Ever used an electric needle scaler?

I have a friend who lives in a tall oceanfront building in Mexico. My friend is a brilliant retired computer engineer who went to CalTech. But he doesn't know about general metal fabrication.

His unit has a front deck. Like all of his neighbors', his deck railing is made of cast aluminum. I believe the railings were powder coated. The coating, whether paint or powder, has suffered badly in the humid salt air and tropical sun. The aluminum itself is also corroding. The obvious solution is to clean, then repaint with the right paint. The problem is that the railings are kind of ornate and there is no obvious way to really remove the old coating.

The railings can not be removed.

It occurred to me that a needle gun might work to blow off the paint. In the US a contractor would park a huge air compressor under the railing and run as many lengths of hose as they needed and use a pneumatic needle gun. But those tools are brutally loud.

I discovered that there are electric needle guns for $400-500 US (and up). He could order one from Amazon Mexico and just plug it in. This might actually work.

There are two questions: how loud are electric needle guns, and in your opinion could one be run on a somewhat corroded cast aluminum railing without destroying it?

metalmagpie

I haven't run an electric needle gun. if it's ornate I doubt it would be particularly effective (access angle)
then there is the work hardening. I was an architectural blacksmith so plenty of impact hammer, needler and sandblasting. Personally I'd look at a soft bead blast. Walnut shell possibly, i was putting texture in not taking paint off.

I would think for 400-500 he could buy a compressor and a pneumatic needle gun, no need for a big trailer mount compressor, an upright 60 gallon big box store compressor will do the job, and HF has a pretty good needle scaler. Depending on how soft the aluminum is, it might affect the detail, but slather a thick coat of paint on and you'll never notice. By regulating pressure you can control how hard it hits too, I typically run at 50-60psi on concrete so it just takes the coating off and not the concrete.

Has he tried paint strippers? Lye, cornstarch and water is cheap and works well on just about any paint, but not powder coat, probably some commercial products that would be safer for the aluminum.

Never seen an electric needle scaler, so no idea how loud they are, pneumatic requires earplugs.

Any needle scaler will be loud and on aluminum even louder. A walnut shell blast will work bit then there the mess. Cheap laborer and hand plus power wire brush is cheapest and easiest. When working very ornate or fragile areas a small brass hand wire brush and Dremel wire brush can be effective.
Defer to shipyard for info on a good primer and paint for finishing.

dalmatiangirl61 said:

I would think for 400-500 he could buy a compressor and a pneumatic needle gun, no need for a big trailer mount compressor, an upright 60 gallon big box store compressor will do the job, and HF has a pretty good needle scaler. Depending on how soft the aluminum is, it might affect the detail, but slather a thick coat of paint on and you'll never notice. By regulating pressure you can control how hard it hits too, I typically run at 50-60psi on concrete so it just takes the coating off and not the concrete.

Has he tried paint strippers? Lye, cornstarch and water is cheap and works well on just about any paint, but not powder coat, probably some commercial products that would be safer for the aluminum.

Never seen an electric needle scaler, so no idea how loud they are, pneumatic requires earplugs.

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absolutely agree its foolish to spend that much on an electric needle gun, and you wouldn't need a 60 gal compressor for this job since as you recommend, dial down the pressure for aluminum. a 120 $ pancake unit would work, but you would have to pause for the pressure to build up, but it would eventually get it done.

one word of caution, Lyle dissolves aluminum FAST. don't use it on aluminum!

It's freaking Mexico! Labor is dirt cheap. Get some sand paper, wire brushes, and dental picks. Let a guy spend a week making it perfect for a couple of hundred bucks.

metalmagpie said:

It occurred to me that a needle gun might work to blow off the paint. In the US a contractor would park a huge air compressor under the railing and run as many lengths of hose as they needed and use a pneumatic needle gun. But those tools are brutally loud.

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Needle scalers don't "Blow off" anything.
Pnuematic needle scalers don't use much air, not needing a "Huge" air compressor.
We are technical people here, use real numbers.
We doo.
As above, walnut hull blasting (or corncob) would be better, however that will require a "Larger" air compressor. But the time spent making noise and dust will be much less.

DDoug said:

Needle scalers don't "Blow off" anything.
Pnuematic needle scalers don't use much air, not needing a "Huge" air compressor.
We are technical people here, use real numbers.
We doo.
As above, walnut hull blasting (or corncob) would be better, however that will require a "Larger" air compressor. But the time spent making noise and dust will be much less.

Click to expand...

I appear to have chosen the wrong tone. I worked in shipyards for 13 years where I used needle guns a fair amount. I have owned an I-R Model 125 pneumatic needle gun since the '90s and I use it a lot. When paint is old and flaky, it can come off rapidly with a needle gun. Even when the paint is tight, going between the needle gun and wire brush can be much faster than wire brushing alone.

My I-R 125 uses every bit of the 18 cfm my 5hp Champion 2 stage compressor puts out. That compressor is not huge here in the US but it is significantly larger than anything I've run across in Mexico. Nor would such be very easy to buy down there. Plus, my compressor costs much more than the electric needle gun.

Yes, it's Mexico, and the prevailing wages are lower. It is still very hard to find skilled motivated workers, though.

Finally, the thought of running a pneumatic needle gun on a small Chinese pancake compressor is laughable.

metalmagpie

pressure washer sand blaster?

After seeing the marks left on the steel parts I use a needle gun on, I imagine the aluminum is gonna look horrible after a needle scaler. Just get "Aircraft Stripper" (...the chemical, NOT the professional )and use it. It will remove powder coat as well as paint.

Heres the stripper from post #4 in action

metalmagpie said:

I appear to have chosen the wrong tone. I worked in shipyards for 13 years where I used needle guns a fair amount. I have owned an I-R Model 125 pneumatic needle gun since the '90s and I use it a lot. When paint is old and flaky, it can come off rapidly with a needle gun. Even when the paint is tight, going between the needle gun and wire brush can be much faster than wire brushing alone.

My I-R 125 uses every bit of the 18 cfm my 5hp Champion 2 stage compressor puts out. That compressor is not huge here in the US but it is significantly larger than anything I've run across in Mexico. Nor would such be very easy to buy down there. Plus, my compressor costs much more than the electric needle gun.

Yes, it's Mexico, and the prevailing wages are lower. It is still very hard to find skilled motivated workers, though.

Finally, the thought of running a pneumatic needle gun on a small Chinese pancake compressor is laughable.

metalmagpie

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I didn't suggest a pancake compressor.
Again, enough with the arm waving and use real numbers, and leave out all your chest beating.
I could care less about your time at a shipyard, it's irrelevant to the question.
Your beyond learning anything new, suggestions at this point is wasted electrons.

metalmagpie said:

Finally, the thought of running a pneumatic needle gun on a small Chinese pancake compressor is laughable.

metalmagpie

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im talking about the little HF scalers, not a IR 125. yes it would still be really slow, but its aluminum. we'r not talking shipyard work here.

I run the HF needle scaler at 50psi using an 80 gallon tank/[email protected] compressor, working non-stop the compressor can keep up, but cycles regularly. I agree, a pancake compressor would be painfully slow.

metalmagpie said:

That compressor is not huge here in the US but it is significantly larger than anything I've run across in Mexico. Nor would such be very easy to buy down there.

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Been awhile since I was in Mexico, but according to google there are at least 14 Home Depots in Mexico, 4 just in Ciudad Mexico, no idea if they carry the same products.I know they used to have a real shortage of goods, but think they are catching up.