Glen-L Poxy-Grip question

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Mark-NJ
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Glen-L Poxy-Grip question

Post by Mark-NJ » Sat Feb 06, 2016 8:10 pm

I'm getting ready to begin construction of a Glen-L Ski-Tow, starting with the frames. Epoxy seems to be the way to go, and I'm happy to support Glen-L.

From what I read, "regular epoxy" isn't good for structural adhesion because it's too thin. Thickening the "West system" epoxy with additives seems like a pain, compared to getting the Glen-L Poxy-Grip, which (if I understand correctly) is already thick enough for construction.

Question 1: Clamping. I've read that tight clamping isn't required, because this thick epoxy can fill gaps. But as a woodworker, I always strive for well-mated surfaces, and clamping in place is just what I do. After all, what is "loose clamping", anyway? So thinking about something like the chine-to-frame joint, how do I clamp the chine in place in any fashion other than tight? For that matter, does it matter? I mean, it says "tight clamping not required", but can I tightly clamp? Is it a problem to do so? Or, if I apply epoxy followed by a screw holding it in place, that qualifies as "tight", right? Is tight clamping a problem?

Question 2: Poxy-Grip is mixed 1:1, but that's unclear to me. Is it mixed 1:1 by volume our weight? The Glen-L website doesn't say. Since the resin has a very different density from the amine hardener, the question seems (to me, anyway) to be a critical one. My desire & intent is to mix by weight, but I don't know if the 1:1 ratio is by weight or volume. Anyone know?

And if the ratio IS by volume, what would the ratio be, based on weight?

Thanks for reading!

Mark
Last edited by Mark-NJ on Sun Feb 07, 2016 8:54 am, edited 1 time in total.

gdcarpenter
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Re: Glen-L Poxy-Grip question

Post by gdcarpenter » Sun Feb 07, 2016 7:11 am

I built a Zip and only used the GlenL regular epoxy, never used the thicker stuff, just thickened the regular epoxy as required. One concern about 'over clamping' seems to be that you get too much squeeze out and risk 'starvation' at the joint.

I used half lap joints for my frame connections and Titebond III. I used the regulator epoxy to install the hull skin. Apparently epoxy gets used because it can compensate or fill in somewhat for 'sloppy' joints.

Build tight joints, clamp away, is my thuoght.

Good Luck
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Mark-NJ
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Re: Glen-L Poxy-Grip question

Post by Mark-NJ » Sun Feb 07, 2016 8:21 am

Not to derail my own thread, as I'd still like to know more about Poxy-Grip, but your use of Titebond III intrigues me.....

- On one hand, the specs look great for inside-the-hull joints where the joint might "get wet" but is unlikely to ever be immersed. Not prone to aging, doesn't breakdown with UV.....seems like a great choice!

- On the other hand, everything I read...including from the manufacturer....says "don't use this for boats". Plus, it won't 'take' anything over it: not paint, not epoxy, not stain...etc.

Sure would make frame construction easier, but I have my doubts. Anyone care to sway me?

If it matters, this boat will live on a trailer most of the year, and see 2 weeks of use in the summer, staying in fresh water. It will never see salt.

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DrBryanJ
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Re: Glen-L Poxy-Grip question

Post by DrBryanJ » Sun Feb 07, 2016 8:30 am

Mark, I've been using poxy-grip exclusively for my joints. The mix is by volume not weight. I think they give you the ratio for weight on the cans. I use 8 oz disposable cups for measuring the volume. They have ridges up the side. Makes it easy to get the same from each can. I can buy 100 for about $2.

As for tight joints, it doesn't have to be loose. Just don't make so tight that you squeeze out all the epoxy. If you've done woodwork before it's the same idea as when gluing two surfaces, you don't want to squeeze out all the glue.
Bryan

Building a malahini "Mona Lisa"

My wife said "If I build a boat, she's getting a divorce."

jcallends
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Re: Glen-L Poxy-Grip question

Post by jcallends » Sun Feb 07, 2016 9:08 am

Most adhesives, including epoxy, will instruct you to coat surfaces prior to bonding them together. All wood is porous to some degree and if you tightly clamp a joint together the epoxy in the pores of the wood is sufficient to make a strong joint and there is always a thin film of epoxy at the joint. Some epoxies are measured by weight but it requires you to have an accurate scale which of course is not necessary if you measure by volume.

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vupilot
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Re: Glen-L Poxy-Grip question

Post by vupilot » Sun Feb 07, 2016 10:05 am

I loved using Poxy Grip for assembly. Clamp it, just don't tighten it with all your mite. I wasn't scientific in combining them, its pretty forgiving, just stir it together well. For encapsulating and fiberglassing I really like the MAS brand epoxy that Glen-L also sells because it is a amine blush free epoxy.

gdcarpenter
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Re: Glen-L Poxy-Grip question

Post by gdcarpenter » Sun Feb 07, 2016 11:42 am

Re Titebond III

I've been a carpenter for years and edged joint, miter joined, butt joined, and basically done a host of glue ups for exterior use, and can go back to projects 15 years old, and those joints are still going strong. Anecdotal I know, but at least first hand.

My understanding is that Titebond III is rated as being 'waterproof' - but - not for immersion. A bit contradictory. I wanted the 'cleaner' look of half lap joints on my frames without the gussets. Titebond requires accurate joints to be effective.

Also bear in mind that once you have 'skinned' your boat there's less stress on the frame corner joints. I did add 'decorative' inside corner reinforcement pieces where my side frame members met the top frame rail.

I like the fact that the Titebond III that oozes out can be cleaned up with water. Once cured sanding will removed any residual glue and not interfere with any future gluing/painting.

Epoxy as glue has it's limitations also. It can break down with exposure to UV, and it can break down in very hot conditions. It's also dirtier to work with!

In the end you do what feels comfortable and best for you. I am not promoting Titebond III, just relating my experiences with it.
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lakeracer69
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Re: Glen-L Poxy-Grip question

Post by lakeracer69 » Sun Feb 07, 2016 2:15 pm

Use 60cc syringes for epoxy measuring. I've been doing it for years. Try a Vet supply house like Jeffers, or use your Google Fu to find them. I have made extremely small batches and have never had a curing problem. If you try to reinvent the wheel and weigh out batches, good luck.

If you want to use Titebond, Gorilla glue, different screws, no screws, latex paint, wood from the big box store etc. go ahead, It's not my boat. I personally won't take the chance. In the end, I find my time involved and material quality is much more important to me than skimping to save a few dollars here and there on those items. I've done that on previous projects (mostly small hydroplanes) and have learned from those mistakes.

My .02

YMMV
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Re: Glen-L Poxy-Grip question

Post by gdcarpenter » Sun Feb 07, 2016 3:20 pm

This forum, I believe, is for the sharing of opinions, techniques, materials and all other things related to boat building.

There are novices, experts, and all skill levels between, represented here.

There are boats built with unlimited budgets upwards of $40,000.00 and there are boats built for less than $5,000.00.

I would hope that tolerance and understanding should be foremost in all discussions, and believe that being judgmental is counterproductive to fostering good communication.
This is my first, last and only boat build.

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Bill Edmundson
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Re: Glen-L Poxy-Grip question

Post by Bill Edmundson » Sun Feb 07, 2016 3:36 pm

GD
I didn't find Lakeracer's comment out of line. I think the point is to use appropriate materials for the intended purpose of the boat. Every boat does not need top end materials for every splinter. I have used inexpensive underlayment, construction adhesive, and porch paint. Saves a lot of money. But, don't cut corners where it matters. People may not understand why certain things are specified. That is why we're here to help people know the difference.

Bill
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jamundsen
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Re: Glen-L Poxy-Grip question

Post by jamundsen » Sun Feb 07, 2016 9:08 pm

I used poxy grip for some of my earlier glue ups but found it hard to work. I mixed thickeners in Glen L regular epoxy. It was easy. If you save some of your sanding dust from your sanders you can mix that in as well. Just remember to mix the epoxy well prior to adding anything to it.
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mrintense
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Re: Glen-L Poxy-Grip question

Post by mrintense » Mon Feb 08, 2016 6:52 am

I've used both Poxy Grip and Poxy Shield with silica beads thickener. There are pluses and minuses to both. Poxy Grip is convenient and seems to have a longer pot life. although I didn't use it for my frames or skin panels (I had just not ever ordered any at that point) I did use it for the transom laminations. It works great. Biggest drawbacks to Poxy Grip, the thickness makes it tiring to mix and it's not easy to pour. Also hard to keep the hardener can clean. In cold weather you have to keep it indoors because it becomes too viscous to work with.

Poxy Shield with thickeners (or any other epoxy, like System Three SilverTip) works well also. It''s nice here because you can tailor the thickness depending upon the application (although don't make it too thick or it doesn't work that well). I like it for filling screw holes (I used silica beads for that) and it is great for filling low spots when mixed with sawdust or better yet micro balloons. Adding a bit of sawdust to it allows you to get a brown color if the application requires something visible. The biggest drawbacks to epoxy with thickeners is that it's more trouble to mix and especially with silica beads, you have to take extra care to insure that the beads are thoroughly broken up so you get a smooth consistency (sort of like mixing flour and water although not quite as bad ). And Poxy Shield (even with the slow hardener) will kick off fairly quickly unless you spread it out or keep the epoxy cool by immersing the cup in ice. The System Three SilverTip has a longer pot life.

A couple of things to remember. Like John said, mix the epoxy first before adding any thickeners. And with Poxy Grip and Poxy Shield (and any other blushing epoxy) be sure to clean off the amine blush after cure before sanding or doing any additional epoxy work (use a scrub sponge and warm soapy water - doesn't take much effort). If you are applying layers of epoxy (as in encapsulating), you can apply subsequent layers as soon as the existing layer is just past the tacky stage (no more than 16 hours - less if it's hot out). If more than than that then a light sanding is a good idea to give the fresh epoxy a better bonding surface. I recommend you buy the "How To Fiberglass Boats" book from Glen L for more on this as there is a lot more than what I am letting on here.

Overall, because you are likely to be doing more encapsulation than joint gluing, the Poxy Shield with filler is more economical. But having a can of Poxy Grip around as well gives you choices depending upon need. Epoxy is going to be one of your bigger expenses so budget for it.

Hope this helps.
Carl
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Mark-NJ
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Re: Glen-L Poxy-Grip question

Post by Mark-NJ » Mon Feb 08, 2016 9:03 am

Thanks to all.

You know how it is...."The more I read, the less I know!" I've always approached epoxy (admittedly, not in boat building) as "mix it, smear it, clamp it...done", but that is clearly not the situation here.

I do have Glen-L's DVD on fiberglassing a boat. Very informative, and encapsulating the hull seems straightforward, but I'm not there yet, having yet to even make my frames.

I don't want to run counter to the majority, but for frame construction, I'm finding it difficult to ignore the possible change of direction altogether for my frames: cut lap joints, and use Titebond III. If this boat, which will only see occasional light duty, ever has the frame joints "continuously submerged", well that's called "sinking / sunk", and I'll have much larger problems to contend with.

"Not for use below the waterline"....I take that to mean "in constant contact with water". Using it on frame joints, chine-to-frame joints, sheer-to-frame joints......these are not "below the waterline", are they? Being inside the confines of the hull, these are more-or-less "dry", and surely in keeping with ANSI Type I definitions / limitations. To the degree that these joints....which will be painted, too....get splashed-wet, I'm not sure I see the problem.

And, even with gussets, I don't see a how a butt joint could ever being as strong as a lap joint. And if I add gussets to that lap joint, with TB-III, that joint surely has to be darn-near indestructible, I would think.

Having read many of the threads on this forum, I see that the majority here say "don't do it"; still, it's hard to ignore others (here & other forums) who have stated that they've had years of successful boat ownership & operations, having used TB-III for in-the-hull structural joints.

I'm giving strong considerations to trimming my sails and going in this different direction. Epoxy will still be used liberally to put the plywood sides on, to do the joinery on the transom, etc., but for internal frame construction, I keep wondering "why not TB-III?"

Now, I know that asking "potentially-polarizing questions" on an internet forum is always dangerous, and I'm new here.....so please believe me, I'm not trying to stir the pot. But if we can have a calm conversation, I'd love to hear what you all have to say!

Thanks,

Mark in NJ

EDIT: I realize that this veers away from the topic of "Poxy-Grip"; if this conversation is better discussed its own thread in a different part of the forum, let me know and I'll start one.
Last edited by Mark-NJ on Mon Feb 08, 2016 11:35 am, edited 1 time in total.

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hoodman
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Re: Glen-L Poxy-Grip question

Post by hoodman » Mon Feb 08, 2016 10:12 am

I've used a regular "thin" epoxy for all my gluing. I bought a three gallon kit. I have used almost half of it so far. Buying the thin epoxy has allowed me to thicken it to whatever consistency I desire as well. I can add less thickener if I want the glue to fill in an imperfect joint or thicker if I want to make sure it doesn't sag. I have only used wood flour as a thickener and it makes for a nice wood colored glue joint that come close to matching the natural color of the wood. The other thing that buying just one kind of thin epoxy has done is allowed me to encapsulate the frames and other parts as I go so a lot of the usage of that gallon and a half that I have used so far is encapsulating. Epoxy is not difficult to work with. There is a learning curve but you'll quickly get used to it. The blue 7 mil gloves from Harbor Freight are what I use to keep it off my hands. I peel off several sheets of blue shop towels to wipe up any drips. I also keep a small piece of plywood that I use to do all my measuring and mixing. I keep an "A" cup and a "B" cup and pour into a third. The A and B cups can be reused over and over. The third cup you can pop the epoxy out of and use it over and over or use old yogurt or other containers and just throw them away.
Matt

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Bill Edmundson
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Re: Glen-L Poxy-Grip question

Post by Bill Edmundson » Mon Feb 08, 2016 11:54 am

Personally, I prefer to thicken my own. I make it about like applesauce for laminating, Peanut butter for gluing. I do like the 2-part cartridges for frame to skin. But, the damn things are expensive.

Bill
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