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Mrodair Airmax Compressor Review: Prep, Poor Build Quality, Fixes, Ultimately Unsafe for Use

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This topic contains 267 replies, has 31 voices, and was last updated by  guykuo 2 years, 2 months ago.

Viewing 15 posts - 31 through 45 (of 268 total)
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  • #251283

    walkonking
    Participant
    quote guykuo:

    The adventure might not be over.

    Oh I bet it is not.

    This is probably just the tip of the tidal wave that is to come in the up coming months.

    Maybe Harbor Freight will start carrying a HP compressor, then at least you can spend a few bucks for full replacement warranty :3: :whistle:

    #251339

    guykuo
    Participant

    Can anyone else who has this compressor check their high pressure rings to see if they are also polymer?
    Just check the spare ones that came with the machine. MrodAir really does believe they are silicon bronze.
    I doubt this is outright misleading on the part of MrodAir, but more likely they got duped by the
    OEM. They even have them colored to look like bronze.

    No matter the reason, this is going to impact longevity of the high pressure ring if I get
    the machine’s oiling issue solved.

    Please just see if they conduct with an ohmmeter. Silicon bronze will conduct electricity.
    Mine are completely non-conductive, and not cold to the touch like metal should be.
    It is some sort of polymer.

    [EDIT: Michael McKeown confirms that his replacement rings are not metallic]

    #251354

    miksatx
    Participant

    My spares the same as yours Guy, non conductive.

    #251365

    bigtinboat
    Participant
    quote guykuo:

    Can anyone else who has this compressor check their high pressure rings to see if they are also polymer?
    Just check the spare ones that came with the machine. MrodAir really does believe they are silicon bronze.
    I doubt this is outright misleading on the part of MrodAir,
    but more likely they got duped by the
    OEM. They even have them colored to look like bronze.

    I wouldn’t bet on this……..He reportedly “tested” a bunch of them, and “knew” the material used by the competitor….but then wants us to believe he doesn’t KNOW the material of the one he decided on after all this research?

    Come on – he’s a SALESMAN

    quote Mrodair.com:

    Be careful who you order these from guys.

    There are no less than 6 manufacturers of this pump in china alone not to mention in Taiwan.

    Davey and ingersol compressor contractors are two of the makers we tested and both work well up to scuba size tanks.

    After seeing the sales figures from Europe, many small shops in china started making this “type” of compressor and went to price war.

    You will know which when you price them.

    Our compressor, I don’t mind telling you where they sell them, as the cost for just one unit is over 1150 bucks from china direct.

    We purchased the base model for those who want to save cost and offer the add ons for convenience.

    We added the option of radiator cooling, to combat the heat buildup when filling the larger tanks if needed and they do the scuba size tanks in well under 30 min.

    Using a larger cooling reservoir (5gallon bucket) works well too, ours just looks better and makes the unit much more portable.

    The upgrades we sell, were designed by Mrodair and submitted to the manufacturer, so they could be manufactured as a plug and play upgrade to be easily added on later if you find the need.

    Our shop tank is an SCBA and 118cu@4500 psi and we fill it with no problem.

    The model we sell also has a digital temp meter, so you can keep an eye on the heat when pushing the limits of volume.

    Of course, instead of buying our upgrades, simply filling in two sessions with a brief cooling in the middle will do the job as well when filling larger tanks.

    The cheaper models, well we tested those too and they build heat much too quickly do to the material used in the rings and poppet valve in the high pressure cylinder.

    Some, didn’t even make the 3000 psi mark.

    We order ours in very large qty, to save our customers money and support our pcp product line.

    This also gets us ALOT of input into how they are made.

    We also test every one, every time to fill a 4500 psi tank before they get shipped without exception and keep spare parts in stock right here in the USA.

    The compressor posted about above, was not the model we sell.

    This is not an advertizment guys, Just a heads up.

    You do not have to order from us, but know what you are getting.

    We Are Mrodair

    #251393

    guykuo
    Participant

    I will continue to give the benefit of the doubt. At least, Michael is responding to me and has offered some support.
    Can’t really tell from here what exactly to believe, but the guinea pig will try. Nothing to lose now.
    I have written and asked for three things.

    Let’s see what happens and if this machine can get improved.

    —— snip
    Michael,

    I’m recovered a bit from the trauma of this weekend’s failure and more ready to move forward.

    Let’s hold off on replacing entire assemblies. Instead, let’s do the simplest steps first.
    There are a couple things that we can probably rule out as being problems based on
    the fill rate and fact that I did get up to 4100 PSI.

    The reed valves and poppets are probably functioning in both cylinders. Otherwise, I would
    not have gotten to 4100 PSI in a Great White tank.

    Also, I am definitely intimidated with working on the crank shaft and
    possibly leaving the rods improperly secured. Last thing I want is
    a rod coming loose during a run.

    Given the above, let’s focus on the following
    three issues to move towards success

    Guy.

    1. Oiling problem in low pressure cylinder
    Way more oil is getting into my low pressure cylinder than for some other owners.
    Charles McKeown’s machine does not make his shop smell like oil and he says
    he isn’t getting the oil staining that I am seeing with each bleed of the separator.

    Plan: Examine the rings on the low pressure side.

    Action:I remove the low pressure cylinder from the crank case and check
    the rings and their clocking. If that looks OK, I replace those o-rings with
    new ones. That won’t rule out the cylinder, but rings are easier than
    an entire assembly

    Need from Mrodair: I will need a set of low pressure o-rings and info
    regarding the correct orientation and order of rings

    2. O-Ring blowout at high pressure cylinder
    My large o-ring that surrounds high pressure reed valve disc has blown
    out. It really shouldn’t have failed at 4100 PSI, but perhaps detonations
    of oil were subjecting it to higher local pressures. If we solve the oil
    issue this would be less of a problem.

    Plan: Replace blown out o-ring with new one. Also find out if higher
    grade o-ring is possible.

    Action: I obtain a new o-ring and dimensions/durometer of ring for future

    Need from Mrodair: Replacement o-ring & size/durometer of the ring

    3. High Pressure Rings are Polymer, Not Silicon Bronze
    This is verified by at least two other owners that their rings are
    not metallic. This means the high pressure rings will be a source
    of more rapid failure than advertised silicon bronze rings.

    Plan: Ultimately replace high pressure rings with silicon bronze rings.
    Convinced dealership this is an issue for machine longevity.
    Meanwhile, use the polymer rings currently available

    Action: Replace existing rings using new spares to ensure full seal
    despite prior fouling. Also, obtain more rings for expected early
    failure of high pressure rings.

    Need from Mrodair: More polymer, high pressure cylinder rings
    Mrodair should investigate availability of the silicon bronze rings
    that were specified. Once metal rings available, replace polymer
    rings with more durable metal rings.

    #251408

    bigtinboat
    Participant
    quote guykuo:

    I will continue to give the benefit of the doubt. At least, Michael is responding to me and has offered some support.
    Can’t really tell from here what exactly to believe, but the guinea pig will try. Nothing to lose now.
    I have written and asked for three things.

    Based on your detailed write up all over the Internet – I think I would go with the Squeaky Wheel theory at this point. There are probably 45 or so others out there who we have not heard of with similar problems who are NOT getting any replies and/or support.

    Good Luck

    #251414

    clgraham82
    Member
    quote guykuo:

    I will continue to give the benefit of the doubt. At least, Michael is responding to me and has offered some support.
    Can’t really tell from here what exactly to believe, but the guinea pig will try. Nothing to lose now.
    I have written and asked for three things.

    Let’s see what happens and if this machine can get improved.

    Dude, he should offer you more than just moral support on all the hard work you’ve done for him on HIS product!
    Good luck!!

    #251475

    guykuo
    Participant

    While I await reply from MrodAir regarding my three requests, I examined the low pressure cylinder to see what has happened.

    The amount of oil in the low pressure cylinder is as much as when it originally arrived. I had assumed all that was due to it being shipped with oil in its crank case. My pre-cleanup effort was in vain. Plenty of new oil has gotten into the cylinder during my Great White filling attempt.

    This time I pulled the cylinder off to look at the rings and piston. There are three metallic rings. The top and middle are simple rectangular profile. The oiling ring has drainage holes around its center. The bottom (towards crank) edge of the oiling ring has a sharper edge. The upper edge is beveled. The sharp edge down towards the crank seems correct direction to me.

    Clocking of the ring gaps was the only thing questionable. The oiling ring and middle ring were at 6 and 5 o’clock respectively (nearly aligned). The top ring was at 12. Ideally, none of the gaps should line up. On the other hand, I don’t know how much these rings spin during run time.

    Inspection of the rings and cylinder wall didn’t show any obvious defects.

    Cleaned things back up and then reassembled with oil, middle and top rings at 12, 6 , 12 clocking to make each successive ring gap 180 degrees apart.
    Recompressing the rings was pretty easy. The cylinder end has a taper that can do the last half of the compression. I just held the cylinder with both hands, fingers extending beyond bottom of cylinder. They I could curly my fingers around and compress each ring before it engaged the cylinder.

    So, the gapping wasn’t ideal. I’ve improved that as much as possible. Don’t know if the gapping with change during run time. Also the ring gaps are simple straight butts. They are neither tapered or stepped. At least these rings are metallic.

    No word as yet from MrodAir. I still need some replacement parts before I can fire this up again to see if the oiling issue is improved.

    #251482

    birdman
    Participant

    Guy , You are more likely the Ernest of compressors . Even Mrodair didn’t go through their product as well as you have done .
    Shame on them for trying to make a fast buck by selling Chinese garbage to the masses without being totally 100 % knowiedge-
    able about the product that they are selling . Seems like they only know halve-ass of what the compressor is . They should have
    taken one apart totally completely to inspect all of its’ parts to make sure that their product was in proper working order and it
    had all of the correct components to make it function properly . Looks like that never happened and now besides yourself how many
    others who purchased this compressor is going to get burned and have to take a loss ? Mrodair knew from the get go that they were
    dealing with a Chinese product and most items made in China as far as quality goes generally will come with a big ? Mark . They will
    not be able to give each buyer a refund if their compressor turns out to be a total lost . Sad but true you get what you pay for . I
    know because I got burned on Two Chinese Scopes that everyone said was a good scope and both came brand new and both were a
    broken piece of shit . Sometimes it is hard to have to learn the hard way . :3: :3: :3:

    FROM : THE BIRDMAN

    #251492

    bigtinboat
    Participant
    quote birdman:

    They should have taken one apart totally completely to inspect all of its’ parts to make sure that their product was in proper working order and it had all of the correct components to make it function properly . Looks like that never happened ……..

    I agree they should have gone thru WAY MORE inspection then they did. Heck they “advertised” (and are STILL advertising) the rings as being “Silicon Bronze”……..and they even had a spare set with each compressor………now how did they NOT know the rings weren’t even metallic? Come on, they didn’t even have to do anything to get to them, they were spares!

    No way they can pull the “we didn’t know” routine here…….they should be PAYING Guykuo for all his R&D done after the fact……..of course these compressors are old news, they now have the MK II’s that just left the manufacturer on April 14.

    http://mrodair.com/airmax_extreme_4500_psi_110_volt_high_speed_hpa_compressor_in_stock_now

    #251499

    guykuo
    Participant

    Michael at MrodAir says I now have the ring clocking correct and he is getting the items out to me.
    He also mentions something about the gap clearance.

    Once parts arrive, I’ll put this back together and see if the oiling problem is improved.

    We still have the non-metallic high pressure ring issue, but one step at a time is still better than nada at this point.

    #251519

    airgunstocks
    Member

    Yesterday I bled my Great White down to 3500 and filled it back up again to 4500 with the Airmax compressor (I didn’t go down to 3K in case I had a failure I’d still have some air…it is turkey season after all ). It took 9 minutes and the head temperature reached 180 degrees f. (I’m using the small reservoir it came with). I bled several times getting slightly oily water each time. Very very little oil. The water on my hand would dry in short order and not really leave any oil behind, just the slightly sweet smell of the Chemlube 501. I do not have the auto-cut off gauge and I accidentally allowed the pressure to climb dead headed for a minute or two while I was looking at something and the pressure hit 8,000psi! I think I want one of those shut off gauges!

    I carefully measured and calculated and made a list of what I think are the o-ring sizes used on the Airmax. After I get my order from theoringstore.com I’ll report back as to how they all fit and any changes, but it’s a cheap enough order if anyone wants to mirror the experiment:
    water jacket x2 N2.50X053
    water jacket: x2 N2.00X005
    2nd stage head: N3.00X016
    separator inlet fitting: N1.50X011 (Guy used) I think it should be N1.80X011.2 I ordered both.
    Poppet: N2.40X009.6
    media holder: N3.00X17

    Michael McKeown

    #251530

    miksatx
    Participant

    So I was filling my 90ci tank when the upgrade filter blew the o ring at 3500psi. Scared the crap out of me and the dog.
    sure glad there was a replacement with the other filters.replaced and finished up filling.

    #251572

    guykuo
    Participant

    These o-ring blowouts are all over the machine. I think part of the reason they happening is how the o-rings are sized.
    For instance, the supplied o-ring on the water separator poppet was too large in cross section. That causes the seal to be a section of o-ring resisting huge pressure without metal supporting it against that pressure. Instead, only lateral friction keeps the o-ring seal and that eventually fails. You can improved it a bit by using more torque, but ultimately, it’s just squished rubber between two flat surfaces resisting force parallel to the metal faces.

    With a smaller cross section 0-ring, the seal acts more like a dowty washer. The rubber only seals. Metal reinforces the rubber against the force. The smaller o-ring sits inside its channel. Directly metal to metal contact seals in the o-ring and buttresses it fully. The compliance of the rubber lets the pressure push it up agains the now, much smaller gap to form a non-failing seal.

    There are multiple places on this compressor where you have this situation and need a dowty washer (if the joint is flat metal to flat metal) or a smaller cross section o-ring (if there is a channel for the o-ring to fit within). An oversized o-ring can make things worse because it could prevent full metal metal contact that forms the reinforced seal. At the very least, you need to be able to torque down far enough to make the sealed gap very small.

    [Edited for spelling and grammar]

    #251578

    bigtinboat
    Participant
    quote guykuo:

    These o-ring blowouts are all over the machine. I think part of the reason it is happening is how the o-rings are size.

    Lack of proper engineering and design.

Viewing 15 posts - 31 through 45 (of 268 total)

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