View Full Version : Creation of resin-impregnated, compacted cloth layers (aka "Micarta") - WIP kinda...
CameronPotter
21st March 2006, 09:47 PM
Hi all,
(takes a deep breath as this is going to be long)...
Well I made a pen from this stuff, but it was originally made by me with the purposes of using it for a knife handle. I have since moved away from full tang knives and so I had some of this lying around and it made a very nice looking pen.
This material feels nice, takes a nice shine, is super tough and can be made to basically whatever size/shape/dimension you want (although trimming will be necessary).
Warning: it is VERY hard. Be prepared to sharpen any tool you might want to use - often.
OK. So, how to make it...
First off get the stuff together in one of the attached photos. Notice that I didn't forget to get the screwdriver or paintbrush they are just "cleverly hidden".
When choosing the cloth, remember that it will look permanently wet, so they will be a lot darker than they appear dry. You will also need to have ripped the cloth into rectangles about the same size as your metal plates. This takes a LONG time, do it in front of TV. Also, take the time to calculate how much you will need it is very suprising. Think several square metres... My blanks are about 60 pieces of cotton thick which makes it approx 12-15mm. I wouldn't use anything other than cotton or linen (basically natural materials) as I don't think that I would trust proper bonding with synthetic materials. Also, I know that some people have used things like soaked paper which apparently looks quite nice.
Now, the metal plates, they should be strong enough that they don't bend under a LOT of force - or at least don't bend much. Mine are grip plate about 5-8mm thick. They will stick to your resin if you don't cover them in in clingwrap.
The clamps are to jam the whole thing together at the end, but it is best to have them handy.
Put on the gloves as the plastic lives a life of its own - regardless of how careful you are, it will get on your hands and won't come off.
The other stuff is all for the the resin. Use the screwdriver to open the tin and fill a 200ml disposable cup with the clear casting resin. Add 2-3ml of catalyst (using the pipette) and stir with the stick. Pretty tough so far huh?
Now using the disposable brush (as this REALLY destroys brushes) that you have on hand; just like mine :o .
Now get a piece of the cloth and paint on resin until it is ENTIRELY soaked. Wet isn't enough, soaked... Then get the next and the next and keep on painting on the resin making sure that every layer is soaked. This will use more resin that you expect - don't be shy, better to use too much than too little.
I have found that you can put down two pieces at once and still wet them enough to soak through. I will leave you to decide how to stack you cloth. At this stage you may also want to think about shape in your stack. If you fold over some bits of cloth and wrinkle them up, the result is likely to be more interesting... My first trial used the grip plate with the grip side in, but this meant that there were some gaps in cloth (which were filled with clear resin). This may be fine, it may not. Just think about it. I know some people who put a piece of wire on the top to get that extra pattern in their work, but I think this runs the same risk as the grip plate patterns.
I meant to take photos of this, but it is pretty important to keep things rolling and it was getting pitch black outside (and this can stink a bit and if you do it in your shed, don't plan on going in there for a week or so).
Thus, no piccies... sorry. If you have any questions, please ask.
Now, 60-70 pieces of cloth and about three cups of resin later...
You put the other bit of steel on the top and crush it down with the clamps. Try to do this as evenly as possible, as hard as possible and if you have soaked the material properly, it should spew resin out the sides - so do it over something that you don't care about. The second attached pic shows this.
After 24 hours or so, depending on temperature, amount of catalyst and your patience levels you can take the clamps off.
The result will be a heavy block of pseudo-micarta (Micarta is a tradename). This will need quite a lot of the edge trimmed off, but should be an interesting addition to many possible wood working projects. Remember, if you cut/file through it you will expose lower layers making for an intersting pattern. Remember that there is no need to be gaudy with this either, you can use dark/dull colours too, but as I said, remember, dark colours will be even darker as they are effectively "wet".
The result might look something like:
http://www.woodworkforums.ubeaut.com.au/showthread.php?t=29696
I will show pics of this batch later on when I get a chance - maybe on the weekend?
Please feel free to ask any questions if something isn't clear.
Cam
KevM
21st March 2006, 10:02 PM
Cameron.
Wow, the lengths that people will go to to achieve something different. Looking forward to seeing the result.
Kev M
Clinton1
21st March 2006, 10:28 PM
Great Scott, Cameron! :cool:
I looked at that and thought "whats this Micarta stuff, what is casting resin, cloth?, can you add other stuff for different effects, is the resin dangerous...."
I'd like to read more, seems that you've got an interesting thing going on.
Good on you.
CameronPotter
21st March 2006, 10:32 PM
Yeah, it is a fair amount of work, but the result is good (and as I said, it started out life as knife handle materials as this stuff gives a nice positive grip whilst also being waterproof - pretty handy for a knife!)
Anyway, here is a pic of the first piece I made (and also the first piece I have turned).
http://www.woodworkforums.ubeaut.com.au/attachment.php?attachmentid=20902&d=1142856345
Cam
ps Sorry dial uppers, I didn't know how to put in a small piccie linking to a larger one.
oges
22nd March 2006, 08:30 AM
Very impressive
CameronPotter
22nd March 2006, 08:38 AM
Skew posted these questions in the pen forum:
I know you say it takes about 24 hours for it to go off (depending on temp., resin mix and how you hold yer tongue) but how long is the actual resin workable? An hour or two? Let's say I've saturated and stacked my 60 layers and want to add some artistic creases, is this something I'd have leisure to arrange or would I have to clamp up ASAP?
Also, when casting foreign objects (eg. spiders, coins) in clear resin I've had to coat 'em with... errrmmm... :o I forget :o something'r'other first to avoid air-bubbles. They a problem with layering cloth?<!-- / message --><!-- sig -->
My answers:
The workable time varies a lot depending on heat and amount of catalyst used. I have had it get thick and gluggy (unable to be spread) within about a half an hour, but in the cool with little catalyst it can be workable for a few hours.
The sooner you clamp the better - as that way the resin will still be at its moistest stage and you can really force those air bubbles out by crushing the cloth down as hard as possible. However, there would be some time to play around if you wish, just my advice would be do it quickly and set up the clamp as quick as you can.
As for casting foreign objects, that is because the other thing may have a tendency to trap air bubbles beside it - this is avoided in two ways.
1. The cloth isn't just embedded - it is soaked, so there is no room for air bubbles. Last I looked it was hard to soak a beetle or a coin.
2. The crushing force should push all air bubbles out later. This really should be about as hard as you can get it. I know people who use 12 tonne presses to do this. I don't know what tonnage I can get with a clamp, but I would guess that I am not too far off that number...
Cheers
Cam
CameronPotter
22nd March 2006, 08:59 AM
Great Scott, Cameron! :cool:
I looked at that and thought "whats this Micarta stuff, what is casting resin, cloth?, can you add other stuff for different effects, is the resin dangerous...."
I'd like to read more, seems that you've got an interesting thing going on.
Good on you.
Thanks Clinton,
Clear Casting Resin is basically like any polyester resin, but it is crystal clear. Now, if you were doing darker or duller colours, I would recommend NOT using casting resin as it is a lot more pricey than normal polyester resin, but for the brighter colours, I reckon that it is worth it. This process takes a while so you may as well do it right.
As for whether the resin is dangerous, nope, well, I mean I wouldn't suck in the fumes nor drink it or anything equally silly, but it is just a thermosetting plastic. Note, this can also be done with a good quality slow setting two part epoxy (not the five minute stuff). The epoxy colouring isn't quite as nice, and the epoxy is more expensive though and this really gets most of its strength from crushing the fibres together rather than the strength of the bonding substance...
As for adding other stuff, well it depends... If it can be thoroughly saturated, then yes you can use it for this process. That is why paper works - I have thought about giving it a go with newpaper - that way you may also get the printing adding texture... Tissues would work, but I don't know that sounds very interesting. I can't really think of much else. You could try kitchen wipe/sponge cloth things - but I wouldn't guarantee it. Basically, I would prefer to use natural materials that I KNOW soak properly.
Now, if you are meaning casting things such as coins or bugs or photos or all manner of other things... Well, that is a different process. You use a mould and pour the resin very carefully, but then it was behave like resin, not like this - which is a lot harder.
A final thing, if you used epoxy instead of the casting resin, I would trust the bond and you COULD incorporate other things, but I would try to keep them a flat as possible with a good number of soakable layers between them. An interesting trial might be to use aluminium foil or the like. Only use it at one thickness at a time and make sure that you lay it flat with no air bubbles and several (minimum ten) layers of cloth on each side... Come to think of it, that might work equally well for the resin too... Also, if you puncture the foil (or whatever you use), the resin will bond through those hole when you crush it down, effectively bonding the two sides together and holding the foil in place anyway!! :D
As for wanting to read more, I will post some more later, but if you have anything specific, let me know.
Oh two more things:
1. The outside may remain a little sticky, that doesn't matter so much. It is the inside that really matters and as the resin "goes off" with heat, the inside will set much earlier than the outside. If the stickiness concerns you, you can wipe it off gently with acetone.
2. This can be cut using any wood working tools, but I have bent saw teeth with it and so now I only use metal work tools on it. For instance, a metal cutting blade in a bandsaw and hacksaws and drills on SLOW speeds and files (that you no longer care about). :D
My next post will likely include me taking the clamps apart (oh, and swearing cause the damned thing didn't work as it got too cold over night here in Tassie ;) ). ASSUMING that it did work, then it will show me trimming up the edges and hopefully result in a turned pen - although as I said, this can be used for pretty much anything wood can be used for. I have thought seriously about making a coffee table top from it.
Cam
AlexS
22nd March 2006, 04:04 PM
Your effort of making your own materials has inspired me.....
.....I just planted a mango.:D
CameronPotter
22nd March 2006, 04:51 PM
Plus mango trees smell a lot better than stinky plastic! :o
Clinton1
22nd March 2006, 08:43 PM
Thanks Cameron.
I had a surf and checked out some sites and their info. "Arms ModelIt" have an ok site. I am sure there are some good books out there.
Is Barnes Clear Casting resin the one you use?
CameronPotter
22nd March 2006, 10:50 PM
I think it is Barnes - yes.
I am not sure about sites or books. My reading has been from the internet, my resins all come from our local fibreglass shop. I have also seen it is fancy craft shops/art shops.
Cam
Schtoo
23rd March 2006, 02:26 AM
To file this stuff, take the desired file and wrap some sandpaper around it. Works much faster and doesn't hurt the file.
Also useful to know if you ever have to work with carbon fibre or kevlar... ;)
Cameron, great idea. Might have to give it a fang myself one day, although I don't know what I will use it for.
Iain
23rd March 2006, 08:45 AM
Cameron, instead of clamps, to make things a little easier for yourself have you considered making a frame and using one or two of these 'clamps' from Mr McJing.
Sorry, would not let me upload as file image is already here:
http://www.woodworkforums.ubeaut.com.au/showthread.php?t=24829
CameronPotter
23rd March 2006, 11:51 AM
I have thought about making a nice big book press style clamp, but I have never got around to it. The problem is that this works and so I have never got around to doing it differently - maybe one day.
As for your advice Schtoo, absolutely right. It will murder your files. I bought a sur-form - or whatever it is called - rasp but it also got blunt very quickly. I now have a special sander thing that holds the paper flat.
You can also use disc sanders etc, but be VERY careful not to overheat it. I used gouges and skews to turn mine, but I blunted about 8 tools in the process - LOTS of sharpening.
Cam
CameronPotter
23rd March 2006, 11:18 PM
My next post will likely include me taking the clamps apart (oh, and swearing cause the damned thing didn't work as it got too cold over night here in Tassie ;) ). Cam
Grumble grumble... :mad: :mad: :mad:
I had to go and bloody jinks myself.
There are two possibilities as to what went wrong (and I think they both went wrong).
The block split when I tried to cut it - I fixed that by supporting the back of the pseudomicarta.
The block split when trying to drill it - I fixed that by drilling it in larger block before trimming it down.
The block split on the lathe... I gave up.
I investigated why I had splitting. I noticed that it either happened towards the outside of the block, which meant that it was too cold (serves me right for doing late at night in Tassie). I should have either started early in the morning or set up a heatbox. I have the stuff I need to build a good heatbox (thermostat controlled), but haven't got around to building it...
The other reason that it split was that as I was doing this late at night and rushing, I didn't listen to my own advice and on ONE layer I didn't soak the cloth enough. This was where it split when I was drilling and turning. There isn't a lot that can be done to fix this.
Now I have a lot of little parts that I will use for laminations but little else.
Oh well.
Anyway, this is what it looks like coming out of the mould...
I may (or may not) have another go on the weekend.
Feeling sorry for myself right now. :(
Never mind. I made my first Pen2 tonight though and it turned out quite well. :rolleyes:
Cam
CameronPotter
27th March 2006, 09:45 AM
Hi,
I talked to the nice people in the Fibreglass Shop and they said that because there was a cold snap, he wouldn't have taken it out of the mould for a week (let alone two days).
Thus, I reckon I took it out a little too early.
I have another in glue up now and I will post piccie in a week or two when it is done.
Cam
CameronPotter
2nd April 2006, 08:23 PM
OK! So after leaving this one for about a week (and leaving it in the sun too when I got a chance) - although I wouldn't do this in Qld...
The result - MUCH better adhesion. I can tell by feel that this is a much better set of blanks. Out of interest, I also used a different technique for soaking the cloth - I actually dipped them in the resin and smoothed it down. This worked really well and was also a lot faster.
NOTE: if you are planning on doing this, remember that you need more resin than you might think. The resin fills the gaps in the cloth and for cloth - there are a LOT of gaps (and in fact the cloth itself soaks up resin), so you probably end up using about as much resin as the block itself would take up...
I also tried a few other things. I tried normal polyester resin (not the clear casting) and it worked really well - the colour was slightly blue but only very slightly and I really don't think it is noticeable. This resin is also about half the price of clear casting. Yay!
A ALSO tried new material... This was the slightly furry inside material (still pure cotton). Kind of like track pants material. It worked really well and each piece of this was worth a few pieces of thin cotton cloth.
So, after a lot of experimenting (ain't I good to you guys?) I have a blank that I will hopefully turn into a pen and I will donate this to Ian's fundraiser - your chance to own your very own bit of Woodwork Forums history...
Again, any questions - please ask.
Cam
ss_11000
2nd April 2006, 08:27 PM
Again, any questions - please ask.
Cam
have u ever thought of selling the stuff???( or giving some out to us for free:p :p :p ) i rekon ppl would buy it, it turns out awesome:)
CameronPotter
2nd April 2006, 09:03 PM
If people were interested I could sell some...
It somehow seems wrong for me to make money from a hobby - it is usually the other way around! :p
Cam
ss_11000
2nd April 2006, 09:06 PM
how much would u sell a pen blank for??
CameronPotter
2nd April 2006, 09:09 PM
I dunno...
I would have to figure out how much it cost to put together.
PM me to remind me tomorrow...
Cam
CameronPotter
3rd April 2006, 10:06 PM
Well, here is the proof from the pudding...
These two shots show the pen at two angles.
Can I just say again - remember those super sharp scissors that your (insert dressmaker/tailor at home) won't let you use. Well, that is because you need sharp tools to cut material, you need sharper tools to cut this!!
Anyway, this pen was finished with wet and dry (used wet) sanding up to 2000, followed by EEE (of course) and that is all that is required - basically this has a sheen like plastic but feels a bit nicer, well I think so at least.
This pen, in the spirit of these great forums will go to Ian007's fundraiser. I hope that someone makes a nice big bid for it.
Cam
ss_11000
8th April 2006, 02:42 PM
I dunno...
I would have to figure out how much it cost to put together.
PM me to remind me tomorrow...
Cam
oops me forgot.... anyway, have u worked it out yet
btw, nice pens
CameronPotter
10th April 2006, 09:56 AM
Just for other people's information, I have decided on $5 a pen blank for now as it is fairly labour intensive and expensive to make. This makes it slightly dearer than the shop bought plastics and slightly cheaper than Dymondwood - although it is done in a backyard operation and each piece is handcrafted.
Oh, also, I have posted a pic of a new pen from this stuff in the pen turning forum.
Cam
felixe
25th April 2006, 11:19 PM
I hope this does not break any forum rules but.....
Just A quick recommendation for a Qld Company,
If anyone is looking at using any resins, expoxys or silicons, then I highly recommend Model it (Barnes QLD) as a source of products and knowledge.
I read that Clinton looked at their site, Clinton this is only the tip of the iceberg with these guys. If you have any questions I strongly recommend you call into see either Al or Shelly (owners) at Clontarf or at least give them a call.
They run classes on a Saturday and for a mere $30 a day you get the full demo, afternoon tea and the chance to pester them with all your questions, as well as a book to take home. I have done the basic and advanced mould making courses, dealing with condensation and addition cleared silicons, types of plasters, resins and other casting materials.
I cannot praise them highly enough for the knowledge you can get in one afternoon.
Their after sales service and technical advice is spot on, also they will deliver anywhere in small managable amounts. They are the QLD rep for Barnes Aust who supply the movie industry etc. As such they will sell managable amounts of all barnes products to anywhere in Australia, and can back it up with extensive knowledge. It is great to find a business that are so good at what they do.
I stumbled on this link, looking for their website, so I thought I should post a recommendation.
And if you are wondering, I use them for my materials and reference for casting objects for my work.
Regards
PS. This is not an ad, just a satisfied customer.
rodent
17th June 2006, 06:30 AM
cam have you tryed using a glassing roller its used by fiberglassers to push the resin into and through the glass matting.
CameronPotter
4th July 2006, 02:55 PM
That was what I tried first. It works, but not that well. The glassing fibres tend to be more spread out, thus meaning that the epoxy spreads to fill the gaps more easily. A better solution is the soak method - it uses more resin (unfortunately) but it guarantees a good bond and it is much faster.
However, you also go through several pairs of latex gloves in a single glue up. :o
Mungo Park
30th September 2006, 02:46 PM
I was told that this stuff gives off toxic fumes, one when you are making the stuff and later on when you sand the stuff. The toxic part is a gas and a particle mask does little to collect it before it goes into your lungs. I am posting this to see if anybody else can confirm this.
Cheers Ron.
CameronPotter
6th January 2007, 05:57 PM
I talked to the guys in the fibreglass shop about this and they didn't have any concerns - maybe they are killing themselves (and me)? However, I think that it is probably OK.
That being said, if I have one, I use a gas-filter mask with a filter for poisonous agricultural chemicals when gluing up.
Still, I reckon it is OK (although it is also worth mentioning that different resins have different smells.
Cam
KevM
6th January 2007, 06:21 PM
:welcome4: back Cameron.
Are you back home:aus: for Xmas or still in the :usa:?
CameronPotter
6th January 2007, 06:46 PM
Nah, still in the land of the free...
I have been meaning to get back on here, but a combination of too much work and lack of ability to do any real shed-type activities here (as I am still in an apartment) has discouraged me from getting back on.
However, now I have a few projects and possibly even the tools to do them, so I might get back on properly.
If nothing else, it will give me something better to do than watch reruns on TV... Oh, and talk to a few more people who understand sarcasm. :doh:
Thanks for the welcome!
Cam
Skew ChiDAMN!!
6th January 2007, 09:22 PM
Good to hear from you again! :wink:
Correct me if I'm wrong... but you don't need a shed to make up castings. Just think of the stockpile of blanks you could have cured & ready for working by the time you're tooled up again. :p
jmk89
7th January 2007, 06:58 AM
Great to hear from you again, Cameron.
Good luck with shed activities? Does you apartment have a LUG? If so, you have a workshop (unless you are driving a Humvee) if you can leave 4 feet free at the end for a bench.
Cheers
Jeremy
rapsod
7th January 2007, 07:18 AM
The best method for making resin-thing laminations is to use vacuum. Cover cloth pads with plastic foil. Glue edges of plastic foil to base of "tool". Than you pick up one tube and insert it under plastic foil at one corner. Another plastic tube is put in corner oposit of first one. Than you use vacuum pump to suck out all air. After that you open second tube that have been sink in resin and continue to suck air until all under plastic foil have been filled up.
I saw this method on one french bow-building forum.
masoth
7th January 2007, 09:03 AM
Thanks Cameron for this thread. Making your own medium is smart, clever, ingenious, fun, etc., - to offer it to others is grand.:2tsup:
I do have a question: Could the 'pad' be put together is stages? That is, say, 20 pieces today and another 20 next week, and the reason I ask is I move VERY slowly so suspect the first layers of resin would cure before I got to the 60th.:doh:
CameronPotter
7th January 2007, 12:48 PM
I like this multi-quote thingy...
Good to hear from you again! :wink:
Correct me if I'm wrong... but you don't need a shed to make up castings. Just think of the stockpile of blanks you could have cured & ready for working by the time you're tooled up again. :p
True, but I did that just before I left... I have a big pile of blanks - luckily I have an offer to borrow someone else's lathe now. It is a long drive, but it will be worth it when I find the time!
However, my first task (while I am finding a convenient time to get in some shed time) will be to make a copper and nickel chess set by cutting and crossing two bits of sheet metal.
Although I may make some more blanks - it isn't a bad idea at all.
Great to hear from you again, Cameron.
Good luck with shed activities? Does you apartment have a LUG? If so, you have a workshop (unless you are driving a Humvee) if you can leave 4 feet free at the end for a bench.
Cheers
Jeremy
Yeah, I don't have a lock up garage. I wish I did - I even looked into finding some kind of storage, but nothing was appropriate - and tools here are so cheap too!! :C
Thanks Cameron for this thread. Making your own medium is smart, clever, ingenious, fun, etc., - to offer it to others is grand.:2tsup:
I do have a question: Could the 'pad' be put together is stages? That is, say, 20 pieces today and another 20 next week, and the reason I ask is I move VERY slowly so suspect the first layers of resin would cure before I got to the 60th.:doh:
It is not really my own idea, I just use it slightly differently. :)
The "pad" really needs to be done all at once. The reason is that the way that resin hardens has a process called cross-linking. The idea is to get cross linking through each layer of cloth.
However, there are ways to increase the rapidity of the process:
1. Don't paint the resin on, dunk the cloth.
2. Use thicker cloth (although you still need to really wet each piece)
3. Call a mate over and have a dunker person and a lay-up person.
Also, to slow it from drying to fast:
1. Do it in cool weather if possible (such as night-time maybe) - often not a problem if you are in Tassie (where I was).
2. DON'T do it in a breeze.
3. DON'T do it in direct sunlight
4. Add slightly less catalyst - this is a little tricky to get quite right - the key is the word slightly.
5. Do not try to make up all of the resin at the start. Making resin is fast, but the resin itself will start to gel up fairly quickly, I can remake the resin as many as ten time in a single lay-up.
I hope this helps.
Finally, if you are still having trouble getting it done, make thinner blanks by all means BUT it won't work as well and make sure that you rough up the hardened blank before trying to glue the next layers on top (and I would do it that way rather than making several blanks) - although really that is just supposition.
Cam
masoth
17th January 2007, 12:16 PM
Cameron, another question regarding this use, if you don't mind. How much resin would you set-up with before starting the process? I ask because 500g is the largest container I found at Bunnings, and the 'flood' suggestion you offered seems to need more (I've cut some scrap steel to about 300x200):?
soth
CameronPotter
17th January 2007, 03:15 PM
Cameron, another question regarding this use, if you don't mind. How much resin would you set-up with before starting the process? I ask because 500g is the largest container I found at Bunnings, and the 'flood' suggestion you offered seems to need more (I've cut some scrap steel to about 300x200):?
soth
Of course, I never mind questions... :cool: My answers aren't always good though! :(
500g is heaps, I usually made mine in 200g batches (I think). I put it in a small icecream bucket then kind of just slopped the cloth around in that - then squeeze it out with your hands (WEARING DISPOSABLE GLOVES, i.e. latex gloves). There are two reasons to do this:
1. It actually squeezes the resin through the cloth more thoroughly.
2. You don't have too much resin (that will later just be squeezed out the sides of the blank).
I am excited that you are going to give it a go. Make sure you post your results here. :2tsup:
Don't rush getting it out of the mould though and make absolutely sure that it is dry all the way through before playing with it - I have wrecked many blanks by rushing them. :C:~. Still, that is what I am here for... :doh:
Cam
masoth
4th February 2007, 12:27 AM
......... However, my first task (while I am finding a convenient time to get in some shed time) will be to make a copper and nickel chess set by cutting and crossing two bits of sheet metal. .......... Cam
I hope we get a couple of pictures of this (hint).
I have clamped-up, using your method, some pure cotton material and it will stay clamped till I recover from a touch of surgery next Wednesday. I hope over clamping/drying is not an error. I had the opportunity to buy towling at very cheaply - boy, does that soak in the resin.:cool:
soth
CameronPotter
7th February 2007, 05:24 PM
Hi,
I hope your surgery went well!
I am looking forward to seeing how your lay-up went.
I will certainly post some piccies of my chess pieces when I get around to doing them - I need to find time to get some sheet metal first though and I am just insanely busy at work right now...
Cam