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Least Poisonous Metal Prep Solvent

Posted: Mon Dec 13, 2010 9:53 am
by john_r_graham
Although I haven't made the decision on exactly what priming system to use, many of the systems call for cleaning / degreasing one or two times with a solvent like lacquer thinner or MEK. I'm wondering if denatured alcohol is an acceptable substitute as I believe that, being mostly ethanol, the vapors are probably relatively nonpoisonous. I've even considered getting reagent grade ethanol without any methanol.

Now, don't get me wrong. I've already acquired a Hobby Air respirator and am about to plumb in a fresh air source for it from far away from my shop. My thought is that it would still be best to use the least personally and environmentally damaging solvent available. Am I off base?

- John

Posted: Mon Dec 13, 2010 10:34 am
by clreding
After trying a bunch of different approaches I finally settled on a simple wash with alcohol and a fine scotchbrite pad followed by rattle can acid etch primer. I went with alcohol for the same reasons you a thinking about it, no or extremely low toxicity compared to other solvents like mek.

All I can say is , so far so good. The primer seems bomb proof with good adhesion. The real test will be 10 years down the line but to be honest my Cessna 172 does not have even a little primer on it and it's over 30 years old with NO Problems at all so who knows if it's even necessary

Craig

Posted: Mon Dec 13, 2010 12:06 pm
by john_r_graham
Same was true of my 170: no primer at all that I could see and, with the baggage compartment back cover removed, the inside of the fuselage looked pretty good for a 50-year-old bird. :)

Thanks so much for the advice.

- John

Posted: Mon Dec 13, 2010 2:59 pm
by Wicked Stick
Metal Prep 79

It's blue in color and is perfect for prepping aluminum.
You let it soak in, rub it around, and then wash off with water.
It's kind of like Dawn Dishwashing liquid, but wear gloves as it does have some etching solution to it.

It works great for killing any minor corrosion on used aluminum too.
Just be sure not to let it dry out on the part, and rinse with water thoroughly. Also, you can dilute it with water to get more mileage out of it.

Posted: Mon Dec 13, 2010 4:34 pm
by cjensen
Are you painting Dave?

Posted: Mon Dec 13, 2010 5:46 pm
by hydroguy2
painting is fun.....he prep not so much. But The amount of cleaner you need is actually minor unless you are doing a full prime and seal every surface. I only used 1qt of acetone and another qt of lacquer thinner during my whole build.

BTW-the guy I worked with painting has an offer from someone who wants to buy his autoshop. There will be a non-compete clause, SO he wants to build a big hangar and start painting planes. He's already done 18 so figured he could do more if people could fly in. We may team up, I need something to do anyway.

Posted: Mon Dec 13, 2010 6:02 pm
by cjensen
Awesome! Keep me/us posted on that Brian...I just sent a request for a quote from the shop that did Lance's 8...

Posted: Mon Dec 13, 2010 7:39 pm
by Mike Balzer
I just used Isopropal Alcohol for wipe down before priming. I put it in a spray bottle and use a clean rag/towel to wipe surfaces dry.

Havent had no issues and is better for you than acetone or MEK.


Mike Balzer

Posted: Tue Dec 14, 2010 9:29 pm
by Wicked Stick
cjensen wrote:Are you painting Dave?
No plans to paint my plane in the near future.
That's why I just did a primer/sealer on it for now.

Posted: Wed Dec 15, 2010 5:03 am
by BSwayze
I followed the advice of my tech counselor, Randy Lervold, throughout the build, using naptha. More commonly known as Coleman Lantern Fuel. It comes in a rectangular can and a gallon costs less than $5.00. It's the perfect cleaner as far as I'm concerned. It's much less obnoxious than MEK or acetone. I use it with a scotchbrite pad to scuff and clean at the same time. Works great.

I've also used some of the Metal Prep 79, diluted with water per the directions. I've had excellent results both ways.

Posted: Wed Dec 15, 2010 8:33 am
by cjensen
That's a great tip! I hadn't heard of using that before... 8)

Posted: Thu Dec 16, 2010 1:47 am
by BSwayze
Thanks, Chad! Sounds like I'm a bit late to help you with your plane, but hopefully it will help someone else here, or for your next project.

For anyone interested in reading Randy's comments about primer and using naptha for prep work on his website, here's a link:

http://www.romeolima.com/RV3works/Airfr ... tml#Primer

Re:

Posted: Sun Jul 19, 2020 2:36 am
by Stephaned01
clreding wrote:
Mon Dec 13, 2010 10:34 am
After trying a bunch of different approaches I finally settled on a simple wash with alcohol and a fine scotchbrite pad followed by rattle can acid etch primer. I went with alcohol for the same reasons you a thinking about it, no or extremely low toxicity compared to other solvents like mek.

All I can say is , so far so good. The primer seems bomb proof with good adhesion enseigne Antibes. The real test will be 10 years down the line but to be honest my Cessna 172 does not have even a little primer on it and it's over 30 years old with NO Problems at all so who knows if it's even necessary

Craig
If I were you, I would have used bleach instead of something aggressive.