Quiet blower?

Discussion in 'General foundry chat' started by Bentation Funkiloglio, Jun 16, 2020.

  1. Bentation Funkiloglio

    Bentation Funkiloglio Silver Banner Member

    Has anyone tried using a quiet 12v blower like the following? http://www.seaflo.com/en-us/product/detail/663.html

    Last thing that I need for my blast furnace build is a quiet-ish blower. Full power shop vac is obnoxiously loud. I have a few options.

    1. Plug shop vac into harbour freight router speed controller. Run vac slower, quieter.

    2. Put shop vac in garage and run something like 3 inch flexible duct hose from garage, out window, and down to furnace. Put ball valve in line to control air volume sent to furnace.

    3. OR ... try out one of these 12 volt bildge blowers. Still need to control air flow with rheostat or inline dump valve.

    Edit: Wife suggested that I specify that thread title was not meant to be a double entendre. She realized this because I'm "not really that funny", in her opinion. Ahhh, wedded bliss.
     
    Last edited: Jun 16, 2020
  2. Melterskelter

    Melterskelter Silver

    I use a 20v designed-for-battery leaf blower. It is powered with a cheap 20v power supply which runs on household current. It is much quieter than a shop vac. I put it and the power supply in an insulated plywood box for further noise reduction. I keep it shuttered at about 1/2 it’s potential output. Similar to this but a eBay bare blower only. Cheap. Durable.

    https://www.amazon.com/BLACK-DECKER...eywords=20v+leaf+blower&qid=1592362527&sr=8-3

    Denis
     
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  3. Petee716

    Petee716 Silver Banner Member

    I use your option 2 with the harbor freight router speed controller.

    Pete
     
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  4. dtsh

    dtsh Silver Banner Member

    I use something similar, but I note that I use charcoal for fuel and my furnace is fairly small (A8 fits best, but I can get an A12 in there)
    Mine is a cheap inline duct fan with a custom made fan blade (because radiant heat melted the plastic one). It's not great, but it does get things up to temp quick enough for me.
    I keep saying I'm going to build a burner, but I've still got charcoal and a slew of other tasks; I know that in the long run this is probably a more expensive fuel but it works.
     
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  5. OMM

    OMM Silver Banner Member

    The diameter of your of your burner has a lot to do with the type of blower you use..... and proximity to the furnace.

    A simple hair dryer can work, but your burner tube will need to be about 1.5-2 inches in diameter and you might need an exhaust port. But some come in two or three speeds.

    A leaf blower will provide a higher CFM, but you might not need it all. It all comes down to the model you settle on. A exhaust port might be needed as well.

    TO have a good full electrical speed will require a three phase motor (on VFD) or induction motor or a DC motor on the blower. Rio-stats give a chopped sine wave that are very unpredictable.

    My burner is so small(1/2 ID) and with 10 feet of air delivery line(1/2 ID), I have a lot of static pressure which psi works in my favour. My big blower a run at half speed (or 32 Hz.), my little blower which is a four stage turbine only has one speed which I can dampen volume with ball valves. But the four stage turbine I can move away 25 feet with a garden hose to reduce the noise. I could put it in a insulated box too.

    There's a lot of things to take into account with a blower. Rpm, static pressure, CFM, psi and how they all work together or need to work together to your needs.

    My big blower turns at 1900 RPM and my little blower turns at 10,000 RPM.
    Big blower pulls about 10 A at 240 V, my little blower pulls 15 A at 120 V. But the big blower is about a third the noise. And has a life cycle of 20 times the little blower. And both these blowers are big $.

    Efficiency and thermal mass also have considerations on melting expectations. I just put my furnace on the wiegh scale yesterday and it is 150 pounds. From cold my record aluminum melt 4 kg, is 18 minutes, using just under 2 L of fuel. The inside of my furnace is 11.5 inch diameter by 14 inches tall. I can still juice up my fuel rates by almost 200%, but I can only juice up my air by 150%. I tried both and things start getting dangerously uncomfortable for me.
     
    Last edited: Jun 16, 2020
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  6. Jason

    Jason Gold Banner Member

    My microwave blower is just about silent. The furnace itself is way louder.
     
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  7. Rotarysmp

    Rotarysmp Silver

    My furnace blower is a 240v single phase 75W squirrel cage blower. Basically silent, or at least not audible over the combustion roar.
     
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  8. Tobho Mott

    Tobho Mott Silver Banner Member

    No idea how well that blower might work.

    I use a hair dryer for my 1" black pipe Moya burner when I am just going to use propane, but if I am running oil it's a 5 gallon bucket sized shop vac. The 2-1/4" exhaust tubing mega-moya uses a leaf blower to burn oil.

    All these blowers need speed control of some kind for tuning purposes.

    And they are all loud except for the hair dryer. :(

    Jeff
     
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  9. HT1

    HT1 Silver


    I had to replace my Bucket Vac Sunday to pour... must be 5 years old or better , running an hour+ darn near every week , I'm happy with that, though I would love for it to be quieter

    V/r HT1
     
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  10. Bentation Funkiloglio

    Bentation Funkiloglio Silver Banner Member

    Hrmmm. Didn’t think a hair dryer would push enough air.

    All, REALLY appreciate info/advice. Think that I’ll start with speed controller and go from there.

    @Jason, sound like you pulled fan from a microwave. How much of a pain was it to wire up power cord for it?
     
  11. Jason

    Jason Gold Banner Member

    The trick is this entire thing is a balancing act. Fuel/air mixture is not a new concept for most of us. If you have a big ass blower thats fine, but you'll need to back it down by some means. My goal has always been to eliminate some of the variables to increase repeatability. I found a blower, run it on high speed and adjust the fuel for peak temp. It took me several tries with different blowers and almost cost me a finger tip.:eek: The hottest I need is for melting bronze. My quiet little blower is PERFECT for my kwiky, furnace size and 15psi compressed air I'm using to move the fuel.

    Yes I did pull my first one from a junk microwave. It was on it's last leg when I tried it. I found out it worked perfect so I bought a good one on fleabay. It was real easy to wire it up. Most of them come with a small capacitor and the schematic is on it. I like the 3 or 4 speed motors. Reason, I start with it running on low, light the burner, shove it in the hole and slide the blower up to the pipe. Then I slowly crank up the fuel while shifting into high speed on the blower. I close my lid and adjust only the fuel for the right flame licking length out the exhaust hole. That's how I achieve the optimum air/fuel mixture. Too much fuel, exhaust gets black and sooty, too little and flame goes back inside. For me, it's 2-3" of flame out the hole. It is extremely possible to overheat aluminum and bronze. I melt my first pot of bronze inside of 25mins from outside air temp (around 20lbs worth) and the next pot in 10-15 mins. PLENTY fast enough for me. Could it go faster? Maybe, but I don't see the point. I want a controlled melt and want to pull my bronze at the right moment. There are things I'm looking for when melting bronze and I don't want to miss them.
     
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  12. Tobho Mott

    Tobho Mott Silver Banner Member

    With the hair dryer maxed out it keeps up with my 0-10psi propane regulator opened up about halfway. I only set the hair dryer on low for startup. Typical melt times starting from cold are about 15 minutes for aluminum, 20 for bronze using #6 crucibles.

    It's the same 300W credenza lamp dimmer switch extension cord and hair dryer on "cool" setup I have used since 2013 when I built my charcoal furnace, but I don't think it moves enough air to run my drip burner on oil. Maybe I should try it with a slow drip in a hot furnace sometime just to see, but I don't have anything handy between that hair dryer and my bucket vac to experiment with.

    Jeff
     
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  13. Peedee

    Peedee Silver

    With my charcoal furnace is stripped down the hair-dryer and it had a 12V(ish) motor driving the fan using volts drop across the tapped heating element. A 6v/12v, high low battery charge gave me loads of control and as a bonus I got loads of nichrome for a hot-wire foam cutter.
     
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  14. Bentation Funkiloglio

    Bentation Funkiloglio Silver Banner Member

    Stopped by harbour freight and picked up speed controller. Lets me run my shop vac between 50% and %100. At %50, vac is really quiet. Probably still need to put a ball valve inline to divert air.
     
    Last edited: Jun 17, 2020
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  15. Jason

    Jason Gold Banner Member

    They work... So does a light switch dimmer. Neither are the correct way to regulate motor speed and will ultimately lead to failure. BUT, all this junk is cheap enough so ya just throw it out in few years and do it again. If you want the how's and why, I'm sure Matt will be along to explain it if ya ask. Motors are designed to run at certain speeds and monkeying with it makes you an enginerd without the expensive edjumkation.:D
     
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  16. Bentation Funkiloglio

    Bentation Funkiloglio Silver Banner Member

    One big difference is that the router speed controller is rated for up to 15 amps. The light switch rheostats that I looked at didn't even list a number for max supported amps. Guessing that its much less than 15. However, like you said, these are cheap China candy. Easy to replace upon inevitable failure.
     
  17. Jason

    Jason Gold Banner Member

    Measure your blower and tell me how many amps it pulls... Then regulate the speed, measure again and get ready to really get confused. If you don't have an amp clamp, you are only farting in the wind. Fans and blowers do some really weird shit when you monkey with rated speed. I have a 9dollar harbor freight ANGLE GRINDER and run it on a light switch dimmer. I shit you not! Now I would NEVER do it to my 90dollar dewalt grinder, but who cares, it's harbor freight junk. Just never stick that speed controller on anything you care about. ie.. drill presses, saws, grinders, margarita machine, etc...
     
  18. Tobho Mott

    Tobho Mott Silver Banner Member

    Another difference between a dimmer switch and a router speed controller is, the router speed controller provides smooth control for my garage sale leaf blower. The dimmer switch I use for my shop vac controls the leaf blower ok at the top and bottom ends, but makes it jump all over the place in the mid range due to electronics jargon.

    They both work fine for the shop vac, but my bouncy castle blower's 'On' switch won't even stay pushed if it's plugged into either one of them.

    My 5g bucket vac is 5 years old too, and going strong running off a wall type ceiling light fixture dimmer switch. ~$37CDN well spent on that vac if it died today IMO, though it's got nowhere near as many miles on as HT1's late blower. I heard somewhere not long ago that you can silence a shop vac somewhat with a simple bearing upgrade, but I have been using propane & hair dryer only since hearing that - taking the vac blower apart to get that sorted out hasn't become a priority yet. My closest neighbours only ever even noticed the sound one time, enough to make them curious but not annoyed. I have thought about building some sort of sound dampening box for it also, after seeing how well that worked at a blacksmith's shop with 4 coal forges running.

    Jeff
     
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  19. Petee716

    Petee716 Silver Banner Member

    It might have something to do with GFI. I wonder.
     
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  20. Tobho Mott

    Tobho Mott Silver Banner Member

    Seems to be the case - when I try it, a reset button has to be pushed once it is plugged into an outlet it likes before it will work again... Someone once suggested a vfd but I'm thinking dump gate.

    I'm not worried as I have blowers pretty well covered, it just seemed worth mentioning. It was a cheap enough kijiji find to grab just on the off chance it comes in handy some day. Possibly it will fit somehow into a future foundry shed ventilation upgrade and not need any speed control.

    Jeff
     
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