How "NOT" to build an i550 guide

[slowpoke]

Okay guys, this is where we all admit those mistakes that make us wonder what we were thinking when we did them.

How NOT to fair a keel and bulb.
Do NOT set your completed keel and bulb on top of a sawhorse in your garage, then open the garage door. It makes a big crashing noise when it falls 3 feet to the floor!

[Chad]

Don't get in the habit of doing all the resin squirts, then all the hardener squirts. One day, as you stand ther mindlessly pumping them out, your mind will wander and you'll lose track. Then, the next day when all that resin is still a gooey mess, you can spend a couple hours elbow deep in solvent and scrapers getting the cloth off. It sucks.

One squirt resin, one squirt hardener, 2nd squirt resin, 2nd of hardener, etc. No thinking required. Haven't screwed up a batch since...

[Shazza 273]

Don't make your keel top plate bolts too short that they will pull through in the middle of a race and let your keel become an artificial reef !

Do not fair you bulb then drop it tail first onto cement twice ! especially after have made an artificial reef out of your first one !

Do not try shaping your hardwood pieces with an angle grinder and think a quick 30min sand will make it all smooth !

Do not use non-galvanised bolts on your i550 hull supports on your trailer ! (it is possible that those bolts will break and you hull will come within an inch of being punctured by an up-right steel support !).

Do not mix epoxy after having worked on the hull for 8 hours plus and expect to get the mix right as you are now cross-eyed and can't read the scales correctly and you now need to scrape that epoxy back off the next day after it has run down the inside of the hull next to the frame you had it nicely filleted against !

[M&S]

When making the hull side glue ups mark and pay attention to the chine edge and sheer of the panels as they are assembled. If you are using butt blocks make sure that you make mirror images. Stitching the sheer to the hull bottom panel does not make for a happy outcome.

[george#212]

Don't use lightening holes on butt joints. I had to dismantle my first build and in the process found that the pannels failed at the joints.

[Kevin]

Don't fillet over your hull stitches. Makes for a difficult taping situation which you will hate.

Do use biaxial tape for a stronger joint and better form fitting properties than straight cloth tape.

k.

[jray]

If during your build you come across some small thing that needs to be addressed but decide to do it later. Understand that the longer you put it off increases the difficulty ten fold or more. Take the time to get it done when your putting it aside, save yourself the extra work later!

[jray]

Don't let 3M 4200 marine adhesive sealant set up anywhere unwanted. Wonderful stuff and chemically resistant to boot!

[jeff.dalsin]

5200 is even worse! I saw someone on SA refer to it as "52 billion"!

[Tim Ford]

Do not sand carbon fiber twill while wearing a hazmat suit in 95 degree heat and 85 percent humidity....it takes a lot out of you.

[jray]

Sounds like a great weight reduction program, need any help? It will have to be after I finish up all my small build projects and launch. Got beer?

[lohwaikin]

Just realised after happily closing off the forward berth panels that the compression post has to go in first...

[lohwaikin]

Nobody said anything about NOT using foam rollers for 2-part epoxy paint...
It swelled by half and lasted 2 minutes.

[admin]

Hah, yeah, I had that happened 2 weeks ago with the Interlux 2000e. I was using West System's rather expensive yellow foam rollers. They have a seam and they fall apart at the seam...really SUCKED. I then went to Lowes and got their white solid foam 7" rollers...they work great and do not fall apart or swell...cheap, too (by comparison)

[Tim Ford]

Cool explanation on the MIST build blog, about bump removal, thanks for posting that, Tim K.

I'd add to the NOT list...do not tape until you double check, triple check and quado check the alignment of all cable-tied seams...I wish I had taken greater pains, then, and not later. (further reinforcing JRAY's post above about 10x more of an issue later)

[slowpoke]

NOW you tell me!!!!!!

[Mist]

Slowpoke, My apologies on the late notice. I only discovered this a week to ten days ago and I brainstormed a few days on how to correct it. I thought of filling the low spots all the way around the hump or replacing the entire panel between fr 89 and 110. Then, I had a eureka moment and thought to just cut the slot and pull the two sides down. I will post more details on this forum page this evening. I’m certain additional first time stitch and glue builders will run into this identical problem. I recommend that when stitching the middle slot in the bottom panel that the wire-tie holes are about 2 to 2.5 inches apart so there is sufficient force to pull the panels all the way together. When building the boat right side up and turning it over so late in the game it is difficult to tell the bottom has this condition.

[Mist]

Mist is the first boat I've attempted to build. The stitch and glue method seams pretty straight forward. Well, it did two years ago when I joined the hull bottom, two sides and the stern. Drill a hole ever six inches and pull the panels together. Well, two weeks ago, when I finally turned the boat over, I noticed and un-fair (and unacceptable) hump between frame 89 and 110 (see the first photo below). The hump on the bottom is not evident until one turns the boat over revealing the bottom. To fair the bottom would require a BUNCH of filler. This condition and the cause of it, bothered me greatly and it took a few days for the answer to come to me. Finally, I decided to cut the joint (center slot in the hull's bottom panel), pull each side down, and re-glue the joint. Upon finding the solution, the cause of the problem became very obvious. I didn't pull the center slot together far enough two years ago when I stitched the center hull together. The second photo shows the gap between where I should have pulled the panels together. The third photo shows the windlass idea used to pull the panels down in a controllable manner. The forth photo shows an external view with the panels pulled into place. The last photo shows the panels glued in place with carbon tape. The batten across the top illustrates the hump is removed.

I have no doubt other first time builders will run into the same problem. The solution to preventing this additional step my be to stitch the center slot in the bottom hull panel every 2 to 2 1/2 inches especially in the aft end of the slot, where a lot of force is required to pull the slot together.

[jray]

Nice fix! I didn't have any problems with the bottom but the hull sides drove me crazy. I believe the problems I had were fixed in the new plans out now. Again well done with the solution to a crazy problem.

[lohwaikin]

Please don't remind me of the 1/8" deep by 1 sq-ft wide depression I had on the starboard chine at the 190" position.
I am fighting to get into the water ASAP...

Oh BTW, my ply-glass keel sleeve is stuck onto the keel foil. I had about 1mm thick of cling-wraps around the primed section before glassing.
I realised last night the cured sleeve is going to be difficult to remove, because the cling-wrap, as I should have understood by its name, would not slide along the foil to free the sleeve...

If I were to do it again, I would used a few turns of Kraft paper followed by the cling-wrap.

[micah202]

Please don't remind me of the 1/8" deep by 1 sq-ft wide depression I had on the starboard chine at the 190" position.
I am fighting to get into the water ASAP...

Oh BTW, my ply-glass keel sleeve is stuck onto the keel foil. I had about 1mm thick of cling-wraps around the primed section before glassing.
I realised last night the cured sleeve is going to be difficult to remove, because the cling-wrap, as I should have understood by its name, would not slide along the foil to free the sleeve...

If I were to do it again, I would used a few turns of Kraft paper followed by the cling-wrap.

.....another good reason to use the big-box and shim approach!
........if the trunks snug enough not to rattle,,,it'll always be 'grippy' going up/downunless you've got the blade perfectly aligned.......

http://www.flickr.com/photos/59103003@N05/7505862536/in/photostream

[noemar]

Help! I applied what I had hoped would be my last coat of epoxy to my boat's bottom.I used cjcomposites epoxy and apparently did not mix it long enough because after returning home from Ellicott City a week later it was not completly harden.I tried to sand it down and all I did was soften it up some more. In fact as I kneeled on the boat my tyvek suit stuck to it. Any ideas on the best way to strip this epoxy off without damaging the fabric would be appreciated. Like I said sanding does not work,only clogs paper . It's supposed to snow this weekend so I guess I will have time to figure out how to get this off. I'm thinking heat gun and scrape off with a putty knike like I did on my house many years ago.Send advice or wish me luck. Better yet do both.
Noel

[lohwaikin]

It was a painful decision, but I slit the keel sleeve in order to release it from the keel foil.

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Hey, doesn't it look like a rudder cassette with safety release feature?

[lohwaikin]

Noel,
I am currently encountering the same problem as you.
I applied Maxbond thixotropic (the thick non-sagging type) epoxy to encapsulate the hull panels, because the paste like epoxy was easier to work with a scaper without resin running off the hull sides.
However, it didn't cure to a sandable hardness after 7 days of waiting.
Singapore's average weather condition now is 85 degF and >80% humidity (rains everyday...).
I still went ahead to sand it with grit 80 paper, only to wear out the wirebrush from clearing clogged papers.
Sanding partially cured epoxy is pretty hazardous I believe, as I'm now on the 4th day of recovering from asthma, though I had an N95 dust mask on during sanding. Anyway 4 days ago as a parting shot I applied the low viscosity clear type epoxy on a small bow area of the still-curing thixotropic resin.
And I'll go back to check on it tonight. From past experience on the cabin panels, I noted the low viscosity clear type epoxy achieves sanding hardness faster than its thixotropic version.

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Cheers and take care,

[noemar]

Looks like a heat gun and a scraper is the way to go,at least that's what I tried slow but effective.Now depending how much snow we get I will have something to do this weekend.
noemar