Hard Dodgers

Hi ebb In fact what I meant by raking out is simple digging out the core between the 2 layers of glass , that is inner layers and outer layers of fiberglass.
This can be done with a router but can also be easily accomplished by using a small round wire wheel in a drill. Its the sort that would be to big for a "dremmel" but suit an air grinder or drill. this makes a real neat job. This cavity you create is back filled with bog filler then sanded smooth with small drum sander in a drill.
Also by doing this (if you dig deep enough say 1/2") you are linking the inner and outer skins together.
Done right it creates a very neat edged opening in you core ( Ill take a photo of the boat windows Im doing and post)

To get to sealant Heres a sight to look at http://www.fixtech.com.au/index.php?id=212 It tells the correct way to install windows onto a surface and I think would alleviate all you concerns
I can tell you for a fact polyurethane or the correct silicon
( GE Silpruf SCS000 is good) applied and installed properly will require no fastenings other than for initial alignment and these would be place outside of the edge of your sheet and with large washers on
They would be removed after initial cure.
A webbing strap retaining pressure is reguired for several days.
Remember the actual pressure is a pulling back one and the very ends of your lexan panel are the ones trying to tear up wards, and away.
The rest of the panel in general is trying to move in sheer to the surface. As youll see in the site I mentioned the thickness of the bedding must be maintained for it to work as its got to absorb expansion and contraction of the lexan (same reason you use oversize holes)
http://www.fixtech.com.au/index.php?id=212 if this link doesn't work let me know
A dam tape is excellent and I try to use 1.5 mm this alleviates the need for "thick" silicon as the job of maintaining a space is done bythe tape also the difficult inside edge where silicon would normal squeeze out in big gobs is kept precise and neat( the edge of the carefully applied tape is all that is seen from inside the dodger) in an area of higher pressure say just about at the ends of your window, where most pressure will be exerted a very narrow second strip of dam tape can be added.
Steve Marshall

Have not yet identified a prefered dam tape here. But seems to be available from the auto suppliers.

But the tube stuff we are using IS the silicone modified polyurethane range that is similar to the Bostik range. There is no reason to believe it is the exact same stuff but EVERYbody is now making their version of it. I just looked.

Still, marketed world wide, it's not readily available to the DIY trade here. This is another reason why our home-grown omnificent WM is a PITA. They certainly seem to be AGAIN complicit in keeping superior products from the public while continuing to sell and catalog less versatile ones.
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I've gone over the installation instructions on that goop site. Thanks for posting. I'm still confused as to the steps needed.

( I do understand that with a proper curing time you can get away with no fastenings at all!
Well, I don't know, I give my reasons for easy removal rather than convenient installation. Easy removal is a maintenance issue.)

I do detect in self some glimmer of comprehension in putting the window panels on with wet tube rubber - per instructions.
That is to prepare the opening with flat pellets or dots or darts of a material around the very OUTSIDE EDGE of the window, so that after we zigzag the goop in it will only squeeze out down as far as the limiting pieces. Small shapes of 1/8" EPDM sheet could be left in place. We could slice protruding tails off after the gasket cured. Better, put them in the middle of the flange surface and forget about 'em.
And then add 'a final bead of caulk around the window.' That's what I think the instructions say. BUT
I would hope that that wasn't necessary, as it would be a messy proposition.

I would guess that running a utility-knife carefully around the edge of the glass after the rubber has set to cut off the squeeze-out bulges would produce a clean look.

The purpose of the risers is to provide a rubber gasket line of continuous thickness. Could be any thickness that the installation data sheet recommends - whatever brand.

THAT is a good idea (even if I don't get the instructions). EPDM I will use because I have some plain non-foam 1/8" sheet. And the data sheets I have for the Bostik hybrid says the caulk likes to stick to EPDM. I'll do a dry run with the bolts to see if the epdm gets pressed thin from bending the polycarb into submission with fastenings.
Don't know that I will use the fancy goop. It might be, as you point out, an aggressive adhesive not requiring any fastenings, Too aggressive. I'm still thinking I'll go with old fashioned butyl tape. Has a good rep for staying soft for a good long time. Have to see about the limiting bits, ie what actual material to use with butyl tape.
AND if it don't fly we go to the miracle caulk.
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If we insist on using the sly-urethane hybrid goop:
Dam tape. How applied?
I understand it is used on the INSIDE of the dodger.
To which surface is it applied? If it is applied on the plastic window, as I believe, it is a narrow flexible tape that has to follow tight curves around the inside of the opening. It would be applied during the dry fit. It has to be thicker than the mini stand-ups used for the gasket.

Another kind of dam tape might be applied during the final dry fit to the FRAME. Not the window. It would create the inner dam by being slightly higher than the frame and just as high as the gasket needed. Unless this is very stiff material, installation pressure might billow rubber on to the glass.

A narrow foam tape, say 1/4" high, 1/2" wide, with a peel and stick surface would do the job. IF WE CAN KEEP IT IN PLACE.
The new fangled rubber hybrid rubber goop will stick to anything. And will certainly stick to the foam tape. It'll even stick to the white vinyl peeler strip we take off.
What I mean is, it don't seem like the dam tape will come off when the damn rubber caulk has gone off.
Is the dam tape there permanently on the inside of the window?
No way.

DEEP BREATH. Think I'll have an ale now!
This thread exchange is fantastic!
Hope I'm not being too stuupid.. Real sorry bout that.:rolleyes:

Hi ebb
to answer your questions maybe out of order
dam tape is exactly what its suppose to be, that is a dam to stop sealant/ bedding flowing beyond where you want it to and totally saves clean up of excess.
Its purpose is two fold, not only to stop uncontrolled spread of sealant/bedding but to maintain a constant space between surface and glass.and thus a constant bedding thickness which stops the sealant shearing
The tape is available in a whole range of sizes generally from a glazier but Ill bet McMaster Carr has it. I use 1/8 thick x 3/8 wide. heres another place I just Google'd
http://corporateportal.ppg.com/NA/Gl.../cat_marcy.htm

It is stuck (it has one side sticky although you can get double sided) to the fiberglass dodger tight around the window openings and will very easily follow the curves you have provided you don't go wider than 3/8" (1/4" wide would work as well)
It is a closed cell tape and when the entire surface is considered it takes a heck of a lot to actually compress it flat.

I think the site I sent indicates putting a blackout coating onto the sanded and cleaned window edge. than applying the bulk of your sealant to the actual dodger rim that the window will press against.

If you were to do one full wrap window, then prior to any of this I would pull lexan all the way around into exactly the right position and be absolutely sure its laying flat on the dodger surface all round.

I would then drill 2 small holes top and bottom of the lexan screen right in the center.
these holes would take temporary locating pins (1/16 steel nails )
These would be for initial alignment, when placing the lexan.

With the window still pulled tight around the dodger and in the precise position, I would mark around it with pen then mask around on the outside,right up to this line.

When you then pull the window around for the final time with sealant on the dodger surface and a black out coat on the window edge, the dam tape will stop the sealant squeezing inwards and the excess will be squeezed out an onto your border of masking tape which also provides a guide as to placement .

Clean off any real big gobs that go over the tape on to the dodger but leave the rest and let the whole thing set and cure for several days.
The dam tape does remain in the job and provides a very neat finish edge on the inside of dodger, provided you put it on neatly and squarely to the edge.
The finish it leaves is far neater and way quicker than trying to clean up or true up black silicon that inverable goes everywhere.

This applies to a full wrap If you going for indevidual windows then you could do just the same but do the 2 side ones first then the center although if your going to make the center curved on open I just dont know what to suggest.

You would find that windows sealed/glued on like this, are in fact easer to remove than screwed and sealed windows.
Steve Marshall

Sounds like this would be a good method for replacing the doghouse portlights as well! Once it's all set, I think I'd still use a few mechanical fasteners to make 'dam sure' that nothing gives way over time and stresses.

OK you gobs, did you ever think you'd get so educated on dodger building?

A few takes here. Brief!
McMasterCarr has a limited collection of foam tapes.
We are looking for GLAZING TAPE as the cross-over.
There are VHB (Very High Bond) tapes that are too thin. They are meant to glue things together: glass to glass, metal to metal, and maybe even polycarbonate to fiberglass laminate - but don't quote me on that! Glazing applications require good UV and heat resistance. Good rubber.

"Blackout" is a new term for me. It don't refer to WWII curtains. What it evidently means is a smooth, prepared, neutral surface that is the base for high-end aps like powder coating. Or, in case of our dodger. finishing off the edge of the cut-outs by making them fair, smooth and sound. That way the tape will have something to stick to.


It's going to take some research and phoning to find the dam tape or glazing tape. It can't stick TOO GOOD (like VHB), because it has to come off. It can't have an adhesive that will be left behind on the frame. The stickum has to be part of the foam tape. The product should mention that attribute. The foam in this use can be open cell.
I don't think that weather stripping or tape will do this job for us here.

Input on this very welcome!

My ap requires this stuff so I will find the stuff eventually........
And no doubt post a source.


:DSteve's method of registering the poly-wrap panel is a champion tip!!!
This is the kind of thing, coming from an expert, coming from experience, that blows all the other BS forums out of the water.

We got lucky.
:D

Marcy Tapes is the one.
Their tapes look excellent but they deal only with professionals and deal in cartons not rolls.
So far I've reached
only wholesalers in California.
So I will try some auto glass installers. Also used in the RV trade.
One guy said that 3M should have something -
Hardware stores have various weather tapes, most of them useless. You really want an OPEN CELL foam to allow air to get in and set up the goop. Somebody like Cabella's probably has it???

One wholesaler said he'd sell me a box of 12 (15') in a roll. of the stuff
Steve mentions......will keep on looking...
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NOTE on the FOLLOWING post by Steve M.

Thanks again for the tip.
The method described is obviously for clear sealant/adhesive. Although it would be perfect for black adhesive too.
True. The best look is when the flange appears to 'border' the window when viewing the finished job. And this method will help to minimize bubbles in the adhesive which are nearly unavoidable.
Jamestown hard catalog, only source I have found lists no clear Bostik sealant/adhesive.
Jamestown also does not appear to recognize that the 900 Bostik range is hybrid silicone/urethane. I would not order from them, just in case this stuff happens to be something else. Product descriptions have to be absolutely unambiguous. Clear, informative. Bostik makes the whole range of goops like all the manufacturers. Including clear silicone sealant which really should not be used for window installation.

BoatLife's LIFE SEAL adhesive/sealant - which IS a silicone/urethane hybrid DOES COME IN CLEAR.
However the stuff skins over faster than a speeding bullet. If you have prepared EVERYTHING before install including placating the seagods, you may get your polycarbonate on in time. I know I can't move that fast.

Using roll butyl tape means I can break for lunch in the middle of the job.
Have not heard any reason WHY NOT to use the stuff (except my roll is dark grey in color) ...... anybody???


DAM TAPE NOT FOUND YET!!!:(:(

Black out is exactly That
By applying a thin evenly applied layer of black sealant to the bedding surface of your lexan which has been carefully masked off before hand you will get a very neat finish window installation.

The Easiest way to mask the surface (I'm referring to the inner window surface) is leave the protective brown paper or white plastic film in place.
Place the window in its position and have a means to register this position for precise repositioning.
While the window is in position, from the inside mark with pen around the perimeter of your opening this may be a bit wobbly due to ??

Anyhow remove the window and place on a table, inside face up
Now with a straight edge or suitable fairing batten mark out a new neat line with real nice neat radius and make this new line inboard of the actual marked line, say by about 2>3 mm.

Now, with a really sharp new razor, cut the paper or plastic protective film on the new straightened inner line and carefully remove the outer rim paper.

Note cut carefully all the way through the film so that you don't screw up the nice neat line when removing outer edge film.

Your sealant instructions may call for very light sanding of the newly exposed lexan and wiping with metho .nothing oily

When your totaly prepared to go and alls set, coat this exposed surface as mentioned above right up to and onto the still remaining center portion of film. make sure this coat is thin its only really to preform the job of (blackout) paint.
Keep any excess that goes onto the masking film to an absolute minimum.
the aim of all this is to provide a constant black appearance when viewed from the outside and a really neat inner finish line when looking through the window accompanied with using the thin black dam tape the job will look really neat.
dont try to pull tapes of to soon

Steve Marshall

Have IDed a candidate for use as a dam tape. A dam tape is applied around a window opening on the inside - before glazing - in such a fashion as to insure wet rubber from squeeze out doesn't get on the virgin plexi or polycarbonate. The idea is that when it is pulled after a generous set-up time we hopefully see a sharp clean window and jamb. The alternative is to scrape off the squeeze-out after bolting the window and clean the mess with a solvent. The scraping would scratch and the solvent screw up the $$$ plastic - and probably leave a cloud of #&^@(?<!! behind on the plastic. Have not found a ready supplier for the real Marcey tape that Steve Marshall mentions. Never seen the actual stuff, so it is difficult to search for a more available substitute.

Going to try a McMasterCarr polyethylene foam tape. [Page 3466, under Polyethylene Foam.] It comes in 1/8". 3/16" and 1/4" thickness. I got 1/4". Comes in widths from3/8" to 2". I got the 3/4".
It's cheap, white, pliable, lite weight, fine cell textured, and has a fairly aggressive stickum on one side. It seems FIRM enough to take the pressure of liquid rubber wanting to squeeze through IF the stickum holds onto the rabbet. If I do the black-out as Steve suggests and have a hard smooth surface the adhesive WILL stick good...Right? May still go with butyl tape. Which will not require the dam tape. Butyl is grey and I guess I'd have to do a Grey-out on the rabbets.

It's great that it is white so it will be easy to place on a dark window surround.** 50' on a big roll for $8.58 plus shipping. It would be ideal if it were open cell to allow air to pass through and help the caulk set-up. But it is closed cell. All peel and stick foam tapes found in the local hardware stores are too soft and smoochy for damming.

Ebb's the guinea-pig for rabbeted in windows - this time!
Soon to follow photo will show the windscreen has two large side lights that will have 1/4" lexan in rabbet, and an openable smaller center light also in a rebate. Will have to preform the plastic. First we'll try the cold bending over spacers method Steve described. Don't know that I can work with all that bending tension on the plastic with a lot of wet rubber - I'm not FAST and I'm not CLEAN - so I'm going to learn how to slump the lexan.
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Our response here to Steve's sharing his hard dodger building methods with us may have helped him decide to produce what sounds like a DIY BOOK on the subject. See his blog. [Can someone post a blue-line here for it?]
I hope he goes into ALL of his dodger styles, and all of his methods. If I may say, he is a natural at it. his work is right-on and results beautiful. There is a crying need for such a book and I hope it is successful.

Steve has been active on his blog - there are some new pictures showing forms and jigs. And how clean he works!
Hope his book is brim full of stage by stage process pictures and or drawings!
THANKS, again!:cool:
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*Could use this polyfoam tape as a dam for an epoxy project. Polyethylene (as in SeranWrap which literally blows off epoxy after it has set.) But a super hybrid goop that sticks almost anything together will, I predict, stick to the narrow edge of any tape that is against the caulk. And pieces of cheap foam will pull off. The tape has its skin sides top and bottom, so it will have a raw side dammed on the caulk. If I go wet I may take some MOLD RELEASE WAX and with a finger rub some on the interface of the foam. Maybe that'll work, maybe not?:p
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**One proper way, one least prone to mess - and time consuming - is to do a complete dry fit - with all the window fastenings SNUG but not tight on the spacers. [It occurs to me that the spacers can be plain ole washers of choice and thickness - and if preglued to the rabbet over the holes (like with 5min epoxy) they'll be right where they need to be when applying the goop. I'll get some rubber ones from McMCarr.] Then using the glass as a guide slide on the dam tape, and press it firmly in place.
Undo the windows, lay just enough goop on the flange, c a r e f u l l y position the window in place (preformed of course), insert the bolts again, and tighten evenly and alternately (like tire nuts). Squeeze-out on the outside, if reasonable, might be left unmessedwith and sliced away later. The protective paper would still be on. Leave it shaved like that or finish off with a finger fillet of rubber or a bead. Neither will be easy.

Steve's single piece cold bent front sure sounds easy now!!!
imco as always

Here's his blog:

http://marshalldesign.blogspot.com/

...but Mr Ebb, I'm not seeing the info there you refer to regarding a book...?

Someone in the harbor here built - while on a mooring - a hard dodger which looks a lot like what Tim has on "Che'". The boat itself is a Tahitian Ketch - full-on classic wooden gaffer. The forward line of his is a bit steep for my eye, but overall - and from a ways away - it looks good. I'm gonna try to get up close and more info (pics too) before he/they/she takes off...

I'm finishing up the electrical and moving of the propane tank right now (pictures and commentary in the "Che" section to follow soon), but have been thinking about the trimming of the inside of the dodger.

http://downloads.c-2.com/photos/1202178012.jpg

I plan on making wood trim for the portholes, but can't figure what to do around the windshield. Any ideas?

Howz doin Kurt?
Thanks for the blue line!

That page works if you keep scrolling on down to the kite-cad view of a dodger on a coach roof. There it's mentioned that he's 'working on a book'. I came in on that piece of the page through a google door that is titled: Marshall Design: Hard Dodgers for cruising sailboats. Custom..
But, going back that way just now I see April 2007 logged on the entry. So that means he's already on the book when he's visiting us. That, of course, is just FINE! ASSUME IS THE MOTHER OF ALL FOUL UPS.


Tim, Thanks for the cockpit view of the CHE shed-water dodger. Actually it's larger than what I imagined, close on like that. Still, big fools like me need a smidge more width here and a poke more height there. Looks useful and dry and didn't take a thousand hours to build either!
Wonder what you have in mind as trim for the dodger???

Find myself feeling great affection for very unadorned Ariels and Commanders.
Yet I seem to be committed to going the opposite way!

Just examined the Marshall Plan 'Hard Dodger Black-Out' tip again. Post #52

First thought is that if we are in a construction stage of building the dodger the black-out for the rabbet or the surround can be colored epoxy. If the color is mixed into thin laminating epoxy it can easily be painted on with a small brush.

When you are doing the final dry fit and have the plastic window with its protective covers still on and it's fitted and snug in place over the openings - why not carefully score the protective sheet using the edges of the opening inside as the guide. Probably an Xacto knife using a flat round tip blade to track easy.
Steve is saying to make the cut 1/64th of an inch inboard of the edge. Not sure why.

Like Steve says: after dry fit you take it apart, peel-off the edge ribbon of protective sheet and scuff the rim where you want the goop to stick. The sil-thane hybrid probably says you don't have to prep the surface. I'm still of the opinion that this installation doesn't need to be structural with everything bonded into a monocoque. The plastic lights will have to be replaced sooner or later down the line. Installing it onto a less aggressive caulk or tape might still keep the water out - or keep the water out WELL ENOUGH - and make it easier to take apart later. Call it a gasket.

The problem is: that 7 years later the tube caulk you used will be as hard as a rock. And replacement of the plastic windows will look like a federal case. So it IS a no-brainer that you choose the new hybrid (locally it's LifeSeal) which promises long life flexibility with excellent UV and ozone resistance. Problem is: it's also an excellent adhesive.
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Or see it as a maintenance issue and use butyl. The butyl tape readily available from Copperstate Roofing Supply
http://www.bestmaterials.com
comes in various but limited thicknesses and widths. I chose 3/32"X1" at $5.35/50' roll with a paper release - because my flanges are 1". It's gray.
Available from McMasterCarr, pg 3361, Butyl-Rubber Sealing Tape. Black and 1/8" thick and only comes in 1 1/2", 2 1/2", and 8" widths. The 1 1/2" is $22.74 for 48'. Too wide for most overlaps and flanges. However it's readily cut with a putty knife and a straight edge*. If you press down on the wstraight-edge when cutting you'll get a preview of its stickiness. Both tapes are tacky on both sides, very limp and conformable. Can tease the width of it around a radius. Have to cut it for corners, but you can smooch it together for a seal.
Doesn't smell nor come off on the hands. There is no interior core like some glazing tapes have, so you can pull it out of shape. The stuff is legendary for staying pliable, supposedly gets stronger the older it is, and has similar UV and ozone resist to the hybrid silthane. It is also conceivable that the material, having no core can squeeze out under fastening pressure and over time. Having equal torque on all the fastenings probably keeps it stable.

Don't know that anybody has reported what it's like taking butyl-taped glazing apart after seven years in the tropics. Have to assume though that it's going to be an easier job, than the hybrid or p.sulfide, prying the glazing off and scraping out the rabbet. It's a gum-like caulk not an adhesive. I'm also using it for the cabin windows. And thinking about putting the hatches and dodger on with the stuff.

*On a slab-on ap, where the windows are not in a rabbet, the too-wide tape could be used anyway and carefully trimmed with a new blade after it's all together? Might work same way with a rabbet installation by merely trimming the too-wide away inside with a knife after its done? It's clean stuff, the tape, no solvents. The putty knife is used to 'separate' squeeze-out from embedded stuff. Silicone coated kitchen implements can be used, if you find the shape you want.
The tape is very sticky but in a wad can be used to clean up a surface of butyl tape pieces and smears by pressing the wad on it.
Butyl tape with a strip of material inside the butyl can be found. I would not use this stuff if you are depending on squeeze-out to create your gasket. Cleanup would depend on cutting the embedded fabric - which would be hard to do because you can't really draw a sharp knife through butyl with success.

[McMasterCarr are the quickest but often not the cheapest! In talking to self here see clearly now that the way to go is with the 1/8" black stuff. And after the installation is complete trim off the excess. Think better in 1/8" rather than 3/32"!]
[WAY LATER EDIT: Control squeeze out of butyl tape by inserting a washer into the tape over each fastening before you put the fixture or lens on the cabin side or deck. The washer's thickness will prevent total squeeze-out when tightening up the window, plate, or base.]

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In the wet installation:
The foam rubber dam probably got glued to the tube supergoo. It MIGHT be persuaded by passing the same Xacto blade between the foam and the edge of the rabbet.

imco - no dam butyl ebb
"Go easy, if you can't go easy, go as easy as you can." radio sign-off by Jennifer Stone

This one looks pretty nice. Not sure about the aesthetics with our stepped dog house though...

http://www.sailnet.com/forums/gear-m...rd-dodger.html

Mike, nice addition here.

Just for argument, the photo sez: Definitely homebuilt, DIY.
Nothing wrong with advertising homebuilt, Some designer pointed out that when making these additions the sight-line of the appendage should point to the stem fitting. They should tilt forward, if they are tall enough. I've noticed that this is good advice for hard dodgers that often make a boat look like it has a pilot house. Or extra cargo.

Soft dodgers which USUALLY don't confuse the boat's lines are often horizontal topped. But then the eye gets a discount when pram dodgers are a darker color than the boat. When in doubt, paint ANY dodger a darker color.

A hard dodger is the most difficult thing to add to a sailboat and make look acceptable. Some boats make it into the character stage where the skipper's personality tops the boat's and the amalgam is completely happy, or otherwise. Usually the color scheme is the give-away. There are boats that are too small or too large to obey this tradition.

Anyway, that the top of the dodger or any other large addition to the exposed deck/sheer of a boat, lines up with the deck at the bow, is a place to start from when designing something the critical eye will accept. Easy as drawing a line on the elevation plan to check it out.
imco It's a reasonable aesthetic that takes into account windage, greenwater and design. Streamlining tells a lot about a fish's lifestyle. Or a boat's, for that matter.
From that datum you makes your compromises.
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Downloaded an early '80s blackandwhite Cape Dory Yachts intro brochure listing all of their Alberg C.D.s.
Definitely designed to be a family of yachts, they each have features that every other has. Except maybe for the babys: the Typoon Daysailer and Weekender have the rounded rudder profile of the '60s A/Cs. The whole line sports the familiar full keel, soft cutaway forefoot and 'Constellation rudder'. (The babies might run aground alot - a round bottom rudder would be easy to get unstuck in mud, while a straight bottom constellator might be difficult to move.)
The no-doghouse coach roof in every case parallels the waterline emphasized with a trimline of teak over rectangular rounded portlights. Club foot jibs are featured. The larger yachts in the line are doubleheaded with short bowsprits.
None of Alberg's designs that I've noticed have shown even a hint of hard or soft dodger, or runabout wind-screen.
Maybe his later boats? I would have liked to see what the master would do with a dodger.