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View Full Version : Best solvent for stripping paint/grease/assorted filth off an old machine?



SteveG_CT
08-10-2011, 01:17 AM
There seem to be a lot of conflicting information on the net about the best way to strip a machine in preparation for new paint so I thought I'd solicit some opinions here. I will be picking up the latest addition to my home shop on friday (an 11" Logan lathe) and plan on stripping/repainting all of the castings before reassembling. I plan on cleaning off all of the accumulated oil, grease, and dirt with simple green and then using a chemical paint stripper. Unfortunately it's been a really long time since I've used any chemical paint strippers and I'm not really sure what would be the best choice out of what's currently available on the market.

Any suggestions?

J Tiers
08-10-2011, 01:26 AM
Plain old Zep Industrial Purple Cleaner does a really good job.

Among paint strippers, Peel-Away #7 I have used with good success on metal....... it's made for wood, but jut makes a mess there.

Use the purple first........ it's lye plus other stuff, and does a great job on paint as well as oil and grime. Dunk & soak whatever parts you can.

Don't use it on zamac or aluminum, but a Logan hasn't got that crap on it, so likely no issues there.

quadrod
08-10-2011, 07:38 AM
When i stripped my mill and lathe i use plain old easy-off. If you want something a little better get mr mussel from ace hardware. The oven cleaner works great on grease too, you can put all the small parts in a baggie and let soak over knight and rinse in the sink. Larger parts can be put in a trash bag and let soak.

garagemark
08-10-2011, 07:49 AM
Since the EPA has tried to save us all, I have yet to find a GOOD paint stripper. Everything that used to be good is junk now, taking multiple coats and a lot of elbow grease to get to the bottom of things.

I might suggest a field trip to the local auto paint store/ shop. We have a great PPG paint dealer, and while they are not technically supposed to sell to the general public, they do so. They could/ might/ maybe have some better answers for you.

Mark

Richard Wilson
08-10-2011, 08:02 AM
There seem to be a lot of conflicting information on the net about the best way to strip a machine in preparation for new paint so I thought I'd solicit some opinions here. I will be picking up the latest addition to my home shop on friday (an 11" Logan lathe) and plan on stripping/repainting all of the castings before reassembling. I plan on cleaning off all of the accumulated oil, grease, and dirt with simple green and then using a chemical paint stripper. Unfortunately it's been a really long time since I've used any chemical paint strippers and I'm not really sure what would be the best choice out of what's currently available on the market.Any suggestions?

A friend of mine worked in a middle Eastern state where alcohol was banned.
The ex-pats in the fitting shop had rigged up a still and had a drum of 'hooch' ready for a party. Somehow, the police got wind of this and came round looking. They asked what was in the drum, and were told 'degreasing fluid'
'Show us' said the police, and watched while the contents of the drum were poured over a Cat D8 engine which had just been removed from the machine.
Aparently it worked a treat, grease, paint, no problem at all.

Richard

Forrest Addy
08-10-2011, 09:14 AM
Work with a system.

Start with a putty knife and peel off all the accumulations you can. Work dry as long as possible disposing of debris in sack and boxes. When you move to wet cleaning - solvent or solution - you up the mess potential by a factor of 10. If you're concerned about scratching the paint use a plastic spatula. Remove sheet metal, covers, and panels in the way. Use a shop vac to pick up the loose material as you make it. Use picks and screwdrivers to extract debris from crevises.

Use mineral spirits paint thinner to remove oily residues. Work small areas at a time using a stiff bristle brush to scour adhesions and loosen fillet of goo bound debris. A cord passed a couple of turns around lead screws and see-sawed will clean them to the roots. You will learn the trick of crossing one end over the turns to skip to the next thread.

Use harsh chemical cleaners only as a last resort. I use 409 kitchen cleaner for final cleaning on paintwork and I don't use much - a mist, let it set for a minute and wipe it off followed by clear water.

Note chemical cleaners are hell on paint and your lungs and mucosa. Careless or universal use of them often causes far more mess and future problems than their seeming convenience would indicate.

Trust me, I'm expert on this. I've cleaned up huge machine tools using minimum materials.

People who suggest pressure washers and steam cleaners on assembled machine tools don't know the risk they run. Why contaminate reservoirs with water and chemicals, promote corrosion deep in crevised and recesses, and blow oily contamination over a wide area?

I cleaned a FILTHY Rockford planer 23 ft long overall with a half gallon of mineral spirits, a couplr of pints of lacquer thinner, a half bottle of 409, a couple rolls of blue paper towels and a dozen cardboard boxes used flattened to catcxh drips. The machine whenfinished was clean enough to eat off (almost) and ready to patch prime and touch-up paint. The screws and shafts were bright, the linkages and plated parts glitted like chrome, the sound paint was still sound and the unsound paint wirebrushed to bare metal ready for prime etc.

It took a couple of days but I finished without causing a superfund site or creating a fire hazard. The immediate area was clean and there was less than a half a garbage can of waste to dispose of. 2/3 the waste could be burned. The rest was disposable via residential garbage.

There's cleaning so the job is accomplished expeditiously, efficiently, without a lot of waste and subsequent clean-up. Then there's cleaning when the item looks clean but sumps are contaminated, the surrounding area winds up a pit of debris, buckets of toxic waste, and spreasing puddles of mess.

SGW
08-10-2011, 09:25 AM
I've heard that lye works very well, though I've never tried it. The directions I got say to use a can of lye per quart of water. Mix it up in a big vat (NOT aluminum!). Dunk pieces in with a wire attached for retrieval, let them soak a while, then haul out and rinse off. Be careful not to get any on your skin or clothes, it will eat them up. Eye protection would probably be a good idea.

If you want a thickened goop that you can brush onto large parts, mix in some wheat wallpaper paste until it's the consistency you want.

I think all this would best be done outside, with a hose handy for rinsing. Lye will take off everything, including the paint.

And be sure none of the parts you are cleaning are aluminum.

J Tiers
08-10-2011, 09:32 AM
Forrest is correct WHEN YOU WILL NOT DISASSEMBLE IT.

BUT if you are going to disassemble, as it seems the OP intends to, there is no reason not to use chemicals of whatever sort you prefer. It is much easier to dunk parts, or paint on the goo and later rinse off, than to scrape and polish by hand.

You SHOULD scrape off any "lumps" and "drifts" of crud, they just waste cleaner if you rely on dissolving them.

As for oven cleaner.......... it is just an expensive way to buy lye...... purple cleaner is cheaper per pint of removed gunk.

Paint strippers.............most are just about as good as using a magic marker to outline the areas where you want to laboriously scrape and pick the particles of paint off..... they do not loosen anything.

But the "Peel-Away" products work well. #1 is a jellied lye that is used best on wood, with the paper cover. When you take off the paper after it dries, the paint comes off 99.99%. #7 is an "environmental" type, but works well on metal, where you can wash it off with water. Have not tried the others.

As for not disassembling...... My FIL was that way also. Then he asked me to help disassemble a lathe apron that had some stiffness. We took out nearly a pint of shavings and miscellaneous swarf that was packed into various places. I have cleared out chips, sawdust, shop towels, etc from purchased machines.
And then there are the ones that were simply put together wrong by the last guy to disassemble them, or ones with missing parts.

The stuff you find out when you DO disassemble can be amazing.....

Dr Stan
08-10-2011, 10:04 AM
Since you will be disassembling the Logan I too recommend a pressure washer.

I recently stripped down a Fray mill and used a combination of cleaning/degreasing techniques. I bought a 55gallon plastic tote and made a reverse electrolysis set up for several of the parts. I my case I was even able to use this set up on the table.

For the column and other large painted parts I took them outside and sprayed them down with Simple Green. Let it work for a while and then went after it with a pressure washer. After it dried I removed the remainder of the paint with a sand blaster.

Finished up prepping the machine then gave it a coat of brown primer and then several coats of industrial grey paint. Looks good if I say so myself.

duckman
08-10-2011, 11:10 AM
Before I got my pressure washer we would scrape all that we could, then put a tarp in the back of the pick up truck spray with the purple stuff and go to the car wash, put them on the ground and wash them, we used to have a place that had a warm rinse most of the time after we were done you could lick them and not get any dirt on your tongue (HA HA).

firbikrhd1
08-10-2011, 11:15 AM
When I stripped the Index Model 40 as part of it's refurbishment I used the strongest stripper the local home improvement Depot store had. It was a gelled product that did a good job. Stay away from the ones called "safe". They are slow to work and not that good at stripping.

spongerich
08-10-2011, 11:19 AM
The ZEP purple degreaser is great. Used straight it removes most paint, buy as mentioned earlier, it aggressively eats aluminum.

Zip-Strip also seems to work pretty well. The newer formulations are a little slower though... Fortunately, I always seem to find old cans of it at garage and estate sales, so I always buy it up.

Rex
08-10-2011, 12:16 PM
I bought a SB 9" a few months ago. Brought it home in the back of my pickup. It was caked with years of neglect and goo, but little rust.While it was there in the truck, I sprayed it down with Gunk engine cleaner, then worked it in with brushes as much as possible, then another can of Gunk etc. Spent about an hour doing that, then ran it down to the quarter car wash and pressure-washed it very thoroughly.
Then back home, air pressure all over, followed by very liberal application of WD40 - about a half gallon from a trigger sprayer.
Worked great, spic and span in about 2 hours. It was clean enough that only minor touchup was needed afterward, and the paint was good enough I probably won't repaint. The WD40 continues the cleaning process, soaking any residual varnish in nooks and crannies for the later detailing process. Sure looks good now.

laddy
08-10-2011, 12:33 PM
I used BETCO Ax-it plus. Worked great....in the past used a paint remover that stripped Imron paint called Aircraft remover... Both have to be used with hand and eye protection but work fantastic Good luck Fred

macona
08-10-2011, 12:56 PM
Absolute best paint stripper out there - Aircraft Remover

This stuff is incredible. I used the aerosol version when I went through my 10EE. Spray it on and within 30 seconds the paint starts bubbling. Couple minutes later the paint starts falling off. It will remove bondo as well.

But it is nasty stuff. It will eat through two nitrile gloves in about 3 minutes.

Several companies make it, this is the one I used:

http://www.google.com/products/catalog?q=aircraft+remover&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&hl=en&bav=on.2,or.r_gc.r_pw.&biw=1430&bih=789&ie=UTF-8&tbm=shop&cid=6983781231469688268&sa=X&ei=eapCTuChEOvSiAKj6LHvCw&ved=0CGcQ8wIwBA

http://www.youtube.com/v/CoqePrVvCHk

rowbare
08-10-2011, 01:05 PM
The electrolytic rust removal process also does a good job of removing paint so that is another option to consider.

bob

Dr Stan
08-10-2011, 01:51 PM
I've seen others mention using oven cleaner for paint & gunk removal. Have not tried it myself.

jkopel
08-11-2011, 03:05 AM
I used to hot tank engines at a rebuilder. The solution was just hot lye.

I just disassembled my 9" southbend down to the last screw. All the cast iron went into a 10 gal paint bucket filled 2/3 with water and 3 bottles of red devil lye. Total cost was $15.

I put each piece in and let it sit over night. When I pulled it out in the morning I just rinsed it in the sink and everything just washed off. Dry it in the the oven, prime, and paint. I cleaned all the fasteners by putting them in a tin can with holes punched in the bottom. Drop the fasteners from one assembly in the can and submerge it in the lye, when you pull it out the lye (and all the gunk) just drains out the bottom.

DO NOT put any aluminum parts in there, or you will never see them again!
I had to pull the bearing shims out of the headstock since they are Al.

It will discolor brass and bronze, but it does not really damage them much. Bearing shells should not go in, but other less precise bits should be ok.

Wear long gloves and don't splash!

The best part is that the solution lasts forever. It takes a LOT to neutralize lye so I just cover the bucket and use it whenever I have some thing that I am taking apart.

Forrest Addy
08-11-2011, 07:00 AM
Hear's the ground rules on using corrosive solutions on machine tools either for cleaning or paint stripping. They can do harm to reactive matals like aluminum or dissimilar metals in contact (a bronze bushing in cast iron for example.) In the one case the reactive metal can be etched enough to alter its dimensions or otherwise damage its function. Some rubbers and plastics are damaged by strong caustics and of course it can be a disaster of slopped in electrical equipment..

The best plan of attack in using strong caustics for cleaning and paint removal is complete disassembly. Thus you isolate the parts you wish the treat from the parts that may be damaged. The problem with strong caustics and household chemicals is eventually you have to dispose of them sometiime in gallon quantities. Some chemicals you cannot by law dump into the sewer system and if enough caustic or strongly reactive detergents are present they may damage the biota in a septic system. This inextricably links you to EPA disposal outfits and their heavy disposal fees.

My preferred paint stripper is safe to use around reactive and dissimilar metals. That is a solvent stripper supplied in a gel base. It coats the work and the solvent (methyl chloride I think) reacts with and lifts the paint to for a goo. It's very effective for all non-catylized paints and a good many two and three part catylized coatings. The catylized coating may take more than one application to lift them. Sometimes scoring the coating with coarse sharp sandpaper allows the solvent access to the base coat and will speed the process.

Smaller parts may be gently heated to 500 degree F. The heat breaks down the paint and the heat if gently applied will not damage or distort the parts. I prefer this for non-critical parts like handwheels, small sheet metal items, brackets, covers, linkage, etc and no chemicals are involved. The baked paint no longer aheres well and has lost much of its film strength. Wire brushing removes the paint residues completely.

A handy paint stripping technique is to use a paint can (steel) a 5 gallon pail, or a steel drum all with close fitting lids. Place the fully disassembled work in the appropiate sized contaiiner and pour in a half cup, a cup, or a pint of cheap lacquer thinner. Cover and let it steep for a day or so. The paint will swell up like wet pie crust and can be pushed off with a stick and scrubbed clean with a fiber bristle scrub brush. Work quickly because once the solvent evaporates from the swollen paint, the paint reconstitute itself somewhat. Again more than one application may be necessary.

The usual path to paint prep of an intact machine tool is to dismantle all easily removed sheet metal, guards, pans, sumps, motors, etc to gain access to the paint system. Clean and buff the existing paint with coarse scotch-brite. Sand and spot prime the damaged paint. Remove and prep failed paint and build up the coating will high build primer or two part body filler. Any painter will tell you that good paintwork is 80% prep and 20% pain application.

Many would like to spray-paint their work but there is much to reccommend against this. By the time you mask, set up a temporary paint booth, arrange to vent the overspray out of doors, etc, and clean up afterwards you could have brush painted the work several times. Unless the coating you choose absolutely has to be sprayed, brush painting is probably the cleanest and simplest method. A good brush paint job is almost indistinguishable from sprayed.

Remember this is shop equipment you're painting, not fine furniture, show cars, or the Mona Lisa. A good workmanlike paint finish free of sags and hollidays is all that's required. Hell, if you use the machine for the purpose it was intended for you will wear the paint off in areas of chip flow so what's the point of perfect paint? Think about who are you trying to impress? People who get off on fancy paint are more concerned with appearances than substance. People who see through appearance to actual merit will be unimpressed with fancy paint but will be pleased with good work and orderly progress.

I've been in a few home shops where all is in excrutiating order. Everything there is arrayed in shining perfection but there's no work in progress. It's a showcase not a working shop. OTH I've seen home shops where things are neat enough but there's work in progress and it shows as the focus of activity to the exclusion of the irrelevent.

So are you a teddy near or a grizzly bear? The level of care taken with non-essential appearance issues hints at one or the other.

gambler
08-11-2011, 03:32 PM
find a local auto machine shop, have the pieces hot tanked. thats how I did most of my logan.:)

lazlo
08-11-2011, 04:51 PM
I've seen others mention using oven cleaner for paint & gunk removal.

The main ingredient in Zep Purple, Purple Power and Castrol Superclean is lye. Which is also the main ingredient in oven cleaner.

I've used oven cleaner, and it works fine, but like any of the lye-based cleaners, it's rough on the paint, and it strips the fat out of exposed skin (you're making soap :) ).

aboard_epsilon
08-11-2011, 05:40 PM
i use the cheapest and most powerful available to me

and that is biological washing powder mixed 50/50 with warm water

it will strip domestic oil based paints followed with a pressure washer with dirtbuster turbo lance thing .

it worked really well on on my j&s 540 grinder ..that was covered in many layers of domestic gloss ..got it down to pristine original factory paint..without harming that layer .

all the best.markj

topct
08-11-2011, 05:56 PM
When I got my SB9 everything was stuck. Or at least very hard to move. I took it apart. Every nut and bolt. All of the carriage, cross and compound. The spindle was taken out of the head stock at the same time.

I think I cleaned everything at least three times. All the fasteners where wire brushed and then washed off again. All of the threaded holes were washed out and a tap ran through them and washed out again. I did find a few holes and bolts/screws that needed to be either replaced or at least cleaned up well enough to thread into the holes they were meant to go into.

Then I put it back together, each group, a couple of times at least, just to make sure of this and that.

There was only one part, the apron. That piece really did have to be taken to the total strip stage. I will assume it had not been cared for since the lathe was built in 1941.

It was the only piece on the lathe that I painted.

I used Easy Off oven cleaner. But the "cold" use type, it doesn't seem to harm paint. That and lots of just plain soap and water.

I really like the way it looks. Used, because that it what it is for.

I need to add this though. If a person wants to strip paint. Aircraft paint stripper is the best no messing around stripper.. You can find it a most automotive paint stores. It is very effective on virtually any paint, including powder coat.