Thursday, January 31, 2008

Test vacuum pull on the daggerboard case mold

Notes to myself on this test pull

  • Could not achieve a vacuum with the plastic tacked to the table. This could be because I have joined two pieces of table top to achieve the length required.
  • Putting the mold in a bag works much better. It is easier to arrange the plastic as it is pumping down, so that there is no bridging, i.e. less pleats. I used an extra piece of plastic underneath the mold for protection around sharp corners etc.
  • The vacuum pump works much harder with this mold; possibly the wood in the mold is degassing.
  • I've been getting away with the Home Depot plastic sheet, I don't see the need for buying more expensive bagging materials.
  • Hats off to the guys doing resin infusion, achieving a vacuum is tough enough for me, thinking about how the resin will flow... is too much for me. I just want this one part done and move on.

Wednesday, January 30, 2008

Cheek block assembly for the daggerboard case

Long days at work and a flu bug have slowed me down somewhat. I was all prepared for the port side daggerboard case lamination and bagging but found that I was short on peel ply and epoxy resin. So another visit to Noah's, which is literally a 5 minute drive from my workplace.

I had started using MAS epoxy resin on the outer float laminations because it has excellent moisture resistance and it was on sale. I've been getting good results so I'm still using it on the daggerboard and case. I also picked up some graphite powder for coating the inner case surfaces.

I also have the first bits of real hardware for my Raven. The cheek block and the anodized Al 6061 T6 mounting plate.

Friday, January 25, 2008

Daggerboard case coating and new boat logo

Thanks to Eric who has sent me a pdf of a completely different concept for the boat logo. I think it is starting to get close but may need some tweaks yet. I like the subtle use of the Farrier boat insignia (I will approach Ian for permission if I end up using this) and the abstract artistic indication of the trimaran floats. Thank you Eric.

Back to the daggerboard case work. I have the HD inserts and the foam pieces cut out and glued together. I've also realized that I will be coating the inside sections of the case halves soon. Roger has used a graphite/epoxy mixture for this coating and I like this decision. The daggerboard will to some extent bear on the case and this kind of coating seems best. I'm also thinking to coat before I actually trim the part sides to the final dimension, as I expect this coating may end up with a significant thickness.

Tuesday, January 22, 2008

Port side daggerboard case mold

I have put the daggerboard case mold together in the port side configuration. Now I just have to get the foam, HD inserts, and cloth cut and then I can vacuum bag this part. I've also got the plate made for the cheek block assembly machined - just have to get it anodized. I'm lucky in that we send out many batches of Al parts for anodizing at my workplace. One more small part in a batch costs nothing more.

Time is getting to be a rare commodity, but I do try to get something done every evening.

Ian Farrier has retired from making further comments on the yahoo F-boat forum so that he can concentrate on the F22 manufacturing activities . I had a mad thought to invite him to the F22 builders group.

Saturday, January 19, 2008

Wingnet rails part 3

The second 9' 2" wingnet rail part is out of the mold. With this done I will be putting my attention back to the daggerboard and finishing off the daggerboard case. Last winter I only finished 1/2 of the part. I want to see my daggerboard moving up and down in a joined case.

I am also looking at the fab. parts and will be getting quotes for 1,5,10 sets of parts to see if there is a price advantage to a bulk purchase. I am finding the drawings require some study before I approach any machine shop. They will ask questions, and these drawings are a bit different from what they would normally see. So, I am putting together a spreadsheet of the separate parts in each assembly. It is helping me understand the various assemblies, particularly the mast step and beam assemblies.

Wednesday, January 16, 2008

F-22 Construction books now complete

Our Canadian snail mail finally moved and I received my copy of Plan Book 2 today. I had already seen many of the drawings in pdf format but the new information is very welcome indeed. It looks like I will be adding some more high density inserts into the float decks and I am relieved to see some more detail on the wingnet rail attachment to the beams and the main sail traveler. With Ian's email of the fabrication part drawings the design information is pretty much complete.

In my day job we design and build machine assembly and test equipment. I have access to good machine shops and fabricators. If other builders are interested in a bulk order for these machined parts they should contact me. Most of the cost of machining is in the number of set ups. So increasing the number of parts per setup can really result in savings and more than pay for the cost of shipping.

Monday, January 14, 2008

Wingnet rails and support part 2

The support part for the wingnet rail turned out very nice. It will be cut into the four 3in wide pieces at a later date. The edges will also have to be trimmed. This will wait until I am fitting them on the float decks. I was surprised at how strong the part appears after two days of epoxy hardening. I suspect 7 layers of s-glass might be over-kill. Looking at how much cloth the rail will be using I decided to use 6 layers of s-glass laminate on the wingnet mold.

I cut the cloth and the 6 pieces weighed in at ~58oz. I have to say that there was about 4 hours of hard work hand laying up the cloth on the mold. One good thing about the aeropoxy resin with the 2 hour hardener is that you really have a long, long time to work on the cloth. I needed every bit of this time for this large part. This resin has an amber colour so it is interesting for me to see this resin with the fiberglass only, no foam underneath.

Two days later the part is hardened enough to remove it from the mold. The untrimmed part weighs in at 108 oz. So it looks like I have a decent epoxy to fiberglass ratio. Bordering on a rave I cannot say how much the extra plastic over the peel ply helps. The plastic allows you to get out the air, pull out the extra resin very effectively and after all this I'm sure the 6 layers of cloth are very tightly packed together. This time I used some vacuum bag plastic on top of the outer peel ply layer. It works even better as it does not stretch like the cheap home depot plastic.

Now I just have to make another one.

Thursday, January 10, 2008

Wingnet rails and support

Work is still proceeding on the preparation of the daggerboard for the final carbon cloth sheathing. The filling in and fairing out on top of the uni carbon fiber is going well. The board is incredibly stiff and I have this idea to get a picture of the board cantilevered horizontal out from the top while I'm standing on the tip. Hmm, as the blind man said, 'we will see'.

I've had the wood cut for the wingnet rail and support molds since the Christmas break. So I've taken some time to glue and screw it all together and get this work underway.

Above you can see the support mold compared to the full sized plan drawing. Jay, if you read this, I only changed your angles slightly. It looks close enough to me.

Above is the 7 layers of 8.9 oz s-glass laid up against the mold. Why 7 layers? Well the specification calls for 4 layers of A - spec.18oz laminate. Four layers totals 4X18=72. S-glass fiber is allowed a 15% reduction. So I require 61 oz total of s-glass laminate. To get the required number of layers, 61/8.9 = 6.9 or 7 layers. I'll be using Aeropoxy resin for these parts, as I consider them more structural and not below the waterline. As a side note I considered using carbon cloth offcuts from the daggerboard but after thinking about it, I did not want to make them that stiff.

I have not bothered with vacuum bagging this part. The cloth is very drapeable and with the use of peel ply and plastic I am quite confident in the quality of the part that I can get.

Here is the 9 foot plus mold for the wingnet rail and taped up, waxed and ready. It's all set to go as soon as cut the required cloth, peel ply and plastic.

Tuesday, January 01, 2008

'Doing the Uni' on the daggerboard

Happy new year! Now back to work.

I could only locally source 9oz uni-directional carbon fiber, which I verified is not close enough to the required specification of 12-13 oz weight.
So instead of the seven layers described in detail in the plan book I decided to lay down 10 layers using the following strategy.

lengths of unidirectional tape starting at top (in mm)


Then going down every 34 mm







I think this preserves the distribution of the carbon as the designer intended.

Here is a picture showing the 10 pieces of carbon uni laid out in the board rebate.

Whetted out and under peel ply and plastic.

Peel ply and plastic removed. The board weighs about 10 lbs with the uni-directional fiber in place on one side. It looks like a finished carbon F-22R daggerboard will weigh ~ 15 lbs or less. The board still looks very rough. I promise it will look better. You can see one error in the above picture, I made the mistake of rebating too deep in the lower part of the board. It means more Quick Fair putty and more weight.
One can always improve... one learns through one's mistakes ...etc etc.