Panga 20 Build

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FluidDynamic
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Re: Panga 20 Build

Post by FluidDynamic » Sat Feb 09, 2019 9:43 pm

Are there any issues using colloidal silica from West Marine if I'm using Marinepoxy?



fallguy1000
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Re: Panga 20 Build

Post by fallguy1000 » Sun Feb 10, 2019 2:09 am

FluidDynamic wrote:
Sat Feb 09, 2019 9:43 pm
Are there any issues using colloidal silica from West Marine if I'm using Marinepoxy?
Nope.

With Marineepoxy, watch out for blush is all.

Also, mix the thixo on a smooth board, aka hawk.

The hawk helps you achieve the proper thickness by allowing a slump test. See if a pile sags...if it does, too loose, add more cab.

The hawk allows you more open time if you keep the mix flat and not big gobs while you work. I use fast epoxy for most of my thixo precoating/fillet work. I graduated up from slow, but gotta go quick! Stick with slow for your bottom work-big area for a rookie.
My boat build is here -------->

viewtopic.php?f=12&t=62495

FluidDynamic
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Re: Panga 20 Build

Post by FluidDynamic » Mon Feb 11, 2019 10:33 pm

I plan on using quickfair to fair the hull after filling. I have one question about filling the weave and one about the quickfair.

Is there a benefit to using a blended filler with silica and micro balloons or should I fill with silica or just micro balloons?

I know quickfair is used to fill the low spots, but I'm a little confused. If it cured, is it like epoxy where it has to be sanded for another layer to bond to it?. If I sand the high spots with the long board, the low spots were never touched by the sander. Maybe I'm thinking about this wrong.

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Re: Panga 20 Build

Post by fallguy1000 » Mon Feb 11, 2019 11:15 pm

No, you are spot on.

But you need to understand some key concepts.

Epoxy bonds in two ways.

Chemically and mechanically. The chemical bond is a far superior bond on a molecular level.

A mechanical bond is subject to the roughness of the substrate. Also called secondary bonding.

For example, a waxed vacuum table has epoxy poured onto the table and it does not stick. This is because there is obviously no chemical bond and the mechanical bond is too weak.

How to overcome the weak mechanical bond? Rough sanding of the substrate.

So, QF....we longboard sand it and as long as we are within their application window for primary bonding; no sanding of the substrate is required because the bond would be primary. However, if they suggest always sanding, then you longboard sand to fair and use guidepowder and hand sand the powder areas; clean and QF again which is the same for if you are outside the primary bonding window. I really dislike shine and always sand anything shiny.

Now, this is all great stuff, but I will tell you that you can also bond test to familiarize yourself. How? Well, fomd a board and put a hole or two in it and test one hole with QF inside the window and another test no sanding outside the window and then sand them in a day and check.

I have done enough sanding to tell you epoxy does not bond well to smooth surfaces in a secondary orechanical bond. A perfect test is a drop of thickened epoxy on a piece of glass vs a piece of wood vs the concrete floor. The mix will easily shear off the glass, and the concrete will ne stuck forever; the wood is generally also stuck, but can have some variation.

I use a balloons cab mix as a base for QF. It would get super spendy to used say 30 gallons of QF. I apply it with slow epoxy and sand it all back with 50-60 grit.
My boat build is here -------->

viewtopic.php?f=12&t=62495

FluidDynamic
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Re: Panga 20 Build

Post by FluidDynamic » Fri Feb 15, 2019 11:04 pm

Nothing to show yet. Took a break while I contemplated what route I was going with filling the areas between the tabs I placed. That was a big mistake. There was a few areas I really needed the tabs, but the majority I could have done without. I decided not to cut and place more tabs between the existing tabs. I decided as fallguy1000 suggested to just fill the gaps with thickened epoxy. I've done one side and now I'm just waiting for it to dry so I can sand. I've also been working on getting the proper radius on the seams. On some of the tabs I placed, the radius was too small and air was trapped between the glass and the wood flour epoxy mix. I ground out all of those mistakes and formed a new proper radius with no air gaps. I learned the hard way. It seams like ill have to grind some areas when I flip it to get a good filet. Is this common to have to prep the inside before filleting?

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Re: Panga 20 Build

Post by fallguy1000 » Sat Feb 16, 2019 3:26 pm

Yes. Absolutely in all building you end up with excess. I use the oscillating tool with a carbide head to remove unwanted chunks.

My boat has 128 feet of bottom chine, 128 feet of mid chine and 80 feet of deci chines where thixo squeeze out excess cutback was needed. We, of course, had to cut the outside vs you the in, but in 320 feet of chines; we had plenty of squeeze out areas.

All said, keep in mind you don't need to fully fill the gap on first go. You get another shot at the gap on reverse, so it isn't vital to fill under the first tape perfectly.

You do need to run tape seams over those chines yet, right?
My boat build is here -------->

viewtopic.php?f=12&t=62495

FluidDynamic
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Re: Panga 20 Build

Post by FluidDynamic » Sat Feb 16, 2019 4:25 pm

I should be able to run the tape over all seams by Monday. I don't know that I'll be able to do wet on wet for the tape and the blanket. Don't really have anyone to help. I would have to wait for a couple of weeks to get some help. All my friends are in that young kids stage and don't have a lot of time.

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Re: Panga 20 Build

Post by fallguy1000 » Sat Feb 16, 2019 8:14 pm

Wet on wet is too hard for the tapes and hull
Combo

But if you have multiple layers main hull; better when possible. Or minimize secondaries..,so you only samd overlap for example if you can't finish a single,etc.
My boat build is here -------->

viewtopic.php?f=12&t=62495

FluidDynamic
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Re: Panga 20 Build

Post by FluidDynamic » Mon Feb 18, 2019 5:04 pm

I've filled the areas between the tabs I placed and sanded it to a smooth surface. All of my radius are about 1/2" with no air gaps. The temp dropped again and I'll have to wait until tomorrow evening to warm up enough to tape all of the seams with biaxial. I'm starting to think ahead and was wondering after I place the fabric blanket over the hull and wet it out, how is the weave filling application of silica/micro balloons applied? Is it with a trowel?

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Re: Panga 20 Build

Post by Browndog » Mon Feb 18, 2019 5:57 pm

You can use a variety of tools to spread fairing mixes. Plastic squeegees, putty knives, and tools for spreading drywall joint compound all work pretty well. In the thread for the FS-19 that I built last year there are some pictures of all the tools I used for both fairing and then sanding the hull.

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