Hey! Im still researching resins for an upcoming project and thought Id finally found a good option when I stumbled onto a nugget of information stating that it`s known that vinylester resins bond well to fiberglass but not so well to carbons and aramids??!!
Anyone? Truth or not?
Ray
VE resin bonds fine to carbon fiber or aramids but it doesn’t bond well to epoxy resin.
The sizing (coupling agent) on most carbon fibers is for epoxy. Something overlooked often, by both the buyer and seller of the fabric. It’s something you need to ask when you buy your resin and fiber…they might have VER or a universal compatible sized fiber, that will be fine.
Aramid is a bit different. While I don’t know if it’s sized, aramid is a bitch and a half to trim, because the fibers will cut/shear WAY after the resin will. When sanding, the resin will sand away, and the fibers will hold on (after all, kevlar IS abrasion and cut resistant!!!) There are methods that work depending on what you need to do. So far, the BEST way to cut an aramid composite is waterjet. Some people have good luck with a bandsaw running backwards.
Trimming VER and carbon, even if the sizing is incompatible is possible, but it takes some careful trimming. Cut carefully, maybe with a diamond abrasive wheel, and sand with a fine paper.
Aramides usually are “loomstate” which is just plain “of the creel” so not washed or scoured. Some is scoured, however.
I have no idea if the properties are better, however…
we use epoxy, vinylesters and polyester resins daily.
epoxy sticks to vinylester and polyester
vinylester sticks to vinylester and polyester
polyester sticks to polyester
normaly the limiting factor is the resin and not the fabric with exception to the Kevlar family where polyester does not work on it, vinylester is ok, epoxy rules.
that’s it.
Τhe vinyl for carbon fiber is good and strong too. But don’t use it for 100 kevlar, the results is bad.
Hi, do you mind qualifying what you mean by Sizing? I know that will be hard to Google out.
Ok, so this is seriously messing up my plans. Im planning on making a carbon fibre fuel tank for my Aprilia Tuono but didnt want something that will crack or shatter if I “happen” to slide down the road so I was planning on putting in alternating layers of aramid between the layers of carbon. I see several people have made their own tank so I know I can do it. But I want it to last and work well, ultimate lightness I`m not to concerned with. Not igniting into a fireball I am concerned with.
Im getting the distinct impression Im going to have to make the tank entirely out of aramid to use one resin that is compatible both with the aramid and with ethanol and then have a carbon cosmetic layer?
From all my looking Ive only come up with two resins that meet UL1316 spec. Actually three resins but Id have to buy 5000 pounds!!!
Ray
Poptop: Sizing (yes, horrible name) is the coupling agent/surface finish of the fiber itself. Straight CF filaments will obviously be smooth. Not much can stick to that. however, fabrics are coated in chemicals that bond to the filaments and create a rough surface. Now, this isn’t purely mechanical…much of the bonding is chemical as well. Somthign about how the hydrogen and oxygen bonds of the sizing attract the bonds of the resin. VER and PER resins have different chemical ends than epoxies. So when a fabric is sized for epoxy, and you use VER, the mechanical bonding might be there, but the atomic bonding of the molecules between the resin and sizing are not there.
Yes, you can infuse CF with epoxy sizing with VER, and get a part. However, it will not be as strong as if it was sized with VER compatible sizing.
rhubarbray: your best bet is to get an epoxy. Then get a gas tank coating kit, instead of looking for a resin that can handle the fuel.
Wow Riff, only because I did Physical Chemistry I think I know what you are talking about. Yes indeed that is a terrible name I had no inkling.
You are talking about boundary-layer chemistry.
https://www.google.com.br/search?client=opera&q=boundary-layer+chemistry&sourceid=opera&ie=UTF-8&oe=UTF-8#q=boundary-layer+chemistry+wiki
I bet most suppliers dont think about it either and you get this bitch of a mat that is seemingly impossible to wet out and dont understand why this time everything has become more difficult and the whole time it was the binder stuff they used for the CSM (if not woven) and/or same the F’ing stuff was primed to be used with epoxy and you are trying stick it down with polyester.
And I tell you man over here in Brasil that is something you want to watch for.
I dont know what it is like elsewhere but I will tell you how Brasil supply chain works - The whole market is internationally owned, as in the suppliers of resins and composite materials to industry is by the big wigs, Reichhold, Chomorat, all the big names. But they refuse sell to clients with less than X bulk. For example for resins it is something like 25 44gallon drums in one minimum order.
So, this causes a pyramid of sub-providers who buy that bulk then add a commission and distribute it out. BUT, they often cheat on it, and are not in it also for the knowledge and long-term name. They pick up over night, they relabel stuff after having added filler (like a cocaine distributer cuts his product and you never know how many cutters there were in the long supply chain from its beginning) and with that whole culture amongst it you get blind ignorance suppliers saying YES, YES, you want this and this…
Basically you must KNOW what you want dont ever ask suppliers what you want and also know what you are trying to track back. This industry is pure chemistry and if something is going wrong you will unlikely work it out easily with so many uncertainties from the supply chain. So business success in Brasil or anywhere then with this game you need know your supplier.
The above probably broken alot of businesses in Brasil.
I did a masters in business systems as well. So when I am looking at this from business side of things is just as complicated. Let me explain more of their tricks like you get a big yacht manufacturer, they are one of the Reichhold direct buys, yes 25 x 44gallon drums of some #resin direct, audited, 100%. In fact reichhold only started up their factory for that batch because that client had booked it in advance. But then something goes wrong with the batch. Its ok but its not to the ISO standard the yachting firm needs to accept it. But remember that Reichhold executives and this yachting firm’s executives have been out on boats and screwed each others wives in mega billionaire super rich superboat orgies. So, they dump the resin onto the lower market, onto the small guys like me, the fools, the naive, the unconsrcipted who never worked out why it was all so difficult. Who are the start-up over-night little resin supply companies who pop-up to dump the above? |Get it? they start-up with a fake front, dump the resin, get 20% complaints/problems from the buyers who had stricter tolerances on their systems, disappear anyway, Reichhold and their big yachting firm partners are all saved for the day. I dont mean speak about Reichhold badly and have no evidence of the above frame other than “I know” because I did a masters in business systems and know how things are from seeing their patterns.
With the facilty I have developed now utilising the engineer consultants off of Odesk I am wanting to go even more extreme about this production machine of my poptop and put it inside a 22ft container, the whole “20 Units Batch” system, shelved and compactly organised, ambient temperature and humidity control…everything so if the machine stops doing what it is told to do I can quickly and confidently work out what it is - How? Because if you have an open factory with it sitting there how do you know if a disgruntled employee didnt slip some cobalt accellerator into your resin drums? Too much power to allow anyone come next to a money machine. This RTM machines, if you got the market, these are money machines. Locked and secured inside the container you can stack them, add more moulds to your factory all have their own checkpoints through their big barn-doors on the containers, and one resin machine running around for the whole shop, wheeled into the container for a session then waltzed around to the next container. For sure, I am going to put this all locked and secured inside a 22ft container and that baby is going to pump me out money and lots and lots of it!!!
But Riff, having done Business Systems masters, all of that said above just means bigger profits for me cause all the would-be guys who are going to come in against me are going to get efd up the you know what from two directions. One will be my chemistry knowledge and the other will be my masters business systems knowledge. They will think they can come into the market competitively, while I am out there causing economic revolution with Kombi vans, they will be wanting to come in and oust me while looking like innocent competitors at worst otherwise nothing to do with it at best. But I will beat them. My 22ft container, that innocuous container, will be carrying a pay-load bigger than the Weapons of Mass Destruction Bush was talking about so vehemently before the Iraq invasion, before they becamse known as their affectionately praised acronym WMDs!,my 22ft container, alone, conquers all of South American and destroys the CIA, that single unit in that single space, with a dead cat in the corner and a drueling dog for every hour bell, side by my side, and a canary there just for a joke, my 22ft container will cause a massive hippy cultural revolution across the entire south american continent and inadvertantly end up having nudged the old movement back into action who resurrected the acts to have the CIA abolished and executed like the Nazis AND, finally, give them a choice of how they would like to be executed and then deny them even that too. If they wanted to be burned we will drown them. If they wanted to be hung we will throw them off a plane from 15,000ft, if they wanted to be shot we will stone them.
Why? Because I want a billion dollars. They will call me a terrorist when I am a lawyer. They will call me a vandalist when I am a camerman. They will call me a traitor when I am a patriot. And so I will stone them when they asked to be shot, I will throw them off a plane at 15000 ft when they had asked to be hung, and I will drown them when they had asked to be burned.