| Re: Peel strength, glass/epoxy on wood.
[Re: Rolf_Nilsen]
#131869 02/15/08 03:48 PM 02/15/08 03:48 PM |
Joined: Oct 2007 Posts: 199 Constanta, Romania isvflorin
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Posts: 199 Constanta, Romania | I hope you are not doing this pull test on the actual hull. Why not make a test panel ? Is it safe to mess with so much work done ? Sorry no advice to give, but still, a test panel might be better.
Florin
| | | Re: Peel strength, glass/epoxy on wood.
[Re: Rolf_Nilsen]
#131871 02/15/08 04:12 PM 02/15/08 04:12 PM |
Joined: Oct 2007 Posts: 199 Constanta, Romania isvflorin
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Posts: 199 Constanta, Romania | Rolf, I assume the peel strenght should be close to the numbers specified in the resin datasheet. The datasheet should provide both chemical and mechanical bond peel strenght. To measure force you can probably use 5litre pet botles filled with water( hanging from a wire clamped to the glass) , and keep adding them until the glass peels. Keep us posted.
Florin
| | | Re: Peel strength, glass/epoxy on wood.
[Re: isvflorin]
#131872 02/16/08 09:56 AM 02/16/08 09:56 AM |
Joined: Aug 2007 Posts: 190 lesburn1
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Posts: 190 | You must absolutely remove any surface coating on the "old" finish ie. your wet out coating of the wood. Sanding with 80 grit paper should to the trick. The problem is that it easy to be a little to enthusiastic and sand to much. In the future I would use peelply on the surface after you put the epoxy on it. This will soak up excess resen and when it is pulled off it leaves a coarse "tooth" for the next layer to bond to. A note on fiberglass, you should use the finish (on the glass) that is designed for your resin. Silane finish for epoxy resins.
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| | | Re: Peel strength, glass/epoxy on wood.
[Re: Rolf_Nilsen]
#131874 04/17/08 03:20 AM 04/17/08 03:20 AM |
Joined: Oct 2005 Posts: 951 Brisbane, Queensland, Australi... ncik
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Posts: 951 Brisbane, Queensland, Australi... | Either the timber should pull up or the fibre will break where it is held. Testing near the edge of a laminate will be tricky because it is usually a resin rich or resin poor area. Otherwise, cut one skin then "crack" the timber to leave just the other skin holding the two parts together. Then try to rip the glass off one part at 90 degrees, one part cantilevered off a bench, the other dangling off the side with increasing weight added to it. There should be an engineering standard around for an alternative test.
Peel plied resin requires a quick sand to get good adhesion with successive laminates, but not as much as non-peel plied resin.
I would personally avoid using water or other solvents to wash an area to be laminated. An air blow-down and/or a good brushing and/or a vacuuming should be enough, and doesn't take very long.
Why didn't you just resin the timber, leave for 30mins or so before getting too tacky, then apply the laminate. No sanding to bother with and a good chemical bond. | | | Re: Peel strength, glass/epoxy on wood.
[Re: ncik]
#131875 04/17/08 08:25 AM 04/17/08 08:25 AM |
Joined: May 2003 Posts: 4,451 West coast of Norway Rolf_Nilsen OP
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Posts: 4,451 West coast of Norway | We did some tests with the cutoffs from the stern, and the glass either broke or it pulled the wood off. An interesting observation was that we had to take care not to damage the fibers where we were pulling. A small "kink" or fold there, and wahoo, it broke there instead. I would personally avoid using water or other solvents to wash an area to be laminated. An air blow-down and/or a good brushing and/or a vacuuming should be enough, and doesn't take very long.
Why didn't you just resin the timber, leave for 30mins or so before getting too tacky, then apply the laminate. No sanding to bother with and a good chemical bond. I have a compressor but I dont know how good the water separator in it is. Using compressed air would make my garage an even dustier place. Brushing is really not enough, there will always be some dust left. I have not tried vacuming, since I am certain my wife would murder me <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" /> Wiping the sanded surface with a moist and hot towel (not wet) have worked OK til now. Better options are definatly wanted! Waiting 30 minutes and then laminate.. Interesting option. We have been working in kind of cold conditions until now so I 30 minutes might be a bit too short for the epoxy to kick or geel. I assume that was your idea, to let the epoxy kick and gel so it dont soak deeper into the wood before we begin to put the glass on? If we have the time for it, we will have a go at that. | | | Re: Peel strength, glass/epoxy on wood.
[Re: Rolf_Nilsen]
#131878 04/18/08 12:07 AM 04/18/08 12:07 AM |
Joined: Nov 2006 Posts: 120 Finland valtteri
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Posts: 120 Finland | I have a compressor but I dont know how good the water separator in it is. Using compressed air would make my garage an even dustier place. Brushing is really not enough, there will always be some dust left. I have not tried vacuming, since I am certain my wife would murder me <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" /> Wiping the sanded surface with a moist and hot towel (not wet) have worked OK til now. Better options are definatly wanted!
I'm currently using a refrigerator compressor for vacuuming, so if you don't need too much pressure that is really cheap silent alternative to vacuum pumps i.e. get it from recycling center or such. You could use also your compressor with ejector (?) but that generates so much noise that I needed to find another alternatives <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />. Also I guess that you'll need to get water separator anyway if you are going to spray paint your hulls.
Valtteri
Blade F16
| | | Re: Peel strength, glass/epoxy on wood.
[Re: Gato]
#131880 04/18/08 04:47 AM 04/18/08 04:47 AM |
Joined: Oct 2007 Posts: 199 Constanta, Romania isvflorin
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Posts: 199 Constanta, Romania | Dry wood should absorb more resin than less dry wood, but is it ok to use undried wood, even if it may soak less resin ?
Florin
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