Weekend progress

So this past Friday, I received my initial order of various fabrics which means that I can now proceed with some work on the raised (flat) section of the floats. I will also be able to do an infusion test in regards to the longitudinal stringers running along the inside of the floats.

I'm concerned about that area because the stringer is a 6" (150mm)W x 1.25" (32mm)H x (various length) reinforcing piece that sits on TOP of some dry fabric and is then covered with additional dry fabric. The worst thing that can happen is that the fabric UNDER the stringer does not get wet out during the Infusion. That's a situation to avoid, so I have some cheap foam pieces cut to size that will be laid up and infused to check the flow. One will be a solid piece while the other will be drilled through every 1" (25mm) to create a permeable surface (this is the recommended method). I'll plan to do that next weekend.

I also made some progress building out the wingnet attachment tube sections for both floats. I again made some "Pre-Preg" to situate between the foam to strengthen the joint. It's worth noting that his was the best infusion to date, because for the FIRST (hopefully not the LAST) time I got a ZERO leak bag without having to touch anything. I literally taped everything down, applied vacuum, did a leak check and infused. Normally, I spend quite a while chasing leaks.

And finally, after running my first fillets on the deck transition areas I was able to lay down the final topping coat of fairing compound on the float interior. The interior surface looks to be really nice and smooth.

Loaded up and ready for use

After this shot, I spent some time covering the fabric with trash bags. Most of the rolls required two bags.
I just ran the metal tube through the bottom of the trash bag and then pulled the trash bag over the fabric.
When I need fabric, I simply have to push the bags over the ends of the fabric roll and then pull off the required material before covering it up again. This should help keep things much cleaner when all the sanding starts.

Before Fillet

After Fillet (Before Tape applied)

13oz Carbon Fiber 0/90 (6 layers) being set up for making some Pre-Preg

All laid up and ready to open the resin intake valve.
A couple of things to note here:
1) The tubing clamp block built out of a small piece of scrap lumber. I simply routed out a tunnel for the tubing to run under the block so I don't have to worry about tape coming loose or crushing the tubing with the clamp.
2) The long clamp also provides a handy place to tape the intake tubing line onto.

(You can also see my trash bag covered fabric rolls in the background)

This picture was taken after the infusion was completed.
I have already cut the intake line past the clamp and taken care of cleaning up the resin bucket.
Immediately after this picture was taken, I brushed a thin layer of epoxy directly onto the foam and then opened up the bag to pull off the layers of pre-preg and lay them into position.

The Carbon fiber is between the pieces of foam and extends out toward the middle of the float.

Twelve hours later the resin was hard enough to allow cutting the excess material that was hanging inside this section.

The next day I spent a few minutes sanding down the "V" section here to a more concave shape in order to accept the tubing

Fiberglass tubing (scuffed with 32-grit and cleaned with Bio-Solv) laid onto a bed of high-density epoxy.
Once cured, I will wrap these with a layer of 12oz  45/45 S-glass.
Then finally I can set one of them into the float for further processing.
(The other one will be for the Port Float)

The Tax Man Cometh...

I just got a call from the accountant regarding my tax filing for this year. I was hoping to get a little bit back, but it looks like I'll get punched in the mouth and kicked in the butt instead.

The news is bad enough that I'll have to put any more supply orders on hold until I dig out of this mess...

Ugh! I'm not getting any younger you know...

:(

Maybe I'll do a "GoFundMe" campaign, it seems to be all the rage these days.

Lightweight Topping Coat

This past weekend was spent back filling the foam joints with a lightweight micro-balloon mixture, working on a couple of test infusions and sanding the hull interior.

I also glued some 16" (406mm) extensions onto eight sheets of 3/4" (19mm) MDF.
This is curing now and maybe tonight I can get started with the beam molds.

The fabrics order should be in later this week or sometime next week.

As for epoxy mixing, I decided to try out a tool I had purchased a while back and found it to be really worth the money and worth mentioning here.

"StirWhip" 8" mixer attachment.

I ran it with my 12v drill at a very low speed and found it did a really good job creating a smooth mixture with less air entrainment than mixing by hand. I start by mixing neat epoxy (part A&B) and then scraping the sides and bottom before mixing again and then adding the filler materials and mixing again. I found it best to tip the bucket towards my chest and use the drill to slowly "roll" the mixture. This allows the epoxy to incorporate the filler material without causing it to float out all over the place too much. It doesn't take long and the results really are much better than hand mixed, not to mention much easier. Once the mixing is done, I'll put the drill on "High Speed" and fling the excess material to the sides. Afterwards, the "fingers" on the mixer are easy to wipe off and make ready for the next batch.

Moving on to the infusion tests, I have this idea of making my own "Pre-Preg" for doing the Beam Layup. The beams themselves consist of several layers of Fiberglass and Carbon Fiber.
I hear that Carbon Fiber can be tricky to infuse and the idea of doing an infusion with a layer of CF buried under some layers of Fiberglass doesn't appeal to me in the least (especially at my skill level and the critical nature of the beams themselves) The other option is to do a hand layup/vacuum bagging.

Hand layups work, but do tend to leave a lot of extra resin (and air bubbles) in the fabric, so if you have the means to use some sort of vacuum assisted method then I think you probably should.

Anyway, to test the plan I used some left over samples of 18oz/yd 0/90 Fiberglass to create a seven layer stack measuring 50" x 7" (1270mm x 178mm).

I wanted to check out a few things:

-       Do I need Peel Ply between each layer

o   No, the Peel Ply actually slowed the resin flow down too much.

-       Do I need GreenFlow between each layer

o   No, there was no real difference between the section that had one layer of GreenFlow in the stack vs. the section that had GreenFlow between each layer of glass.

-       Will the epoxy flow well enough through the Enka-Fusion, or do I need to use the standard Spiral wrap?

o   I couldn’t see a difference in the Resin and Vacuum flow between the sections with Enka-Fusion or Spiral wrap

-       How difficult will it be to handle the wetted out “Pre-Preg”

o   Very easy to separate the layers, roll up and manipulate.

-       Will the top layer stick to the other layers and create a lot of weave distortion/tearing

o   No, the layers separated easily and any weave distortion was easy to rectify.

-       Does it matter if the GreenFlow is at the top or bottom of the stack.

o   No difference in Resin distribution, except that if I leave the Greenflow at the bottom of the stack it serves to lift the fabric off the surface allowing any pooled resin to collect there.

§  Next time, I will install a “Reverse Pull” T fitting into the supply line. This will allow me to remove excess resin from the inlet side before turning off the vacuum. I did notice that the bottom layers were much wetter than the top layer. However, this was mostly my fault since I didn’t cut off the supply until the entire stack was nearly finished infusing.

So all in all, it was a good test that answered a lot of questions.

It does take more time on the setup side, but once the patterns are cut out and infused, I’m thinking I should be able to lay it into the molds in almost no time at all without having to play around with a squeegee and chip brush.

This is the left 1/3 of the Test Stack.
The bottom left is Resin Supply.
Resin goes directly into GreenFlow media via standard Spiral Wrap and then moves to the top of the picture towards the Enka-Fusion Vacuum channel. Seven layers of glass are fed with one layer of GreenFlow at the bottom of the stack.

This is the middle 1/3 of the Test Stack.
The Resin supply switches to from Spiral Wrap to Enka-Fusion and the Vacuum path switches from Enka Fusion to Spiral wrap. You can also see towards the right side of the picture where I start to add GreenFlow media between each layer of glass.

This is the right 1/3 of the Test Stack.
Vacuum leaves the stack at the top right hand side.
The whole infusion took 15 minutes at 65F (18C)

Lightweight Topping layer added to seams.
30% Micro-Balloons (for lightness)
5% Cabosil (for thickening)

Eight sheets of MDF with 16" (406mm) extensions glued in place awaiting the glue to dry.
These will be used to build four Beam Molds

Starboard Float Foam Edge Prep & First Fill

I spent this weekend routing out the gap between the foam sheets and then back-filling with a reinforced epoxy mixture. I used 9% Cabosil and 4% milled glass to thicken and reinforce the epoxy. The resulting putty was a "spindle grease" consistency which was easy to work with. I applied a bead of this epoxy caulking with a disposable cake decorating bag and tooled it down to a concave joint.

The joints should be airtight at this point, but I will to follow up with a lightweight (microballoon) top coat next weekend.

Two joints filled - One joint to do

Filled screw holes in addition to the joints

Ready for the topping application

I also need to start working on the inboard wing net attachment tubes.
I'm still waiting on my fabrics to arrive, but I do have some samples that I can put under vacuum to dry out if I end up having enough material to work with.

New Toys...

So if you believe the hype (like I did), I'll have the smoothest hulls around in about fifteen minutes or so (maybe a little more - but don't interrupt my dream)

I've seen these floating around here and there, but the original company "Flexicat" seems to be defunct and is now replaced with a new company "FlexiSander". I'm not quite sure what happened there, but the tools are the same - only a different color.

I tried contacting the sales department of the USA Distributor regarding the Credit Card functionality failure on their site and then <nothing>, I even called and left a message - no reply... still to this day.
So I turned my attention to the overseas manufacturer site and inquired about shipping a set of tools to the USA. I got a quick reply (considering the time zone) and then took a real leap of faith and wired (yes, WIRED) the payment to the Czech Republic in hopes of receiving some goods in return.
After the money was gone, I squinted my eyes and held my breath while waiting for shipment confirmation. To my great relief, I received nothing less than a completely professional response and immediate shipping. The package arrived today with two filling knives and three sanding boards.

This would be the "Professional FlexiSander Set-A Kit"

The packaging was not so great, but no damage was evident and everything seems to be in order.
I'll need to pick up some Velcro backed sandpaper for the boards.
They'll be put to use here soon enough.

More Foam on the Starboard Float - Cleaning up the Outboard Half

Henny contacted me last week regarding the ridges in the foam on the first half. He chewed me out a little bit for not pressing the foam into place well enough and that it would come back to bite me later on with the fairing... He's right, I knew it and really couldn't argue with him, so I took his well founded advice and went back through the float reheating some sections of foam to push them down a little more where I could and secure the foam better in other locations.
I also removed two pieces of foam near the aft section and replaced them entirely since I wasn't happy with them at all. The rest of the float was really pretty good, it was only near the big curve section that I had problems getting it pushed down enough.

In the meantime, I also got some advice from Phill (currently building an F-85 - his 15th boat from what I recall). He's a great guy with a ton of advice. Anyway, regarding sanding down the foam he suggested a Straight Line Sander with 36-grit. I like new tools, so without hesitation (and much delight) I went on over to Amazon and made the purchase. When it arrived I thought it might be overkill, but a light touch and an hour or so later I had a pretty good looking float half without removing too much material. I found the sander to be really easy to control and am very happy with the results.

One word about that though (switching gears here for a second), I did read a bit about the cheaper versions made in China and lots of advice on how they should be avoided. So you can imagine how upset I was after my new sander started bogging down after only 20 minutes of use! I tried blowing it clean and putting in a few more drops of oil to no avail. It would work really well for about 15 seconds then start bogging down again. I thought surely I'd have to return it so I let it sit for a while to take care of some other things.
When I got back to it, I hit the start trigger and felt some cold liquid spray against my hand and thought for sure it was adding insult to injury by spitting oil all over the place, but after a few seconds I realized it was simply some water from the compressor. This made me start thinking that this might be the root of my problem. I did have a water separator on hand that was purchased some time back for a piece of spray equipment. I plugged that into my compressor and after using the sander for another 40 minutes the problem never showed up again. When I was done for the day, I went over to the water separator and opened up the drain valve to release almost 1/4 cup (60ml) of water! I guess I'm writing all this to say that those "cheap" sanders might work just fine if you ran clean, dry air through them...

Starboard Float Outboard half after sanding

This was the BEFORE picture (before replacing the two planks and sanding the rest)

This is the AFTER picture,
I should have got a bit closer, but you can readily tell how much smoother the foam is.

Ingersoll-Rand (IRT315) Straight Line Sander.
Also, referred to as an "Air File"

Water Separator installed mid-stream. The blue hose goes to the sander

Anyway, the Starboard float is coming along with the aft section completed and the bow section nearly done. I'm having a much better experience with the foam on this half as the pieces are fitting better against the battens and I'm not spending as much time on it. So again, it really just comes down to a learning curve. I find it best to get that big curve bent mostly into place before inserting the foam plank into the mold. If you do that, it's easy to push it into position while it's still hot and then secure it before moving on to the rest of the plank. Much less drama that way.

You can see the planks are laying down better this time

Almost done with forward section

Pre-cut pieces for the WingNet Lashing Tube section.
I cut enough material to pre-fabricate this area on both floats

If you look closely, you can see a small piece of foam sitting on top of the lashing tube.
I was using this set up to determine what angles would work best for the cut and how thick the second piece of foam would need to be.

One problem I am having now is that I'm down to my last sheet of foam...
The Manufacturer is particularly proud of their Core-Cell product and the pricing reflects this fact.

$$ Uggh! $$