Dope thinner

I'm with Mr. Haddad- I never use MEK, based on the thiry year-old popular info we used to get in the workplace. If you like it, go ahead and bathe in it if you so choose. Put it on your cornflakes in the morning- it's harmless, remember? It can be a Darwinian thing... It sounds like a no-brainer to me, I try to minimize exposure to these chemicals as much as possible. I'm avoiding MEK altogether, because to use it anywhere is to breathe it, and I try not to get epoxy, dope and thinner, fuel, acetone, lead from solder etc on my fingers and hands any more than is unavoidable. None of that stuff is good for you. It ain't that difficult... Paul

Exactly. Well written.

-- Ray

Spot on, Paul. Down here in Australia, asbestos is a huge problem. A nationwide company used it against warnings back in the 1950s and nearly every home in Australia is affected by the use in some way. People here do a lot of DIY stuff and when they start ripping out the old asbestos panels, roofs or fences, the entire neighborhood becomes subject to clouds of airborne asbestos particles. The workers are all dressed up from head to toe in filtering and protective clothing handling the stuff while children on their way to school walk by.

Every now and again an idiot comes out and states that there's really nothing all that dangerous with asbestos.

Sounds a lot like the MEK crowd here. They should all gather at the MEK Cafe for lunch.

-- Ray

All chemical reactions have an activation energy between the starting materials and the products. Think about it this way. You are sitting at the bottom of a hill. You know on the other side of the hill the valley is 100 feet lower then where you are at the start. But even though the whole trip results in going down hill the first thing you must do is go up hill.

A chemical reaction is exactly the same energy wise. The starting materials are at some given energy level and the products are at some other lower energy level. If this were not so the reaction simply would never go. You can not go uphill in total energy.

But before you can get to the products the starting materials must climb an energy hill that is called the activation energy.

All a catalyst does is lower the height of the hill enough to make it easier for the starting materials to get to the top by normal random thermal vibrations. A catalyst is anything that will lower the activation energy AND is not consumed in the reaction. Both things must be met or it is not a catalyst.

MEKP breaks down (almost imperceptably at room temperature if not catalyzed) to form active intermediates called free radicals. These free radicals react with the components in polyester resin to make resin free radicals. The resin free radicals react with more of the polyester or with the styrene to make the resin bigger and bigger until it becomes so big it is rigid.

The problem with just adding MEKP to the resin is that the MEKP breaks down so slowly as to be useless unless you heat the system way up. So most room temp cure polyester resins come with a catalyst pre added which will speed up the breakdown of the MEKP to free radical products. Very often the catalyst is a cobalt compound. The cobalt is not consumed and is still in the final cured product in the same form as when it was in the uncured resin. The next time you use a liquid polyester watch the color after you add the MEKP. If cobalt is the catalyst you will see a significant color change as all the cobalt originally is in the 2 valence state and the MEKP oxidizes it to the 3 state. But the 3 valence state also reacts with MEKP going back to the 2 state and giving another free radical.

Polyester resins usually also have a stabilizer to prevent early cure due to traces of free radicals from oxygen in the air for instance. Some use hydroquinone for such inhibition. This also gives the advantage of increased pot life. The result is when you add the MEKP the first MEKP that is broken down into free radicals is immediately consumed by the stabilizer. It takes some minutes for all the stabilizer to get used up before the free radicals are available to start polymerization.

Thats about as good as I can do in a short version.

Put up or shut up. No data provided is proof of no data available magician. Hardly a profession which qualifies you technically for anything.

Taking on your theory requires no effort aside from allowing you to use MEK as your heart desires. You go for it, mate. You will reap your rewards for that. Just don't advise others to be as casual as you are regarding MEK or any other dangerous fluids or materials.

There will be no "put up" other than to redirect you to the label on the MEK can. As to the "shut up" bit, that's up to you.

-- Ray

SNIP

Really? I put the MSDS out there for everyone...reasonable people would accept what is on the MSDS all others are not smart enough to be called a newt.

-- Keith Schiffner So what's so bad about HARD proven data?

Wow! Pretty good explanation, but I think I'm sorry I asked. I did manage to follow most of it, but that is more detail than I ever need to know!

Its a good thing neither of you are in anyway concerend in studying human biology, or you might be scared to death as to what the human body itself uses in internal reactions as part of its normal operation

Well, here we go again. Everything in the world is dangerous so let's all raise a glass of MEK and toast the morons here!

-- Ray

Yes, everything in life is dangerous if misused. At least we seem able to agree on that. There are even essentual nutients that cause you to die if you do not get small amounts. But those same things will kill you if you overdose. Just a few examples. Iron, copper, selenium and some vitamins. People have died from over exposure to all of these.

Say you are a hobbiest who is excessive about his hobby. Perhaps you might use a gallon of MEK per year. I doubt it but perhaps. With any decent hygene at all you will ingest way below an once of that gallon over the course of a year. About the only way you could ingest that much is if you swallowed it. Inhalation and skin absorbtion will not give you an ounce a year ingestion exposure no matter how sloppy you are. If you are swallowing it you are so careless you are stupid.

So what are the facts about an ingestion of less than an ounce a year? The data clearly shows you have zero chance of getting cancer from such an exposure. Not even a chance in 10^12. The data also shows you will not suffer any other adverse health effects. No reasonable person should take this as a reason to be careless with it either. Use it such that you minimize your exposure as best you can.

On the other hand what are the chances you will get killed in your car driving to a flying field ten miles away? Well the statistics say you have about a chance in 10^6 of getting killed on that trip. So driving to the flying field is at least a million times more dangerous then a small exposure to MEK.

But most of us are happy to jump into the car and drive 20 miles round trip and not think a thing about such a risk. Why? Easy. It is a risk we all know of and are prefectly comfortable taking.

If you refuse to provide the manufacturers name, the label statement you claim says MEK causes cancer and the lot number then your claim is meaningless. Others have provided data and references. You have not.

And stop saying I am suggesting people should drink MEK or brush their teeth with it. I have never said that and to the contrary I have repeatedly said it is prudent to minimize your exposure to any chemical by following prudent handling practices.

Put up or shut up.

And here we have the belly bucking contest continuing. As I have stated over and over again, use it yourself if you wish. Just don't take it upon yourself to advise others to be as casual as you are regarding the use of MEK. Period.

-- Ray

Thers a novel copncept which doesn;t sem to have permeated whats left of your Brain Ray, its called 'relativity'

The question is not whether something is dangerous or not, the question is how dangerous.

And in what context.

Plastic bags have killed. So have stairs. Should we ban them?

Well I used a lot of it yesterday and today as it happens. Welding plastic guttering parts together.

Apart from being classed as an irritant which it isn't much, as I ended up smearing the goo it was incorporated in with my fingers when the brush broke, and the usual warnings about not sloshing it about in confined spaces, I can't say I am actually dead of cancer art this point in time.

I used tons of it when I was a kid 40 years ago: My mother would come into my bedroom and say 'coo,. thats smells strong: I'll open the windows and clear the fumes. I never died of it then either, or developed cancer since.

OTOH there was at least one case of a kid who was found dead over the open gasoline tank of his fathers motorcycle...I remember that as no one had told me (unlike dope thinners, where they HAD told me not to breathe in too much') that petrol, as we call it here, was in anyway dangerous as long as you didn't light it..

Frankly unless you drink it, or suffocate yourself on fumes its probably very hard to damage yourself, and it is probably less dangerous in ether of those contexts than than gasoline.

Which, I was utterly surprised to find , having decided to use it to clean the gunk off my Cox Pitts special CL biplane, actually dissolved the plastic on it! Plastic that could handle 15% nitro fuel!.

First of all, I have never advocated banning MEK. I simply ask that you and others here refrain from discussing how "safe" it is when a person asks a serious question about using the stuff. At least be honest and state that it is, indeed, dangerous. It may not be dangerous enough for you but it certainly does warrant careful handling. As do many other substances and things.

That's the point of this exercise and discussion of safety.

If you want to use it casually, go right ahead and do so. The Darwin Award awaits you. All I ask is that you allow others to consider the risks without your constant niggling away at how dangerous it really is when it's clearly not safe at all. There are dangers. They need to be noted and avoided.

-- Ray

Thank goodness for that otherwise your address would be snipped-for-privacy@heaven.com and you wouldn't need an RC airplane to fly.

-- Ray

SNIP

All the time I just KNEW you were the one proposing that, not others. Thanks for clarifying it for us. That being said, I think that is a great and wonderful idea of yours, Ray. I will even buy the first round for you!

On Sun, 12 Aug 2007 23:43:34 GMT, I said, "Pick a card, any card" and "Six_O'Clock_High"

Drink up, Jim! Enjoy!

Since you fail to see the difference between a serious proposal and my mocking of the idiots here, you unfortunately go to the head of that classification! Well done.

-- Ray

Well Ray even if you NEVER use a single drop of MEK you are still being exposed to it. You see there are quite a number of components of food, cosmetics and perfumes which have chemicals which your body turns into MEK as part of its normal and natural metabolism. In fact this "natural" MEK would likely exceed any amount that a hobbiest would ingest if he used anything at all like reasonable handling practices.

So bottom line is YOU ARE EXPOSED even if you think you are making life safer for yourself by not using it.

Exactly the same thing is true of acetone (nail polish remover). Your own body makes acetone every single day you are alive as part of protein metabolism. In fact on some low carb, high protein diets your body makes so much acetone you can smell it on the dieters breath.

There is an old saying among Toxicoligists that goes "The dose makes the poison." All they are saying is everything is toxic and can poison you if you get the dose high enough. But we all know that lots and lots of things do not poison you at reasonable doses. Water is a fine example. Drink proper amounts and you are just fine. Drink improper excessive amounts and you are dead in hours. As I have said before it is well documented that several people die each year due to drinking too much water. Face it, it happens.

This is really very basic stuff and not hard to understand.

So put up the requested information or shut up. As you do not have the requested information because you lied you have one choice.