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HTP Quick Spot II spot welder - quick review

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    Hi,

    I bought a spot welder: a HTP Quick Spot II spot welder  (along with a Tig welder) over the Black Friday time period (sale still going on now fyi) and was asked by someone reading my "bringatrailer" 240z build thread to share some information about it after I got it up and running.  Well, here goes:

    Here is the spot welder.  The special offer is currently $300 off on qualifying products when you buy the Tig welder.  This spot welder counted as a qualifying product, so that is nice...

    IMG_20191216_172905.jpg

     

    It comes with the copper arms and tips you see in the pic.  These are good to get you started with making spot welds in basic configurations.  USAWeld sells other tip configurations if you need to spot weld different areas that these tips won't reach.  There is a control panel which allows you to choose parameters for different welding situations.  The settings from left to right in the picture below are basically "on/off pulse power" vs. "continuous" power, selection of thickness of metal being welded, and fine tuning of the duration of weld operation.  There is also a pressure setting, which adjusts the amount of pressure the two contacts close upon the sheet metal with.

    IMG_20191216_172911.jpg

    The pulse operation can be used for high strength low alloy, galvanized, or weld thru primer coated metals according to the manual.  It uses time between heat pulses to burn away contaminants for a better weld.  Continuous can be used for clean metal.  You follow the guidance in the manual and set the second setting based on the total thickness of the panels being welded.

    In the next pic (I only did one sample piece) the welds correspond to the following settings:

    Weld order from top left to right to bottom left to bottom right is:  1, 4, 3, 2:

    Weld 1: (top left): 175 lbs, continuous, 1 mm + 1 mm, and default duration

    Weld 2: (bottom right): 265 lbs, continuous, 1 mm + 1 mm, and default duration

    Weld 3: (bottom left): 265 lbs, continuous, 1 mm + 1 mm, and 1 step up from default duration

    Weld 4: (top right): 265 lbs, pulse welding, 1 mm + 1 mm, and maximum duration

    IMG_20191216_173135.jpg

     

    If it isn't apparent, you should notice that the size of the spot welds is quite small.  That is, the diameter of the "divot" is much smaller than that of the factory spot welds on our Datsuns.  Here is a reference image:

    IMG_20191216_173159.jpg

    The factory spot weld on the lower edge of this rocker of my 240z (apologies if it is hard to see) is about 5 mm in diameter.  The largest of the example welds done above on the test piece is about 4 mm.  Here is another reference photo:

    IMG_20191216_173300.jpg

     

    So, a ready made observation is that the HTP Quick Spot II isn't going to replicate the 240z's factory spot welds.  However, it's kind of close... and if the performance is as good as shown in the video below, then maybe getting factory "performing" spot welds is a box that can be checked with this welder.  And perhaps making them look factory is pretty easily done with a bit of creativity?  I'll be exploring that coming up in the new year in my 240z build thread, if your interested in checking that out. 

     

     

    Hope this helps someone. 

    Garrett

     

    Edited by inline6
    • Like 3

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    I wonder if you reshaped the copper tips some if the weld puddle would get larger? Maybe flatten the tip some for more contact area. Not suggesting you modify your tips unless they're cheap. Just a thought

    they look like they might be reversible

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    Thanks for this update.

    In the video, the commentator points out that the bigger STP model (VersaSpot) produces a weld dimple that's noticeably deeper (and bigger in diameter) than the one produced by the smaller, QuikSpot unit.  He attributes this to the greater clamping pressure (300 lb) generated by the VersaSpot's pneumatic system.  I'm going to guess that the QuikSpot's manual clamping system can't generate much more than 200 lb.

    Flattening the tip profile might create some unwanted consequences for weld quality. Here are a few quotes from a feature article on spot welders that appeared in the Spring 2014 issue of the British auto magazine, 'Practical Classics':

    • ""Welder power is measured in kVA.  The higher the kVA, the larger the diameter of weld you can achieve.  The points of the arms need to be sharpened regularly to a diameter that creates an effective weld at the given power... The welder must provide enough power the weld tip to melt the material. A 2kVA welder is only suitable for welding thin steel (up to 0.9mm) using short arms.  You'll need a 6kVA machine to weld effectively with longs arms on 1.0mm steel." 

      For reference, inlinesix is using a 1.6kVA machine.

      The Practical Classics article included a photo of the adjustment guide chart for a 6 kVA machine.  It specifies recommended tip diameter, clamping force and weld pulse time depending on the metal thickness and arm length.    For joining 1.0mm+1.0mm, it recommends that the tips be 'sharpened' to create a flat contact surface of 4.5mm diameter.  Recommended clamping force for a 6" arm is 200 lb.  Recommended weld time is written as 0,28" (which, I believe, is how certain parts of Europe and Asia write what us North Americans would take to be 0.28 seconds).  FYI, 1.0mm sheet = 0.039" (which sits at the thick end of the tolerance range for 20 gauge).
       
    • ""It is important to bear in mind that the longer the arms used, the less power is available at the weld tips - so use the shortest arms possible to reach around the item that is being joined."
       
    • "The arms and body of the welder need to be kept cool.  A temperature rise equates to higher resistance and a loss of power at the weld tip. Larger welders will usually be water-cooled.  With a smaller welder, allow time for it to cool between welds." 

      BTW, the water cooling feature includes water jackets around the arms.

    In Britain (small country, big population, lots of big cities, robust DIY community), spot welders can be rented by the day.  Wish we had that where I live!

    Looking forward to reading more about your experiences with your spot welder as your build progresses.

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    Thanks for this info.  Very informative.   

     

    Here are the specs of the Quick Spot II for reference.  I am not familiar with kVA.   Can you tell me how you arrive at 1.6 kVA?  I assume an equation of some sort and some of the following as parameters?

    Quick Spot II Specs
    Maximum Welding Current:    6000 Amps
    Welding Voltage:    2.5 Volts
    Max Electrode Pressure:    265 Lbs.
    Input Voltage:    220 Volts
    Input Amperage:    30 Amps
    Maximum Absorbed Power:    13 Kw
    Rated Power:    2.3 Kw @ 50%
    Spots/Hr:    180 (continuous mode, 20 gauge panels)
    Maximum Double-Sided Spot Welding Thickness:    14 gauge (.075") + 14 gauge (.075")
    Dimensions:    17" L x 4" W x 7" H
    Weight:    30 Lbs.
    Warranty:    1-Year
     

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    On 12/26/2019 at 10:58 AM, Namerow said:

     

    "Welder power is measured in kVA.  The higher the kVA, the larger the diameter of weld you can achieve.  The points of the arms need to be sharpened regularly to a diameter that creates an effective weld at the given power... The welder must provide enough power the weld tip to melt the material. A 2kVA welder is only suitable for welding thin steel (up to 0.9mm) using short arms.  You'll need a 6kVA machine to weld effectively with longs arms on 1.0mm steel." 

    For reference, inlinesix is using a 1.6kVA machine.
     

     

    On 12/26/2019 at 2:10 PM, 240260280 said:

    Max VA = power = Voltage * Current = 2.5V * 6000A = 15,000VA

    Max kVA= VA/1000 = 15kVA

     

    I think I missed the difference here the first time I read your comment, Hoover.  So, my spot welder is actually putting out 15kVA not 1.5kVA (or 1.6kVA)...  That is what your math shows.  Namerow, you agree with this math? 

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    Actually, 1.6kVA is the rating on the welder itself. The max rating for clamping is 269 lbs, per the label.

    With 220VAC and 30A input, I doubt the output could be 15kVA. The max input kVA is 6.6.

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    It seems the specs have errors? I just multiplied welding Voltage X welding current.  It looks like the 6000A may be incorrect. Some possibilities below.

     

    Quick Spot II Specs
    Maximum Welding Current:    6000 Amps  < 600A or Max Weld Pwr= 6kW
    Welding Voltage:    2.5 Volts
    Max Electrode Pressure:    265 Lbs.
    Input Voltage:    220 Volts
    Input Amperage:    30 Amps
    Maximum Absorbed Power:    13 Kw
    Rated Power:    2.3 Kw @ 50%
    Spots/Hr:    180 (continuous mode, 20 gauge panels)
    Maximum Double-Sided Spot Welding Thickness:    14 gauge (.075") + 14 gauge (.075")
    Dimensions:    17" L x 4" W x 7" H
    Weight:    30 Lbs.
    Warranty:    1-Year

    Edited by 240260280

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    14 minutes ago, 240260280 said:

    seems the specs have errors

    I see it's "made in italy" that explains a lot... i make a double left turn when i see "made in italy"…. 🙄

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    12 hours ago, inline6 said:

     

     

    I think I missed the difference here the first time I read your comment, Hoover.  So, my spot welder is actually putting out 15kVA not 1.5kVA (or 1.6kVA)...  That is what your math shows.  Namerow, you agree with this math? 

    I lifted the '1.6kVA' rating from your photo, which I took to be the unit your are using.

    IMG_20191216_172911.jpg

    There are two things in play with these welder ratings:

    • When an electrical device relies on power bursts to do its job, the basic electrical power formula of 'P = V x A' is too simplistic and doesn't (directly) apply.  That formula is most appropriately used for continuous conditions, such as calculating the power delivered by an electrical transmission line.  And even in that case, there are correction factors that need to be used.
       
    • The power rating for a welder only makes practical sense if it's measured and stated specific to a particular duty cycle (50% in this case).  You`ll see a similar approach used for MIG welder ratings.

    Back in my days as a mechanical engineering undergrad, electrical engineering ratings and calculations always gave me a headache.  They still do.

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    Hmmm. So, I guess that means the standard rating is 1.6 kVA, but perhaps the capacitive discharge feature may make it punch above it's rating in real world application? Maybe I should test some thicker samples 

     

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    Not sure what to make of y'all's info. I am pretty ignorant about this subject. 

    Also, I notice that the "same" unit has a very different label in the Youtube video previously referenced:

    image.png

    So, 2.5kVA?  What does Sn stand for?

    Another reason I'd like to understand this better is so I could compare this unit to this one, for example:

    https://www.harborfreight.com/240v-spot-welder-61206.html

    So, $160 vs. $649...  And the cheap one has 2.5 kVA in the specs.  Not sure any of the labels are going to be trustworthy?  

    Is inverter technology anything to warrant discussing?

     

     

    Edited by inline6

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    The "inverter technology" means that it's more complicated than a AC output with heavy duty variable tap transformer and contactor with a timer.

    The variable tap transformer stuff is heavy and contains a lot of copper. The inverter stuff is light and contains a lot of electronics.

    I don't know what "Sn" means, nor do I know how to interpret the goofy numbers on the spec sheets. From what I've heard (from people who supposedly know such things(, welders are one of the prime candidates for "specsmanship". The specs are often convoluted, misleading, and highly dependent on lots of variables and how the unit is used. Fine print and all that.

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    20 hours ago, Captain Obvious said:

    The specs are often convoluted, misleading, and highly dependent on lots of variables and how the unit is used. Fine print and all that.

    Yeah... definitely getting that sense at this point.

    Edited by inline6

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    Since you're not planning to use this in a professional every day heavy use application, my recommendation would be to use reviews instead of specs to compare.

    I suspect the big difference between welders is the duty cycle. And you probably won't be taxing the limits.

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    11 hours ago, Captain Obvious said:

    my recommendation would be to use reviews instead of specs to compare.

    I'm inclined to agree.  It can be really challenging to translate engineering specs into real-world outcomes. 

    However, some of us like playing with numbers, so...

    The duty cycle (%) means that the machine can sustain the stated power output for x% of the time.  If the machine is rated as 1.6kVA with a 50% duty cycle, it means that it can produce a stated output of 1.6kVA for, say, 2 seconds, provided that it gets a 2-second dwell time before the next actuation.  Or at least, that's the way you'd interpret it for a MIG welder, where the operation tends to be somewhat sustained (as in running a 1/2"-long bead).  However, for a spot welder it's a little different.  Here, the normal electrical operating mode (selected by the operator, but controlled by the machine) is a continuous and rapid on-off cycling (1 time unit 'ON' followed by 1 time unit 'OFF' = 50% duty cycle).  For reference, notice the 'square wave' icon next to the green indicator light on the machine shown in the video.  

    So: the 'n' in 'Sn' means 'normale'.  This is written as 'conventional power' on British-spec welders.  Probably stated as 'regular operating power' or 'regular duty cycle' in North America. 

    I do not know what the 'p' in 'Sp' means for your machine, other than the fact that it's probably tied to the 'I2p' current rating.

    I do know that 'I2 cc' refers to the machine's closed-circuit (or 'short-circuit') current rating.

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    I don't think it's a typo. I think there's a way to interpret that spec that makes it "correct".

    The 2.5 Volt welding voltage is probably the open circuit voltage at the electrodes. Problem with converting that to a simple KVA rating, however, is that as soon as the electrodes are closed, you don't have 2.5 Volts anymore. You'll have something less.

    The 6000 Amp max welding current is probably a very short burst of current that occurs for a tiny instant of time when the electrodes are first connected. The "realistic" welding current is probably something much lower than that.

    The "rated power" is probably an averaged rating of how much power it draws under "normal circumstances". At 180 spots per hour, you're doing 3 per minute. If it takes ten seconds to position and ten seconds to weld, you've got a 50% duty cycle. My guess is you're drawing an ave of 2.3KW under those conditions.

    And something else thing to remember... The electronics inside the device consume power too. It's not all presented at the electrode tips. Some of the power consumed from the line cord goes into powering the device itself. It'll get hot inside and that power came from the same cord. So it may draw 500W quiescent power when just idling between welds. No idea.

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    According to the label, that spot welder is made by Telwin. They are Italian (we already knew that).

    Web page here showing their products (prodotti)  >>  https://www.telwin.com/en/prodotti

    That welder is their Modular 230 (or an earlier version of the same), and if you dig down into that model, you can get to a datasheet. Here's some info from the datasheet that may help with the above academic discussion:

    telwin1.jpg

     

     

    telwin2.jpg

     

    telwin3.jpg

    Enjoy.

     

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    The numbers are probably accurate but, as CO has pointed out, may be difficult to apply real-world results. Perhaps we should get back to your experiences with your equipment.  We can draw conclusions (possibly wrong :cool:) afterwards about how they relate to the specs. The choice between spot-welding vs. MIG stitch-welding seems a really under-discussed part of the hobby-restoration process.

    Edited by Namerow

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