Alteration to the Harbor Freight Powder Gun

[Dragonheart]

After looking as some of the more expensive powder guns I made a couple of changes to my gun that helps me. A copper multi wire tip & powder diverter.
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[dahermit]

What does it "help" you do? What fault were you correcting?

[Kraschenbirn]

Little more explanation, please? Your last pic shows the added 'powder diverter' with a screw-on cap in place...how does that work?

Bill

[Dragonheart]

My powder spread was too large using the any of the included HF plastic tip diverters, no diverter worked better.

With my add on's my powder stream is reduced and denser. I also think the copper tip gives me a better charge as there is more contact surface as well as copper a better conductor. Its all subjective, but the powder seems to bond more even and faster.

If no one has guessed the diverter is a plastic bottle slipped over the gun barrel and taped. The cap just seals the end of the gun when not in use.

[popper]

I added the wires and it does help. The step in the bottle may help with powder 'dumps'. Cap helps keep the powder dry. I used a 45 PVC pipe but no reducer or cap. Clean the wire after a while, to keep the charge going.

[Dragonheart]

I added the wires and it does help. The step in the bottle may help with powder 'dumps'. Cap helps keep the powder dry. I used a 45 PVC pipe but no reducer or cap. Clean the wire after a while, to keep the charge going.

Good to hear. Since it's copper, I easily clean the tip by dropping it into a 1/1 mix of hydrogen peroxide and white vinegar

[RP]

I take it the powder builds up faster with the added contact of the wire? I have tried moving the direction of the air that swirls the powder that seemed to help very little. Also added some airsoft bbs into the mix that seemed to help here and there one thing for sure it making sure the powder gets up into the air stream.

[Kraschenbirn]

Thanks for added info. I've experienced much the same thing...wide spread/low powder density...no matter which tip I used. Might just get my HF gun out this afternoon and see what I can cobble together.

Bill

[popper]

Just brush off the powder from the wires or blow it off with the compressor. Extra wires expose more powder stream to the static field.

[Dragonheart]

Bill: You might want to start out with just the bottle, assuming you can find the right size to just slip over the barrel, and see how that works as little time and effort is involved. I am sure others will come up with better ideas. I considered cutting down a plastic funnel, but I had none the right size.

If anyone wishes to make a multi-wire tip. The thread size on my HF gun is 4-40.

Any other questions I will be happy to answer.

[Beagle333]

Pretty neat! The HF gun does need a little help getting more static to the powder. 8-)

[popper]

Clean the powder off the wires frequently - powder build up on the wires reduces static.

[Walter Laich]

I used a 5-Hour Energy drink bottle. It requires one wrap of duct or similar tape for a tight fit. Does a good job tightening up the powder stream

[Dragonheart]

Hi Walter,

Is your bottle a #5 (Polypropylene) bottle as I would think this would also help by giving off electrons? What I am using is a #2 (Polyethylene), but looking for all the help I can get.

[bangerjim]

I always have a soft 3/4" artist brush handy when using either of my ESPC guns to brush off the powder from the busniness end. I does seem to help with the speed and qualtiy of the coating to have a clean end!

Amd I blow out the gun body each time I end my session. HF sells a 12" long air "needle" blowgun that is great for getting up inside the tubes.

Been too sick and now too busy to do any coating in the past 3+ weeks. Just now catching up on all that delayed engineering work I put off while under the weather.

banger

[RP]

Has anyone given any thought to a spring inside the guns nozzle tube attached to the electrode? That would surely give it a lot more surface area to charge the powder but may build up with to much powder to fast to make it worth the effort. Just thinking out loud since I do not have the time to test it myself.

[Dragonheart]

Here are a couple of pictures showing how controlled, dense and well bonded my spray pattern is also note the lack of overspray even outside without my wind shield. I didn't get these results with the out of the HF box gun before my additions.
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[RP]

Looks good I have noticed the older my powder gets it must be sucking in moisture and its not working as well. I am going to try the improvements on my gun and see if that helps its been a real wet winter.

[Dragonheart]

Check out my post "Keeping your Powder Dry", showing my very effective and inexpensive homemade in-line air dryer. Any moisture in your air supply is not good because the powder tends to cake and moisture dissipates the charge.

[Walla2]

It looks like you soldered the additional wires on. Correct?

[Dragonheart]

It looks like you soldered the additional wires on. Correct?

Yes, I did.

[rondog]

This is a very interesting thread, let's keep it alive! Any new stuff to add? How does this mod work for, say, automotive or motorcycle parts?

[rondog]

So, what gave you the idea for the 4-pronged wire thingy? And are those soldered to the rod in the gun, or are they soldered to some threaded piece that just screws on? More details please!

[Dragonheart]

I got the idea of a multi tip from seeing one on a high dollar powder coating gun. It made sense that more surface area and a better conductor, copper, would transfer a better charge to the powder as it flowed through. I first started out trying the little plastic powder diverters supplied with the Harbor Freight gun , but quickly found they spread the powder out. I felt like what was needed was a tighter flow, not larger. I went through my box of funnels because what I wanted was to compact the air stream, like a funnel. I couldn't find anything on hand then I started looking in my box of jars and found a small plastic bottle. When I cut the bottom of the bottle off it fit almost perfectly over the HF gun nozzle, secured with a wrap of tape. It reduced the width the powder flow and allowed me to direct all the powder to a much smaller area, just what I wanted.

The multi-wire tip I made from a copper welding tip for a MIG welder. I shortened the length of the tip some, as it was a little longer than needed. I drilled out the center of the MIG tip with a #4 drill bit so I could later thread the tip. I drilled two 1/16" holes perpendicular to each other completely through the barrel of the tip and inserted two short pieces of copper wire into the holes, then bent the copper wire on all sides so the wire would lay flat against the against the outside of the MIG tip and the 4 wires pointed to an end of the tip and extended a little past the end. I soldered the the 4 strands of wire to the outside of the MIG tip. Then I redrilled the center of the MIG tip with the #4 drill to cut through the copper wire I had inserted through the drilled holes in the sides. I tapped the center hole using a 4-40 tap to cut the threads and cleaned the tip with a short soak in 1 to 1 mix of Hydrogen Peroxide and white vinegar and a little a little wire brush. Now the tip just screws onto the existing threaded shaft of the HF gun and my bottle diverter slides over and covers the tip. I have found this to be a big improvement over what I had to begin with; if your goal is a tight dense spray pattern.

[rondog]

I got the idea of a multi tip from seeing one on a high dollar powder coating gun. It made sense that more surface area and a better conductor, copper, would transfer a better charge to the powder as it flowed through. I first started out trying the little plastic powder diverters supplied with the Harbor Freight gun , but quickly found they spread the powder out. I felt like what was needed was a tighter flow, not larger. I went through my box of funnels because what I wanted was to compact the air stream, like a funnel. I couldn't find anything on hand then I started looking in my box of jars and found a small plastic bottle. When I cut the bottom of the bottle off it fit almost perfectly over the HF gun nozzle, secured with a wrap of tape. It reduced the width the powder flow and allowed me to direct all the powder to a much smaller area, just what I wanted.

The multi-wire tip I made from a copper welding tip for a MIG welder. I shortened the length of the tip some, as it was a little longer than needed. I drilled out the center of the MIG tip with a #4 drill bit so I could later thread the tip. I drilled two 1/16" holes perpendicular to each other completely through the barrel of the tip and inserted two short pieces of copper wire into the holes, then bent the copper wire on all sides so the wire would lay flat against the against the outside of the MIG tip and the 4 wires pointed to an end of the tip and extended a little past the end. I soldered the the 4 strands of wire to the outside of the MIG tip. Then I redrilled the center of the MIG tip with the #4 drill to cut through the copper wire I had inserted through the drilled holes in the sides. I tapped the center hole using a 4-40 tap to cut the threads and cleaned the tip with a short soak in 1 to 1 mix of Hydrogen Peroxide and white vinegar and a little a little wire brush. Now the tip just screws onto the existing threaded shaft of the HF gun and my bottle diverter slides over and covers the tip. I have found this to be a big improvement over what I had to begin with; if your goal is a tight dense spray pattern.

Beautiful explanation, thank you! I think I'ma gonna try to make something similar, that wide spray pattern is my biggest gripe too. I also plan to use my gun to coat small motorcycle and auto parts, whatever I can fit in my old Kenmore oven.

[dahermit]

Then I redrilled the center of the MIG tip with the #4 drill to cut through the copper wire I had inserted through the drilled holes in the sides. I tapped the center hole using a 4-40 tap to cut the threads...You lost me here...according to my references a 4-40 tap uses a #43 tap drill bit not a #4. Is that a typo, or am I missing something here?

[Dragonheart]

Yes, it is a typo, should be #43 drill bit for 4-40 thread, not #4. Thanks for catching it.

[rondog]

Don't know what it is, but the threads on my HF gun definitely AREN'T 4-40. Metric doesn't seem to work either. So I may forego the prong thingie, and just go with the bottle extension.

[Dragonheart]

Don't know what it is, but the threads on my HF gun definitely AREN'T 4-40. Metric doesn't seem to work either. So I may forego the prong thingie, and just go with the bottle extension.

Sorry to hear that, I made a couple of tips for friends and the fit, but with HF who knows as their chinese suppliers seem to change? Just like the bottles the HF powder comes in, one would think the plastic bottle would fit the gun, but no such luck.

[MyFlatline]

Been searching for this thread for weeks. Giving it a bump .
Good info, thanks.

[Dragonheart]

Probably not needed as most are probably aware, but making sure you compressor air is as dry as you can get it makes a huge difference. The small inline plastic filter that comes with the gun is next to worthless for drying the air sufficiently.

[Beagle333]

I have a lot of trouble in my area with the moisture too. Which filter do you use?

[Dragonheart]

I have a lot of trouble in my area with the moisture too. Which filter do you use?

I originally made a simple coalescing filter out of pipe and stainless scrubbing pads that then fed the air into desiccant. This filter was set up to dry the air as it came out of the compressor tank.

I have just purchased a new 60 gallon compressor that delivers 18 CF a minute, so I am presently working on a system that will dry the air before it goes into the tank. I have several ideas that I am playing around with involving coalescing filters and a refrigerated dryer. I would have had it finished by now, but my TIG welder had to go in for repairs and Everlast Welders is taking their own sweet time about getting the unit turned around.

Living on the Gulf Coast our humidity is almost always very high unless we have a cold front move in.

[wrinkles]

I've seen several other forums mention that they changed the hopper to allow it to be connected and hang down instead for up and over the gun but none of the sites have pics of what they did. Anybody done this here.

[MyFlatline]

I've read that also.

[Beagle333]

I don't see how that would work. The whole point of the gun is to make a "tornado" of powder that is stirred up by the incoming nozzle at the bottom (which is buried in powder) and get picked up as it rises by the outgoing hooked tube at the top and then goes whisking on down the barrel of the ESPC gun and then gets its charge from the electrode(s) as it passes. If it were inverted, there would be no powder between the short incoming nozzle and the opening of the hooked tube as the air goes out. But I would definitely be up for taking a look at any other redesign of such before I said it didn't work.

[Dragonheart]

If it helped with too much powder being fed to the HF gun then it might be an improvement. In comparison the HF gun comes up second to my Eastwood Dual Voltage Gun anyway, so I will probably never use my HF again and only keep it as a backup. The Eastwood gun does have a bottom feed and the powder flows so much better without any modification. One of the big pluses are the extra powder bottles for the Eastwood are cheap, so a bottle for each color is possible.

[RP]

Now a Sticky to never be read again lol well we see.

[Beagle333]

Now a Sticky to never be read again lol well we see.
A sticky?!?...... yep, it's gonna get old and dusty now. haha!!

[greenhornet-1]

Don't know what it is, but the threads on my HF gun definitely AREN'T 4-40. Metric doesn't seem to work either. So I may forego the prong thingie, and just go with the bottle extension.

I just checked mine. The threads aren't any iv'e ever seen before either....

[milsurpshooter]

Hi, i just got one of the HF gun ,i would be interested in building one of the modified tip,i am thinking of useing a bullet instead of the welder tip.Would it work ,or having a lead core would not ? I am trying not to have to buy a 10 pack of tips that i would not have any use for.

[rondog]

Dredging this back up. I gave up because I couldn't find anything to screw onto the "mystery threads" on the rod. I just had this freakin' brainstorm - why not just wrap the copper wire tightly onto the rod w/needlenose pliers?

Must re-address this. I've had dismal coverage results with the spray gun, and I hate the roughness of shake 'n bake coatings.

[Dragonheart]

My old HF gun works, but no where near as well as my Eastwood Dual Voltage gun, so the HF is retired unless needed. I just used what I had available to fashion a tip. Anything to get a better charge through the powder flow should help. The big thing to be aware of when spraying is making sure the compressor air is as dry as possible because high humidity will kill the charge.

[popper]

Yes, just wrap bare fine copper wire around the tip and point the ends of the wire toward the target. It works but needs to be cleaned often.

[Grmps]

Do you have pictures of the modifications to the HF gun? the old pictures aren't accessible

[Dragonheart]

I am not sure what happened to the photos, but they went away a while back when posting photos on the site changed. Here are the photos showing the copper threaded adapter and a plastic bottle used to restrict and better direct the powder flow.
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[Grmps]

Thanks for the info. I was going to get an Eastwood gun but found a deal Recently:
4# Eastwood ultra clear, 2# Eastwood reflective chrome (both ASBBDT great)
https://i.imgur.com/0SF4bLZ.pnghttps://i.imgur.com/cNstA6L.png

An old Harbor freight oven
https://i.imgur.com/mRruKjR.png

and a Harborfreight PC gun that had only been used a couple of times for $90 total ... I couldn't say no

It also came with 5 bottles of HF PC that I dumped to use the bottles for my PC. Some would say that was wasteful BUT my PC (some of "smokes" and a lot that I bought/acquired/traded for is far superior to the HF pc and I wouldn't wish HF pc on anyone plus it's not worth the cost of shipping of someone did want it.

IRWIN HANSON 4 - 40 NC Tap and No. 43 Drill Bit Set, 80209 amazon $6.15 prime https://www.amazon.com/dp/B00004YOAO/ref=sxts_kp_bs_lp_1?pf_rd_m=ATVPDKIKX0DER&pf_rd_p=8778bc68-27e7-403f-8460-de48b6e788fb&pd_rd_wg=dWdn6&pf_rd_r=ED2G9VB7T9GC7ESQ918J&pf_rd_s=desktop-sx-top-slot&pf_rd_t=301&pd_rd_i=B00004YOAO&pd_rd_w=aJ9hH&pf_rd_i=4-40+tap&pd_rd_r=d400c5b8-bf24-457c-b63e-72ecc155058c&ie=UTF8&qid=1539637172&sr=1

Online auction site $5.76 shipped #4-40 HSS Plug Tap and #43 HSS Drill Bit, Qualtech

and I have .030 in. MIG Welding Contact Tips

I have some copper penny PC that the manufacturer says works best under chrome, my ASBBDT results wern't satisfactory.

[Dragonheart]

I hate to tell you but the bottles the HF powder comes in do not fit the HF gun.
Looks like you found a deal and the HF gun does work. It just does not work as well when the humidity gets high like the dual voltage Eastwood gun. Since I live on the Gulf Coast humidity is a problem. That was the reason I made the tip for the HF gun, to increase the charge. Getting the compressor air as dry as possible also make a big difference.

I agree HF powder is a poor choice for bullets, but it works fine for some things. I used up the one container I purchased several years ago spraying coffee cans to be used for bullet storage. Just heat the can up to 350+ degrees and spray. The powder melts on contact; then just do a regular cure. Same process works for PC other things also.

Some powders will not tumble coat, copper penny is one of them. So far all the solid color powders I have tried will tumble coat, but some better than others. Yellow powder just like yellow paint will need more than one coat. Blue's & Green's seem to work the best.

[Onebad06vtx]

I seen a thread some where that people where drilling the air nipple with multiple holes to help the powder mist better.
But now I cant find it.
Anyone seen this mod?