I have been using sprayguns to do gelcoat for many years but we are doing larger and larger parts so I want to invest in the proper eqpt, using a modified spraygun is all and well but cleanup is a nightmare and it cant lay it on thick enough on big stuff.
Has anyone used the G200-6 External Mix Gel Coat and Resin Spray Gun? and if so what ya reckon? I have seen the normal G100 cup gun.
bump *************
Not external mix dump guns but I have the same model in a non external mix gun and a Polycraft knock off one here.
I use Smart and Final 44oz cups and saves cleaning out the PE cup on those…
For better mixture control, I’d suggest using the ES G100, with this: http://www.esmfg.com/attachments_&_accessories.htm
dougie i have just ordered a new gun from gs and will be selling my old one it is a binks b5 but i am having trouble with the fluid section it will need to be rebuilt probably by a profesional in this field it is working for me now but running too fast i droped the catalyst on the slave arm to compensate would take 1500 for it after my gs gets here the gun and hoses cost me 1700 they are 2yrs old the cat pump was 2000.00 and is only 1yr old
if you are spraying a lot of parts these guns are the only way to go only reason i am selling is gs dealer is only 20 min from our shop and they could be here to help me with it the same day i call them wich is very important to keep production going
my new gun— http://www.gsmfg.com/littlewilliegelcoater.htm
thanks for the offer advantage but I really didnt want to spend that much at the moment. It is nice to have the right gear though!
The only thing that worries me about the external mix guns is if something messed up with the catalyst ratio or it got blocked or didnt mix properly or something like that and then I went and sprayed a big mould unaware, disaster 
There is a dye used in MEKP that comes out purple when sprayed, but goes clear as the PE cures. Not sure what it’s called, but it definitely helps when spraying with a chopper gun. You might be able to use the same stuff in this application as an added precaution.
you are correct dougie when i first started using external mix it hapened several times --forget to turn on the cat.valve-small piece of dirt plugs it whatever
but spraying 3-5 gall of gell at a time you learn real fast
we put a filter in the line and filtered cat. when pouring in the gun
danny we also started using the red vanishing norox mekp-9 very impresed with it it does work good enough to patch with clear cat!! and it is the same color