Thread: Needle scalers

They work great on removing slag when MMA (stick) welding.

Oh, and wear a dusk mask, safety glasses and ear plugs.

Used these things on offshore oil rigs and ships for years. They are ok for removing larger patches of scale and rust, but if you use them to get down to bright metal, they tend to fold over the microscopic surface of the metal, producing small pockets that trap moisture causing corrosion. Any paint applied cannot penetrate into those "pores" and the metal starts to rust from under the paint.

Abrasive type blasting, such as sand, does not damage the surface, providing the correct medium is used. In many cases a chemical rust converter is a better option, again used strictly as intended by the manufacturer.

When I used to do 'confined space entry' and entered a round tank, I was given one to try to descale a surface. Even with ear muffs on it was like being in side a large bell. it was deafening.

I am extensively using needle scalers on a project.
The expensive ones work vey well, I have borrowed a few.
My budget only allows for cheaper ones , usually being a conversion of air chisel kit.
Some air hammers/chisel s work better than others with a needling attachment and if you have a section of different old needle attachment and air hammers it pays to swap them around to get the best combination.
I find it pays to get spare needles.
If a needle falls out, fit in a new one soon as possible as the head of the old needle is still in the hammer of the tool and is now lose and free to do damage if it moves out of its hole plate.
Lube the tool regularly .............if it starts to feel warm or hot.....time to lube it including the the needle hole plate.
The cheaper set ups promote white hand more easily.
I find a hour at a time is enough for me.
Plus side of things is only a small air compressor is needed compared to sand blasting.
Noise is a very big problem.
White hand is a problem with prolong use.
A slow process for some types of surfaces, finishes and conditions.
Works better on thick dry rust and paint.
Thin paint and surfaces which require smooth finish not so good.
If you can put up with the noise and have a budget and plenty of time it is a good process.
On my project I find I am a using sand blasting, needling,electric wire wheels , chemical stripping and sanding as all of them have good and bad points and work differently on different types of surfaces and what ever you are trying to clean up or remove.

I am currently needling 2mm alloy removing about six layers of paint and getting the alloy back to a shinny surface.
It will require the light and quick use of a electric drill or angle grinder with wire brush attachment just to improve the surface of the alloy for painting.
Can post pics later if you want.
Ron

Thanks Ron - there's some good info in that post.

Hadn't thought about broken needles since I haven't suffered any yet, but could see your point about damage from the broken head remaining inside.
Thought I'd jump on online and order some while I thought about it - not many options, and none cheap.
What I did notice that was interesting, is that one of the brands (Trelawny) has needles that are tapered at the working end. Not to a sharp point but down to 1mm or less flat on the end. My Kinchrome ones have no taper so just a 3mm flat on the end. Would definitely be a difference in how the 2 versions behaved on the job.

When using the expensive tools that performed better, did you notice any physical differences between them eg stroke frequency/force or needle shape?

Steve

Do you need one as a one off or longer term for multiple projects. I might know a hire company that keeps 240 volt versions and I think we still may have some air powered ones.

Could probably organise a decent rate too.

A Thousand dollar needling tool has alot less vibration and therefore if used in a commercial sense less problems with workers getting white hand during long periods of use.
Commercial needlers just work better and last longer with fewer problems with the internal hammer breaking up.
All the different needling tools I have used run at different frequencies and strokes and one may be good for thin metal and paint while another may be good for knocking back rust and heavy thick paint.
I find the needles work well when new as they have a sharp edge, but soon the tips of the needles wear round.
I find laying the tool over at 45 degrees to the surface to be chipped is best as the debris is pushed away,gives less vibration to the hand.
I have been laid low with a cold today.........I see if I can post a pic of a large alloy tail gate I have been needle gunning tomorrow.