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Needle scaler for paint removal

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jwmay

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#1
Does anyone have a strong opinion for or against the use of a needle scaler to remove old paint on painted cast iron surfaces? Being a rough surface, I’m doing a lot of digging with a pick, so this just popped in my head.
 

Richard King 2

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#2
When I paint machines I just wipe clean, scrape off any loose paint and then feather sand them. prime them before painting. If you strip down to the casting you will need to Bondo the bad spots. I would think the scaller would work,may help relieve some stress too. Rich
 

Hukshawn

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#3
I think a scaler would be fine as long as you stay away from any areas it can damage, such as ways or slides, etc. Also, be careful around areas that are thinner if your scaler is of the larger and more powerful variety. In factory, I used to use the scaler on a slight angle, worked better to chip rather than pound. The maintenance guy used to get ****** cause it would make all the needles pointed. Apparently he didn’t like that.
 

dlane

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#4
I used a HF scaler on my lathe in the small places that were hard to get with stripper and scraper , worked good but uses some air
 
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Crank

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#5
I used an HF needle scaler on my Takisawa and it made short work of digging the oil soaked Bondo out of the nooks and crannies. Be careful around any precision surface and you should have no problem. As Richard stated, if you don't need to strip to bare casting, DON'T!!! as it adds a lot more work. Unfortunately my lathe was pretty bad and having to re-apply filler was a less than enjoyable task.

Mark
 

Uglydog

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#6
I've used one when cleaning up old machines. Seemed to work well.
I got the paint dust and other detritus all over everything and everywhere.

Think about what the vintage paint and etc is made from and where it is blowing/settling.
In your lungs? On your clothes? Where will your clothes be washed? Will the grand kids be playing in the dust pile next weekend. etc
I'm not suggesting that it is a bad idea. Merely that you make informed decisions and consider the long term consequences.

Daryl
MN
 

benmychree

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#7
It is not a good idea to remove paint and filler when it is adhering to the castings as it should, remove paint and loose filler as needed, degrease and add new filler, sand things down smooth, re prime and paint. As stated, removing all the paint and filler is not necessary and makes a lot of miserable work necessary to bring back a decent surface; this was the advice of Mel Heinz, a used machinery dealer in Berkley Ca. who I bought many pieces of used machinery from.
 

mhooper

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#8
I am currently using a needle scaler to remove multi layers of paint and a very old asphalt base coat on cast iron (gear hobber).
I had tried several types of paint removers, solvents, wire cups wheels on angle grinder and sand blasting. The needle scaler seems to work the best.
I found that the colder the paint and asphalt, the better the needle scaler works removing the paint and asphalt ( less than 20 degrees F.).


M Hooper
 

woodchucker

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#9
I have used a needle scaler, it works well.
I also have used Citristrip, and I have boiled off the paint in a pot using water and tsp. It comes off very nicely in sheets that just peel off.
All have served me well. I avoid sanding to remove paint.

I don't bondo when I paint it. I just prime and paint. It usually is good enough.
 

cjtoombs

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#10
Needle scrapers are great, if you want to get down to bare cast iron. I also use them on things like angle iron to remove most of the mill scale. One thing to be aware of on the more modern machine tools is the smoothing coat. They bondo up any really bad casting defects and then shoot the whole machine with a coat of "leveling primer" which is basicaly just a spray version of body filler, usualy to a depth of 1/16-1/8". If you take this off, the machine may not look quite right, unless you want to smear it back down with bondo and sand it. My recomendation on machines like that is to just sand off the top layers of paint, bondo up the scars that you feel you can't live with, and paint it. I work on a lot of antique machines, so they don't have this to begin with.
 

bfd

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#11
I wouldn't be too aggressive with the needle gun could cause peening and change sizes also stress relieving and warping just be careful bill
 

Eddyde

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#12
I agree with not taking off all the original finish, it will only make a lot of unnecessary work for yourself. Also there may be Red-Lead primer present which is quite toxic. As far as needle scalers, they work well when the needles are sharp meaning ground flat on the ends, not pointed. I touch them up, in the field, with an angle grinder.
 
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Bob Korves

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#13
Allow me to go against the grain here a bit and give a vote for sometimes choosing to leave old machinery looking old. They ARE old, and that is an important part of their charm. They have survived many decades of use and abuse, and are still able to do their jobs, and often some of those scars are quite visible. Sometimes I think it is best to leave the aesthetics just as they are, carefully fix whatever is broken and needs work, clean up the handles and the dials and all the sliding ways, bearings, and other things important to the work they do. The chips and dings add character. Use the machine as it was meant to be used. My 1946 B&S surface grinder has been repainted multiple times and multiple colors, and shows all of those layers in different places. I cleaned up and painted the table because most of the paint was missing on it and there was rust. For the rest of the machine, I cleaned up the handles and knobs and painted them, like new. The ways and most of the working parts of the machine were in good operating order. I did have to rebuild the plain bearing spindle, a fussy job. It looks like an OLD grinder. It IS an old grinder. It works good.

I had the honor of a private tour of a large private collection of antique machines, including about a dozen beautiful antique planers, some as old as the mid 1800s. The machines were painstakingly and tastefully cleaned up to show their age while still looking like working machines from the era. They are perfect examples of machines from the era. The owner also has a completely renovated old band saw, the type with the giant exposed spoked wheels. It was completely and carefully disassembled, each part cleaned and polished, paint stripped and repainted with shiny new paint, in the contrasting and gaudy colors of the late 1800s as part of the restoration. The work appears flawless. The machine looks like new. He told me it was his first restoration, and that it makes him sad every time he looks at it, because he took away the beautiful age of the machine, which can never be returned to it. He was correct, it looked completely out of place with the other fine old machines.

Please think long and hard about how you approach putting an old machine back in service. They are not making any more of them, and they are tangible history. Yours may not be that old now, but they will be someday, with some care and luck.
 

bfd

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#14
I used a needle scaler to remove some left over cement in a portable mixer I bought. don't put your head in the drum while you are scaling. you need ear plugs and earmuffs. one mistake I will never make again. it worked though cleaned up the left over cement. bill
 

jwmay

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#16
Well here’s what it looks like now. It’s that green paint that’s being difficult. The blue stuff mostly just peeled right off. It wasn’t flaking at all at the bottom there, which is why that portion is still blue. I probably won’t use the needle scaler, but I wanted some opinions about it from more experienced folks. I’ll just keep picking at it. I think it looks ok, but I’d sure like to have it all OEM color eventually. Thanks to everyone who replied. I appreciate your consideration on this topic greatly. 105733C7-95D7-4E76-8899-E8934A8BC8F6.jpeg
 

Eddyde

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#17
I used a needle scaler to remove some left over cement in a portable mixer I bought. don't put your head in the drum while you are scaling. you need ear plugs and earmuffs. one mistake I will never make again. it worked though cleaned up the left over cement. bill
Another trick to remove cured concrete from a mixer, throw in 20 lb. or so of corse gravel and run it for a while. It's also a good way to keep the drum clean after each use.
 

Glenn Brooks

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#18
Interesting to see some people have had success with a needle scaler. I use one to clean up stick welding by products, and large rust deposits. Works great as a first pass to get rid of loose, scaly material. But never have had much success taking all the old finish done to bare metal. Well, if you want it to consume the rest of your life, maybe. Very slow and inefficient for me. Maybe I don’t have enuf air pressure working the gun.

I like a 4”angle grinder with wire wheel for wholesale paint removal. Doesn’t work in corners. Etc. but a wire wheel has been the most efficient and quickest method I have used. Followed by hand scraping, solvent wash, and so forth for final prep work. Actually I sometimes use use phosphoric acid to cut machine oil on the original paint, as a first pass. Then usually always give the bare metal a final coat also. It’s surprising how much rust exists on bright shiny, freshly prepped castings. The phosphoric acid chemicaly changes the iron oxide to iron phosphate, which makes a great sealer coat for the metal, before painting.

Iam with the others who say leave the bondo and undercoat in place, if possible. Particularly, the early day asphaultum finish, aka Gilsonite, often found on machine tools made thru the 1920’s. makes a supurb undercoat. It is very resistant to moisture penetration.

Glenn
 

Buffalo21

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#19
I made the mistake to try to repaint my 1940 round colum Bridgeport, the last piece, I ever tried to paint/repaint. Nothing I did, stopped the new paint from blistering and falling off in sheets. Tried cleaning all the paint, filler and whatnot off of the mill, acid washed it, 3 or 4 different times, tried automotive epoxy primer, nothing worked. I finally talked to a industrial coating engineer (I took care of their boiler), he gave me a sample of some old time machinery paint, they made in the 30-40s. Some isolated blistering, after scraping the blisters and many coats, I finally got a paint finish on the mill, not pretty, but everything is now covered. Since then, I avoid painting machinery, The Jet lathe and mill arrived, had minor scratches and chips, and came with touch up paint, never used it, decided at was a machine tool, not a new Buick, so I leave them alone.
 

woodchucker

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#20
I made the mistake to try to repaint my 1940 round colum Bridgeport, the last piece, I ever tried to paint/repaint. Nothing I did, stopped the new paint from blistering and falling off in sheets. Tried cleaning all the paint, filler and whatnot off of the mill, acid washed it, 3 or 4 different times, tried automotive epoxy primer, nothing worked. I finally talked to a industrial coating engineer (I took care of their boiler), he gave me a sample of some old time machinery paint, they made in the 30-40s. Some isolated blistering, after scraping the blisters and many coats, I finally got a paint finish on the mill, not pretty, but everything is now covered. Since then, I avoid painting machinery, The Jet lathe and mill arrived, had minor scratches and chips, and came with touch up paint, never used it, decided at was a machine tool, not a new Buick, so I leave them alone.
Sounds like you had some oil issues. I have used paint thinner/mineral spirits, TSP (very good), and acetone for stubborn remnants. The acetone will get anything off practically. The TSP gives a good bite for the paint.

While I understand the need to keep old machinery old looking, I subscribe to the theory antiques don't need to be untouched to be antiques. Especially wood stuff. During their time if something happened to them they would have been retouched. So why is it sacrilegious to redo it. Same with a machine... Every now and then a good rebuild is in order, including the paint.
 

dlane

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#21
My machine runs better when it looks good :confused 3:, my car and truck get better mileage when there clean :oops:.
 

MikeInOr

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#22
I also prefer an angle grinder with a "TWISTED" wire wheel. I have striped and repainted many machines using a twisted wire wheel. The twisted strands in a twisted wire wheel greatly reduces the number of strands that break off and lodge themselves into your hands.

Letting the metal form a very light powdery surface rust before wiping the powder off with acetone and painting with a rust transforming primer seems to give the paint a lot of bite into the metal / casting! My favorite paint is Hammerlite which adheres to metal and metal with a touch of surface rust very well. Rustoleum hammer finish is a very similar if not identical paint to Hammerlite.
 

f350ca

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#25
Im also a fan of keeping machines painted. Pigpen from the Peanuts cartoon is my mentor. My shop is seldom clean but the machines do occasionally get wiped down. Without a smooth painted surface thats a chore and probably would never happen.

Wiping a surface with solvent prior to painting is usually a futile operation. The solvent dilutes the oil and a rag will remove some of it but a residue is always left behind. A water based degreaser dissolves oil and a water rinse carries it away. Test the surface prior to painting by spraying water on it. If the water wets the surface entirely your good to go, if it beads at all then there is a film on the metal and paint won't stick.

Greg
 
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