"Learned" from my 1st attempt =(

General Composites Discussions Composites Talk
#1

Well, spraying Gel coat failed horribly. Didnt care about the gun first off, had a 1.4 tip drilled with a 2mm bit. harbor freight. had it for awhile. glad i had a backup :wink:

So im buying a gel coat gun 2morrow. lets see where i get with that.

I tried to spray, and it worked… but not fast enough. then brushed the rest on. i had waited about 20 mins till b stage, and wow, i f-ed up big time. i should of waited till it was fully cured. the stuff was to sticky and when i had to move it, the gel coat came off the mold =(. so i was upset and ripped the fiberglass out. glad it wasnt carbon!
but i gotta say, this stuff is NICE super clear. not to brittle. i gotta make sure my mix ratio is good. it called for 100 / 2% mix. so i had a batch of 4 oz gelc. + .08 oz of mekp. is this right??

well… hopefully i can scrape the rest of the gel coat out 2morrow… and give it a try when the gun gets in. any tips when its dry and then put the 1st layer on? if its not in b stage, but fully cured… i wanna see if airtac2 is a good product.

oh well… live and learn i guess… i do have a major headache from smelling the gel coat. i even had a mask on =(

#2

B stage is virtually dry.it will leave a slight fingerprint but NONE will stick on your finger…

#3

Airtac2 is the same as 3M Super 77.

For the Harbor Freight HVLP spray gun, you can purchase a 2.2mm tip on eBay. No need to drill out the 1.4.

#4

i hate more of the 30 mins i spend cleaning the gun. i hate it! =P.

So cup gun it is.
the trouble im going to face is, will the epoxy resin im using eat the super 77 =(. ill try my best to spray as little as i can. but im really afraid it wont

#5

I sold my cup gun to someone on here…I FREAKIN HATED IT!

Never use anything but my HVLP GUN again.

I brush all my tooling resin on though…that stuff is way too thick.

#6

NEVER spray any epoxy resins!

I like the gel coat dump guns but then I had a large spray booth…but with the class gone…?:o

#7

When spraying gel-coat, make certain you have a product intended for spray application. Brushing gel-coat is thicker, and wont spray as easily as the thinner spray material.

#8

my gel coat gun should be here friday! =)

lets see what happens then. im going to let it fully cure … then spray some super 77 on it.

#9

PS: You didn’t “fail” your first time but learned from it!:wink:

#10

I am not sure if Airtac is the same or not. We find the airtac dissolves better for clear carbon applications, where as 3m77 doesn’t dissolve as completely.

#11

doogie, your also using an epoxy resin?

#12

Based on the research I’ve done, both products appear to be exactly the same. The forumlations listed on both products’ respective MSDSs are the same right down to the “Trade Secret Registry Number.” Perhaps the nozzle on the Airtac allows for better atomization?

Airtac2
http://www.airtechonline.com/catalog/pr_cat/misc/MSDS/Airtac_2_Spray_Adhesive.pdf

Super 77
http://www.shopmaninc.com/pdf/adhesives/3m77.pdf

#13

strait from a tech at airtech it is the nearly the same thing.

#14

Me the last two times I leave it to full dry and when I finish with the part, it was very very good.

#15

I think th best thing i can do is be patient, and wait for the cup gun. :wink:

#16

If you thin your gel coat with 15% (by weight) with acetone it sprays easily, won’t clog up and cures just fine.

Do you vac. bag polyester just like epoxy? Same peel ply and everything? I was told long ago that Polyester couldn’t be Vac. bagged.

SEM

#17

i missed this post. WErks, thanks for those words… helps me and other keep going ! =)

#18

Your welcome L.

cce, welcome (I’m behind in sending out the welcoming messages…)and the reason most people doesn’t vacuum bag PER parts it that it starts to “B” stage too fast before you can get the bag on it to do it any good!

Keep the questions coming!

#19

Thanks Werks. I’m very glad to find a web site like this. Thanks for all of the work involved in running it. It can’t be easy.

SEM

#20

:smiley: just keeping the “spammers” from FG out is the not so fun part of doing this! :eek::rolleyes: