I worked the waterfront for several years. The scaler was used for heavy rust and made quick work of that. Sandblasters came afterwards and cleaned up the rest to get ready for paint.
Was gonna say: these are two tools for two different applications that sometimes overlap. Like a box wrench or a socket? IDK. Either way, having both is beneficial and neither is too expensive to not have around if you're restoring things.
@@jwm6314 This is what's wrong with youtube. You get people who don't know what they are doing either claiming to teach or they make comparisons on things they know nothing or very little about that results in extremely skewed wrong information. In the mean time you have the youtuber who is actually professional who doesn't get view or hits because all the nobody armatures dilute the search making the real experts harder to find.
Yep, two different tools for two different jobs. BTW, I was in the navy, the reason we used scalers is because the salt water quickly causes metal scale. Surface rust we just painted over cause they added rust inhibitors in the paint.
@jerseygamingtv3537 yeah, good luck using the sandblaster when you have 10-20mm of thick rust.. there is a reason those exist and personally we often use them in the warf I work at repairing boats. When there are thick buildup of rust a sandblaster won't do much, or atleast you'll be standing there for ages while slowly removing it. The rust this guy is showing in the video is purely cosmetic compared to what the tool is designed for.
Make sure TO NOT USE REGULAR SAND! I have a business that uses a sand blaster every day. You have to use glass bead or other appropriate blasting media. If not you will get silicosis, a lung disease. The only way you can use regular sand is with a high quality professional respirator/breathing apparatus. Please do not try to save money and use inadequate equipment. Your health is more valuable. Anyway, sand blasting, especially when properly set up/tuned is amazing. You can buy different grits resulting in different results and finishes.
Video starts at 4:00. Also for that project I would say a paint removal wheel would have been much faster than either of those. Especially if mounted on an angle grinder than a drill. You can remove in 2 seconds what took 2 minutes on the sand blaster. If you have lots of open space like this then use the paint stripper wheel. The other tools are mainly for internal detail work.
Others have mentioned the true use of the needle “scaler”. Another great use for the needle scaler is to knock scale off of welds, this also hammers the weld to cause the weld to relax and not pull the metal as much.
I was an “impact surface abrasion technician” for a number of years. This test is not really correct as as others have said the needle gun is for heavy scaling. For example. Steel of iron that has seen much salt water for decades or a stock trailer chassis that has taken thousands of beasts on their last journey to the slaughter house. The layers of delaminating steel will just absorb the blast cleaning. Needle guns, lump hammers, cold chisels and even SDS drills with chisel attachments get the worst off. Then hit with an abrasive shot. Steel shot or copper slag. That blaster though looks like it wouldn’t clean the skin off rice pudding to be honest though. Still, good effort. Keep the videos coming.
I used the scaler a lot while working tankers, yours just didn't sound like it was adjusted correctly.. Also they are better suited to removing heavy scale rust, then finish with sandblasting before finishing. I believe both tools are well suited to their roles, but those roles are a bit different.
i think its to do with the compressor not being able to have enough air to feed it. you need a stupidly high CFM to work a needle gun if it doesn't have that it won't work as well you can also tell the compressor isn't big enough because of the periodic stopping and starting.
@Rowan Brecknell yeah just did the calculations its roughly needed is 26 CFM with the needle gun and 10ft of hosing which is in the realms of 2 stage compressors. his is only a single pump probably why the needle gun isn't working because his compressor isn't big enough to run optimally.
@Rowan Brecknell if your looking for high CFM compressors for cheap go for the old army surplus compressors the ones with the scuba bottle tanks can produce that all day every day i picked mine up for $500 best bang for your buck.
When welding cast iron, after grinding your weld, hit it with a needle scaler and the repair almost disappears. Does a nice job of blending the surface. Also when detail grinding flash and excess cast off an engine block, the needle scaler does a great job of making everything blend in.
The needle scaler if used straight after the weld is laid, not only removes the slight, but can also relieve the stresses in the joint like a series of tiny hammer blows..
I remember using a large needle gun on a large lump of concrete one day. After many hours, lo and behold, there was a truck chassis under it all. (Was formerly a cement agitator truck). The scaler was surprisingly gentle on the wiring and airlines as they had some give in them. The old hard concrete just peeled off in layers.
Just to echo what others have said, the needle scaler is used to remove heavy scaly rust. Just as you don’t use a hammer to drive screws, you don’t use a needle scaler for smooth powdery surface rust.
Those are two different tools for two different jobs, you can't really compare them. If you had a decent blaster not a little hobby one you would find a world of difference too for that job. Mine feeds perfectly and holds a lot of sand so I can work much longer with out hassles.
yeah, the scaler is more for removing welding slag . cant immagine it being any good for rust like what he is dealing with... I'd use a 4" grinder and a wire cup for what he is doing.
yeah...I know what you mean...the kind that you need an air supplied bee keepers hood and gloves. For that frame , I would take a grinder and grind all the flat sections with an 80 grit disc...and leave the nooks and crannies to the sand blaster.
The needle scaler has its place on heavy rust with layers or chunks of rust that are leaving holes when the chunks are chipped off. Much of the time, that metal can still be used, and because the chunk of rust is removed the metal can be coated with paint or similar product and it will not continue to rust in those areas. The sandblaster has its place on surface rust but most of the time will not remove chunks of rust thus not stopping future rust under those chunks which will eventually fall off and leave rusty divots. They both have their own advantage. Sometimes, depending on the metal, both are useful since many rusty surfaces have a combination of the two types of rust. In the application this person was working, he had only shallow rust and the sandblaster was the better tool.
Use the needle scaler on tools and equipment that have leftover concrete on their surfaces. it rocks. sand blaster has no chance. make sure your air pressure is adjusted correctly on the scaler so it will be more effective.
I work in a factory that build transmissions. I can tell you that just because products are built in the same factory that does not mean same quality. Some builds look exactly the same but seals or bearings will be larger. Or other small changes can change a product. That’s what the entire aftermarket industry is based on.
I used the needle scaler on a fire hydrant and it did a 97% perfect job getting into the lettering even. Have to hold it at a 90 degree angle to your work and you should adjust the recoil setting before starting. The sand blasring guy wanted over $400 I paid $97 harbor freight on the heavy duty model. Well worth it.
I came to say "two tools for two different jobs" and then notice that almost everyone else is saying the same thing. Really appreciate you making videos to help people. I'm not trying to be disrespectful but these are two very very different tools. I'll leave the other commenters to elaborate thanks again for your videos!
I would've bought a 4” grinder with 36 grit sanding disks. These are what you've got though, so what I would've done doesn't matter. Sandblasters are great tools, good comparison video
Yep, those kind of blasters are for small jobs, for large jobs need a pressure pot blaster or something along those lines...i would have done the same with a few 36 grit wheels for the flats and blaster in the corners
wire cup / wire wheel as the first attack with the grinder, then if you're not happy with how quick and smooth the surface is, come back with the flappy wheel.
Navy vet. Plenty of needle gun experience. Also was lead PO of a sand blasting team in the yards during drydock. The Navy used needle gunning because it's cheap. Sand blasting with a real setup is easily the better option if you want it done fast and easier. Could do that whole trailer in our walk in booth probably 20-30 minutes total and it would be ready for the oven and powder coat.
The needle scaler is designed for removing mill scale and weld slag, that's what it does best. It's not intended for rust removal and (of course) it doesn't perform well at that task.
It is actually intended for removing rust as well. There are SSPC specifications for cleaning with a needle gun. You can't expect to get sp1 or sp2 quality no a blast profile that some coatings spec out, but, there is an appropriate place for it when removing rust as well as scale slag etc.
The needle scaler isn't for taking paint down to metal, but rather for removing big chunks of material to get to a workable surface. I use it to remove thick undercoat in car restorations, a job that the sand blaster wouldn't touch, then I use a sand blaster to quickly finish the parts off once the bulk of the material has been removed.
An up-side to the needle scaler is you can reliably use a shop vac with it. Just get an extra crevice tool and cut a semi-circle into the end and cup below or above the scaler and it should get most of it.
As a young seaman in the Navy I earned plenty of experience with a needle gun chipping paint…right tool for the right job, they both have ups and downs.
I've had a needle scaler for years I only really use it for chipping the slag off of welding after arc welding that's all I really use it for it does a great job with that
I mainly use a needle scaler for removing the slag from "MMA" (SMAW) arc weld beads. ALSO: You really should get an N99 particulate filter mask in addition to full eye protection for sand blasting. You don't want to get any more of that crap in your lungs than necessary.
Having spent some time with the needlegun (as we call them) restoring a WW2 combat vessel, it's best against heavily layers or flaking paint, and wasted metal. But at least you can see what you're doing with one. The sand blaster would have an advantage in tight spaces where you can't fit the needlegun. In either case, working overhead is the worst. A friend and coworker cobbed together a little 3-needlegun 'dolly' for easier deck scaling. Yeah; noise x 3.
Try doing the sandblasting in an enclosed small shop. It makes a mess of everything. I use the needle scaler for big rust patches that I can then phosphate over and paint.
I think that application is where the needle scaler work fine. On an old frame like the one he was working on, the needles knock enough rust off, then a rust converter will take care of the rest. A good primer on top will be good enough, maybe not as good as the sandblaster, but it is an old frame, it isn't a classic car.
As a professional welder, needle scalers are best for removing rust, paint and mill scale on smaller areas or straight lines for weld preparation. Sand blasters are way better for larger areas, paint prep etc. I absolutely love my scaler as I repair farm equipment now and then that is very rusty, and use thicker steel which usually has heavy mill scale that eats up grinding/sanding discs. As you also said, a scaler is LOUD good ear protection is a must lmao.
So the needle gun will remove mass, but not provide a finish. Sandblasting makes for a true finish(after a wipe down of course) So for a project like this, the needle gun would be the paint stripper and the sand the finisher. That way you use less of the $$ media. One method is left out in this video. Considering the type of surface being prepared, a 90 degree angle grinder would make short work for little cost to prepare the surface. Considering how open it is, a large 7-9" grinder could be used. A wire cup first to remove the majority of everything, followed by a flap disc to prepare most of the surface. Return with the sand blast to get into the corners and other hard to reach edges.
This is my current delema right now. Great video and thanks for the comparison. I’m about to restore/get running a ‘87 chev square body it has heavy rust flake on the frame so needle would be good but rest with the sand. 👍🇨🇦
If you are going to take it down to the frame, send it out to a blasting service. Don't waste your time with a tiny little blasting gun. A guy with the right commercial blasting setup can have a truck frame and a bunch of other stuff done in an hour. Did this with my '68 C10's frame.
Basically just comes down to knowing what your tools are best suited for, needle gun breaks up heavy rust and covered surfaces while the sandblaster is best used to completely clean a surface, albeit needing blasting media and inevitably making a dusty mess. This video did a great job demonstrating the capabilities of each tool.
If you have a 3000+ pressure washer, you should try the hybrid pressure washer / sand blaster! Way better wet specially if thinner metal that can warp by heat of just media blasting. Use both needle gun for big scale to de bulk and then water blast. Also "GET PPE"!
Not seen this mentioned, so, I found that with the sand blasting material it had to 1). Be dry. 2). At a level equal too or slightly above the level I was going to use the sand blaster at, with no dips or bellies in the feed tube. I did not find the needle gun at all effective on thin layers of paint or surface rust, but, knocking cement of old bricks I wanted to reuse it was amazing!
Railroads also use need scales a lot on large metal parts to remove rust scale. Sand blasters perform best with dry medium as it offers less likelihood of clumping up leading to clogs. Also, the speed of a sandblasted will depend on numerous factors, including nozzle diameter and available air volume, as well as the type of medium being used. I deliver large volumes of garnet to the naval yards in Virginia, which seems to be their preferred method of removing rust and paint. On the other hand, bare rust can be removed with something as simple as baking soda. Crushed glass is good and maintains cutting ability when sifted and reused as a medium. It all depends on using the best medium for the task.
I've done both systems, Try putting a pressure regulator set at about 50 to 75 lbs using the needle scalar.Also you probably know to clear the suction hose on the sand blaster to shove the nozzle against the work piece. So glad to see you back, you have been missed.
I always used both on frames and heavy metal. Needle scaler for paint and heavy rust, then cleaned up the mess and finished with the sand blaster. Set up a canopy and put down a tarp, swept up and reused the sand at least once. I know you speeded up the video but I never danced around. Slow even movement keeping the sand cleaning a wide path side to side.Did several frames, great results
In case you didn't know judging by the comments but that needle blaster is for heavy scale. Evapo-rust is an amazing product. Safe on the body, doesn't attack metal and protects the metal after its settled in. I purchased some to break free the mirrors on my bullnose and decided to try on my bumper. The bumper itself has holes drilled for round spot lights and were all rusted out; a quick spray and a wipe with a paper towel removed 90% of the rust and 6 months later the rust hasn't returned
I use a needle scalar everyday as a field welder. In fact I have 3 of them. They work great for removing heavy rust and dirt to prepare for welding. If your working on old paint use a respirator! Lead paint is still a problem!
The needle gun takes off thick rust scale that the sand blaster will not shift (working on a 45 degree angle with it is usually better than head on), the sand blaster leaves a nice finish for paint to key into though - depends what you are trying to move as to which is best for the job.
🤔 never seen a needle scaler used for rust. The application I know is for removing hardened concrete from metals. It’s super good for that. They ARE however really hard on the material. They take more or less everything off of aluminum, they also produce a very distinctive texture 🧐 if you’re into that.
The Navy uses both. Which one depends on the application. A buddy borrowed my 12 horse, 4,000 PSI pressure washer and used it with a sand pick up to prep his Cat for painting, before shipping it to gold mining site way up north. Previously, he rented the big, commercial compressors to do that kind of work. They allowed him to do the job, but it took a lot of sand and made for a small dust storm. After using mine (water and sand combination), he said he'd never go back to the other way. He said he did a quick rinse, cranked up the heat in his hut, dried the Cat over night, and was able to prime and start painting the next day. You still wanted to wear a respirator, because the high pressure did toss a lot of vapor into the air and a little sand.
Your problem with feed on the sand is moisture. Your compressor makes it and your sand loves to soak it up and stick together That is the problem that I had once I dried the air up it worked great
Years ago there was no problem with sand blasting as far as the environment goes but in today's time it is illegal in most areas if you cannot reclaim or contain the blasting media.
Adjust your air pressure to get the best suction on the sand hose. 80psi works best on mine. If you go too high on air pressure the suction is reduced due to back pressure at the nozzle & you get less sand. You need at least a 5 hp air compressor to keep up with it. Blasting with too low a pressure is a waste of time. The sand you use makes a difference too.
I use the needle scaler on heavier corrosion, in preparation for a wire wheel or wire cup on an angle grinder. Before wire wheeling, i use wd40 and soak the object down the day before. It seems to help dig out stuck on rust. Any tight spots i use the siphon blaster with coal slag. I then wipe down and degrease. I'll follow up with with 80 grit on a 2 inch mini da. Wipe off again, then use Picklex 20 and a scuff pad. This will remove most remaining loose rust and stabilize the remaining stuck on rust. I'll finish with painting with Zero Rust paint, 2 or 3 coats. Thin it 10% lacquer thinner and spray with lvlp gun. The reason i do it this way, i don't have a large compressor to run a pressure pot blaster. It's yielded me excellent results.
Flap disk on a grinder is how you can get most of the rust off in this case. The blaster is only good for the hard to reach places. P.S. Wear a respirator!
@@ESLinsider The flap disk is more aggressive than a wire wheel and will grind the metal. I use both. Use a knotted wire wheel or a knotted cup brush on an angle grinder.
I tried the flap disc recently and it works pretty good but the guard seems to get in the way. Seems like you get get a lot more done faster if the guard wasn't there but then it becomes a safety hazard I guess.
@@ESLinsider I run mine without a guard. Just be careful and wear some stick welding gloves...and a face shield. Metal in your eyes is not fun and it's happened more than once to me.
In a steel fabrication environment, the time taken to remove mill scale was dependent on the age of the steel stock. When allowed to age for a time the scale becomes loose and delaminates ,making it easy to fracture the scale and expose the surface rust hiding beneath. It is also useful for rattling off slag shells from tightly cornered welding sites where a slag hammer proves awkward. When the steel stock is freshly milled the scale is tightly bound to the surface the use of a blasting treatment is far less expensive in manufacturing time , even if the quotation for the job was for wire brush or rattle gun preparation. Where it is impractical or impossible to use a blast process, surface preparation time will be much longer and the state of the prepared surface will dictate the quality of the coating required to finish the job. For small home jobs where a paint finish is the thing, the blaster will always be first choice. Needle hammers should be useful for welding slag and loose paint. Shipyards, with a lot of flake rust to deal with, are ideal places for lots of needle hammers. Cheers from Downunder 👍🇦🇺😷😷😷
I have a truck that had a heavy rust scale on the frame. A needle scaler worked very well to knock the scale off. It does not remove all the rust. I painted over that with a paint called Agri Guard sold by a company in Wisconsin. So far no rust has appeared in the past 2 years. Keeping my fingers crossed.
I would have probably gone with a grinder and a combination of flap discs/wire brushes for that job. It would be nice to have the sandblaster around for hard to reach spots.
Owning multiple grinders for years ... I regret how long I went before discovering the “instant effectiveness” of flapper discs. Flapper discs = super time saver
@@williamgeorgelopezjunior8533 they can take quite a bit of material off though, so not so good on thinner metal. twisted wire cups on a grinder are also great
@@beeftec5862 I’ve been noticing that and have been trying to lay off on the pressure... sometimes welding metal patches are the only decent option... but yeah I noticed that quickly
@@beeftec5862 also I find various wire wheels tend in some cases to bury foreign debris into the material be it paint, grease dirt or what have you... so you still gotta give it that extra good clean after
I've ran both a dry ice blaster ($$$$) and a media blaster in a cabinet for a couple of years, and I'll take a media blaster any day. Once it's set up with the proper pressures, and media, it's versatile, cheap, and pretty consistent in the finished goods that it produces. Rust, oxides, corrosion, old tractor paint, it's the right tool for the job.
A few more things to consider when thinking about a sand blaster: 1. A lot of air is needed which means a large 220v air compressor with a big tank and 2. the air must be dry so you will need an air dryer and 3. the medium goes everywhere so you get to clean it up if you aren't in an outdoor setting where you don't care about the mess. The other thing of course is you need a serious mask for your face to keep the dust out of your lungs. You should also wear a decent mask for removal with the scaler or a wire wheel but for blasting it should be top notch.
I have pent many hundreds of hours doing both. That needle scaler is way underperforming. I use a Ingersoll Rand air hammer with the scaler attachment. I can achieve nearly identical results most of the time. Snadblast has its place but the scaler is best at thick flaky scaly rust
The needle gun is used to chip off paint and scale rust. The sand blaster is for fine cleaning ready for paint. They’re as different as sand paper and wire brushes.
Needle gun works real good on heavy scale rust go through and knock the heavy stuff off with the needle scaler is save you from using so much Bob media blasting your sand and also a needle scaler is great for welding cast-iron you taking make your welding and you preheat your cast-iron do some maybe an inch or so welding and I hit it with a needle scaler the health stress relief welding the needle scaler has its place but in Junction with each other you got a good combination like I said knock the heavy stuff off with the needle scaler and then use the sandblaster to finish
The needle scaler is great for welding repairs on heavy equipment as well. Knocks all the junk off fast and is good at knocking slag off in between passes.
This. So very much this. Needle scaler for the godforsaken rust blisters and rust pockets, then angle grinder or die grinder with steel brushes for broad stroke and tight spaces, respectively; and to thoroughly derust the entire thing after all that, it's sandblasting. Once all that is done plus surface contaminant clean off, a coat of either rust converter, cosmoline, oil or etching anti-rust primer of your choice for the appropriate application as soon as reasonably possible, and it should last a reasonably long time before any rust reappears on that surface.
Every DYI starts with the cheap. Industrial sand blaster with appropriate air could be done in a hour. Might even be cheaper when you consider the man hours and figuring out how to the cheap gun actually do work. Side note. My daughter likes to pick up old rusty railroad spikes to paint. She wanted me to clean the rust off. Put sand in cement mixer and tumbled for 2 hours and worked perfect. Just make sure neighbor don’t mind the racket.
I prefer the needle scaler only for the simple fact that i never had to wear a tyvek suit whilst using it those things make you feel like you crawled inside hell and turned the heater on
Every situation is different. Scaler, blaster, discs, chemicals; judgment and experience will tell you which will be fastest, least destructive, and most appropriate for what you are attempting to achieve.
The needle gun is not as clean, but does provide a varied textured surface as a casting might display... the sand blasting can provide a finer texture and a depth of removal based on time and type of media used. Each has its pros and cons.
My son in law is a research chemist, he gave me some phosphoric acid. Mixed 50-50 with water, painted on rust turns the rust into magnetite, magnetite cannot hold an oxygen molecule, so rust is cleared. I used this on my camper van, cured the small pieces of rust, just paint over.
Not necessarily. They don’t profile the substrate for coating adhesion so takes extra materials and time to sand and prep for sting bond for the coating. Sanding doesn’t anchor as strong as a blasted surface. Lasers are cool though and definitely have their place
I feel ya! '60 Shasta Deluxe and '69 Play-Mor trailer owner here, I ended up buying 60 gallon compressor and fairly large sandblast pot to clean scale and rust.
Most "blasters" have a concrete slab, just three walls and no roof. I used "big red" which is the pressure pot sandblaster specifically made to blast trailer frames, farm tractors, steel rims and other stuff. You need a 20 cfm 220v compressor and be dressed like a storm trooper. That trailer on a "rotary" would be done in under an hour. The slab allows you to sweep up the media and re-use it, plus no roof allows the small debris to "blow off."
Needle scalers cannot get to the bottom of rusted pits but it does shift the big stuff. Grit blasting gets into the pits - if the grain size is small enough. Ideally use them both followed by a chemical rust stopper bird it’s primed.
I bought a big bench top milling machine and converted it to CNC. The original finish had a thin layer of bondo covered with white paint. It was easy to chip and wasn't very durable. So in the conversion process, I disassembled everything and stripped it all down to bare castings. I used a cheap HF needle scaler and it made quick work of it. It took it down to clean iron. I removed over a gallon of old bondo and paint. I repainted it with some 2 part urethane paint and it is a lot better finish. About half way thru the process, my old compressor bit the dust and I couldn't get any rebuild parts for it anymore. So I had to buy a new compressor. I bought a Quincy QT-54 60 gallon and it supplied plenty of air for the air sucking scaler. There was a noticeable difference with the scaler using a better compressor. My old compressor was a 60 gallon oil-less type that was slow and noisy. Nice useful video. Beards give men the right to pee standing up.
Well thanks, I WAS going to buy a needle gun but you saved me from that. I always use a hood and ski goggles to keep the sand out AND made a dryer out of copper tubing and an ice bucket to cool the air (with dryer) to prevent clogging the sand in the gun. Don't forget to capture your media so you can reuse it. For what You do and me too, blaster is the way to go.
I used to refurbish in-ground hydraulic lifts and the needle scaler is really only meant to remove heavy encrustations . I would go over once to get off the heavy stuff then use a wire wheel on a heavy duty grinder to finish it up .
For what I need, a blaster is the end finish I require. Even with the PITA factor on media clogs. I will spend time getting my blaster to flow better, and I think I will be happier. Thanks for putting this out there!
Needle scalers aren’t designed for rust removal! They were designed for removing scale from castings and forgings as well as removing the flux from stick welding. They will remove heavy flaking rust, but you still need to remove all traced of rust if you don’t want it coming back under the new paint.
If you are sifting your own sand one thing that will help is to put the sand in the oven at 250 degrees for an hour. The drier the sand the better it flows
Both tools have their time and place , needle gun and air blower for layers of paint and major rust jacking , then sand blast to finish the metals to a clean and very grippy for new primer and paint , heat your sand or garnet to prevent it gaining moisture and sticking together
Both of those tools are far to small for what you want to use them for. I have both also but the media gun stay in my blast cabinet or (I have another) is used for smallish jobs that I can't put inti the cabinet such as blasting the corrosion off of suspension components so they cam more easily be removed. I have a much larger gun and compressor for BIG jobs. The media to are large degree can be recovered because I put a large tarp down to catch it all, then refilter is and reuse it. The descaler is primarily for large heavy rust that a blast gun would take much too long to cut through. My descaler is also a larger more powerful unit. Descalers are not for removing surface rust just large scale. The gun is them employed to finish the work. Another method you might consider is this" Make a container out of plywood that your large piece such as a trailer can put rolled into. Line the container with heavy plastic. Roll the trailer into one end of the box and secure the end cap and plastic. Fill the box with water making sure to cover all the metal you want de-rusted. Thoroughly mix in a few pounds of Calcium Carbonate (washing soda)to facilitate electricity. Hand anodes of rebar or old metal around the trailer, but not touching. The hook up a power source like a generator or mobile welder to the anodes and the trailer (which becomes the cathode) and turn on the juice. The reverse electrolysis will have all the rust off of the piece in a few hours. Pump the liquid into plastic barrels, filtering it as it goes. The trailer or other piece will be covered with a black coating which can them be easily scrubbed off. Something else you can use is a dustless wet blasting set up.
After spending more than a couple years painting boats, I have to say that I've never used a needle gun. We knocked off heavy rust with a big hammer. I would say the needle gun is meant to replace swinging a large hammer to remove heavy rust scale or cleaning up welds. The needle gun is faster than a chipping hammer.
I work as a mold polisher and the needle gun leaves damage and we would never use the sand blaster is controllable and can adjust pressure to let more or less media so you won't damage or remove much material. For a better job a sand blaster is always recommended it takes more time and money but it leaves a better job.
It's called a needle scaler for a reason. it removes scale ie. flakey rust. weld slag, loose flaking paint, or the flakey build up of corrosion on metal from batteries. Not at all meant to remove surface rust. Not to mention it does dimple the metal when used.
They have something called a water blaster it’s a kit for your power washer that introduces sand in the stream . It works really good and you can diy the device
