A PVA Mess!

i USE to get museum pieces handed to me worth thousands and thousands of dollars and had to make moulds from them so was a coat or two of pva to protect the artical then a jonstons wax and another pva then make the fibreglass mould . I was absolutly scare shitless the first couple of times but never once had a problem !!
Wax !! use johnstons soft floor wax and rub it into the clay surface and let it dry then another second coating and a light rub and let it gas off and dry completely then mould !!!! do a little exsperimenting with the johnstons wax , without pva and with pva but its light thinned pva that i found works best on almost everything !! can spray it twice or even three times if in doubt of the coverage just make sure its dry between each coat . ITS mist coats that are what you looking for !!
Playing with differant guns and differant air pressures is a complete waste of time and the finer the spray and the more air the better !!.
LIKE IVE SAID BEFORE "IF YOU CAN SEE IT ON THE SURFACE YOU HAVE TO MUCH ON "!!!

 

Hello Kosmos,
I think you should discuss your toughts about the country you are living in another forum. If you are not happy in Brazil so f..off, go back to Australia. Why are you here?
Do as tunnels does, he lived in many countries and he is not here complaining about them, he is here sharing his knowledgment. I know all the problems you are talking about but you are talking too much. And if you dont like to f... the hot Brazilian girls go back to Australia to suck Kangoroo's dick. I lived in Australia for four years and love it. If you want to stay you are welcome but if you hate f..off

 

Hello
I totally agree but he's an Australian and they don't know any thing different .

So tell me what's the Brazil boating scene like at the moment ?? what about the economy in general ???
GETTING BETTER ?
CHANGED A LOT OR A LITTLE ?
if THERES LOT MUSIC AND DANCE CANT BE ALL THAT BAD !, LONG AS PEOPLE HAVE FOOD AND SHELTER !!
TAKE CARE MY FRIEND!!
if I GO TO A PLACE I DONT LIKE I LEAVE !!
I BEEN HERE IN CHINA FOR 3 YEARS AND NOT EVEN THINKING OF GOING BACK TO NZ !!

 

Hello tunnels, well this is my opinion too, love it or leave. I lived in Australia for 4 years and love there, I´ve been in NZ twice and loved as well, I got many NZ freinds that used to work with, nice people.
I really appreciate your effort to help people on this forum and your skills worth a lot, you got a lot of hands on skills. I am starting to build a boat from the mould and I would like to count on you to complete the process sucessfully. Could I have your email? I would like to write something like my boat involvement and what I am doing at the moment, your opinion is very valuable. Cheers

 

Hello tunnels, well this is my opinion too, love it or leave. I lived in Australia for 4 years and love there, I´ve been in NZ twice and loved as well, I got many NZ freinds that used to work with, nice people.
I really appreciate your effort to help people on this forum and your skills worth a lot, you got a lot of hands on skills. I am starting to build a boat from the mould and I would like to count on you to complete the process sucessfully. Could I have your email? I would like to write something like my boat involvement and what I am doing at the moment, your opinion is very valuable. Cheers

 

this thread should be a PVA stiky

thanks again great info here, I now spray pva as directed by tunnels with zero issues I do however have a question regarding using it it high humidity, should I for go it and just use wax? and the wax of which you speak of the S. C. Johnson wax for floors sold in the big box store the release wax you are talking about?

 

As long as the air coming from the compressor id 99% dry its never going to be a problem its would take a while for the pva to become wet from humidity and if the humidity was that high you should not be gel coating any way survey standards require 70% or below most places I've worked the high 80s is ok but add a little warmth into the equation and that help a lot !!

Johnson wax !! sound like the stuff alright !! but for the sake of safety do a test panel so you are satisfied with the results !! one with wax+pva and one with just wax !!!
its magic and is real easy to use with a well wrung out damp rag to apply .a light smeary coat well rubbed into the moulds surface and left for 5 to 10 minutes then lightly hand buff it to a shine has saved my bacon on many occasions .

 

Can I wait 24 hours after shooting the PVA untill I gel coat the plug. I like to work in the early mornings when the temp is in the mid 70s, rather than the afternoons when its in the high 80s in my work area.

rich

 

the choice is yours !! what are you saving by leaving it 24 hours ???

Pva is activated by the presents of moisture ! its designed to dissolve immediately the water comes in contact with it !,so if you spray it with dry air from a gun and in minutes its dried on the surface and if you leave it over night can you be 100% positively sure the dew moisture in the over night air will not have softened it PLUS NOW THINK ABOUT THIS !!! because its can draw moisture and you just go ahead and gel coat over it will the moist PVA inhibit the surface cure of your gel coat !!
After all moisture is what slows and even kills the gel and cure of gel coats and resins

 

Tunnels, so are you saying that I should gel coat the plug shortly after shooting the PVA? I have no problem with condensation from the night air, as I'm working inside. the temp inside my garage is about 75 degrees at 6AM, climbs to 80 about 10AM, and gets to the high 80s for the rest of the day. It's the low 90's outside with the usual showers in the afternoon. I live in the Tampa area. I thought shooting the PVA one morning early, and then gelcoating the next morning early.

rich

 

You do what you think you should do !!!

its your choice what you do ! we give advise to help you because it was you that asked the question , but its your choice at the end of the day if you follow it or not
I am just pointing out the possibilities !!
temperature has little to do with pva ,
Its humidity that's the worry !
and now you say its rains usually during the day !!
so when it rains the humidity goes off the scale then what happens to the pva ??
Moisture is everywhere there's air !a movement of air it has no boundaries ,inside or out side ,under through and over like everywhere !!
I have given you the basic facts and its up to you to do what you think you want to do , if you spray just a short time before you gel coat only takes a short time to dry and If you blow air all over the surface it will dry completely and how long would all this take 10 minutes ?? wouldn't it be better to spend 10 minutes just before the gel coat goes on rather than risking a possible stick up because the PVA got damp and didn't do its job properly ??
But you do what you like !!

 

The PVA is water based, you can spray it in the morning and once it's dried you can gelcoat it. Once it's set enough, 5-15 minutes, put a fan on it and within 30-45 minutes it should be ready. The biggest problem I always had was laminating too soon after the gelcoat and causing alligatoring, so I always liked getting the gelcoat on in the evening and letting it set overnight before laminating in the morning.

 

Tunnels and SamSam have given me lots of good advice, I appreciate the help, but as tunnels mentioned I have to make my own plan. As I mentioned before the plug is a small center console, not a hull. I can carry it without touching the exterior. Its all waxed up at this point, So tomorrow, I will shoot the PVA as to Tunnels recommondation, then carry the plug inside my house, the AC will be turned down to 75 degrees and set it in my living room under the ceiling fan turned up to high, for an hour or so. Later on I will carry it back to the garage, and I will brush and roll two coats of tooling gel coat on, letting the first coat tack up. After all that is done, I'll bring it back inside where the house is cool, and let it sit ovenight, and then laminate it up the next day. Does this sound OK?

rich

 

Toting the plug inside and out sounds a nuisance, if you scratch the pva coat, you have problems. The gelcoat will stink up your house and like cat piss, the smell won't go away easily. If you chill down the pva coated plug in your house and then take it back outside, and humidity condenses on it like it does on my eyeglasses sometimes, you have a problem.

Spray the pva in the morning and let it dry. Don't put a fan on it immediately as you don't want to dry the outside and trap moisture under it, and when/if you do put a fan on it you are only trying to move the air to give a change of air not blasting on the surface. Fanning the air with a piece of plywood occasionally will do what you want. If there are pockets where the air can't circulate much, you have to move air in and out of them.

I have never had success brushing gelcoat, so you're on your own there. There were always thin areas left and when the second coat of gelcoat was applied it would alligator in those areas. Give plenty of time between coats to allow the first to cure.

Rushing gelcoats or rushing laminating over gelcoat can make big problems and take a lot of time to fix. My supplier told me a primary bond to gelcoat can be achieved up to 24 hrs after shooting it, so I ran with that and always tried to shoot gelcoat in the evening and laminate the next day. For sure I waited 4-6 hours with a fan running to blow styrene fumes from concave molds.

I'm assuming you're using an un-waxed gelcoat for the mold.

As far as the goes, I used that at first and it worked perfectly, but eventually went to other waxes. Back then it said on the can 100% pure carnuba wax, but looking at the ingredients now they have changed, so I would be leery of using it until I had done a few tests first. The msds sheet says it's only 5-10% carnuba, 10-30% parafin and 75-85% isoparifinnic hydrocarbon solvents.
http://www.freemansupply.com/MSDS/scanned/Other/Johnsonpastewax.pdf

 

Good boy now you are thinking !!
doesn't mater how big or small the job is there are steps to be taken in the right order and its pleasing and gratifying to see all your hard work pay off and get a nice mould and still have your plug as well !!
When I finished a small project I always fit the mould back over the plug and keep them together !! that way the mould will continue to cure but wont change shape and stops it from getting damaged !!.