Lamination process

[tunnels]

Originally Posted by rxcomposite

"tacky" means when you touch the gelcoat, there is some stickeness but the color does not transfer to your fingertip.

If you just put you finger on the gel it should feel tacky !!
if you wipe you fingers lightly over the gel surface and you dont get any of the gel on your skin then it is ready to be glassed over and has cured enough.
The tackyness is the very surface has not gone off so when the resin and glass is appied over the top there is a chemical etch between the two .You have the same thing with unwaxed resins when building a panel, to get rid of the tackyness you can simply add a little styrene wax to some resin and mohair roller a light coat over the gelled surface !!

[Herman]

For a beginners sake, and in less then tropical conditions, I recommend at least a 90 minutes cure for normally catalised gelcoat ("normal" varies with common temperatures in that area. Sri Lanka is not the same as Finland...)

Preferably an overnight cure. This should be no problem for any good gelcoat. The surface cure is inhibited by air, and there is a broad "open window" in which to laminate the next layer.

One other thing to mention, is that boat moulds tend to trap styrene fumes. (styrene fumes are heavier than air). Under a styrene blanket, gelcoats tend not to cure at all (and the guy mixing the stuff gets kicked...), so make sure there is some forced ventilation. A fan from some distance is enough, usually. Or rotate the mold so the styrene can get out.

[tunnels]

Originally Posted by Herman

For a beginners sake, and in less then tropical conditions, I recommend at least a 90 minutes cure for normally catalised gelcoat ("normal" varies with common temperatures in that area. Sri Lanka is not the same as Finland...)

Preferably an overnight cure. This should be no problem for any good gelcoat. The surface cure is inhibited by air, and there is a broad "open window" in which to laminate the next layer.

One other thing to mention, is that boat moulds tend to trap styrene fumes. (styrene fumes are heavier than air). Under a styrene blanket, gelcoats tend not to cure at all (and the guy mixing the stuff gets kicked...), so make sure there is some forced ventilation. A fan from some distance is enough, usually. Or rotate the mold so the styrene can get out.

Yes i got caught on this myself a couple of times over the years . A good fan set up and blow air gently over the mould does wonders to get rid of the styrene if its not possible to put the mould on its side .

[rxcomposite]

Originally Posted by Herman

One other thing to mention, is that boat moulds tend to trap styrene fumes. (styrene fumes are heavier than air). Under a styrene blanket, gelcoats tend not to cure at all (and the guy mixing the stuff gets kicked...), so make sure there is some forced ventilation. A fan from some distance is enough, usually. Or rotate the mold so the styrene can get out.

And could trap volatiles. Once, the spark from plugging the industrial ventilation fan ignited the fumes. The laminate received an early post curing.

I have always used an extractor fan and a tube since. The fan is outside the boat mold.

Originally Posted by Landlubber

Apex,

..what is it that you feel tunnels has said wrong here on this site, I see no problems at all with his comments.

I do Mate!

Quite too often he has given just wrong advice, showing he is NOT what he claims to be. Remember his VE recommendations on almost every single post in his first weeks here! (before we told him the limitations of VE)

Parroting Hermans or my comments does not make a expert.

Regards
Richard

[Landlubber]

....I certainly normally agree with you Apex, but this time I feel maybe tunnels hass had the experiences he says he has, he would not know many of the little subtleties he referrrs to if he had not had his share of "ichy" nights.....I believe him.

[tunnels]

Ichy days and itchy night and my wife got a rash all over when my son decided to grind some glass next to the car that had the door open and the dust went all over the cloth seats .
I origanaly came from the automotive industry and was Spare parts manager for the local Ford dealers . I had a love of boats since my schooldays . Designed and built model boats when i was at school and when i started work Scaled up one of my designes and built my first boat all by myself with no help . Designed all may own stuff rudder and shaft steering system , strut etc The boat had a Vee drive so drew up what i wanted and found all the ford bits , gears bearings and seals plus a universal joint , got an engineer to make the vee drive casing and put it together, then i proceeded to hot up the motor . Dad had shown me how to gas weld so i made the exstractor exhaust and intake manifold .Went like a cut cat !!
I started work at a fibreglass boat company a few years later . I knew absolutly nothing about glassing but i sure learned a lot in a hurry . I had a thurst to find out as much as i could so worked for every boat company i could find and saw what was good and what wasnt . I even did industrial glassing with a friend and that was really interesting . I worked for television as well making props and doing special effects but although it was exciting and stimulating boats were my thing . I prided myself on being able to turn my hand at making anything at all no mater what ,Car parts, boats, i even had a go at small aircraft parts as well . I aqumilated a vast amount of knowledge and expertise and was sort after by many differant companies during the hay days of our boat building . I went from the bum with a broom to laminater , Leading hand,gelcoat gun operator , chopper gun operator , foreman, factory manager, and project managing on a few projects , mainly overseas where i am at now !! so there we are in a nut shell .
I have worked with guys like apex1 a few times ! He probabaly does know a lot but he has a real attatude problem and sounds to be pretty insecure !!
Simply Hes a nut case !!

I even lived and worked in Brisbane for a while , Made all the fibreglass roof panels for the brisbane town hall when the did a revamp in 1986 or there about !!!Lived at Wishart in the caravan park close to Mt Gravatt !!