Air needle scalers

[radiomike7]

I have noticed that several of you have used needle guns rather than sandblasting. What are the pros and cons and can anyone suggest a decent one; I have seen the Sealey on offer for £60 or so.

[Stormin]

I'd be thinking of using both.

Needle gun is really for getting heavy rust scale off. It's not going to get you to clean metal all over, which is were the shot/grit blasting comes in.

[sirhc]

Needle guns are good on thick sections, they are great for taking the many layers of paint off armoured vehicles. Blasting can be quicker and is definitley the way to go for small or thin parts.

 

Chris

[antarmike]

You dont have to strip everything after needle gunning, Sand blasting (or Copper slag) whatever, gets into absolutely everywhere. If can't be used near bearings, It will find its way into hinges, everything, and for years after everytime you open a hatch or move a brake lever, you will hear the grinding, feel the grating unless everything is pulled apart and blown out with an airline then re-assembled.

 

Sand blasting can distort panels, even quite thick ones, because the repeated hammering on one side stretches the metal, and the panel, now being longer on one side than it is on the other, has to bow.

 

I shared a Yard with a Sand Blaster for a number of years, and have had work done myself, but it can be destructive, It won't get off plastic paints, it doesn't shift thick dried grease. Any brass plates will need covering or unrivetting, or they will be badly damaged. Bearing surfaces will be ruined, if the blast hits them.

 

Sand bounces off a surface at high speed and can, on the rebound mark surfaces up to 18" away in any direction from where the balst is aimed.

 

Needle gunning needs to be restricted to thicker sections, chassis etc. I would choose it over sand balsting 9 times out of ten. Simply because of the mess that sand blasting Causes. My wife had a dormobile Camper chassis sand blasted, and two year later when you started it up you could still see little piles of sand dropping to the ground, as it worked its way out of everywhere it had got in it wasn't supposed to.

 

Then there is the health risk,, Some blasters, and most DIYers used dried Paviour sand. This is illegal for commercial use, because it causes Silicosis in the user, and those in the vicinity. It does a good job, it is fast, it leaves a near perfect roughened finish to accept paint well, but it is highly dangerous and illegal.

 

The legal alternative is Copper Slag. This is much courser, much slower to use, the Abrasive is 4 to 6 times more expensive, and it causes pitting that may show through normal paint, unless you blow on plenty of High Build primer first, but paint ain't cheap, and why put yourself in the position were you need two thick coats of primer to cover over the surface damage you have done.

 

We use the bigger of the two needle guns (the straight one) out of the Machine Mart Catalogue. It has done a lot of work. Provided the gauze filter is kept clean, it works well.

 

Then you are down to compreesor capacity. A needle gun uses about 6'ish CFM, so you need at least a 15 CFM compressor, to keep the duty cycle reasonable.

 

The chap I shared a yard with had a 250 cfm compressor, for sand Blasting, but it should be possible of a 125 CFM, two tool screw compressor. To do industrial sandblasting, you need that size compressor, A needle gun will run from a good condition 3 or 4.5 Horsepower Electric compressor.

 

The chap I know paid about 4 grand for his equipment, including a Hodge Clemco 4 bag pot, and Clemco air fed helmet.

 

You pay your money and you make your choice.

Edited February 2, 2009 by antarmike

[Lauren Child]

We also use needle guns for some jobs, but for lots of tasks we go to plain old sanding (as in a team of folks with hand sandpaper and/or air sanders).

 

With needleguns it can be difficult to get into all of the nooks and crannies, and any paint left un-gunned shows up badly unless you remove it through other means, or feather the edges by hand sanding where that's not possible.

 

Hand sanding the edge of umpteen layers of paint under a hinge or "knobbly bit" can be a time consuming and arduous task.

[Grumpy]

Bought a couple of cheap Machine Mart ones that double as air chisels expecting them not to last too long, two years on and lots of work done and they are still going strong.

[Richard Farrant]

With needleguns it can be difficult to get into all of the nooks and crannies, and any paint left un-gunned shows up badly unless you remove it through other means, or feather the edges by hand sanding where that's not possible.

 

 

 

 

I use a Sealey needle gun and can say they are very good for around bolt heads, nuts, in corners where a rotary wire brush will not get. Mine has lasted about 8 years so far, with no problems. They get my vote, better than wearing your fingertips down