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Utah OB20

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I prefer to use bugle headed decking screws, having given up on black phosphorus drywall screws decades ago. Drywall screws just break, usually when you'd rather they don't. Deck screws are much tougher. The bugle head will suck most materials down by themselves, though I have boxes full of 1 5/8" deck screws with a 1/4" thick 2" square plywood pad on them, so I can improve hold down and adjustment and not leave a big head divot. Square drive are nice, but not as common in the economy fastener market in the USA. You can get them, but you pay twice as much and for a temporary fastener, hard to justify. Lastly, a counter sunk (or bugle head) fastener offers more holding power than a button, pan or truss headed fastener. On the other hand, if you need some minor adjustment under the head a slightly over size hole will permit a pan style (button truss, etc.) to accept this movement, which is why I use the plywood pads under my bugles occasionally.

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Thanks for the great tips and interesting discussion on fasteners.  

 

I'll go with screws with (and without) plywood pads at the bow sections and composite nails or staples aft.  I'll try nails first, since I have a brad nailer that accepts the size of nail I want to use.  I'll also be switching to deck screws.  I've always thought the cheap black drywall screws were one of man's greatest contributions, but after this discussion, I'm wondering why I mindlessly put up with their shortcomings for so long.

 

Speaking of those cheap black drywall screws, I've told myself that if one or two of them were to break off in my boat, they would become entombed in epoxy and never be exposed to moisture or oxygen and won't corrode, stain, etc.?  Correct?

 

Also, I've been assuming that to laminate the planking (or to join any two pieces of wood) I need to apply unthickened epoxy first to prevent the joint from being too dry.  Necessary, or not?

 

JP, I like your notched scraper idea to screed the epoxy onto the planking.

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I quit using drywall screws years ago.  Pocket screws are more expensive but I reuse them over and over.  I usually predrill but it is often not necessary since they will drill themselves.  Never had one break and the heads don't strip like phillips can. Once you wuit using Phillips you won't go back.   If they get stuck In cured epoxy I give them a blast of heat with a heat gun and out they come.  I use plywood washers when there is a lot of load to pull a plank in but often don't need to since they have a washer head.  I actually like them to make a very slight impression in the surface of the wood. It makes filling the hole easier, particularly on horizontal surfaces.  The indentation keeps the resin inplace as it soaks into the hole and accepts filler better. Bottom line is what you think will work best for you. 

They are available at most woodworking supply houses and Amazon. Pocket joinery has become quit common.  I find that the prices can vary quite a bit. I keep a number of different lengths with 1" being the most used length on this project.

Cheers,

Ken

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I quit using drywall screws years ago.  Pocket screws are more expensive but I reuse them over and over.  I usually predrill but it is often not necessary since they will drill themselves.  Never had one break and the heads don't strip like phillips can. Once you wuit using Phillips you won't go back.   If they get stuck In cured epoxy I give them a blast of heat with a heat gun and out they come.  I use plywood washers when there is a lot of load to pull a plank in but often don't need to since they have a washer head.  I actually like them to make a very slight impression in the surface of the wood. It makes filling the hole easier, particularly on horizontal surfaces.  The indentation keeps the resin inplace as it soaks into the hole and accepts filler better. Bottom line is what you think will work best for you. 

They are available at most woodworking supply houses and Amazon. Pocket joinery has become quit common.  I find that the prices can vary quite a bit. I keep a number of different lengths with 1" being the most used length on this project.

Cheers,

Ken

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The build looks great. Location is to much :)

 

On the screw end i pretty much use those square headed pocket screws all over they are great 

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Instead of those quite costly "Kreg" pieces, consider a button head "tech" screw, which are a lot cheaper and made the same way of the same stuff. Deck screws scan be found with square drive, though not as easy to find in the USA. 

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That is a funny one.  But, at least a Phillips-head rock can be used as a hammer...I hope my dad didn't hear that.

 

Lots of interesting and helpful discussion on screw selection, thanks.  Any quick comments on the other two questions?  Broken screws safe to leave in encapsulated in epoxy, or is it imperative to chisel them out?  Also, what about pretreating the planks with clear epoxy before laminating with thickened stuff? 

 

Carter

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I don't  know if encapsulated screws actually cause problems.   However, If you worry about them, that's a good reason to take them out.  The boat's supposed to make you forget your worries, right?

 

The usual method for gluing is to coat the pieces with clear epoxy, then add the thickened stuff and clamp when everything is still wet.   The thin stuff penetrates the wood fibers better.   If you let the clear coat cure, then there's an opening for other problems such as the dreaded amine blush and weaker bonding.

 

 

 

 

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The only fasteners I've seen buried in wood that have survived, are bronze and good stainless, in epoxy. I have removed old galvanized, bright steel and black phorous screws, some also in epoxy, though not as well as a bonded fastener, that rusted. When in doubt, dig it out. A hole saw, with the pilot bit removed can get them out neatly (with some practice), so the hole can simply receive a dowel or repair. 

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Good advise, thanks.  I used most of it. 

 

I have completed the planking on one side of the boat using screws with plywood pads and screws only for fasteners and I'm pretty happy with it.  Slower than the plastic staples, but I liked watching the screws snug the planks up to each other and to the stringers, plus squeeze a little glue out.  It left screw holes, but they were easy to deal with.

 

Besides JP's notched scraper to trowel the thickened epoxy around, I liked his idea of cutting the planks a little more narrow than specified, which helped.  I also tapered the last few planks at the bow just a bit to accommodate the complex bending up there.  So far, the most difficult task has been crawling up, under and inside the hull to clean the squeeze-out from the planks and stringers.

 

This is a very large and challenging project for me and I appreciate your comments and tips.  PAR (I figured out your name is Paul), I just discovered (and read) the Tips and Tricks link on the signature block of your postings.  Thank you.  It's very generous for a professional boat builder to spend the time to assemble a do-it-yourself manual for the rest of us.

 

Carter

 

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Carter- she is looking great-  those planks at the bow are a treat, huh?  :huh:

 

I better get going on mine-  you are catching up quick-  I am fairing out the bottom glass now and looking forward to getting the boat right side up-  weather/job/family commitments/other projects all seem to be conspiring to slow me down.  

 

Take care-

 

JP

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Great posts, thanks for sharing.

 

I am inching along on a OB20 build as my first ever project.  One question I have is when I am ready to cover the hull with fiberglass, should I first apply a coat of epoxy to the hull, allow it to get tacky, then lay the cloth and apply more epoxy; or keep the hull clean lay the fiberglass then apply epoxy?   It's a rookie question I'm sure, but it seems to me if epoxy is first applied the cloth will be difficult to lay smooth.      Greg 

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Laying the cloth down on a wet hull would be a disaster.  It is better to put it on the dry hull, and scootch it around to tease out the wrinkles.  Lay enough resin on the cloth to thoroughly wet out the cloth.  Then, squeegee off as much of it as you possibly can.  This is very important for the first layer of resin.  If you don’t remove that resin, the glass will float up and away from the hull, giving you an uneven surface.  It is a waste of epoxy, or so it seems.  But this is critical.  Watch Alan’s CS15 build on YouTube.  His technique is beautiful.

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Part 18 is the prep work, and part 19 is the glassing.  Offcenterharbor.com has a great video on glassing technique, but you would need to join.

 

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When you go to sheath the hull, several prep steps need to be done first. The first thing is to seal the hull with epoxy (see my site for detail about this step). Next you'll fair the hull, particularly around seams, chines fastener holes, etc. This seems redundant, but trust me, it makes applying the fabric easier and future fairing (yeah, you'll do it again) much better. The reason is simple, you don't want to do a lot of fairing (read sanding) on the sheathing, which can threaten cutting into fibers, but if the underlying surface is already pretty darn fair, so will the sheathing be and just a light fabric weave filling coat, will be all you need.

 

There's two basic sheathing techniques, the wet and the dry method. I don't recommend the wet method for novice builders, as there's usually not enough environment controls in place to insure this goes well (bumps, puckers, lumps, suicidal bugs, etc.). The dry method has you apply the fabric over the hull, then pour a quantity of neat goo in the middle, spreading it out with a plastic applicator or squeegee. You just push around this pile of wet goo, until  the fabric goes transparent, then move on to the next area, pushing goo as you go.

 

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The advantage to giving her a sealing coat is that some areas if the surface will soak up more epoxy than others.  Sealing it first prevents these areas from being starved of epoxy during the bonding coat.  The disadvantage is that you need to sand the entire bottom before bonding.  Still, this is the best way.  Thanks, PAR!

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GAP333,

 

Thanks for asking some of the questions I've been pondering and thanks for posting it on my thread.  I might have missed it otherwise. 

 

I'm just completing the side planking on my boat and will be fairing and glassing this winter.  I guess these projects all look pretty much the same, but I'm posting a current photo.  Are there photos of your build?  How about your build JP?  I've poked around on the forum a little, but I haven't seen pictures of any OB20 builds, besides Chicks, which are fantastic, and another early one by the Bacons in Montana, which are also very good and include lots of early construction shots.

 

Thanks again to Paul, Don and JP.

 

Carter

 

 

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