Tooling gel coat application

Discussion in 'Fiberglass and Composite Boat Building' started by jiggerpro, Oct 2, 2011.

  1. Landlubber
    Joined: Jun 2007
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    Landlubber Senior Member

    re read Glasser...he certainly knows what he is talking about, just very difficult to read, but worth the effort, thanks mate, good comment.
     
  2. jiggerpro
    Joined: Sep 2007
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    Location: spain

    jiggerpro Senior Member

    I will insist on reading Mr Glasser´s speech ............ until I understand it then.
     
  3. tunnels

    tunnels Previous Member

    Glass Craft gun model ??

    The glass craft gun you have can you tell me the model please and what gel coating nozzles came with the gun ??
    for resin spray what nozzles do you have for that ?? :?:
     
  4. jiggerpro
    Joined: Sep 2007
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    jiggerpro Senior Member

    Hello Tunnels, the model of the gun will be "Formula" and it is suppose to be the top of the line gun glascraft offers and we will have 4 nozzles as advised by the seller ( who happens to be a very serious and responsible person) but I satill can not tell you for sure about the exact sizes of them.

    All I know is that one of them will be for suppliying resin and will be larger another, and that to avoid excessive orange peel on the applied gelcoat´s surface we that could lead to a surface deffect called " gun shot " or something like that will be small diameter to produce smaller gel coat droplets into a more atomized mist that will help produce a relatively ( for airless guns) smooth surface of the gel coat in the inside part of the mold .......... I will keep you informed.

    The other two nozzles will be as advised by the seller relying in his experience with other customers who also apply gelcoats
     
  5. jiggerpro
    Joined: Sep 2007
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    Location: spain

    jiggerpro Senior Member

    Hello Tunnels , those are the spray gun and system purchased
     

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  6. Herman
    Joined: Oct 2004
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    Location: The Netherlands

    Herman Senior Member

    Make sure you have enough spare nozzles, seals, mixers and other overhaul parts in stock, so you can repair the pump overnight if the need arises.

    They are relatively simple to overhaul, but you do need the spare parts.
     
  7. tunnels

    tunnels Previous Member

    I will feed you a lot of information in the next wee while so print it!
    Translate it and store it away some where for the future !!! it could help you or it could help some one else !! its what we are here for to help one another .

    Damn there must be a heap of differant models of guns around world wide .
    Look simular to venus just totally differant .
    Has acetone flush because it is internal mix so will be a air pressure gauge for that
    has air assist quite close to the gun head so there will be another air pressure gauge for that
    there is a main pump and a air pressure gauge for that
    the catalyst pump is operated off the main shaft of the gel coat pump and has an adjustment i see there with a scale marked in percentages .
    Both the main and the catalyst pump are possitive displacement pumps !! they pump going down and also coming up !!The up stroke pumps a little more than the dwon stroke so up get a irregular beat to the pump !!
    They are very simple in there operation and totall reliable!! always , The gauze fillter on the end of the pick up pipe is the first place to look if the pump slowes down next is the air to the pump motor icing up if its been going for a long time , Water in the air line is the cause !!! Always have good airline water separators , drain the compressor tank every day !!.
    The most important thing is to keep everything 110% clean , cover the gel coat drum with clear plastic all the time to keep dust , glass fibres and dirt out .
    The catalyst bottle will have a very fine strainer just under the filler cap when you screw it off !!
    Make sure always the acetone container never gets below 25% full and when you are filling it up dont drop any glass fibres in the container !!! they do and will find there way right to the other end and get stuck some where and cause all kinds a problems believe me !!!
    Being a gel coat gun they will have supplied you with 1 or 2 gel coat nozzles maybe !! Check the nozzle for numbers
    Venus have 4501 only example !! 45 is the spray angle about !! one could be for big areas and the other smaller for small areas just the 450.5 number could be differant but the 45 could still be the same spray angle just changes the amount of gel coat coming out .
    01 is the kilograms per minute of get goat the will come out through the nozzle hole , about
    Why i say about is because every thing relates back to the air pressure setting of the pump !!!
    High pressure more gelcoat!!
    lower pressure less get coat ,
    Everything is simple !everything is related to air pressures .
    Find a nice place somewhere you can practice spraying onto . Start with you pressures low and adjust one at a time learn quckly what happens when you adjust each one and understand which gause changes what part of the operation . After spraying gel coat get into the habit of flushing acetone immediatly for 3 to 5 seconds then you can leace the gun for a while and the gel coat should not go hard in the end of the gun . Fint the manual and read the assembly instructions and know what goes where and what each part is called . It will have a strange looking piece of plastic in the tube called a turbulant mixer !! this is vitally important and never never operate or try to spray anything with out this mixer in place !!Dont forget .
    Tommorrow when i get to work i will take some close up pictures of what we have , we use all venus guns but will look a little differant but does the same job .
    The catalyst setting should be 1.5% is the normal setting to gel coat with . when you get everything working take a sample and check to the gel time !!!
    Very important to write down 4 things and later you will understand why
    1 THE TEMPRATURE !!
    2 THE HUMIDITY !!
    3 THE CATALYST RATIO !!
    4 THE GEL TIME !!
    When you spray for a sample make sure what ever you spray onto is hard and not able to absorb the styrene out of your gelcoat as this changes the actual true gel time !!.
    Every hour of every day there are changes taking place we normally never notice , its warm and thats ok or its about to rain !! so humidity could be high maybe .
    Humidity has a great effect on the gel time even when its hot !!!
    Alway record and check and write it all down ,very soon a picture will come to you and you will understand what is affecting the gel time each time you spray on differant days of the months through out the years . Temprture could be the same each time just the humidity canges and so the gel time id not the same . Most people never take any notice of what i have just discribed to you they just blame the product or the person that supplied the product never them selves for not understanding what they are doing and working with .
    Here in china we have minus -15c or lower in the winter, to the extreme of plus +40c in the middle of summer !!, But we still used the same gel coat and the same catalyst all through the year .
    The winter is bad for us because the gun wont spray the cold gel coat so we have a inline heater that brings the gel coat up to 32c degrees and will sprays fine !!
    Plus we raise the catalyst to 2.25% spray in the late afternoon and leave over night next morning all is hard and ready , not cured hard but able to be glassed over !! .
    Make sure the catalyst you put in the gun is for Gelcoat !! normally gel coat uses i differant catalyst But i have been proven wrong when i came to china because here they use one cataylst for every thing !!
    Catalyst is dangerous stuff wear cloves always !!!
    Store the gun away from strong light, specially the direct sun light .
    Catalyst looses some of its stength if its in the strong light for to long . :D
    Havent finished yet part 2 is to follow . :p
     
  8. jiggerpro
    Joined: Sep 2007
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    jiggerpro Senior Member

    Hi Herman,
    The gun comes with 4 nozzles, and one rebuilding kit with neccessary spares, the model chosen, is supposed to be the top of the line Glascraft has to offer for gelcoat spraying and resin dispensing, and it has no needle and less parts to wear ( or so I have been told ). A technician will come to our shop to install it and give us some instructions about the system. We will very likely hire the services of a guy who has a lot of experience spraying gelcoat for our mould.

    We will try to use it as much as possible and also for resin dispensing when laminating our mould.

    And very very likely we will use it as well for spraying our tooling gelcoat and duratec surfacing products.

    Lets hope the Dura products are as good as claimed to be because the sanding of the plug is quite an enormous job .

    Hi tunnels, I have printed your tips already and will review them before gelcoating, but we have a quite mild quite stable weather temp always very close to 20ºC.

    I have so many things in my head all the time ......... that my life has become a boat
     
  9. Herman
    Joined: Oct 2004
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    Location: The Netherlands

    Herman Senior Member

    About what everyone seems to call catalyst (mek peroxide or acetyl aceton peroxide). This stuff is dangerous in 2 aspects mostly:

    -eyes. Wear eye protection when handling the stuff, and prevent spilling and splashing. If you ever get it into your eye, stop whatever you are doing, flush you eyes with loads of water, and arrange someone to bring you to a doctor.

    -fire risk. Spills on material that can burn (fabric, wood, cardboard) can ignite even hours after the spil occurs. Cause #1 for fires in polyester shops.
     
  10. Herman
    Joined: Oct 2004
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    Location: The Netherlands

    Herman Senior Member

    Check the times of your post and mine. Wow.

    To add to your post:
    Things that might wear as well are pump seals, perhaps have pump throat seal oil in stock as well, and same for the complete peroxide line. (seals, piston, or when in a hurry have a complete peroxide pump in your spare stock.). Non-return valves in the pump and the gun are also nice things to break down. (stock all NRV parts, they cost near to nothing, but you always need them in the worst possible moment.)

    Your supplier should have a good idea of what has to be replaced most. The commercial version is "our system does not break down". The truth is that every machine has its quirks, and needs regular attention and a dose of spares.
     
  11. tunnels

    tunnels Previous Member

    The first gun i ever had enything to do with was way back in 1972 from then till now i have only ever had 3 main pumps apart in all that time and it has always been something to do with the resin or the gel coat thats been at fault never the pump its self so all you should ever need are the seals !! Catalyst pumps usually never give any problems at all ever . Cleanliness is absolutly important .

    I never heard of any one spraying duratech with one of those guns . thats a first !! or did i get the wrong impression ??

    I always use a pressure pot to spray duratech and i build my own every place i have been and worked at . dont need anything fancy just what ever is laying about mostly .
    Pressure pots are so universal and can spray almost anything with them . Dura tech with a paper cup of q cells added makes a good high build easy sanding coat and the final coat dont mix anything just the duratech and catalyst .

    Here i have a big pot for gel coating up to 6 kgs of gel coat and just change the hoses onto a small pot about 750 mls for speckle coating and multi colours with a base colour over the top , I always use plastic containers inside to save acetone for cleaning with . :D
    Am going to take some pictures if you want then as well . :p
     
  12. tunnels

    tunnels Previous Member

    You took the thoughts right out of my head .
    Always have eyewash bottles on hand and every one know where they are and never work alone when spraying or useing spray equipment . guns are always pumping at high pressure and things do happen when you are least exspecting it.
    I had a staff of 24 laminators and ran a emergancy shut down one day just to see what woud happen !! it was like a comedy movie to watch !!!
    most couldnt find any of the safety equipment and what they did find less than 5% worked . So was a good lesson for every one concerned . also got the local fire department to come and help another time as to what burns and how easy it ignites and what goes bang etc etc . plus they inturn were always welcome to come and inspect what we had in the factory and were using and where everything was situated for there own referance as well . firemen and women put there lives on the line the moment they get out of the fire truck when theres a fire so the more they know of a given situation the safer and quicker they can do there jobs . :D
     
  13. tunnels

    tunnels Previous Member

    The big pot is a standard pressure pot , in this case we have 2 of them we also use when vac bagging as a dump pot for any thing that comes throught the line .

    I found all the fittings in boxes in our store when i arrived here , as a safety feature theres a blow of valve i found in the bottom of a box !,thats set at 50 psi .I used snap connections for the air supply to the system , a pressure regulator and gauge for the pot pressures mostly only need 10 psi .

    The small pot is part of another system i found that had bits missing or broken so again made my own . Has a regulator for the pot and a gauge ,is only a screw together top and pot so pressure is set for the blow off at 5 psi . I have a snap off air connection for the air line so it goes straight onto the big pot or the small pot , The air pressure to the gun has a regulater and gauge as well !!
    To spray standard gel coat 10psi on the pot and 35 psi on the gun is all thats needed !! up the flow of gel and enough air to give a decent spray keeps the over spray down to a minimum and makes a pretty cool job !!.

    The panels i was playing with speckled coated was to show wet on wet spray and what makes colors leach out into each other . You know the causes but trying to reproduce in a exsperiment is some times impossible .
    Its the speckled effect that was the point of this excise and wet on wet and the colors did not bleed into each other! . This is all done with standard 3 differant colored gel coats catalysed as you go sprayed through the same gun all within minutes then left to harden !, then tissue and csm glass behind .:cool:
    I did the spray onto a clear sheet of waxed glass so everyone could see during the spray process what was actually happening in real time .
    One exsperiment i have not been able to reproduce is pigment separation as yet . i have some on a mould and i understand the causes but have not been able to make it happen as yet !.
    So thats my pressure pots !,have over the years made and left at places ive worked maybe 20 over my time in glassing .
    They are simple ,cheap and very efficent , you dont need a giant compressor for the system .
    Biggest boats ive gel coated with a pressure pot were 38 footers . Once a week ,hulls, decks and all the small stuff !!
    Same system can be used to spray duratech , or enamals or two pots or polyurethanes just about anything at all :D:p:p
     

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  14. Herman
    Joined: Oct 2004
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    Herman Senior Member

    Here is a fun picture of one of my colleagues, spraying barrier coat over tooling gel, at one of my customers. The customer wanted to hire the equipment, which my colleague brought. He decided now he was there, he would also like to spray the stuff...

    They sprayed both gelcoat and barriercoat. The boat is 52 ft.
     

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  15. jiggerpro
    Joined: Sep 2007
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    jiggerpro Senior Member

    Hi Tunnels, you where right, the right tool for spraying duratec products is a pressure pot, I was hoping it could be done with the automatic dispenser just like gelcoat, but with a finer nozzle, unfortunately not so, we have a nice pressure pot and spraygun with 2.5 mm nozzle.

    I just do not like working in a hurry, nor cleaning spray guns so often.

    Do you know if the pressure pot gun and system has to be cleaned with acetone every batch? or can several batches be loaded and sprayed and the new batch dissolves the residues of the last one ??
     
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