Nelsonite Problem

Here is an update on my Nelsonite vacuum chamber problem;

Jim was kind enough to send me several gaskets made of Durabla, a rubber gasket, and some grapfoil tape. Durabla appears to be fibrous material, somewhat similar to some automotive gaskets. I was unable to compress any of the durabla gaskets enough to get a seal around the rim of my vacuum chamber (actually a HarborFreight 2.5 gal paint pot).

I then tried the heavy duty rubber gasket Jim sent. The rubber gasket did seal the chamber. My vacuum container has never held a perfect seal, so every few days I have to suck the air out of the chamber again. I've never established whether the leak is through one of the teflon taped threaded ports or through the rim of the lid. In any event, the rubber gasket held up for about a week, then I began to lose the vacuum more rapidly. When I removed the lid today, I found that the rubber gasket had gotten quite limp, and it's inner edges were beginning to deteriorate.

I have not yet tried the grapfoil tape, but at this point most of my open Nelsonite is used up. Rather than opening another gallon of Nelsonite, I think I will order some of Cue Components Resolute and a piece of Floran tubing. The smell of the Nelsonite and the speed with which it disintegrates gasket material is starting to make me leary of it, especially since I have been keeping it in my basement and can smell the fumes whenever I open the basement door.

Jim, thanks again for the gaskets. If I get the grapfoil tape to work, I'll let you know. Hopefully you have received the Nelsonite treated wood I sent you by now and can make good use of it.

Mike, if you get a chance to look at the Cue Components site, perhaps you could offer your opinion as to whether their Resolute is actually less toxic than Nelsonite. Inquiring minds would like to know.
 
Chris, I would bet that the Resolute is probably safer than the Nelsonite, but that is a relative term.

Mineral spirits is one of those generic terms like "quench oil" that can mean many different things. It is a mixture of petroleum products, and can vary quite a bit in composition. It can contain some of the same nasty crap like benzene that you find in naphtha.

If you read several MSDSs about mineral spirits you'll find that they have differing descriptions of toxicity based on their specific mix. Where I could find industrial rating values in MSDSs, both mineral spirits and naphtha carried a "2 (Moderate)" health hazard rating. They both carry the same spectrum of generalized concerns, so it is probably only to a matter of degree that their hazards differ. Resolute is by no means non-toxic.

What I would personally do before I purchased is request a manufacturer's MSDS. Better yet if they'll provide one for Nelsonite, too. If they refuse to provide an MSDS, I wouldn't personally trust their claims.

All that said, we paint our houses and use paints that are loaded with crap like this. Most of the time, the health concerns are for people who use it in industrial settings, with heavy exposure day in and day out. Longterm exposure to a great many of these solvents can cause cancer in susceptible individuals. Regardless, I wouldn't want the fumes in the basement constantly and I'd strongly recommend some manner of ventilation, like a fan in the window blowing out when it reeks.

One other point I'd make is that, since they claims it smells a lot less, it probably means it has a lower "vapor pressure" (chemistry term), or evaporation rate. That means it'll take longer to dry, and soaked blocks could smell of solvent for months. When Nelsonite was first gaining popularity, on of the cue sites stated that the blanks frequently smelled months later after prolonged storage and subsequent shaping.

That's just my opinion. OMMV
 
I bought the big bag of B-72 in pellet form a while back and it goes a LONG way!! you can make the minwax wood hardener too thick. Less than 1/4 cup to a whole can of hardener is pretty thick, almost too thick to absorb. After I set up my mason jars if they are too thick I cut it with MEK. I am extremely pleased with the hardener/B-72/MEK. I still use a thin bead of caulk wet on the gasket to get a seal. when the lid gets tight the viscosity of the wet caulk is too thick to pull through and leak. It was messy at first, but then I got a system down and I only have to peel off the caulk after it is dry from sitting during the vacuum for days.
 
Mike, Thanks for the info. I had not heard of that Acryloid B-7 stuff, but it sounds interesting. Whatever I end up using, I think my enclosed back porch would be a better place to store the stuff. That way, any noxious fumes that escape will not be in my house.

Gixxer, I notice you've mentioned in the past that you intended to try Resolute. Did you ever get around to trying so and, if so, how did you make out?
 
1) You need nitrile or, even better, fluorurate rubber, which is impervious to any chemical aggressive and is used for chem lab safety gloves and bench mats.
It's also very expensive.
2) That stuff you are using may be SERIOUSLY DANGEROUS! It may contain benzene, or toluene, or xilene, which are seriously carcinogenic.
 
Chris, if you think Nelsonite is a problem you should see what only 5% nitric acid will do to a gasket. I am currently looking for a better container for my Nital etchant, as it will turn a rubber gasket into goo in about a week:(. While I would not drink, or intentionally breath the fumes from Nelsonite it is not exactly radioactive or nearly the hellish venom that it is being perceived as. My salts have to be ten times more likely to kill or injure me and they are still pretty handy as long as I respect them. I have pure xylene, toluene, naphtha, MEK... all sitting in containers in my shop and I use them with the appropriate care all the time. Am I concerned about carcinogens? Yes sure, but I have also been told that grilling my steak will give me cancer, countless food additives have been proven to kill me, the very the air we breath is our demise, if we get too focused on all of this.

Be aware of your materials and hazards, be appropriately careful, but remember that virtually everything in our shops can hurt us; just because it can swell a gasket is not enough reason for me to flee in terror yet.
 
You just have the wrong gasket, Kevin. Try Teflon. :)

Any chemical can be worked with safely. It is a matter of awareness, training, and proper handling. The purpose of the dire warnings on MSDS is to state "worst case"; to try and insure that proper precautions are taken.

I've worked with chemicals so toxic that 1mg would kill you, and yet this very chemical was a beneficial pharmaceutical in a very tiny dose. I've handled radioactive substances at lethal levels, too, and yet in small doses they are therapeutic drugs. The chemical cabinet in my lab had several of the chemicals on that carcinogen list. Toxic chemical exposure was an everyday occurence, but we were expected to know their hazards and protect ourselves appropriately.

It's all about proper awareness and correct handling. Wear the respirator, wear nitrile gloves, clean up messes immediately. The whole idea is to not consider yourself impervious, but as Kevin says, it doesn't mean you can't handle them safely.
 
fitzo said:
While there is no disputing the toxicity of xylene and toluene, it should be noted that they are NOT listed as carcinogens in either their US MSDS nor are they on the OSHA carcinogen list.
http://www.epa.gov/tri/chemical/carcinog.pdf
Click to expand...

Yep, but have been forbidden here in Europe and in many countries for that reason.
It may be a disputed point, but are you willing to bet your life on it?
Use a breathing mask and protective gloves, and you should be fine.
And, one thing is reading government material lists.
Another is meeting a guy who got blood cancer due to continuous exposure to such shit.
:rolleyes:
Believe me.
Better safe than sorry.

Edited to add: Fitzo and Kevin: my point exactly. If one should be paranoid, he shouldn't mess with red-hot steel to start with :D
I just meant that around certain substances one should take appropriate protective measures.
 
Regarding gasket and container compatibility, here is an interactive table where one can figure out what to use for different applications. We used ColeParmer's chemical resistance tables all the time. http://www.coleparmer.com/techinfo/chemcomp.asp

Kevin, if you search on both the nitric acid and the particular alcohol and "blend' the two, you will find that there are numerous choices available for containing your nital. Polypropylene will probably work just fine. I don't know what your needs are, but perhaps one of these would work: http://secure.sciencecompany.com/HDPE-Plastic-Bottles-C2626.aspx

Hope that helps.
 
Chris Meyer said:
Gixxer, I notice you've mentioned in the past that you intended to try Resolute. Did you ever get around to trying so and, if so, how did you make out?
Click to expand...

No I did not try the resolute. I was so happy using my current setup that I have not changed yet. Not to mention that since the Acryloid goes so far it was more cost effective to start off with the hardener and adjust with Acryloid and MEK. Not to mention that the MEK and hardener are readily available at Depot.

Some folks have been concerned about the acrylic impregnated stuff turning to plastic after finishing. I can tell you that after finishing a piece of walnut burl to 2000 grit, you can feel the difference from before the superglue was applied and after. The superglue buffed out to glass and the plain wood was super smooth but slightly dull looking.
 
Kevin R. Cashen said:
...I have pure xylene, toluene, naphtha, MEK... all sitting in containers in my shop and I use them with the appropriate care all the time. ... just because it can swell a gasket is not enough reason for me to flee in terror yet.
Click to expand...

Kevin, I agree, but you may not have noticed that I am (foolishly) using the Nelsonite in my basement. I live in two story house with a full basement, so when the vapors leek out of the vacuum container they are getting into my living area with my wife and kids. I don't want to put them (or me) at risk, so I'm going to move the stuff out of my house. Then, when I do find a better gasket it will just cut down on my Nelsonite consumption.

Gixxer, thanks for the update.
 
Chris, I read this knowing I sent an email asking about it and right after that the wife gave me the package with a Oh this came for you. I am not sure of the make up of the rubber gasket but, it was neopreme at a minimium. That stuff has to be harsh. I will go down to the alkilization unit and look at their teflon gaskets and see if I can find one that will work. I was in the main store when I was making the gasket and they have lots of exotic gaskets but, none that would fit. Try taking the durabla gaskets and taping them with the graphoil on both sides. The graphoil doesn't have to go on perfect as it will smash out easilly to form a uniform surface. It should work a couple times then just tape on an another layer. I would keep all these chemicals out of the house. I am 56 years old and I have seen many chemicals that were thought to be ok get added to the terrible list. I would keep them stored air tight and use them outdoors. We don't need to stablize our lungs. My wifes dad is slowly dieing from lung failure mainly due to using automobile paints.We all need to watch this and lots of other vapors and dusts.
Jim

Ps thanks for the scales. You sent way to much and I owe you. Welding rod. a piece of stainless, brass rod, stainless rod stainless tubing you name it.
 
Jim, I just sent you a reply to your email and now I see you've posted here too. (I'll try to avoid being redundant.) I'll try your suggestion on the doubling up the grapfoil and durabla. If that doesn't work I'll try the Fluran tubing. I'll let everyone know how those materials work out. The vacuum chamber is going OUT of the house today, so the fumes won't really be a consideration from now on.

As far as "owing" me, you certainly do not. You were kind enough to volunteer to cut and send me those gaskets, which I never would have had access to otherwise. I already have more wood than I'll ever be able to use, given my current production rate, so those piece were cheap coinage for me. I just hope that you can get some use out of them. Thanks again.
 
Chris Meyer said:
Kevin, I agree, but you may not have noticed that I am (foolishly) using the Nelsonite in my basement. I live in two story house with a full basement, so when the vapors leek out of the vacuum container they are getting into my living area with my wife and kids. I don't want to put them (or me) at risk, so I'm going to move the stuff out of my house. Then, when I do find a better gasket it will just cut down on my Nelsonite consumption.

Gixxer, thanks for the update.
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Ahh yes, I have the MSDS sheets on Nelsonite and since they have nothing on the recommended daily dietary allowance of it, you would be wise to limit that. I just spoke with a friend this weekend that had an allergic reaction to dust from wood that had been treated with Nelsonite. So if nothing else it may be best to avoid itching, sneezing and swollen watery eyes, which I am sure would only increase on more exposure. I have to wonder if they were not concerned with peoples ill ease with the chemicals, as I have noticed that the newer Nelsonite I have bought has a fragrance; it smells a bit like baby oil now, instead of the harsh hydrocarbon chemical smell it used to have.
 
I'm a plastics guy, but I do get involved with rubbers, elastomers and seals from time to time. So, from my experience:

Common seal material such as Buna N (nitrile) EPDM and probably SBR ain't gonna work to well for these applications. Other less common seal materials such as silicone or Teflon (a fluoropolymer) stand a better chance.

For your applications I tend to think a thermoset polyurethane gasket might work best.

A foamed polyethylene gasket material may make a good low cost option too.

You can order any of these materials from MSCdirect.com
 
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