Wednesday, August 31, 2016

Thanks Arno!

Arno contacted me after that last post and suggested I use a fine toothed saw blade to cut the LFS Beam Anchors next time. So in the shop last night I set up my table saw to see how this might work by re-cutting one of those messed up pieces. As it turns out, just using the the blade I had in there (Standard Ripping Blade) worked just fine! I have some better blades picked out that I'll be ordering later on.

(I just love the community support among builders!)

After confirming this would be "the" method to use, I ended up using the saw to cut the core panels for the next attempt at making these pieces. I also cut the panel I made a while back for the float bow gluing surface.

I did wear a respirator, hearing and eye protection when doing this job since fiberglass dust was all over the place for a while there.

After getting those cut out, I got the router set up to mill down some foam panels to the 5/8" (15.7mm) thickness required. Then ran them through the table saw to get them cut into size.

Since this is my second time doing this job, I learned from the previous attempt to add 1.5" (38mm) to the width of the blank. Doing so allows you to cut off and discard the rough outer edges of the blank while also negating any concern regarding kerf allowance.

The foam is now glued to the core panels and set to cure.
Tonight I should be able to clean up the edges and get the back edge rounded over and sanded smooth. I should also have the replacement G10/FR4 tubing delivered soon.

Everything is going so much smoother this time around...

A nice practice cut


Clean edges, no tear out


Moving on to cutting the core plates for the Lower Folding Strut Beam Anchors


Foam panels milled down, cut to size and prepped for gluing to the core plates 






Monday, August 29, 2016

Junk parts...


:(

This past Friday morning, I picked up my Lower Folding Strut Beam Anchors from the shop.
Apparently, I spent a lot of time and money making junk parts...

I was upset about it for a day or so, but there's not much I can do about it.
These parts will not be used in the boat, but I'll be hanging on to them to use as "practice parts" when setting up the router for the next step & etc.

You can clearly see the major problem in the pictures below...
Next time around I'll make the Hi-Density mixture a lot thinner so that it can actually be poured after degassing (like a very thick syrup) instead of being troweled in place as a thicker mixture like these were.

The other issue was the use of a water-jet machine to cut the parts.
The guys did a good job but it was the wrong tool to use to get the blanks sliced up.
I'll have to look around for a different method next time.

Currently I'm thinking of locating someone with a big wet-saw, or maybe even use a diamond tipped bit on my oscillating saw.

(I'll be able to check that method on these junk pieces...)

Anyway, I'm starting from scratch to rebuild these parts.

Huge Voids in Hi-Density Fill

Water Jet cutting is not the correct method to use for these parts.
Notice the concave section of the tubing.

Layup in place for rebuilding these parts.


Tuesday, August 16, 2016

Best infusion to date

I'm still on the learning curve regarding resin infusions, but every time I get to do one I learn something new and try something different.

In this latest example, I was building the Lower Folding Strut Beam Anchor Base Plate.


I spent one evening getting the fabrics prepared and everything laid up correctly.
I then applied the Vacuum Bag and pulled down the pressure. One small leak near a pleat was quickly isolated and fixed and then I turned the pump off and let it sit overnight since it was too late to mess with resin, but I did take the time to run the resin amount calculations:

34" * 16" = 544 sqin x 8 layers (of 18oz) = 4352 total fabric area
4352 *.31grams of epoxy per square inch = 1350 grams of mixed resin

1350/1.30 = 1038g PartA
     (1.30 is the 100:30 mix ratio)
1038 * .30 = 311g Part B

(This is an approximate amount required to fill the fabric itself, plus the feed lines and the amount left over in the consumables with some left in the bucket to ensure no air is pulled in near the end)

Note: I ended up with about 120 grams of mixed resin left in the bucket.

The next day after work I found that I still had a very good seal and had only lost 15 millibars over a 24 hour period.

I mixed up the resin and fed it into the stack via the small 1/4" (6mm) line to throttle the flow.
The wet out was really good and even.
Total infusion time was right at 40 minutes.

Once the resin had soaked into just over half of the Enka Fusion on the vacuum side, I clamped off the inlet and outlet tubes leaving the tube connected to the VacMobile (turned off) to keep a vacuum on the line itself.
What I was wanting to test/validate this time around was the "self leveling" characteristics of the excess resin. Since the inlet side of the infusion will always be a little heavier and thicker I was hoping to see that excess material flow into and fill up the Enka Fusion.

In this case, it worked perfectly as expected!

Infusion nearing completion.

If you look closely, you can see the difference in shading near the left side of the stack.
The darker green area to the right is where the stack is fully saturated, while the lighter green areas on the left edge are still pulling resin in.
Also notice that I moved the Enka channel on the right side about an inch (25mm) over the fabric stack, this is not a problem since I've found that the resin will move in all directions (to an extent) seeking to fill the voids.

When I first started practicing infusion, I was under the impression that the resin would only move toward vacuum and would never move in the opposite direction.

Some part notes


Scraps of foam are used to create an inlet pad.
I use a Dremel tool to bore a hole through the middle and then I cut a flow channel underneath the part while a quick pass on the sander rounds off the edges.
Puncturing the vacuum bag for the resin inlet is the last thing I do before introducing the resin.
Doing it this way eliminates a potential leak source.

Vacuum consumables removed - Nice looking part!


And a close-up shot