Plug building

[Nick F]

Originally Posted by jim lee

It seemed fine to us. But we infuse our molds onto the plugs. So there is print through issues that are going to mask the PVA issues.

-jim lee

What Resin were you using to infuse your molds? what gelcoat? I hate print through, but i do enjoy troble shooting its problems. what was your lay up close to the gelcoat?

Nick

[13AL]

O.K. Jim. So I've got you beat in the workers comp colume, dose'nt mean we are making any profits. Just signed up to L.C. biz, looks like fun. So how did you recruit all the help for the deck infusion. When ever I try somthing like that I always seem to run out of friends.

[jim lee]

The resin we're using for everything is something called IVEX400 or something like that. Its a pre-promoted vinyl ester. The gelcoat is standard tooling gelcoat. We use a 1 oz mat skincoat over the tooling gel on the molds. (not on the parts).

How do we end up with so many helpers? At the time I had 3 full time employees and there were two more people that were just interested in the finished product. So they wanted to see mold infused.

The big thing I had going for me here is that we live in a boat building town. Jim Betts is next door, San Juan composites is down the hill, Nortic Tug, American tug, Northern marine, Core builders (BMW Orical) are all right here. And the boat building industry just stopped last fall. I've the pick of the litter for boat building staff. I'm turning them away.

-jim lee

[SamSam]

Originally Posted by jim lee

It seemed fine to us. But we infuse our molds onto the plugs. So there is print through issues that are going to mask the PVA issues.

-jim lee

Why do you infuse the molds? Do you let the mat skincoat set up good (12-24 hrs) before doing the rest? For molds, I always used 2 mat skincoats 12-24 apart and then some light layups (starting with mat) with poly resin mixed for a slow cure.

I also sponge pva on. I have a defunct foam mattress I've been cutting chunks out of for years, whenever I need a sponge.

Spraying pva over wax is hard because if you get too much the surface tension breaks and fisheyes and then you have to wipe it all off and start over. A trick from the pro boat mag (I never tried it) was to spray a haze over the mold that was pretty dull looking, and then go back with a wet coat. I don't know if the wetcoat remelts the haze so it all flows or what, but the haze held the wet coat together so it wouldn't fisheye and the finished coat was like glass.

[Herman]

Yep, that was the trick. I tried once, but my PVA was colourless, so after a haze, then a wetcoat, you are tempted to overdo, as you cannot see where you already applied enough. I highly recommend colouring the PVA for this.

[13AL]

Originally Posted by jim lee

How do we end up with so many helpers? At the time I had 3 full time employees and there were two more people that were just interested in the finished product. So they wanted to see mold infused.

The big thing I had going for me here is that we live in a boat building town. Jim Betts is next door, San Juan composites is down the hill, Nortic Tug, American tug, Northern marine, Core builders (BMW Orical) are all right here. And the boat building industry just stopped last fall. I've the pick of the litter for boat building staff. I'm turning them away.

-jim lee

Some guys have all the luck

[tunnels]

While i worked in Australia the company used only pva as a release for everything ! we had a spray gun hang on the wall dedicated to spraying just pva . We never had any sort of waxes at all in the whole place . Took me a long while to come to grips with this as i was not a fan for pva at all !!. I watched then talked to the guy that did all the gel coating and he filled me in on all the points about using pva !
Pva straight from the bottle is to thick and needs to be diluted 50% to 60% with plain water from the tap . so that a saving for a start , you need to spray it always if possible . The trick with spraying is really quite simple . Screw the air pressure to the limit as high as it will go , turn the flow control needle to closed so when you pull the trigger nothing comes out just air . scew the fan control so the fan will spray about half it maximum width . AS you hold the trigger in slowly screw the needle out till you can see just a very fine spray coming out, Thats it !!no more !!!and dont be tempted to make it any heavyer . The trick is when you spray the pva and water will be very fine and by releasing the trigger on the gun till just air is coming out you can instantly blow dry the microscopic film of pva you have just sprayed on the mould .Blow lots of air across the surface from a distance of 600mm t0 900mm away from the mould surface !!.
It possible to pva a mould and spray the gel coat just 5 minutes after !!!its quick its easy and its 99% fool proof !!!well sort of theres always some one that will thinks they know better ! hes the 1 % fool !!
If you can see any of the sprayed pva on the surface of a shiny mould you have to much on !!. Takes a lot to think about this and even harder to get used to . but it works 100% everytime . The water slows the drying down long enough to let each of the passes with the gun to all blend in together and not end up with dusty dried pva all over the place causing the surface to look dull .There are lots of pva's on the market in every country i have worked in . they are all pretty much the same and i have never had a problem ever for any reason at all . Korea had dry granulated pva that we had to mix with warm water like wall paper paste . same thing mixed the mix with 60 % water and sprayed with out a hitch .
It is possible to apply a coat of wax over the top of this fine sprayed pva BUT it must be a very light coat of wax and cant be polished!! , its best to wax first and the pva over the top .I always double pva spray areas like tread patterns on decks as it helps to stop the excess wax in the pattern from coming off with the deck when it is released !.
You will have to practice untill you see what i have said . it is so simple it frightening !! all the experts that have been in the industry for a life time with there own ways of doing things are to shudder after reading this !!.


One thing i have noticed during my travels ,pva is always the same no matter where you go it never seems to vary in any way !. But not all waxes are not completely compatable between one country and another!! .

[keith66]

I used to do a lot of insurance write of repairs, some of them were quite bad to say the least, we would often have to take a one shot or splash mould of another boat or a puddened up broken area before it was cut out.
We would fair with DA & air file with 80 grit go to 240 & then 400. then polish roughly with G7, 2 coats of wax & one PVA wiped on with sponge & you were ready to go, moulds always popped of.
Tried a release agent called mold whiz once, got given a sample, sanded with 400 on the DA didnt bother with wax just put the stuff on, that mold popped of better than PVA, I would like to get some more!