Molds are finally done!

[stac1627]

After almost 3 years of building the scale Scarab plugs, the deck, hull, engine cover and cowling molds are DONE. The boat will be 60" long and super light.
Next will be waxing the plugs and PVA release. Just ordered white gel coat.
I'll post pics...20190502_145629.jpg

[fweasel]

Looks good. Can't wait to see the first one!

[larryrose11]

Nice work.
Pretty small flange there. Will this be done as an infusion?

[stac1627]

"HOPEFULLY"...the flange on the hull will be trimmed to fit to the inside of the decks rub-rails. I'm gonna use marine epoxy to bond the two at this contact point. This is all uncharted territory for me...
I'll figure it out...that's the fun/challenge of it Larry!

[larryrose11]

stac1627,
Have you ever done vacuum infusion?
I currenty am doing the largest mold I have ever done.
This is the rear hatchback of my friends track car.
We are remaking in in Carbon Fiber. It will be a vacuum infusion with a foam honeycomb core

Deck_lid.jpg

[stac1627]

Larry,
I've never heard of it...is it like vacuum bagging?

[larryrose11]

its a step beyond vacuum bagging.
It is a way to get Class A finish of exposed fiber, right out of the mold.
It is where the fibers is layed out into the mold, and all the layers a built up, all dry. Additional layers are added to let the resin flow.
The whole thing is put in a vacuum bag, with 2 ports, 1 for vacuum, the other for resin.
Turn on the vacuum, and let the resin flow in. Once the part is infused, the resin line and vacuum line are clamped. let it cure.
It also uses a vacuum hose called MTI, Its a vacuum hose for inside of the vacuum bag that is gas permeable, but not resin permeable.
You end up with a part that has zero voids, pinholes, or bubbles. Makes things super easy.

There is other fancy things you can do, like a boat hull top and bottom that come out of the mold as a single piece, nothing to join.
That requires that your top and bottom have a alignments points along the flange.

[NativePaul]

Check the specs for your foam honeycomb Larry, most have enough gaps in that they will let the resin flow through them, and you shouldn't use any extra wicking layers/infusion mesh in areas reinforced with it.

How do you get the hull to come out of the mold in one piece, with nothing to join? I cant get my head around it in any practical way, all I can think of is to: Lay up the mold halves and vacuum as normal then when semi cured remove the vacuum paraphenalia, trim one side flush but leave an overlap on the other side and tease it away from the edge, put a bladder inside, join the molds, inflate the bladder to push the overlap against the other side, and leave to fully cure?

[larryrose11]

Paul,
Im aware of the flow properties of honeycomb, They work great!!
To be honest, I have not tried this on a hull yet, but in concept. It is a way around the issue of the weakest point of the hull, the seam between upper and lower.
Yes, it seems odd, but workable. Your not far off. it rely's on the upper mold having a big hole in it , as an access point. The hatch will work fine for this job.
Essentially, the upper becomes part of 2 part mold.
You need an inner vacuum bag. the inner one is the shape of the hull, with some extra where the hatch access point is. It needs to be tested first.
It rely on a few products. MTI hoze, and a COMPOFLEX peel ply.
It requires that your upper and lower have locating points in the mold flange that do that alignment for you.

The upper and lower layers are laid out, and use spray adhesive on all of them to afix them to the mold. they are trimmed flush to the edge of the hull on the upper, and about 12 mm past the edge of the hull on the lower.
MTS Hose is at the hatch edge on the upper, and the resin inlet is on the lower at the nose of the hull, and at the keel. lay out the tubing.lay the inner vacuum bag in the mold
Put top and bottom mold together, carefully tucking the extra fiber layers from the lower into the upper, so they overlap, and will seal together. Bolt the upper and lower together. Gum tape is places around the mold flange edge, to make a seal.
the inner vacuum bag is attached to the hatch edge of the upper. Turn on the vacuum, and let the resin flow. It should flow from the front over the entire hull, top and bottom.
Once done and cured, peel the inner bag out, and peel off the Compoflex. It comes of super easy, nothing like normal yanking that you must do with regular peel ply.

[srislash]

Larry, that system sounds awesome

[RandyatBBY]

Paul,
Im aware of the flow properties of honeycomb, They work great!!
To be honest, I have not tried this on a hull yet, but in concept. It is a way around the issue of the weakest point of the hull, the seam between upper and lower.
Yes, it seems odd, but workable. Your not far off. it rely's on the upper mold having a big hole in it , as an access point. The hatch will work fine for this job.
Essentially, the upper becomes part of 2 part mold.
You need an inner vacuum bag. the inner one is the shape of the hull, with some extra where the hatch access point is. It needs to be tested first.
It rely on a few products. MTI hoze, and a COMPOFLEX peel ply.
It requires that your upper and lower have locating points in the mold flange that do that alignment for you.

The upper and lower layers are laid out, and use spray adhesive on all of them to afix them to the mold. they are trimmed flush to the edge of the hull on the upper, and about 12 mm past the edge of the hull on the lower.
MTS Hose is at the hatch edge on the upper, and the resin inlet is on the lower at the nose of the hull, and at the keel. lay out the tubing.lay the inner vacuum bag in the mold
Put top and bottom mold together, carefully tucking the extra fiber layers from the lower into the upper, so they overlap, and will seal together. Bolt the upper and lower together. Gum tape is places around the mold flange edge, to make a seal.
the inner vacuum bag is attached to the hatch edge of the upper. Turn on the vacuum, and let the resin flow. It should flow from the front over the entire hull, top and bottom.
Once done and cured, peel the inner bag out, and peel off the Compoflex. It comes of super easy, nothing like normal yanking that you must do with regular peel ply.

Larry out of all the stuff to do the infusion, is the MTI vacuum hose and Compoflex reusable? It looks like when it is pealed off it is all thrown away.

[srislash]

After almost 3 years of building the scale Scarab plugs, the deck, hull, engine cover and cowling molds are DONE. The boat will be 60" long and super light.
Next will be waxing the plugs and PVA release. Just ordered white gel coat.
I'll post pics...20190502_145629.jpg

And geez I got to reading all this infusion stuff and forgot to give kudos to the subject. Looks great and also can’t wait to see the first out.

[larryrose11]

Larry out of all the stuff to do the infusion, is the MTI vacuum hose and Compoflex reusable? It looks like when it is pealed off it is all thrown away.

Randy,
The MTi hose is mostly reusable. Only some of it gets exposed to resin. it makes infusion SO much easier!! No catch pots, it eliminates bubbles, no pin holes, class A finish. The compoflex can be hit or miss. you have to use your judgment if it feels saturated
https://www.fibertex.com/products/composites