SteelMike

SteelMike

Well Known Member
Since I’m rattle-can priming, I haven’t had the pleasure of working with MEK yet. Now I’m sealing the tanks so, of course, MEK is inevitable.

Here are two general questions:

First, this stuff is gnarly. You know how you’re supposed to “wash” your rivets? Well, here I go merrily along pouring rivets+MEK into a plastic cup. Little did I know… I turn around for a couple of minutes and when I look back, the cup is completely melted into mush on my workbench. Also, I can smell it through my respirator (and I can’t smell other compounds), and I swear I could taste it when I was done last night. I’m wearing thick gloves and a respirator – is that safe or do I need more? Also, when it gets to sealing with proseal, am I okay with gloves and a respirator? Checkoway’s rvproject.com refers to proseal as “Black Death” and mentions that he’s under a full face hood. Do I need similar? [edit: does proseal melt cups, too, btw?]

Second, regarding cleaning: I have a clean, brand-new rag that I’m basically soaking with MEK and using to scrub tank parts. Is that acceptable or do I need to do more? For instance, do I need to rinse the MEK off with something else or does it just evaporate away?

Many thanks….

MB
 
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SteelMike said:
Also, I can smell it through my respirator (and I can?t smell other compounds), and I swear I could taste it when I was done last night.
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Do make sure your respirator fits and seals correctly. Horror story: I'd never used a respirator before I got my first one from HD. The instructions said to place my hands on the cartridges, inhale and hold my breath for 10 seconds. The air should not leak through in that time. I couldn't get that test to work, even though I was positive the mask was very well sealed around the sides. I figured it must be leaking around my hands on the inlets and proceeded to use it. It would seem to work - it filtered out almost all the smells, and I could do a full hour of priming and cleaning before I would get a headache.

After a few sessions of this, I got a second one for my helper. The seal test worked on this one! No smells at all anymore, no headaches. I used MEK and proseal on the rudder wedge, no problem (I have no idea what they smell like).

I returned the bad respirator and now take the leak test more seriously.
 
SteelMike,

For MEK cleanup I used a couple of old coffee mugs (Porcelain or glass). One was a "clean" mug and the other termed as "dirty". The dirty mug was for soaking cleco's as I pulled them from the tank when riveting. The clean mug was just to hold a small amount of MEK or Acetone for dipping, enough for the current cleaning/cleanup job. MEK cuts through proseal quicker than Acetone and doesn't evaporate as quickly.

For rags I used a combination of the boxed paper shop rags, and clean cotton rags. (Old shirts) The paper I used primarily for cleanup after working with the proseal. The cloth rags were for cleaning the surfaces prior to prosealing. With each I cut them into small squares, about 4 to 6 inches. This made cleanup a breeze... grab a square, dip it to soak it, wipe and toss.

Gloves and a good respirator definately recommended.
 
Thanks for the input, guys. Is proseal as bad? Does it melt plastic cups?

I'm doing the "hand over catridges test" on my HD respirator and it works... okay. I haven't smelled any of the other stuff I've been using (primer)... Okay, maybe just a little teeny bit. The MEK was pretty strong last night as soon as I opened the bottle.
 
Proseal smells a lot like burnt gunpowder. By itself it is not particularly harmful but it does stink and is incredibly sticky so get plenty of gloves. It cures slowly and does not generate a lot of heat. It is also not corrosive so it won't eat plastic cups. For MEK or other solvents, I use glass jars. A respirator is a good idea, as well as making sure the area is well ventilated (otherwise the smell hangs around). You don't need to rinse off the MEK; it is the rinse. It dissolves all the oils and such that might prevent a good bond and allows you to wipe them away with the rag. Then the remaining MEK evaporates leaving a good clean surface for bonding. That's another good reason to wear gloves; so you don't put oils back on the parts after cleaning them.
 
thanks again, guys. I think I'm okay. I got some glass jars to use. I think I might try to return my HD respirator if they'll take it.

Seriously, though... you don't want to screw around with that stuff, huh?
 
SteelMike said:
thanks again, guys. I think I'm okay. I got some glass jars to use. I think I might try to return my HD respirator if they'll take it.

Seriously, though... you don't want to screw around with that stuff, huh?
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This has been discussed at length (search "MEK"). Even though MEK smells like certain death, and you should use lots of ventilation and a respirator, it is not as harmful to our health as some of the other stuff often found in a shop.

I much prefer to use Coleman Lantern Fuel for final prep before proseal since its primary ingredient, naphtha, leaves no residue and the stuff doesn't cause a headache like MEK. It is, of course, quite flammable, so use with care.
 
I walked in on a friend using mek to clean some parts once and immidiatly inhaled what must have been just shy of a mist of it, now every time I smell it I get something resembling a respritory infection for two weeks. As for proseal, I don't really even notice the smell anymore.
 
The smell of MEK reminds me of the glue I used to use as a kid to build balsa wood airplanes. Much more sensitive to the smell now though--definitely need a respirator, but whenever I get a little whiff, it brings back good memories.
 
MEK vs. Lacquer Thinner

I started using MEK and switched to lacquer thinner to clean tools, rivets, and parts which I thought was acceptable but none of the comments on this thread mentioned the use of it. MEK was too disagreeable for me so I switched and have since built 4 tanks and repaired a 5th with no leaks although 2 haven't had fuel in them yet. The others all have 250 plus flight hours and about 4 years on them.

Dick DeCramer
RV6 N500DD flying
RV8 Wings complete
Northfield, MN
 
Having experienced a "episode" using this stuff and being a safety professional I give you the MSDS.

Don't inhale, don't let it get into your skin, don't expose yourself.

The PEL's are a baseline. Reactions are specific to prolonged exposure, the more you suck up depending on your own metabolisim, the more you are exposed, the greater chance you will experience an over exposure event. Note the many "unknown" results.

It ain't pretty.

http://www.sciencelab.com/xMSDS-Methyl_ethyl_ketone-9927358
 
MEK

SteelMike said:
Since I?m rattle-can priming, I haven?t had the pleasure of working with MEK yet. Now I?m sealing the tanks so, of course, MEK is inevitable.

Here are two general questions:

First, this stuff is gnarly. You know how you?re supposed to ?wash? your rivets? Well, here I go merrily along pouring rivets+MEK into a plastic cup. Little did I know? I turn around for a couple of minutes and when I look back, the cup is completely melted into mush on my workbench. Also, I can smell it through my respirator (and I can?t smell other compounds), and I swear I could taste it when I was done last night. I?m wearing thick gloves and a respirator ? is that safe or do I need more? Also, when it gets to sealing with proseal, am I okay with gloves and a respirator? Checkoway?s rvproject.com refers to proseal as ?Black Death? and mentions that he?s under a full face hood. Do I need similar? [edit: does proseal melt cups, too, btw?]

Second, regarding cleaning: I have a clean, brand-new rag that I?m basically soaking with MEK and using to scrub tank parts. Is that acceptable or do I need to do more? For instance, do I need to rinse the MEK off with something else or does it just evaporate away?

Many thanks?.

MB
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Not necessary to use MEK, and it's expensive. I used lacquer thinner for cleaning the tanks and rivets. Roll of plain paper towel, a cheap glass or ceramic dish(small one from Big Lotts or Wally World), and a table spoon. Fill the small glass dish half full with lacquer thinner. Pour in some rivets, enough for the job. Let them soak, stirring occasionally with the tablespoon. Wearing examination gloves, powder free if you're latex sensitive, soak a couple of sheets of clean paper towel with lacquer thinner. Wipe down your tank skins, let them air dry. On a clean piece of paper towel spoon out a tablespoon of pre-soaked rivets, let them air dry. Place a good bead of proseal along you rivet line. Clecoe the ribs in the tank skin-all the ribs. Rivet away. I used a cheap stainless steel mixing bowl, like for large salads, and filled it 1/3 full of lacquer thinner and just dropped the clecoes in it as I took them out while riveting. When all done riveting the ribs run another bead of proseal over the flange and smooth it in with your finger, so all the rivet shop heads are covered and the flange is completely covered, another small bead on the web side of the rib doing the same thing with your finger to push the proseal into the gap between the rib web and skin. Clean you soaking clecoes with a small wire brush. Most of the proseal will come off the clecoes so you can reuse them on the other tank. Soak the cleaned clecoes in clean thinner and let them air dry before using them on the other tank. Be sure to clean the clecoe stem completely and the base so you don't contaminate the other tank when you use them.
Hope that this helps,
Mike H 9A/8A
 
The 'smell test'

After many years around processes that used paints, thinners and exotic materials, I can only offer the advice that if you can smell or taste these materials through your respirator face mask, you need to get out of there and find out why!!! Immediately!!!

As in most tools, you get what you pay for. Most auto paint supply stores can show you several brands (and sizes) of quality respirator face masks. Pay the $18-25 and get a quality mask. Purchase one set of cartridges (2) and use them religiously. Purchase a second set of cartridges and plane them inside of a sealed can for future use. Throw out any cartridges that let the hazardous materials through.

It is important to get the right size respirator mask. Try on a few sizes until you have a complete seal as mentioned by a previous poster.

As a boy and young man, I ignored warnings like the one and as a 'rookie' firefighter forty plus years ago, I was known as a person who could take a real beating at fires and at hazardous materials incidents. It was macho (and not very smart in retrospect). We didn't know much about hazardous materials. I am now paying the price with cancer but you all don't have to if you just keep in mind that if you can smell or taste the hazardous material, you need to get out of there asap and get to fresh air. Cancer is pretty serious stuff!!! Don't be dumb like I was!!!
 
MEK

Never used MEK and hopefully never will. I have used Lacquer Thinner for all of my cleaning and soaking. I found that an old ashtray works great for soaking rivets before riveting. Lacquer thinner leaves a residue but I understand it effects nothing.
 
One of the points touched on here is that you can overexpose yourself (calm down, perverts) and end up with a lifelong sensitivity to the stuff. I say use a respirator and, probably more importantly, do it with LOTS of fresh air around.
 
Nobody has mentioned acetone...We used acetone with no problems. Large garage with door open when working with the acetone, which wasn't much time, actually--clean rivets, skins, put the rags outside & go to work with the Proseal. No respirator.

Look at the MSDS for MEK, under "Personal Protection": "A system of local and/or general exhaust is recommended to keep employee exposures below the Airborne Exposure Limits". Notice "recommended". And for acetone, same thing. So set up a fan to blow from you to across where the chemical is if you are worried, but it won't kill you on the first whiff. Note that acetone is used as nail polish remover. Women use it all the time at home, in the house without injury.

If you feel a respirator is really necessary, be sure you get the right kind. Most are simply filters to remove particles and won't remove vapors.

Not to downplay the problems some folks have reported, but my father in law was a paint chemist starting in the 1930's & hazard protection was pretty minimal. He got his hands in MEK, acetone & other chemicals and breathed the vapors routinely & died of heart failure well into his 80's.
 
QUOTE: Not to downplay the problems some folks have reported, but my father in law was a paint chemist starting in the 1930's & hazard protection was pretty minimal. He got his hands in MEK, acetone & other chemicals and breathed the vapors routinely & died of heart failure well into his 80's.


Maybe he would have made it to his 90's...everyone is different...like smokers who make it to thier 100's
 
Another Option!

The purpose of cleaning parts is to remove the oils and grease that comes from handling the parts and from manufacture of the metal. These contaminants weaken the bond of paint or sealants. A great non toxic solution is using dishwashing detergent and water. For 20 years I have used a solution of dish soap in warm water with a Scotch Brite pad to clean my parts. A good rinse and drying off with a clean towel will leave the surface squeeky clean and ready for excellent adhesion of paint and sealants. No respirator required and your hands stay clean too!

Martin Sutter
building and flying RV's since 1988
 
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