipe that is threaded and coat the inside with what you want?

because i dont think im capable of getting hold of that, also economy.. would also be nice to have it so you can see whats going on in there
but i dont know what i should coat the inside with tho..

but just mold it around the container??? when you have a airtight system of some sort theres usually something relatively soft (rubber ish properties) that you can screw it into so there wont get any leaks.. im not sure about the properties of glassfiber but arent they pretty hard?
looked abit around and what i found was some pretty pricey stuff (~65 euro) for a set for making fiberglass
i would need to spare up some time for that, in order to keep my economy in balance

Fantasma4500 - 26-4-2013 at 08:22

Quote: Originally posted by watson.fawkes

Quote: Originally posted by Antiswat

glass is properly heat and chemical resistant, but you cannot make holes in it

well the problem is that the equipment for that would be rather pricey and properly limiting it to needing larger diametres than needed.. i know you can cut glass with ''diamonds'' i guess this is wolfram carbide, but again the price, and how would i make it fit my cell? i mean i cant apply too much pressure on glass, it can break relatively easily

Fantasma4500 - 26-4-2013 at 08:38

Quote: Originally posted by Xenoid

I have made various types of lids over the years, both for chlorate/perchlorate cells and other chemical processes.

The procedure is very simple, and I have mentioned it several times on this forum.

I first scribe circles on 15mm thick grey PVC which are slightly larger than the outside diameter of the jar neck you are trying to fit it to.
Drill about a 5 or 6mm hole in the exact centre and then cut out the circle using a fret or coping saw (stay outside the scribed circle).
Fit the plastic circle onto a 5 or 6mm bolt or threaded rod using large washers, lock washers and nuts.
Place this assembly in a portable electric drill chuck and mount in a vice, so you can use it like a lathe (poor man's lathe).
For a cutting tool I used an old 5mm chisel, and for cutting the "O" ring grooves I used an old screwdriver blade which had been sharpened appropriately.
It would be best to try and provide a simple tool rest, but many of the lids in the pictures were done "free hand".

I now have a proper lathe which makes things somewhat easier, but I still use the same basic process. If you have set of appropriate sized "hole-saws" these can be an easier method of obtaining the original "blank".

The largest of the lids are about 11cm in diameter and fit 5 litre "pickle" jars.
One drawback of this method is that you always end up with a hole in the centre of the lid. In chlorate/perchlorate cells I use this for the venting tube, or a thermometer, etc. If you don't really want it, plug it with a bit of plastic rod. Some of my early lids were made from HDPE "chopping boards" and some were made in two parts with a bolt through the centre (Perspex upper with HDPE lower) - not recommended.

hm.. so you cut out PVC with a holesaw or drillbit
you then use some sort of a lathe to decrease the diametre of the rest of your lid leaving some sticking out over the edge from the cell
but then.. you put some type of rubber around the edge to make it fit the top of the container or what?
i mean rubber bands could be used but would need to be changed im sure, perhaps bicycle hose instead, duct tape etc.
but yes that seems pretty straight forward.. i might attempt to make my own disc of PET plastic by melting it on steel as its relatively easy to come by

oh wait i missed something.. using a chisel.. thats not really hard to come by, i might have a place where i can create this thing..

but again about that rubber piece on
http://www.sciencemadness.org/talk/files.php?pid=282371&...
on the top right.. where did you find that?

also for the diamond drillbit, thats affordable indeed, next problem would be shaping it as a lid

watson.fawkes - 26-4-2013 at 09:28

Quote: Originally posted by Antiswat

well the problem is that the equipment for that would be rather pricey and properly limiting it to needing larger diametres than needed.

"Would be"? Apparently you didn't search the second time either, since there are more ways to do this than with diamond-impregnated hole saws (although that does work).

Oh well. I've got no interest in spoon-feeding.

chemcam - 26-4-2013 at 11:21

Well I don't have a problem further explaining this topic to you as I have a fairly good understanding of making container but what I don't understand is your question can you explain to me exactly what you want and how much money you can spend. And are you skilled with power tools or just hand operated? There are so many ways I just need to know your skill level

Fantasma4500 - 27-4-2013 at 04:39

Quote: Originally posted by chemcam

Well I don't have a problem further explaining this topic to you as I have a fairly good understanding of making container but what I don't understand is your question can you explain to me exactly what you want and how much money you can spend. And are you skilled with power tools or just hand operated? There are so many ways I just need to know your skill level

well i have worked making all sorts of things out of metal for abit more than 2 years.. welder etc. but i dont really have those things in my apartment..
but well... i can get stuff like a chisel, i prefer if its easily available things because then theres a chance near family that have a workshop have it laying around (:

i would say using a thick piece of PVC is a really good idea, because its relatively heat resistant and it wont really react with chlorine, it will take alot of heat to melt a that big piece, its easy to shape as you want to, and hopefully i will be able to fit PVC to my lids

thinking about easy to fit.. i guess wood could work aswell, as long as its kept away from the water there shouldnt be any problem and it can easily be shaped aswell