Wednesday, January 31, 2007

Vacuum bagging notes

I have been very impressed with vacuum bagging -- it amazes me how easy it is for a newbie builder to produce good quality laminates. I have so far followed Ian's instructions in the boat plans pretty closely, and have been very happy with the results.

I have not spent any time analyzing my laminates to check for fiber\resin ratio, etc. I have learned enough to recognize a "dry" laminate, and I keep an eye out for that. But in general, I just trust that the vacuum bag will work its magic.

Bill Quig's site has a nice page devoted to vacuum bagging. For the most part, I've ended up re-creating his setup. For my first couple of bags I had the bag connected directly to the pump which ran continuously - this got quickly annoying due to the pump noise, and I was mildly concerned about the needless wear-n-tear on the pump. So I bought a vacuum switch and relay from ACP, got an air tank for a reservoir, and life is grand now. I have the switch set to pull ~25", and it kicks back on when the vacuum falls to ~21". My "table" is pretty primitive: just a sheet of melamine, which was helpfully trimmed to 4'x6' by Home Depot for me (because full 4'x8' sheets don't fit in the back of my wife's SUV). I place the melamine sheet on top of of my table saw, with a saw horse under one end for extra support. I've been buying vacuum bag consumables from Fiberlay (they're in Seattle, and it's pretty easy for me to drop by there on my way home from work).

At first, I was anal about waxing the board down with a mold-release, but this process had the negative side-effect of producing some serious static electric shocks. Because of the shocks, and because the laminates\epoxy don't seem to stick to the melamine anyway, I've quit doing the wax step. I've never had a problem getting a laminate to release.

My first few parts I started out by tracing the patterns onto the foam, then bagging them. As noted by other builders, this is bad because usually the ink will diffuse\disperse with the epoxy, and your careful lines are gone when you un-bag the laminate.

I have found that it helps to develop a system when doing vacuum bagging, and follow it every time. That way all of the steps become habit, and you don't think about it much. I have no pretensions to being an expert in this area, but here is my current procedure, perhaps it will help others:
  1. Get the rough dimensions of the part from the patterns
  2. Cut out a piece of foam to those dimensions (generally just a rectangular piece). In some cases I've had to glue foam pieces together to get a large enough piece.
  3. Drill holes in the foam using a cordless drill. (This step does get old, but I'm almost done with my flat parts and don't want to create a tool to do it.)
  4. Run a RO sander over both sides of the foam, mostly to knock down any bits of foam sticking up from the drilled holes.
  5. Sweep and blow off any foam bits or sanding dust.
  6. Cut a piece of bag film to suit the part size, lay down bagging tape around the perimeter, and set it aside.
  7. Cut a piece of breather material (glorified Christmas tree felt, I swear) and set it aside.
  8. Cut a piece of perforated release film and set it aside. (On one bag I didn't use this stuff, and had a heck of a time getting the felt off of the peel ply).
  9. Cut two pieces of peel ply, and set them aside.
  10. Cut the glass pieces, and set them aside.
  11. Lay first layer of peel ply on table, then lay the first glass piece on top of that.
  12. Mix epoxy.
  13. Wet-out bottom layer of glass & peel ply (Ian says to do peel ply first, then glass, but I do them together). I try to leave this bottom layer a bit "wet", since some of the epoxy will get sucked up through the perforations in the foam.
  14. Lay foam on top of the glass.
  15. Lay top layer of glass on top of foam.
  16. Wet-out top layer of glass.
  17. Lay peel-ply on top of glass, and squeegee it out (usually there is sufficient excess epoxy in the glass below, to wet-out the peel-ply in this step)
  18. Lay release film on top of peel-ply.
  19. Lay breather fabric on top of release film.
  20. Lay vacuum bag fitting on top of breather film (not directly on top of the part). I kept forgetting this step the first few bags, very annoying to have to pull part of the bag film up to fix.
  21. Lay the bag film over the part. Get it positioned, and then remove the paper off of the mastic. Press down on all edges, especially the corners.
  22. Cut a hole over the bag fitting, and attach the top fitting to connect the bag to the pump.
  23. Turn on pump, wait for it to pump down and shut off, listen\look for leaks & fix if any. Then walk away and leave it alone.

Usually I will leave the bag overnight (I'm not in a huge hurry). On a good bag, the pump only runs about once every 1-2 hours. On a bad bag it will run every 20-30 minutes (and of course I can never find the leak). After unbagging, I strip off all of the consumables, trace out the part pattern, and cut out the part with a jigsaw. Voila, done.

(Side note about cutting glass: as a novice, I've been dismayed to learn how fragile raw fiberglass is. Even careful handling is bound to snag it here or there, and it really does not like being folded. If your fingers & hands are not smooth\soft, the glass can even snag on your skin. To avoid this, I always wear gloves while handling the glass (a good idea anyway, to avoid the itchies). Normal scissors\shears will not cut glass very well (you end up with a lot of "runs"). Instead, the "pizza-wheel" fabric cutter works well, and I've also been using some "composite shears" from ACP composities that have serrated edges to minimize the runs. I'm also considering some electric cutting shears.)

Bill Quig says that he weighs the glass before bagging, and mixes that much, plus another 25% extra resin. Theoretically I like this approach, but don't like the extra handling that the weighing process entails. For now I (think I) have gotten pretty good at intuitively knowing about how much resin I will need. Occasionally I'll run short in the middle of a layup, and need to mix more which is not a big deal. If I end up with less than 4oz wasted epoxy, I'm satisfied.

Here's a picture of my largest bag so far (it barely fit on my board). This was destined to become one of the main cabin rear bulkheads.

And here's a picture of some of the finished results:

Boat building shelter

When I decided to move ahead with this project, I had to figure out where to build it. My choices were limited: my garage was too small (both in length & width), and I didn't want to build anywhere else but my house. So it had to be outside, and I couldn't afford to build a new shop. After some investigation, I went with a Clearspan 14'x28'x10' shelter:

Clearspan Storage Master

To the above right is a picture of the pallet in which most of the parts were delivered.
Before I made the purchase, I did hear some warnings about Clearspan's quality and their product support but so far I've been pleased with both. The "skylight" feature is very nice and provides a ton of light; during daylight hours I hardly ever need to turn on the string of lights I've hung up.

One annoying thing was that the initial delivery shorted me on some critical parts (two of the frame pieces were missing) but they promptly sent me replacements, with no hassle.

One of the reported quality issues was about these shelters' performance in high wind conditions. I wasn't too concerned about it given that the Pacific NW is not really known for high-winds, plus this shelter is located in the lee of my house, a mere 2 feet away. Well, this year we had a terrible wind storm -- some rural areas were without power for over a week. I had skimped on the shelter anchors and only put in three per side. Even so, the shelter only moved about six inches to the side -- that's roughly due to the slack I had left in the anchor tie-downs.

Our weather is pretty wet usually for most of the year, and I was worried about condensation & humidity in the shelter. Fortunately this has not been a problem after installing a gable vent at each end.

Here's a picture of the finished shelter (vents not yet installed):

I think it looks really great, and actually adds a touch of class to the back yard, and serves as a conversation piece for backyard parties. Every house should have one of these, right? Well my wife wasn't too happy about it -- but hey, it should only be around for ~2 years or so.

To make the shelter more liveable, I've made a few other small improvements. I layed down a blue poly tarp to act as a moisture barrier...

(those beams are the foundation for my strongback, more on that later)

...and layed some cheap OSB boards on top of the poly to serve as a "floor". I am lucky indeed to have great neighbors; and one of them loaned me a 10-light bulb string, and a 200,000 btu propane burner. The propane burner can't beat the cold entirely of course, but it is useful for taking the chill off of things and getting rid of any condensate in the peak of the shelter. I have not yet run a circuit to the shelter yet, but will probably do so soon (for now I just run an extension cord out there from the garage).

Site and other prep

I knew where I wanted to place my boat building tent, but the location needed some improvement. The garage needed a new side-access door, to make it easy to get to the boat. To put in the door though, I had to move a gas pipe and an AC compressor out of the way. To save some money, I did the trench digging myself:

(by the way, that gap there between the shed and the house should be wide enough for a trailer with loaded F22 -- if not, I'll be having fun moving that shed some day. The AC compressor in the corner is no longer in the way.)

This trench is 24" deep its entire length:

(It was warm out that morning while I was digging, and I have to admit that thoughts like "do I really need a boat" kept crossing my mind...)

Next step was to have the gas and AC contractors come out to reroute and move stuff. After getting that done, my neighbor came over on a weekend and helped me install a door (where that window is, in the above picture):

Here's the nearly finished product (still needed to pour a step, you can see my form in the picture):

Other prep work included making a place to store the rolls of glass. I designed and built a plywood rack that attaches to my garage wall. Here's a picture:

Okay, I admit it's a bit rubegoldberg-ish, but it works:

Next step was to get working on the boat building tent.

General notes

Available options on the F22 include standard-cabin, cuddy-cabin, aft-cabin, racing "R" version, and daggerboard vs centerboard. I have decided to go with the standard-cabin+aft-cabin+daggerboard combination. The choice of the aft-cabin will probably raise a few eyebrows, since most folks seem to feel aft-cabins make no sense until you get into a larger craft. I just thought 1) it looked cool; 2) the extra space won't hurt; 3) I liked the idea of a slightly more protected cockpit. (I certainly don't plan on spending much time in the aft-cabin myself -- I'm a bit big for that. Maybe for grandkids someday.) As for the "R" version -- the guidelines for what actually constitutes an "R" version seem a bit loose. Using foam instead of wood is a obvious requirement (along with a taller rig) but to really get a light-weight boat you'd need to track down sufficient quantities of the lightest possible materials (foam, glass, etc). As I've learned, that can be hard to do for retail quantities, so I just buy the best available without going to extremes. Not sure about the taller rig yet -- we'll see, that decison is a long way off anyway.

I am building this F22 out of Corecell. I tried to use the A400 weight (4lb foam) as specified in the plans, but when buying at retail quantities this density is not commonly available. Given the price of A500 offcuts from Noah's Marine, it just didn't make sense to spend extra money for full sheets of A400 (and I would have had a long wait for the product). So, my boat will be almost entirely A500, with a few spots of A400 here and there (got lucky once when calling Noah's -- they had A400 offcuts available). Ian says that mixing foam densities will not cause any issues.

I wanted to keep the a boat a pure-Corecell boat, but similar problems exist when it comes to 3/8" A1200 high-density foam. Apparently this is hard stuff to get -- never available in offcuts, and ordering through Noah's can take several weeks, depending on when you order it and when they last got a shipment. I looked at Coosa composites (Ian suggests them as an alternative high-density material), but again ran into availability issues and super-long order lead times. In the end, I've decided to fall back on good old marine plywood for at least the float deck HD inserts and the main hull keel strips. I did order one full sheet of 3/8" A1200 from Noahs (still waiting for it) which I am planning on using in the daggerboard case.

I briefly considered using some of the more exotic laminates (s-glass, carbon fiber), but in the end decided that since this is my first fiberglass boat I'd be better off sticking to basic e-glass and just getting the job done. Noah's is my glass supplier as well, and I am happy with their quality so far. My initial order of carbon fiber was done through Ian himself.

I am using System Three's Silvertip Laminating Resin (with Slow hardener)...

...for all laminating jobs, and their General Purpose resin for everything else. While slightly more expensive than other brands, I chose them for the following reasons:

  • Familiarity with S3 products from previous projects
  • Blush-free
  • Not affected by humidity (I'm building outside, and in the Pacific NW humidity is often a factor)
  • S3 is a local company, and I try to support local companies (awww, aren't I nice)

I originally wanted to use their Phase Two epoxy, but S3 recommended against this since that product is less humidity-friendly. However, I am planning on post-curing the boat, and S3 says that the post-cured strength of the Silvertip epoxy will approach that of Phase Two.

Ian's plans are of super high quality, and are everything that was promised. I've had nitpick questions about a couple of small details here and there, and Ian has always responded graciously with answers in a timely fashion.

One thing I am not doing, is closely tracking my time and expenses. I have a busy professional life, and doing time\expense-tracking feels too much like work. And to be honest, I'm not too concerned about either -- the time investment will be done when the boat is done, ditto for the $$. I'm not going to cut corners just because I hit some artificial threshold.

Since I am building outside, and I didn't really get started until late November 2006, I haven't been able to do much lamination work. I finished the strongback, mounted the float form frames, and have finished planking my first float half. Since I can't laminate right now, I've been concentrating on finishing as much other small stuff as I can inside: float chain-plates, bow-web, all of the vacuum-bagged flat-parts, daggerboard case, float decks, etc. None of this is very time-consuming, and I should have everything done by spring (at which point my inner boat building demon will be unleashed, and I'll be building like the wind). Okay that last part was hokey, but that is the basic plan. I have been saving a bunch of vacation time at work, so that when the weather warms up I can take 2-3 weeks off and make some serious progress.

One last point. I've made a committment to my wife, that this project will not result in our vehicles getting kicked out of the garage (well, at least not her vehicle). This means that I spend a lot of time cleaning up the garage every day after working on boat stuff, and that space is a bit tight. The vacuum bag "table" overhangs and nearly touches the hood of my car when it is parked inside. I have to be careful when I bring my my car in, and slowly inch it forward... :)

Why build, and why an F22?

There is a lot of excellent advice on the internet from fellow boat-builders about why one should buy instead of build. I did read all of that advice, honestly. In the end, I felt that building this boat is something I really wanted to do for the fun of it. Beats sitting around playing video games, that's for sure (but more expensive).

I'm certainly not building to save money -- it was pretty clear before I started that this would be a bad idea, and by now it's quite crystal clear that I'm spending a lot of money. As a novice builder I tend to be a little sloppy on new procedures at first, and I don't always economise on materials as much as I should. I think these are just skills you learn, and I am getting better as time goes by.

Why an F22? Pretty easy there: the boat had to be a trailor-sailor. And I wanted it to be a lively boat, not something slow. My wife and I are novice sailors, and I think we will both enjoy the experience if we're on a more or less even keel. And given the light weight, I won't need a new tow vehicle to pull the boat. And while there are other light-weight trailerable multihull designs out there, Ian Farrier's boats have a great reputation, and this was a chance to build his newest and (hopefully) highest quality design.

Finally, I have to give credit here to a boat builder whose web site I spent many hours perusing, which first gave me the notion that someday I could build my own boat, and got me interested in multihulls. That would be Tony Bigras, who had a great site detailing the construction of his 50' aluminum catamaran. Tony's site was quite simply inspiring. Unfortunately, that site is no longer up, which is a shame. Thanks again Tony.

Numero uno post

Test, test, test. Can anyone read this?

I am building a Farrier F-22 trimaran, sail #25. I've been taking a lot of pictures along the way, but haven't been making much progress on the web site part. My goal for this blog is to show friends & family what I'm doing, document my progress, and help motivate myself to maintain momentum. I'm not convinced that the blog format is ideal for project-status-reporting purposes, but the impressive ease-of-use of the Blogger toolset outweighs that.

This is a picture of me, holding one of my cabin bulkheads. (You can't really tell since I'm hiding behind it, but before I actually finish the boat it would be a good idea for me to work on eliminating excess personal ballast.) I like this picture, since it gives a good idea of the overall size of the boat.

Since I've been already working on this boat for about three months, there will be a flurry of somewhat lengthy posts to begin with, which should eventually subside into semi-regular status reports. I am nothing special as a writer, but I'll try my best to be at least somewhat coherent.

By the way, I take all pictures at the highest resolution my digital camera will allow. So clicking on the pictures to see the original (at least, I think they are the originals) will result in a large download -- fyi.