Groper has made me an infusion convert

Discussion in 'Fiberglass and Composite Boat Building' started by khaos, Feb 22, 2013.

  1. khaos
    Joined: Feb 2013
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    Location: Virginia, USA

    khaos Infusion Padawan

    I have done hand layups for fishing boats for a while. I think I like the idea of strength without extra weight and i especially like the idea of having all that time to get the layup correct. :)

    Given all that I need a vac pump. I have seen some vacs that hook to a compressor that pull 28+ inches

    I have a 6hp compressor that can roll 16cfm @ 90psi it has an 80gallon tank. Is there an issue with this type of pump?

    My thanks in advance,
     
  2. khaos
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    khaos Infusion Padawan

  3. groper
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    groper Senior Member

    Dont do it... get a proper vacuum pump that will pull 30inches. You wouldnt want a large compressor running for 12 hours each time you do an infusion do you? Energy consumption...

    Also, you want as close to absolute vacuum as possible - moisture will not boil off at room temp until about 28.5inches mercury. The more air and moisture you dont remove prior to infusion, the more voids / pinholes you will end up with after infusion.

    If you wanna learn infusion - which i highly recommend - then get a proper rotary vane vacuum pump and resin catch pot with o-ring seal and pressure guage. Both are not expensive these days...
     
  4. khaos
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    khaos Infusion Padawan

    Now I am a little confused about vacuum. Perfect is 30"Hg. But the math for some pumps looks like 5*10^-2 or 6*10^-2 (pa)? so .005 and .0005 mm Hg ?

    .0005 mm Hg seems like no vac at all since its 30" away from 30". And I am sure that I'm not looking at something correctly.

    Some pumps I have looked at:
    coleparmer
    lab pump unknow mfr
    pfeiffer
    Found the lab pump unknow mfr for less this is a nice price :)

    Ref sheets to try and understand what I am purchasing:
    http://www.orbitec.com/documents/Orbitec_Vacuum_Reference.pdf
    http://www.usvacuumpumps.com/upload/file/UltraVacDataSheet.pdf

    I'd hate to come a gutser spending 400-500USD because I was afraid to ask a question.

    My thanks in advance,
     
    Last edited: Feb 25, 2013
  5. FibreGlast
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    FibreGlast New Member

    Thanks so much for the mention khaos. If we can help, we'd be glad to!
     
  6. Herman
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    Herman Senior Member

    There are 2 ways to look at vacuum:

    1. relative to ambient pressure. So vacuum means -1 bar, -30"Hg, or whatever unit you choose.

    2. relative to absolute vacuum. So vacuum means 0 bar, 0"Hg. This is how the vacuum guys look at it.

    So a good pump pulls about 0,01 bar, or anything close to that. (actually 0,01 bar is considered the maximum acceptable, for excellent results)

    The pumps you show are basicly all airco evac pumps, which WILL smoke when not reaching ultimate vacuum (eg, whenever there is a leak). For small projects these pumps are OK, but try to put the pump outside, or install an exhaust filter. (to be purchased with the pump).

    There are also industrial pumps, which generally have regenerating exhaust filters built in. These are the units that most professionals use.

    A third option is to use diaphragm pumps, which, in dual stage setup, will reach some 20 mbar. This is just enough for some smaller projects, but at least the pumps are oil free.
     
  7. khaos
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    khaos Infusion Padawan

    getting ready to pull the trigger

    I want to get this one based on both vac and price. Is there a better option for US delivery?

    [​IMG]

    Thanks for all the guidance. :)
     
  8. groper
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    groper Senior Member

    A pump like that will work fine - it is a 2 stage rotary vane pump so it should pull down to around 25 microns from absolute. Its the same style pump i use. You should be able to do better on the price tho, nothing special about the price listed in your link... theres some cheap chinese copies for sale on ebay, To get started you might try one of these and if it dies and you want to keep infusing you could get a quality pump at a later date?

    http://www.ebay.com/itm/2Stage-Rota...049?pt=LH_DefaultDomain_0&hash=item5aee614e29

    If you want something immediately, go down to your local HVAC wholesaler and see what they have in stock - these pumps are used to evacuate HVAC / air conditioning systems and boil off moisture contained within prior to gas charging.
     
  9. khaos
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    khaos Infusion Padawan

    Sweet. Thanks. Bid placed. :)
     
  10. khaos
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    khaos Infusion Padawan

    @Groper, Pump is on its way! :cool:

    @Herman, thanks for the breakdown. It made it easier to compare products with some surety. :)

    Do you guys have any great suppliers for the consumables?
     
  11. groper
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    groper Senior Member

    sure i do, but im on the other side of the planet so it wont help you :)
     
  12. khaos
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    khaos Infusion Padawan

    I figured. :) The pump should arrive tomorrow. :) I am rebuilding an old v-hull race boat. There is a metric butt ton of work to do. I may be certifiable :eek: Project page here.
     
  13. Herman
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    Herman Senior Member

    I am also on the wrong side of the planet...

    Look into Airtech materials.
     
  14. khaos
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    khaos Infusion Padawan

    Their site does not seem to show prices. Even after creating an account just to look around. Are there any prices on the site?
     

  15. Herman
    Joined: Oct 2004
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    Location: The Netherlands

    Herman Senior Member

    Look for a distributor of their materials in your area. Drop Airtech a mail to find out who they are.
     
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