Chop Gun or Hand Lay

Discussion in 'Fiberglass and Composite Boat Building' started by mrbcurry1, Dec 3, 2012.

  1. tunnels

    tunnels Previous Member

    All this need a new posting as its not really relevent to what this post was all about in the beginning !! interesting all the same !!:D
     
  2. FMS
    Joined: Jul 2011
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    Location: united states

    FMS Senior Member

    I reread the first post and the question was:
    "I build fiberglass racing bodys for go karts. I am just wondering if I switch using a chop gun system, does it hold up in same layer thickness?"

    "Does it hold up" is undefined.
    1.) The question could be interpreted to be asking if it's easy to maintain a consistent layer thickness using a chopper gun, or
    2.) The question could be interpreted to to be asking whether the same layer thickness as hand laminated or vacuum bagged will have less strength or durability at the same layer thickness.

    I see that there was no specific question regarding weight.
     
  3. tunnels

    tunnels Previous Member

    Its a simple question and weight is possible not a part of it !!remember he is refering to something small even if you added a cup on resin to the amount of lay up it would be soggy to say the least .
    But if on the other hand if it was something bigger it would hardly make any differance at all!!

    As for holding up the same as what hes using now !!,there shouldnt be hardly any noticeable differance at all !!.

    Bagging has nothing to do with the question !! so why are you mentioning it ??

    Anyway csm alone is pretty pointless on such a small itam !! , But in a mass production set up with better glass as well as some csm Infusion would be the best method !, :).
     
  4. ondarvr
    Joined: Dec 2005
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    ondarvr Senior Member

    The OP hasn't been back since the first day, that was 6 days ago.
     
  5. tunnels

    tunnels Previous Member

    Its 0ver !!!

    Its over its just another place to rant and rave again !! :confused::p
     
  6. FMS
    Joined: Jul 2011
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    FMS Senior Member

    I didn't see it specified what he was doing before the chopper gun, anywhere. Sorry I did not find this information.

    Not directly related to the topic, I found this article interesting
    http://www.compositesworld.com/articles/in-mold-preforming-cost-justifies-closed-molding
    RIMFIRE (Robotic In-Mold Fiber Reinforcement) could be the future of the chopper gun. I would be interested to read how RIMFIRE worked over the past several years since the article was written.
     
  7. tunnels

    tunnels Previous Member

    Interesting !
    yes seen a robotic gel coat guns and chopper guns at the shanghai composites show earlyer this year .used for making parts nothing to do with the boating industry !! but still a chopper gun just the same !!:idea:
    Choppers are mounted on rails and used to make csm matt just they are numaticly operated but same as all this controversy has all been over !!. there are squirting nozzels avalible with multipal holes that dont produce very much smell or over spray at all !!
     
  8. tunnels

    tunnels Previous Member

    These are what can be used . the spray nozzle and the squart nozzle with loads of holes !! (venus products ) And if you read the number they stand for ???? anyone know?? 6504 what do they mean ?? Yes they are old !!:p:D
     

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  9. ondarvr
    Joined: Dec 2005
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    ondarvr Senior Member



    I have customers that use variations of this method to make preforms with robots. When I was working with Sea Ray they had the robotic gel coater and they were working on the rest of it. The cost is high and a great deal of time goes into developing a system that will work for each type of product a company may want to build. For high volume items it can work well.
     
  10. ondarvr
    Joined: Dec 2005
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    ondarvr Senior Member

    The numbers on the tip can be arranged in different orders depending on who you buy it from and who they contracted to built it.

    This one is a 65 thousands orifice with a 40 degree fan angle, but it can also read the other way....465, sometimes there is a dash between the two (4-65) and sometimes not. This one is stainless steel, carbide would be used for gel coat.

    You can also get an impingement tip, instead of many small holes to distribute the resin you have two that are angled towards each other, the size of the orifice and the angle at which they meet creates the final angle of the fan. Most people like these better than the multi hole version pictured.

    Some tips also use a different measurement system. They measure the actual fan at a specified distance from the tip and then cut that number in half. So a 65-4 or 4-65 would be a 65 orifice and an 8" fan at X number of inches from the tip. The actual fan angle won’t be 8" though because every type or brand of fluid will create a different fan. I say fluid because these tips are used for many different things.

    Because of the various ways to mark tips I’ve had to go through the entire stock of tips for some customers and explain what each one was and put them in order of size and fan angle. Sometimes you can only know how it was marked by looking at it and comparing it with a different size tip.
     
  11. tunnels

    tunnels Previous Member

    Very good try with the numbers !!
    65 degrees is the angle of the spray
    04 is 4 lbs of resin per/minute (about )flow rate . The gel coat nozzels we use two both same angle just the flow rate id small and bigger . Small for the areas round the deck and all its shapes and the bigger for the big areas and the hulls .

    On boattest .com there was a video and in there they had robots spraying gel coats , interesting to watch . some items they spray glass with no resin over a former and drap the glass etc and then sprinkle powder binder and cook ,then press and semi compacts to form a and looks like a bird nest shape so when it comes off can be simply placed into the mould for resin transfer when the two halves are joined together ! thats real high production stuff.
    I worked at industrial glassing for a while and thats the place to go to lreally learn about glass . boats are just a small part of the industry .
    even did hand spiral winding in a tank mounted on a spinning table tank was for toxic acids and had to be really strong so spiril winding was used
    special gel coats and then a vale or tissue layer of glass then continuous strand glass 2 layers and chopped strand with a chopper gun really wet and the spiral glass 4 strands at a time . beautiful to watch and really had to be 100% focused on what you were doing another guy used to roll the glass into the wet csm . when the tanks were finished when you tapped them they had a high pitched ring sound like hightensile steel sort of
    Industrial glassing and boat repair work are amazingly good places to work for a couple of years each place to learn about another whole completely differant way of glass !!, but boats were me i couldnt get excited about pipes and tanks at all . Boats is like the bottom of the list so to speak ,it uses materials and techneques learned form other places and materials the same its mostly come from other parts of the industry . aviation and aircraft parts has got to be the very top , i worked with a korean guy that made small aircraft and he is the best glassing person i worked with for long long time .
    Its easy to see on here how much people mouthing off really dont know by the answers to some of the questions !!i know what i know because its what i have done myself .
    Happy days !! :D
     
  12. SamSam
    Joined: Feb 2005
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    SamSam Senior Member

    Yes, you're so wonderful and full of knowledge. Why can't you answer the question and tell us what the point is with your rambling, off topic accolades to yourself?

    No matter what you say (actually, according to what you say), while a chopper gun layup can be as strong as a csm layup, it all depends on operator abilities. Since good operators are few and far between, the odds are very high it will be weaker for a similar thickness laminate. That there is all the answer needed for the OP.

    Since simple fiberglass and polyester composites rely on fiber for their strength, and since chopped composites have the lowest fiber to resin ratio, they are at the bottom of the list as far as the 'strength' of different composites go (i.e. chop, cloth, woven roven, bi-axial). Taking into account the short length of the fibers in a chopped layup degrades it even further.

    Being that chop is what you build boats with doesn't necessarily mean that you build weak boats, but I doubt you build efficient boats. You use more of an expensive, petroleum based product to begin with and for the rest of it's existence it will take more petroleum based fuels to lug the extra inert weight of those weak composites around. It's like loading some barrels of resin unto your boat and then carrying them around forever.
     
  13. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    You must use the old school tips from the HIS era of guns, they had that method of marking the tips. The #4 indicates a 52 thousands orifice. We don't see those old guns around here very often anymore, those were the next generation of guns after the old 8:1 inline units I started on. That was in the 60s and 70s. Most use the FIT tips now that are marked the other way.

    As I said, tips can be marked in many ways depending the buyer, manufacturer and market segment.
     
  14. El_Guero

    El_Guero Previous Member

    Tunnels, that goes to cost .... and cost is bottom line in any business model.

    IMHO.

    And then you go off on another tangent again ....
     

  15. tunnels

    tunnels Previous Member

    so what !!

    Im not chassing my tail here any more so do and say what ever you want . Technology , Old or new so what, its still catalysed resin being sprayed and wetting glass strands and rolling bubbles at the end of the day and not a lot has changed in the last 30 years !! people still making the same mistakes and having the same problems world wide , workmanship is still the same , materials keep changing slightly and the end users (workers ) are always the last to know and if there mishaps they get the blame . gelcoaters still dont really understand what the causes of the problems are that thye get and just keep doing the sam old same old and dont want to know why .White collar know it alls are increasing in numbers like the plauge . data and computer nerds are the new breed of no hopers with all the answers to questions be fore the question need to be asked and they still cant get it right because they never handled the materials and got there hands sticky . there limitations and they keep trying to streach and starve fibres of what hold it together because that whats needed so we are told .
    I dont want to listen to spoken garbage and crap any more and sure as hell dont want to become another "off shorewinger"
    Xmas is coming and im going home and i dont really care any more !! so sit on it !!!:(:mad:
     
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