Bogging, Fairing, Highbuild, Roof

Enough roof

Posted by Paul

I am over the roof work and ready to move on. Dont get me wrong, I have really enjoyed doing the roof, it has been one of the most satisfying achievements of the build (big call, but I got some serious “you are in big trouble” vibes from so called professionals on this fix and have done it myself) but I am now keen to get on and finish the rear steps and get onto fairing the hulls.

Sanding the highbuild was not as hard as sanding the bog, except that in places I quickly sanded through the highbuild and was again sanding bog, but overall it was easier to sand. Mostly it was easier because I was on 120 grit paper. Having said that, even easier is still hard work. Especially on the hot days. Sweat just dripped off me, and quickly soaked my t-shirt. One day I had to stop. It was just too hot.

44 degrees

So plenty of pics not much more to say. The roof is pretty fair to look at, it still feels a little lumpy in places but you cannot see it, even with a glossy surface on. I wet the roof down numerous times to take a look at the gloss surface from various angles, trying to catch reflections of light to see if the surface was true. I cant see any problems except for tiny nicks and marks that fine filling will fix, and pinholes, also fixed with fine filling.

I have received a couple of emails from builders with advise, which is gratefully accepted and will be acted upon. For example I had a car body filler recommended to me, unfortunately I am still a bit skint until Jo starts her new job, so for now I am using cheaper car body filler on the pinholes but as soon as some money rolls in I will buy some of the Evercoat product, and also some advise that you can actually use a spatula and fill pinholes with highbuild. If there are any that I have missed on the second highbuild stage I might try mixing some up just to fill pinholes and see if it works, thanks Karel. Karel also suggested I wet the boat down and sand it wet, it stops dust and preserves the paper. I will try that on the 240 grit sand of the second highbuild coat. Check out the dust cloud each time I blow the job down after sanding a section.

roof highbuild dust cloud

Now that the window frames have highbuild in them I plan to put plastic over the windows to keep dust out of the insides. I have also had a perspex guy come and measure up for another quote. I have also chatted to a friend that has seen perspex bent over molds using heat guns and thinks I could easily do the windows myself. I am considering that too. Am having a really hard time finding a window tint that goes onto the outside of plastic windows, normal car tinters dont want to touch the job warning that it will bubble and wont last long. I am still sure I will eventually find the tint I want but for now, no luck. For those that dont know, there are a couple of cats out there that have silver tint film on the outside of the windows, one of them over clear perspex and this is the finish I want. The theory here (and according to one owner the practice works) is that being big windows, a traditional black tint window will heat up and transmit that heat through the perspex to the inside acting like a heater. Silver tint on the outside of the window reflects up to 80% of the heat and not being black also helps. So much so, that the owner that has silver tinted clear perspex reports that he can feel heat radiating under non tinted black perspex hatches but cannot feel it under the silver tinted windows. His only warning was to ensure I cove the window sealant over the edge of the tint film to stop any moisture getting under the edges and forcing its way along making streaks and bubbles. Other than that he fully recommends silver tinted clear over pre-tinted dark perspex.

Perspex also crazes after time in the sun, the better the quality perspex the longer it resists but eventually even good perspex (cast is better than extruded) eventually crazes. For those of you that have never seen crazed perspex, imagine a clear sheet has been rubbed with steel wool until it is no longer clear but opaque. Ultra fine scratches. Lots of them until eventually you cant even see through them. Tint on the outside will reflect away most of the UV and prolong the life of the windows. So this is what I am trying for. There are purpose made films for use on plastics, TintGard/PolyGard is one brand and I think 3M make another. But I cant find a tinter that uses them and understands the application on plastic. Any referrals gladly accepted. I have had one promising lead and will report on it if it progresses. As I said, I am also considering bending the curved windows myself, the price for the raw materials (clear 10mm cast acrylic sheets) is about half what the window quote will be. I might compromise on this one, buy the material myself, cut the windows myself and just pay the window guy to curve the corner windows. Again, I will report on the progress of this one as I get more info or work done, but any advise from anyone that has done or seen it done will be gratefully accepted. I am told that perhaps molding in an oven is better for evenness of optical quality and that attempting it with heat guns makes that less likely.

But back to where I am up to. As mentioned previously, most of the roof will be covered in either solar panels or non slip paint. Oh, on that, having sanded the first highbuild with 120grit the surface is very smooth and…..yep slippery. I have to be very very careful walking around up there now whereas my feet didnt slip before, evidence that non slip paint is going to be very necessary. Anyway, I hand sanded the entire roof with a curved sanding board made from a piece of 5mm foam with velcro attached to secure the paper. With both hands on it, it forms to the curve beautifully leaving just the tiny nicks and deeper sandpaper scratches that the highbuild did not properly fill (because they were too deep), the highbuild did fill very much of the sand paper marks as this pic shows:

roof first highbuild fills sanding lines roof first highbuild sand curved sanding block roof highbuild first sand through

And the pinholes that are magically revealed with a blow down. They are near invisible beforehand as the dust fills them. But the blower removes it again. So I got some supercheap auto body filler, 2 part stuff like I used on the forebeam. It sets enough to sand in about 20 minutes (but even set it still clogs the sandpaper) and is pretty sloppy, at least until it starts to go off. It sets rock hard and pretty fast, it is set in about 5 minutes, even faster than regular epoxy bog, so you mix small mixes. A lesson I learned on my first mix as I threw half of it out as it had set on my mixing board before I could apply it to the boat. Ironically, the mix I had mixed to about the same color as the pink bog.

roof highbuild pinholes filled before sanding roof pinholes filled roof pinholes filled 1

Other than sanding the filled pinholes and marks the only other thing that I did was apply another coat of highbuild. I have not yet sanded it. I figure there is only really one more sand with 240 grit and fill and sand of any more found blemishes and that will just about be it until topcoat. So the rest of the pics are of the various wet downs looking for unfairness and second highbuild pics.

roof first highbuild sanded and wet down starboard front 1 roof first highbuild sanded and wet down starboard front 2 roof first highbuild sanded and wet down starboard front 3

roof first highbuild sanded and wet down starboard front 4 roof first highbuild sanded and wet down starboard front 5 roof first highbuild sanded and wet down starboard front

roof first highbuild sanded and wet down roof first highbuild sanded and wet down 1 roof first highbuild sanded and wet down 2

In some pics above the window cutouts are in place, this was to show the perspex guy the molds and where they came from to ascertain if he could use them to make the windows, he could. He will make the windows oversize then once they are shaped they will be trimmed to the correct size, leaving 10mm all around as expansion space (the windows expand and contract again each day as they heat up and cool again). I will probably go for 10mm sheet leaving about 8mm of sealant bed for the to sit on and come out flush with the boat (except where I have had to bog fairly deep to fair the shape out, where they will be slightly recessed). I dont want the perspex to stand proud of the boat surface, so flush or slightly recessed is what I want.

I still dont have decent spray gear, I have a compressor but dont have a gun, or an inline water filter and my compressor is very small. So I decided to roll the second layer of high build on. It went on much easier and used a lot less than the first coat but I still wish I had of sprayed. Rolling is so uneven. Having said that, I am really only concerned now with a 100mm area around the edges of each part, around the edges, the windows, the hatches and the bottom 100mm or so of the solar panel pads. All the rest will be covered with non slip. And of course, even or not, it all gets sanded again anyway so it does not really matter, but I would have liked to have sprayed it.

Jo and I went to Singapore for a week (2 weeks ago) which burned through my cash reserves for now so more expense will have to wait another month or so.

roof highbuild second coat starboard front corner 2 roof highbuild second coat starboard front corner roof highbuild second coat starboard rear corner

roof highbuild second coat stern roof highbuild second coat forward roof highbuild second coat port front corner 2

roof highbuild second coat port front corner roof highbuild second coat port rear corner roof highbuild second coat starboard front corner 1

All up 4 months now on the roof but I am fairly happy with that. I have a couple of side projects I want to work on next, making a radar dome tower is one of them and getting the outboard wells working is another. So I might have a little rest from fairing for a couple of months then get back into it with the hulls and decks once I have the rear steps in.

Its getting exciting around here. I have applied plastic to the windows to try and keep fairing dust out of the interior of the boat. I want to start on some of the interior finishing but the dust is a problem, hopefully this will fix it. Its exciting times, getting quotes on windows, progressing with fairing and stuff like upholstery (I have been waiting for a mate to do the job, and the deal with mates rates is you get your job done when it least inconveniences them, fair enough, and linings (Terry bought some fine grain cork sheet for his steps and I got in on the deal, I will cover the steps and seat tops -3mm and cockpit floor -6mm with it, very nice stuff, just deciding on what finish I will apply to it, I am leaning towards oiling it as I want to retain its soft, cool underfoot feel and non slip properties which I believe is lost if you apply a clear coat over it).

 windows plastic sealed windows plastic sealed 1 windows plastic sealed 2

As many of you know, having followed my build for that long (yes sorry about that, I will wrap this up as soon as I can), the boat and blog started out as mahnamahna. I have just had the entire content from mahnamahna added to this Yikes blog making the entire history all appear here. Eventually I will also index it with reference to the type of work being done at the time so you can look things up by typing say forebeam and the forebeam related blogs would appear. Although this website looks very professional, I am only an intermediate computer expert at best, I have no idea for example how to read or write html. I use programs like wordpress that make amateurs look like pros. But every now and then I have problems I cant solve, or jobs that are just too big. For that I have a website guy that does fantastic work for me. I want to recommend him. His name is Paramjeet and can be contacted here: Web Apps Interactive.

One final word, thanks for all the comments and advise the last few months, please keep them coming, I really enjoy hearing from you and benefit greatly from the advise. If you dont want them published I wont but would love to hear from you either way.

You May Also Like


1 Comment

  1. Karel Michielsen

    Can’t remember whether I gave you a copy of my build cd, anyway here’s a link to a pdf version I did which works well on a tablet.

    Plus, when you are fed up with building, here’s a link to what comes after.


    PS I used cork in the hulls, stuck it down with contact which works well and sealed it with Tung Oil which is quite servicable, clean well and is very slippery when crew spills cooking oil on it

Comments are closed.