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Results 91 to 105 of 233
Thread: Nice rowboat, nothing fancy.
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3rd December 2013, 07:37 PM #91
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Well, I got the bits that needed masking masked (to keep resin off) and got the glass and the peel ply cut to shape. At the moment they're just sitting on the boat, with a plastic drop sheet over them in case bats or birds drop bombs during the night.
Tomorrow afternoon, barring misadventure, I'll glass this sucker, and find out if this here new-fangled peel ply stuff is the duck's nuts or straight from the pit of Hell. hey ho.You know you're making progress when there's sawdust in your coffee.
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4th December 2013, 02:29 AM #92
On two of my newest designs, both glued lapstrake, this is the way I do the bottoms, which also both have a flat bottom panel, eliminating a centerline seam. I cover the bottom panel and the garboards with fabric, including the lap. I razor the fabric flush with the top of the lap, when it's in the green stage, knowing when I glue the broadstrakes in place, I'll have a tiny little fillet along the top of the lap on the inside to cover this thickness of fabric and goo. A lot of folks don't "dress" this portion of the lap but I do, to help shed water that collects on top of them, inside the boat. Of course, this trick wouldn't be very attractive on a brightly finished interior, but I tend to paint plywood, rather then varnish it, as the usual wild grain is offensive to my eyes. I suppose you could add pigment to this mini fillet (more like a smear of goo to protect the end grain) to match surrounding wood color, if you wanted a bright finish. The prototype of one of these recent designs was done this way, in fact the whole boat was, leaving not a drop of paint anywhere, so inspection of the assembly, joints and other details could be easily made. My only logic for this (no paint thing) was to sell the prototype and a boat that hides nothing under paint is easier to sell, I've found, then one that's got putty and paint everywhere. Naturally, it depends on the buyer, where some may want a turnkey, with little to do, while others may desire to make it "their" boat with paint and other finishing details.
My point of this post is, I don't think your hard point concerns are warranted (though understandable) in this assembly, mostly because of the fabric weight used. You'd need a fair bit more material to create a "hard point" over the stringer or inside the lap, so I wouldn't be too concerned, though the belt and suspenders approach can't be discounted either. From what I see, you're doing a well thought out and neat job of this build, including the inevitable frustrations that come with any build.
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4th December 2013, 07:12 AM #93
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Makes sense, but I have an aversion to bog fillets anyway. I'm not that worried about water sitting on the stringers as the boat will be stored under cover and will be light enough to invert easily. Storing it upside down will keep the bird poo where it's easier to wash off, and will allow for excellent drainage.
With the possible hard point, what I was thinking was if I glassed after the broadstrake was on it'd be more of a PITA because of having to come up to the lap, and the glass stopping right next to the lap (on the outside of the boat) didn't make sense in engineering terms. So, better to run it part way across the stringer. Easier and stronger.
But yeah, if I was painting that area on the inside I'd just run the glass all the way across the lap like you do.
Incidentally, the rebated stringers I'm using do have one thing going for them. The planking, or the patterns for it, sit nicely against the rebate. This is quite convenient when fitting planks or patterns.You know you're making progress when there's sawdust in your coffee.
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4th December 2013, 05:22 PM #94
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Ok, so the verdict is in. This peel ply stuff isn't straight from the pit of Hell, but not really a duck's nuts sort of thing either. Well, not both of them anyway.
At the moment, if asked to summarise it, I'd say that peel ply is the left testicle of a basically well-intentioned duck that happens to have sold its soul to Satan.
Would I use it again? Maybe, depending on how I felt at the time about providing employment for ducks of that persuasion.
I got the glass down fine, even though it's been years since I did this sort of thing. All I did was the usual stunt: pour the resin along the bottom panel and spread it around with a squeegee, with a little bit of help from a steel roller here and there. It was the lovely "honey on toast" look everywhere and sitting nicely. No problem.
So then, being an intelligent lad who is susceptible to the marketing of anything new and techy, I got the peel ply out. I really had been an intelligent lad, and had rolled the peel ply (already cut to shape) onto a 1.5 metre cardboard tube so I could just roll it out along the boat. That worked ok, but it didn't go down without lumps and wrinkles.
I could have had fewer lumps and wrinkles if I'd split the peel ply into side and bottom panels like I was thinking of, but I didn't. Since it had been sitting nicely just draped over the boat in one go during the dry fit stage, I left it all as one panel. This may have been a mistake. OTOH, I doubt I would have had time to deal with three separate panels anyway.
Even with Bote-Cote's slowest available hardener (Tropical) I was running into trouble with the first batch of resin starting to kick off by the time I decided to leave things before they started getting worse. Sometimes you have to make that call.
One thing I did notice is that the peel ply doesn't work like glass cloth. Since it's a very lightweight polyester, it stretches. The wrong way. Naturally, it does this when you don't want it to and that puts more lumps and wrinkles in. This makes it a bit of a bugger to roll the bubbles out. Also, you have to add enough resin to totally wet out the peel ply, because otherwise you run the risk of starving the glass underneath. All things considered, I don't think it saves resin, although the glass laminate should be more compact.
I think it has turned out pretty good, and it's perfect in places, but it sure isn't perfect everywhere. I will have some work to do to clean up the mess once I ditch the peel ply. I'll be doing that as soon as the resin is at the "can dent with fingernail" stage (tomorrow morning) because I don't want to deal with it when the resin is rock hard.
If there had been two people who both knew what they were doing, the job would have been a lot easier and probably would have given a better result. With a bit more practice, and possibly chilling the resin and/or selecting cooler conditions, and with splitting the peel ply into three separate panels (sides and bottom) to make getting rid of wrinkles easier, I could probably get it pretty slick by myself.
I will say though that starting at 3pm does make for a good job with regard to gas out. There was hardly any at all. I probably should have started around now (5pm) and gained myself a little more working time.You know you're making progress when there's sawdust in your coffee.
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4th December 2013, 10:41 PM #95
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Ok, update. The resin has now reached the stage of being a tad rubbery but basically set. So, I stripped off the peel ply to see how big a disaster was waiting for me.
It's actually not that bad. About two thirds of the total surface is looking immaculate. The Bote-Cote peel ply has a very fine weave, and a thick primer could pretty much go straight on.
There is going to be a bit of filling required here and there, where the peel ply bubbled and the weave of the glass is showing, but the areas involved aren't large.
I'll also need to get rid of some waviness caused by excess resin under the peel ply, but the good news is that the glass under the excess resin appears to be sitting nice and flat against the plywood. I knew I'd done that bit right, but it's nice to see the glass didn't float or wrinkle later when the Great Peel Ply Bunfight started.
So, that means tomorrow I get busy with a scraper (again) and a fine set plane (not necessarily in that order) and knock that wavy surface down to something pretty flat before the resin goes rock hard. It'll need a bit of final sanding too, of course, after the resin has cured hard.
On the basis of this assessment it looks like the duck has grown a second testicle and repented of its sins, although its behaviour is still not exactly saintly.
If anyone is thinking of trying peel ply on a largish surface, and hasn't used it before, just make sure to think things through before starting and get a system worked out.
Also be aware that the peel ply itself is not at all forgiving to work with. Unlike glass, where you can fairly easily roll lumps flat, peel ply has a strong tendency to get worse very easily. You want to get it on totally smooth and exactly in the right place at the beginning. If you can achieve that, the results should be excellent. If you can't, you may not save any work over doing the job without peel ply. If you get things really wrong, you'll be in for a lot of extra work.You know you're making progress when there's sawdust in your coffee.
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5th December 2013, 03:49 AM #96
Many of these techniques are a bit like sex. Your first attempts result in barely pleasing yourself, though after some practice and maybe a little instruction, you might be able to please a prom date.
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5th December 2013, 07:18 AM #97
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Oh I never had a problem with sex. That went just fine for me and the date. It helps if the date is experienced, and if both of you are determined to have a good time regardless.
Peel ply is a lot trickier. However, I can definitely see its potential. I can also see why some people swear to never touch the stuff again. I would not recommend peel ply for a job like this if the person doing the job had no experience in glassing a hull. They'd get themselves in a hell of a mess.
What I ended up with is shown in the pix. First pic is a close up towards the bow. It's a damned nice surface, and most of the boat is like this.
Second pic is the worst section, just forward of the midship frame. This wont be too bad to deal with. As mentioned, it's just excess resin sitting on top of a good glassing job, and I'll be using cutting tools for the worst of it because they give me better control when going from this towards a flat surface, and because they generate no dust (which is important given the resin is still at partial cure).
Doing the whole thing with abrasives would be more hit and miss on the fairness, with the likelihood of sanding into the good sections too much. If I do this right I should be able to completely avoid generating any fibreglass dust, and wasting any strength. OTOH, I wouldn't recommend a plane and scraper for anyone who wasn't confident using them for rather tricky work.
Third pic is a small area more towards the stern. This shows where bubbling in the peel ply left the weave of the glass exposed on the surface, with slight ridging of the resin around the bubble. These are only a minor nuisance. I'll just knock things flat around the divots and then fill them fair.
All things considered, this time around I haven't really saved myself any work. Applying the peel ply still counts as work, and I have some cleaning up to do. OTOH, the work I have to do now isn't that unpleasant and wont take all that long.
Having thought about it some more, if doing the same job again I'd use peel ply again, and just revise my approach slightly.
If anyone is wondering, all up this job used about 1.5 litres of resin. That's for 6oz/200gsm cloth and peel ply over an area of around 2.8 square meters (30 square feet in Jackson, Mississippi). Given the amount of excess resin in this result, I'd say that you could get it down to 1.2 litres easily enough, and possibly down to 1 litre if everything went perfectly.
Total weight added to the boat will be less than 1.8 kg (4lb), which isn't much for the extra oomph it gives.You know you're making progress when there's sawdust in your coffee.
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5th December 2013, 01:35 PM #98
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I got on the blower with the bloke from Boatcraft Pacific and had a bit of a chat about this. Apparently they make a fourth hardener (they call it "Equatorial") which is not usually stocked and is not listed on the Bote-Cote pages of their site.
This is quite ok to use in the 25 degree and up range, and gives quite a lot more working time than the Tropical hardener. If I'd had that stuff, it would have been a big advantage yesterday. It's very rare for anyone to complain about having too much work time available.
The catch is that it isn't a standard stock item, and is only made in batches when there is sufficient demand for it. If anyone is about to tackle a similar job in our Australian summer, I think it'd be worthwhile to find out when they're likely to be making another batch of Equatorial hardener, and try to get your hands on some.You know you're making progress when there's sawdust in your coffee.
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5th December 2013, 11:02 PM #99
Yeah, cure rates can be prickly. I use a special super slow from my supplier and have to buy significant quantities of it at a time. I use it nearly exclusively now, using heat to make it kick off in cooler weather, which is a bit of a relative term to me, where 50 (10 c) would be cold (I ain't going outside) and the mid 80's (29 c) being very common most of the year (6 months) and the summer (3 months) being about 95 (35 c). I also have to do larger goo runs than most, using several gallons at a time, so working time is mandatory. We're in the coldest month of the year for us, so my super slow doesn't kick off below 70 (21 c). This forces me to use heat, which often is just a tent over a progect with some space heaters inside for several hours. I just resurfaced a 200 sq. ft. (18.5 sq. m.) deck for a fellow and fortunately it was in the low 80's, but working such a large area in one shot requires working time, especially if you're doing extra stuff, like bagging. I still tented the goo overnight, because I wanted it hard, not gummy the next day.
Now that you've played with duck balls from hell, would you do it again and how will your techniques differ? I don't use a roller on peel ply, just a plastic bog applicator or sometimes a squeegee on very compound surfaces. I almost always work from the center out, pushing resin as I go. If I have to work from an edge to an edge, I'll place some protection on the edge I'll be pushing resin towards, with a bit of bleeder cloth or even just some paper towels taped there, to catch excess resin. With practice, you'll find you can nail down the amount of resin you need, so the feeling of guilt about the waste is greatly minimized.
I also don't actually use "Peel Ply", but just buy a common fabric called Rip Stop (polyester taffeta) from the local craft store. There are two types and to prevent contamination isues I get the stuff marked "virgin", which hasn't any finishing chemicals on it, that sometimes can screw with the finish. It's cheaper and a lot easier to get. One of these days, I'm going to get a yard or two of several polyester fabrics, with various denier and weave arrangements and test them for a substitute, in the hopes I can find a more flexible product with a tight weave. This would solve a few issues with peel ply.
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6th December 2013, 07:44 AM #100
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Yup, I'd do it again. The things I'd do differently can be split into two facets: resin and technique.
For resin, and assuming Bote-Cote, and assuming the same job (bottom and garboards on a 19 foot boat):
If I was working in the same conditions as the other day, which was ambient around 30 C (86 F) at a guesstimate, I'd start later in the day just to get a little more temperature drop. I'm building in the carport, which has crap lighting and massive bug invasion after dark, so getting things wrapped up by 7 pm was a consideration. I could have started at 5 and still easily made it by 7. That might roughly knock 5 degrees off the average temperature during the bunfight, which makes a big difference to gel time. Tropical hardener at 30 C has a nominal 40 minute gel time, and it jumps to 70 minutes at 25 C.
I'd also use Equatorial hardener if I could get it. It's not recommended below 20 C, but by the time the temperature dropped that far the resin would have begun kicking off anyway, and if only building for myself there'd be no tight schedule the next morning.
One other thought I had is chilling the hardener. This is not something I'd automatically do next time, but might be worth considering. The Bote-Cote hardener has a fairly low viscosity, while the resin is much thicker. If the resin is at 30 C ambient and the hardener is refrigerated to standard household fridge temperature of 4 C, when the two are mixed together at Bote-Cote's 2:1 resin:hardener ratio that should drop the temperature of the mix by around 9 degrees C (assuming equal latent heat for resin and hardener, which may not be true) to around 21 C.
Obviously this is going to be a very short term temperature drop. Once the resin is spread thinly over the hull it will quickly get up to ambient temperature, but a trick like this could gain an extra 5 or 10 minutes of work time for almost no extra effort. It'd certainly slow down any initial reaction during thorough mixing, which may not a bad thing.
One possible catch is that it might introduce condensation into the mix. I don't think that would actually be a problem for the smallish mixes I'd be using, but it could be tested easily enough. I might also invest in a thermometer and take some temperature readings for the time of day in question, so I have more of an idea what I'm up against, and how to maximise any advantage.
For actual layup technique:
I'd do the initial glassing the same old way: pre-cut the glass and tape it in position, then just pour the resin along the centre of the bottom and spread it with a squeegee. Not much else you can do there. The Bote-Cote web pages recommend first rolling out a wet coat of resin, then placing the glass on top of that. There is no way I would follow this advice as doing it that way is a nightmare. It's much better (IMO) to position the glass dry and then wet things out. It works, and it's a lot less hectic.
For the ends of the boat, where the glass has to be wrapped around stem and sternpost and lapped over itself, I'd have a stapler ready to go with some non-ferrous staples. That would mean the glass could be wrapped around and instantly whacked into compliance, which would save a couple of minutes at each end. Naturally, I'd have some handy solvent to keep the business end of the stapler from death's door.
For the peel ply, and assuming Boatcraft Pacific's peel ply (the only stuff I'm familiar with) with this sort of shape (flat bottom and two garboards) I'd definitely split the peel ply into three panels. This means each swath of peel ply only has to fit a simple developable surface and does not have to drape around any corners. I'd want that, because as I mentioned this stuff is not at all forgiving to work with.
The bottom panel (peel ply and boat) would have the centreline clearly marked on it, so it could be rolled out accurately. Each of the three peel ply panels would be wrapped around a cardboard tube or similar, so it could be easily rolled out. I would check that it was going down flat on the way, and smooth it if necessary.
It might be worth hot knifing the cut edges of the peel ply, just for belt and braces. Getting it too neat wont hurt.
I only bought 3 metres (10 ft) of peel ply and joined it for length. It comes 1.5 metres (5 ft) wide and the width I needed was a bit under half that, so I went cheapskate. Since the stuff is so cheap, I might just buy a full length next time. If I was joining it for length I wouldn't just tab it together with a few bits of tape like I did this time. I'd use masking tape full width, just so the peel ply didn't have any tendency to pull into funny shapes under tension. The tape can always be removed once the ply is in position.
For resin application I was just using a "squeegee" I'd made out of an offcut from a 3mm MDF cover sheet. This works well. It's a bit flexible, but not too much. It's real cheap too. Labour cost was horrendous: a few cuts with the drop saw and a few minutes hand sanding the edges to a nice radius. I also had the standard ridged steel roller for any recalcitrant bits.
Working from the centre out makes sense, and is what I was trying to do anyway. What I did find was that since this time the ply went down lumpy as f***, I had to get inventive very quickly to get some semblance of order (sound familiar to anyone?). Using the steel roller diagonally, from the chine down to the garboard's top edge, was pretty effective in persuading the ply to behave.
I like the paper towels idea. Might try that next time.
Personally, I wouldn't try using peel ply on a compounded surface until I really had the process sorted on simpler surfaces, and preferably with at least two people who knew what they were doing. Adding compounding into the equation is bound to compound the potential for disaster.You know you're making progress when there's sawdust in your coffee.
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6th December 2013, 09:57 AM #101
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Thought of something else.
Bote-Cote make their TPRDA additive, which is recommended for initial "saturation" coats on bare timber. This is apparently based on a solvent-free low viscosity epoxy. It's not the old dilute-the-crap-out-of-it-with-solvents deal that typified things like Everdure.
AFAIK, TPRDA has no adverse effects on moisture resistance, or on other mechanical properties of the cured resin (would have to double check the latter). Bote-Cote resin has a thixotropic additive to make it more well-behaved when building up surface coats on sloping or vertical surfaces. However, this isn't really applicable when using peel ply over the surface. Any resin under the peel ply is going to stay put anyway. Any resin on top of the peel ply is just waste.
So, it may be worth experimenting with using the TPRDA simply to thin down the resin for laminating with peel ply. This should enable easier wetting out with no obvious drawbacks. Wetting out the glass itself is easy, but the peel ply is translucent when wet out rather than transparent like the glass. This makes it more difficult to detect resin starvation under peel ply*, and the peel ply does tend to draw in resin to wet itself out, so a thinner resin that will wet out with less hassle might be useful.
*Speaking of resin starvation, my finished result was borderline in some areas. What has happened is that the tiny squares between weft and warp in the glass cloth are empty of resin in some places. This was a combination of being pushed for working time due to the resin kicking off, and due to the difficulty of seeing dry pinholes under the peel ply. The result is acceptable though, since the actual glass is fully wet out and firmly stuck to the timber. It's only the gaps between the actual glass that are hollow. This just means scraping a thin coat of bog over said areas. I'll be using a talc bog since I don't want it super soft anyway (it's only filling pinholes in a solid epoxy surface) and talc is what I had handy. There's no way of getting those pinholes sanded, and the resin was past any reasonable expectation of a chemical bond, but it should be fine anyway. Damned if I'm doing the whole thing again.
ETA: I should note that I didn't use TPRDA for my initial coats onto bare timber, even for areas that were only being epoxied without glass. "Epoxy saturation" is largely mythological anyway as the resin wont go much into the surface regardless of what you do. The standard resin sticks really well to bare wood, and I'm not at all worried about the bond there. This is my own judgement call though and I wont hold Bote-Cote responsible if it goes tits up (but it wont).You know you're making progress when there's sawdust in your coffee.
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6th December 2013, 11:37 AM #102
I commonly use TPRDA for the initial coat on ply. As it is thinner, it must aid in penetration. It is also supposed to have 'preservative' properties and while I haven't looked into this, it can't be a bad thing.
I also used it once on a subsequent coat when I wanted a thinner mix. The cure time was substantially slower - so much so that I haven't done it again. Again I haven't looked into it but I was concerned that some property may have been compromised.
Mark
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6th December 2013, 11:46 AM #103
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Fair enough. I haven't asked the BC people about any possible compromise in resin properties yet. It's something I'd check before going ahead and using it as a general purpose thinner. The standard resin is workable for laminating at these temperatures anyway.
You know you're making progress when there's sawdust in your coffee.
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6th December 2013, 12:36 PM #104
Without getting into a highly technical battle, the depth of epoxy penetration (according to tests) has little bearing on a coatings waterproofing abilities. Simply put, it's the quality of the film and it's thickness, not how much it's penetrated (regardless of penetration technique). Lots of heated discussions on this subject, but when you look at the data (industry peer and independent), there's no debate, as it's very clear.
Typical lower viscosity resin formulations also have lower modulus of elongation properties. Some formulators take this way past reasonable, with mixtures well past 60% weaker cured goo, but most have realized this isn't the best way to market a product, so are using formulations, though are slight weaker, but still well above the typical breaking strengths of common substrates. This is the case with BoteCoat's TPRDA mix, which should only be used on the raw wood coats, not subsequent coatings.
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6th December 2013, 06:39 PM #105
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Ok, well if it's weakening the resin that rules it out for laminating, and given that adhesion to bare timber is certainly more than adequate without TPRDA I think I'm fine with omitting it from coatings too.
You know you're making progress when there's sawdust in your coffee.
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