Molded Beam - Fail

The first molded beam was a total failure.  The part turned out so, so, but I had to destroy the mold to get the part out.  All the waxing and mold release worked perfectly with the exception of an area on the top of the beam, about the middle for about 20 cm.  This area stuck so bad, the beam still has plywood bonded to it.  Needless to say, I was very disappointed.  However, I didn't get that discouraged to scrub the entire project.  I got out the plans and modeled the beam using a CAD tool and sent the model to a local composite prototype company that often does work for Mercury Marine.  They looked at the design and wanted to meet with me to discuss the project.

When I described all that I had done with my attempt they came up with two suggestions that would have probably gave me success.  First, the suggested that the mold should have been built so it would split or for a side to come off.  Once this suggestion was made, I saw how simple it would have been to make the mold split in half.  The other suggestion was to change the process of laying up the part.  In the instructions, Ray states that you apply a coat of resin to the mold and let it tack up.  Once it is tacked up, you start to apply the cloth as per the laminate schedule and you can not stop until you finish.  The composite company told me that when you lay up a laminate using this method, the part will shrink very tightly to the mold and if the mold is a light weight plywood mold like this mold, it often will suck the mold in when curing making it almost impossible to remove the part.  This is exactly what I experienced.  The composite company suggested that I should have let the first layer of the laminate (chop cloth) fully cure before adding the remaining layers.  This will greatly stiffen the mold and probably prevent the distortion of the plywood mold.

I then talked to them about what it would take to have them make the 4 parts for me.  I instructed them to give me a quote for 4 molded beams, untrimmed and unfinished.  When I got the quote for the mold and four parts, I told them to proceed with the build!  I figured the little extra money was worth knowing the beams will be built correctly and not fail.

Since the beams are under way, I will now focus on building the hull, floats, and finishing the centerboard.  The seven sheets of plywood on the workbench are for building the two strongbacks.

More to come....

Molded Beam Build

Over the weekend I started to mold my first beam.  I grossly underestimated the amount of work it would take to make a beam.  Overall, once the mold is ready to go, it took 10 hours and 2.5 gallons of mixed resin to make one beam.  Here are the details.

On Saturday I spent approximately 5 hours cutting all the fiberglass cloth for the one beam.  When I saw the pile of cut cloth, I was amazed that all that cloth would go in to one beam.  I had everything laid out on the floor so I could easily take each piece when it was needed.  I paid special attention to the unidirectional fabric to make sure I rolled it carefully.  When cut in smaller pieces, it has a tendency to unravel and fall apart.  Roll it once, set it aside and don't touch it until its needed.  After 5 hours, I was itching like I had fleas from the glass fibers, so I called it a day.

The next day, I started by applying a coat of PVA mold release to the already waxed mold.  This release is a water soluble mold release and is recommended to make removing the part from the mold easier.  After the mold release dried for an hour, I applied small pieces of masking tape over the holes in the beam mold for mounting and pivot components.  Pilot holes will be drilled prior to removing the part from the mold.  Next, I applied a coat of epoxy to the mold as recommended on the plans.  Once this set up for a short time, I began the messy part.  There is a lot of cloth in one part and it takes a long time to put it together.  Once you start, you can't quit until its done.  I also recommend using the slowest curing hardener you can find.  I used MAS medium and it was way too fast.  I could feel the resin getting warm before I was finished.  This step took 5 hours to complete.

More to come.....

Work has started again.

I had to take a break from building my Scarab 650 because of a neck injury.  My winter was spent with many visits to Chiropractors, Physical Therapists and Doctors.  Everything is better now so I have started to work once again on my boat.

Quick update on the Centerboard:
The Center board is fully glassed and needs finish work and paint.  I also need to fabricate the pivot bushing and install it.  I will upload photos when complete.

Update on Beams:
The mold has been waxed with 5 coats of mold release wax.  I am waiting for a shipment of epoxy to arrive and then I will attempt to mold my first beam.  I'm very nervous about molding the first part! 

Update on Materials:
Over the winter I've been contacting suppliers of foam to get quotations.  I'm very disappointed at the cost of foam.  I've also priced plywood and I have found the foam is 3 times the cost of plywood.  So, having said that, I'm rethinking my "wood free" boat comment.  I'm working with one, last ditch, supplier in Minneapolis as a source of foam.  I have not received their quotation at the time of this posting.  I'm hoping it will come in better than the rest.  More to come.

That is all for now. 

It has been a while since I've posted anything since I hurt my shoulder/neck/back recently.  I only wish the doctors can figure out what happened and how to fix it.  Meanwhile as I heal, I decided to do some research on materials and design enhancements for my version of the Scarab 650.  For example, as you all know, most boats have some sort of symbol or logo on the mainsail to indicate the type of boat.  The Catalina 22 uses the red diamond with a C 22 in the center.  My Hunter 216 has the blue Hunter logo on the sail.  And, there is a Scarab Trimaran that was built in Canada that has an Egyptian style Scarab beetle on his sail.  I found this really cool design that I'm considering for my sail.  I think it would really be an eye catcher, not that a tri needs to call attention to itself.  Comments, thoughts?

More to come!

Centerboard work continues

I made some progress on the centerboard.  I completed all the shaping and sanding and the board is now ready for fiberglass.  I was concerned about the stiffness of the board before I started sanding but that greatly improved with hydrofoil shape.

Next step, glass it.

I also have an update on the beam construction.  I'm having difficulty locating the heavyweight unidirectional glass specified by the plans.  I've sent off a couple of emails to see if I can special order the material or if I can use an alternate laminate schedule.  All the material I've order so far has come form Noah's Marine Supply of Toronto.  I know it is a Canadian company, eh, but they have a US shipping location so you don't have to deal with customs plus their prices are really good.  They are also very helpful and friendly.  I give them a high recommendation.  I hope they come through for me. So, take off you hoser!

Later eh!

(no disrespect intended for our northern brethren)

Centerboard Work Started

Now that the beam mold is complete and I'm still sourcing the cloth needed to build the beams, I decided to start the centerboard.  One decision I made about this boat was that the boat would be wood free with the exception of maybe the tiller handle.  The plans for the centerboard say that the centerboard and rudder are built using two layers of 1/2" plywood with two layers of triax cloth between and two layers of triax cloth on the outside.  Since I'm not using wood, I purchased some high density PVC marine foam (130kg/cu meter) and I will use this material instead of the 1/2" plywood.  I also wanted some additional mass in the board to aid in raising and lowering the board.  To get this mass, I cut a groove in the foam to accept a piece of 1/8" x 3/4" x 36" long piece of steel.  Each piece of the two pieces of foam will have the steel.  I cut the groove the full length of the foam, dammed up the end of each groove, installed the steel and filled the groove to the top with epoxy completely encapsulating the steel plates.  The steel will be in line with the pivot bushing. 



Once the epoxy cured, I cut two pieces of the triaxial cloth and laminated the two foam pieces.  I weighted and clamped the foam together to allow the epoxy to cure.  One last note, since the temperature is starting to drop, I got to use my garage heater which really worked well at keeping the garage toasty warm to allow the epoxy to cure.  However, it won't be long before I'm going to have to stop work in the garage and start to lay up the fiberglass beams in my basement.  Here is a photo of the centerboard curing.

 The next step is to sand the hydrofoil shape, cut to the final shape, round the corners, and fiberglass the outside.  The last steps will be installing the pivot bushing and paint.  More to follow.

Beam Mold Complete

I finally completed the beam mold for my Scarab 650.  The time to build the mold was 16.5 hours.  Here are a couple of photos of the completed mold.

The mold was constructed using 3/4" cabinet grade plywood for the sides and 1/4" plywood for the bottom and flanges.  The corner fillets were constructed using epoxy thickened with wood flour.  After meticulously sanding and filling all dings and dents, the mold was coated using tooling gel coat.

Before I can start to lay up beams, I need to apply multiple coats of mold release wax to the mold.  I will do that when I'm ready to get started.  Right now I need to find a source for the different types of fiberglass cloth that will be needed to lay up the molds.  I'm currently searching for this material.  I anticipate laying up the beams during the winter.

Next step: Centerboard