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gjdale

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  1. John, Thanks for looking in, and for the question. The answer is, I have absolutely no idea! I don't understand why a chopped mat would be less weight - at 2oz. this cloth, while not the lightest available, is still pretty light. As for layers of resin, from what I've read (and experienced so far), three layers seems to be the common wisdom for "minimum" number of layers of resin: first layer to adhere the cloth to the substrate, second layer for general filling of the weave, third layer for final filling of the weave. Of course, more layers may be necessary, but I can't see fewer layers being used, unless using something like the method mentioned above by Pamela. I have to say, that with two layers of resin so far, the hull feels nice and solid without feeling heavy.
  2. Thanks Mark, This is only the second coat of epoxy, prior to sanding. It will get one more coat of epoxy (at least) to fully fill the weave of the cloth. Then another sanding followed by several coats of spar varnish, which will be sprayed on. After the epoxy and before the varnish, I will apply the vinyl artwork so that it gets sealed under the varnish, just like on the full size version.
  3. Thanks for that tip Pam - though a little late to be used for this build. I just had a quick look at the Peel Ply and while it looks good, it does have some limitations. I found this on one suppliers' site (http://www.clcboats.com/shoptips/epoxy_and_fiberglass/peel-ply-release-fabric.html): "We’ve written before about the challenge of getting smooth surfaces with epoxy and fiberglass. It takes at least three coats of epoxy to “fill the weave,” and then hours of sanding to get to a surface finish that’s ready for paint or varnish. What if you could skip two of the three coats of epoxy and most of the sanding? Well, you can. Sometimes. “Peel Ply,” also called “Release Fabric,” is a synthetic cloth that you drape over your epoxied surface as the epoxy sets up. Once cured, you can peel off the fabric, and what’s left behind is a perfectly smooth surface that’s ready for a quick sanding, or for the next round of epoxy. No runs, no sags, no low spots. Not only is the surface under the peel ply nearly perfectly smooth, it actually has a texture that improves adhesion if you have anything else to stick to it. We use it here whenever we can. Like all things, there’s a downside to this miracle. Peel ply isn’t stretchy like fiberglass, so you can only use it on really flat surfaces. Hatch covers, for example. Or the components of a stitch-and-glue boat that haven’t been assembled yet, but which are pre-coated in epoxy and/or fiberglass prior to assembly. If you try to get peel ply to conform to curves, you might end up with wrinkles in the peel ply. And the peel ply will cast those wrinkles in solid epoxy, leading to a horrifying sanding session." Nevertheless, an interesting concept and useful tip thanks Pam. Maybe next time.....
  4. Thanks for all the kind comments and the likes. It's been a while since I updated this, but not because I haven't been making progress - it's just that this is a slow process! Anyway, here is a little update of sorts. Fibreglassing the Hull Having declared a win with the trials, I commenced the process of glassing the entire boat. Although the instructions say not to bother glassing the bottom of the boat as it is plastic (Sintra), I decided to take the precaution of glassing it anyway. This is a slow process overall as it is necessary to work on only one surface at a time and to allow it to fully cure before proceeding to the next surface. Here is a couple of in-progress shots of the first phase – applying the glass mat with the first layer of epoxy resin. It followed much the same path as the trials (happily). I began with the bottom, cutting the glass mat slightly larger than required. In hindsight, I could have trimmed this much closer prior to applying the epoxy. The resin was applied by pouring a small amount into the centre and spreading outwards with a rubber squeegee. Care needs to be taken to avoid any drips landing on the overhang and sticking itself to the hull sides – don’t ask how I know this! The sides were next: Here is a close-up of the side, showing just how much of the weave of the cloth is visible at this stage. Remember, trust the process! Once the epoxy had cured (overnight) the cloth was trimmed back using a single edged razor blade: It’s not clear in the above photo, but I found that with a little caution I could run the blade right along the adjoining edge, making final clean up with some 80 and 120 grit sandpaper that much easier. Speaking of clean-up, this next shot shows the side after it had cured, been trimmed and lightly sanded with both 80 and 120 grit. The purpose here is to remove any high spots and create a smooth (but toothed) surface for the next layer of resin. As you can see in this photo, it looks pretty ugly. There were quite a few “blemishes” where the cloth may have lifted slightly during the initial coating. Remember, trust the process! Once both sides had been done, the transom followed, and finally the deck. All went pretty much as shown in the above photos, though perhaps with fewer flaws as I gained experience. Then it was time to apply the second layer of epoxy. Again, it was a case of doing just one surface at a time, keeping that surface as horizontal as possible to allow the resin to level and not overflow the edges. As per the trials, the second coat was applied with a stiff brush, care being taken to ensure that the “oopses” from the first phase were filled in by firmly stippling the area with the brush until the oops disappeared. I didn’t take any “in-progress” shots of individual panels, but here are a few on completion of the second coat of epoxy. At this stage, the epoxy has fully cured but no clean up sanding has been done. This will be carried out prior to applying the third coat of resin. However, I thought it useful to post these overall pics to show just what a difference the second coat of epoxy makes. It has almost entirely filled in the weave of the cloth and the “shiny-ness” gives an indication of what is to come. It’s very difficult to take pictures of a highly polished and reflective surface, but I think you can get the idea. And yes, you can see a slightly uneven “wavy” effect on the surface – this will come out with the between coats sanding. Hopefully, one more coat of resin will be sufficient prior to commencing the finish coats of spar varnish. If not, we’ll keep going until it is! It will be a little while before the next update as I'm travelling for work over the next couple of weeks.
  5. Hamilton, Some good news and a good decision! As far as debonding goes, DO NOT use water - it won't do your plywood any favours. Instead, use Isopropyl Alchohol. Either paint it into the joints, or soak a paper towel in it and clamp that along the joints for about 10 minutes. Depending on how much PVA you used, and how long it has been set, this should do the trick fairly easily. IF not, simply repeat until it does. As the alchohol evaporates fairly quickly, there is less chance of distorting the plywood. If you are not familiar with Isospropyl Alchohol, it is sometimes sold as rubbing alchohol but we warned that it comes in diffenrent concentrates. Some of the rubbing alcohol is 50% water - you don't want that one. I get mine from the local hardware store and it is 90 or 99% alcohol commonly used for cleaning computer keyboards and the like.
  6. Tough break Hamilton. For what it's worth, I'd go with the harder option of re-doing the keel. If you don't, it's going to bug you forever. A little extra cost, and a little extra time now, vs regret at leisure for a very long time. Good luck with whichever option you choose.
  7. Hey Bill, This is why spreadsheets were invented my friend! Once you know the conversion factor (1.333 in this case), let the spreadsheet do the heavy lifting and give your brain a rest. Then you can concentrate on what you are bettter at than the computer - making sawdust!
  8. Lovely work, as always, Bob. Your extra details and replacement parts make all the difference!
  9. Thanks Sam. I used thick CA to bond the planking to the Sinatra. It required a LOT of kicker! That's just one more reason to coat the whole thing in a fibreglass jacket - I don't really trust the CA bond strength over time. If I were to do this build again, I would replace all the Sinatra subplanking with timber - either light plywood sheeting or balsa strips. The Sinatra is supposed to be a weight saving, but I think it introduces more problems than it solves.
  10. Thanks Slog and Carl. Slog - it was watching the Paul Budzik videos that sent me down this path in the first place. I can thoroughly recommend the Airbrush Megastore - check out their website. Great friendly service, reasonable prices, prompt delivery, and good advice. Go on, you know you want to............. Carl - that gun has a 1.0mm needle as standard but also comes with a 1.2mm in the package. With the recommended spraying pressure of 40psi, you can cover a large area very quickly indeed. To answer your question, I made up a batch of about 50ml and used only a fraction of it. I was able to decant the leftover back into a glass container afterwards. Not sure how well it will keep, but we'll see.
  11. The Fibreglass Trials As I have never attempted fibreglassing of anything, ever before, I decided it would be prudent to do some trials before “going live”. I read a number of “how-to” guides, and found that the one by Pat Tritle on RC Groups Forum was probably the simplest to follow. For anyone that has never done this before, my advice up front is “trust the process!” It is really quite a simple process, but if you don’t know what to expect along the way, it is easy to think that something has gone wrong. It hasn’t (probably…..) Materials used for the test were exactly what is planned for the actual job, and comprise some 2oz. fibreglass cloth, West Systems Epoxy Resin (No 105), West Systems Hardener (No. 207, which is supposedly designed for use with a clear finish), Feast Watson Spar Marine Varnish, and Krylon Premium “Copper Brilliance” (rattle can spray paint – for the below the waterline colour). I made up two test pieces of roughly three inches by four inches Sintra (the plastic sheeting that also forms the sub-planking). One of these was planked with Mahogany strips just the same as the sides of the hull, and the other was left ‘au-naturale’, the same as the bottom of the boat. The first step was to cut some cloth a little over-size and drape over the test pieces. The Epoxy was mixed according to the West Systems directions (a three to one ratio by volume in this case). A lot of folk say to thin this mix by adding up to about 20% denatured alcohol (methylated spirits here in Australia). The reason given for this is that it supposedly helps the epoxy penetrate the timber substrate and also reduces the chance of bubbles in the mix. The West Systems website advises against thinning and states that strength is significantly reduced by thinning. I decided to stick with the West Systems advice and did not thin. I applied the epoxy by pouring a small amount onto the centre of the test piece and then using a hotel room keycard (same size and shape as a credit card) as a squeegee to spread the epoxy and press it into the weave of the cloth. The important part of the process here is to ensure that the epoxy gets into the weave all over, and right up to the edges (though excessive over spill along the edges is to be avoided). Here’s what the test pieces looked like after this step: Once the epoxy had cured, the excess cloth was roughly trimmed back with a single edge razor blade, and then block sanded with 80-grit sandpaper to the edge of the test piece. The surface was then lightly sanded with 120 grit to remove any high spots. Care needs to be taken here not to sand through the glass itself. Note that the weave of the cloth is still visible here. Don’t panic! Here’s another couple of shots to show clearly how much of the weave is still visible. A second coat of epoxy was then applied, this time with a stiff brush. The aim of this coat is to fill the weave of the cloth. This is what makes the cloth seem to totally disappear. Once that coat had cured, it was again lightly sanded and a third coat applied. The aim here is to get a smooth surface with the weave of the cloth completely filled. If it isn’t to your satisfaction you can keep adding more layers until it is, but I stopped at three coats for the purpose of this trial. Here is what it looked like after the third coat and wet-sanding with 240 grit. Not sure if the variation in “shiny-ness” is due to light reflections (which is what I think it is), or whether that section was still wet from sanding. Again, the aim here is a flat smooth surface – don’t worry about “shine” at this stage (remember, trust the process!). At this stage, it is time to start adding the clear coat (or colour in the case of the bottom) I brushed on one coat of Spar Marine Varnish on the planked test piece, and then lightly wet-sanded with 1200 grit. On the unplanked piece, I sprayed one coat of Copper from the can, followed again by lightly wet-sanding with 1200 grit. My observation at this point is that the Copper paint probably needs at least two coats, and probably no sanding on the final coat. For the remaining clear coats, I wanted to spray the varnish. I thought that a standard airbrush with a 0.35mm needle might not be the best approach, so after seeking some advice from the Airbrush Megastore (based in Adelaide), settled on this as my weapon of choice: The directions for the Spar Marine Varnish say to thin by 10% with Mineral Turpentine for spraying, so that is exactly what I did. Oh boy, what a piece of kit! Took no time at all to lay down a good coat of varnish and I can see that when I’m painting the whole boat, I will be praising my good sense in purchasing this! As the varnish is thinned just that little bit, it also levels very well. Here is a picture of both test pieces having had one coat of varnish sprayed on. It's really difficult to capture the gloss shine on these pieces in a photograph. You'll just have to trust me on this. The copper painted piece shows both some variation introduced by sanding, and also a blemish where the initial epoxy coats did not quite level. Lessons for the “real thing”. And finally, here is a shot of the planked test piece next to the un-treated hatch cover. Notice how the grain is much more apparent after glassing and varnishing, as well as being a slightly richer colour. At this stage, a few extra coats of varnish would be followed by further shine imparted by very fine sanding and polishing. I'm not going to bother with that on the test pieces as the purpose of the test was purely to get comfortable the fibreglassing process. Okay, on that basis I think I’m ready to declare a win and proceed with glassing the whole boat. I’ll be back once that is well and truly underway.
  12. Another interesting update Slog. Safe travels and we'll look forward to resumption of play in due course.
  13. I'm reserving a front row seat for this build once you start it Mike. On the question of fittings, I have read where some guys have done there own copy chrome plating. The DIY plating kits are relatively inexpensive - look for Caswell plating kits.
  14. Okay then! I've shifted my chair, now in the front row for a close up view. Can't wait to see what you do with this Bill.
  15. Congratulations Mike - I'm sure you will enjoy this adventure. I look forward to following your build log in due course.
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