CPES compatibility to 635 epoxy
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=28480
Printed Date: November-18-2024 at 3:21pm
Topic: CPES compatibility to 635 epoxy
Posted By: tbeard
Subject: CPES compatibility to 635 epoxy
Date Posted: December-03-2012 at 2:52pm
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Placed an order with US Composites and the tech. at US Composites told me “do NOT use CPES on wood and then apply 635 Med epoxy”. I have researched the site and found this has been addressed in the past and have had input from other members say it is an acceptable practice. Just puzzled why US Composites do not recommend this process. ------------- Thanks.......Tom |
Replies:
Posted By: Gary S
Date Posted: December-03-2012 at 2:58pm
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I have done so with out any problems yet. I wonder if it's because they don't have any experence with it or because they don't sell it? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: TX Foilhead
Date Posted: December-03-2012 at 3:39pm
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I recently read a very good explanation of what your trying to accomplish and the various systems available to someone laying up a new boat. Although it was geared more to strength and weight for building go fast boats they had some interesting things about the materials and how they work alone and with each other. My guess would be from reading that that they are worried about the secondary bond between the CPES coated wood and their laminating epoxy. Epoxies bond to anything, but they are slick on a molecular level because they so completely react when they cure, not a whole lot left for the next layer to bond to. So the bond between the CPES treated wood and the fiberglass laid over it may not be as strong as it would be if the fiberglass was on untreated wood. Not saying that it is bad, people have done a lot of boats that way around here and I don't think anybody is having issues from it. That would be my guess as to why they said that. If you were worked about that then you could get the stringers faired and in the boat so the fiberglass goes after the CPES and everything cures together. That sounds a little difficult timing wise though to me. Another solution would be a good scuffing with some sand paper before you begin laying the fiberglass so there is a better secondary bond. |
Posted By: tbeard
Date Posted: December-03-2012 at 3:47pm
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That is a good idea! I will apply 2 coats CPES. Let it dry, scuff with 120 grit and then start the lay up process. ------------- Thanks.......Tom |
Posted By: Gary S
Date Posted: December-03-2012 at 4:17pm
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Tom that is what I did to the side panels I'm building for my Mustang.I used 1/4" ply and in places I laminated them together after cpesing them and had used 635 to do it. I just went out and hit a cutoff piece with a hammer. here are the pic's,it did not fail at my joint. before  hit side  back side  ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: tbeard
Date Posted: December-03-2012 at 4:25pm
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Awsome.....I personally think that they do not recomend the CPES due to the unknown reaction with their product and you may use less 635 due to absorbtion and lastly they do not sell CPES. Is there a need to sand the CPES prior to 635 application? ------------- Thanks.......Tom |
Posted By: Gary S
Date Posted: December-03-2012 at 4:36pm
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I sanded Tom but I have a D/A sander so it was fast.It removed the glossyness of the cpes,I had used about 3-4 coats and I don't think it hurt.Since I was bonding 2 together I had also added some cab-o-sil to the resin mix also. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: 8122pbrainard
Date Posted: December-03-2012 at 8:53pm
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I'd go with the CPES. I too would say US composites just doesn't have any experience with it. Gary, Thanks for you little test. It says plenty!! ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Gary S
Date Posted: December-03-2012 at 9:08pm
Thanks Pete. See that last picture,you can also see where the plywood has a gap that I filled with the epoxy and cab-o-sil and amazingly it did not break there either. Now your going to say you could have fitted them better  but all that was added later when I realized that stapling into 1/4 might give me trouble,so I had to add a tacking strip all the way around the back side.These things have taken way more time than they should.I traced Johnb's panels but they needed quite a bit of modfication to fit my boat,they were too long and too tall to fit mine,but I'm thankful for the start they gave me.------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: Morfoot
Date Posted: December-04-2012 at 9:52am
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As a guy who works with composites and resin everyday.YES You have to lightly sand the cured epoxy before applying another coat. Think of it as Polyurethane on furniture. You have to rough it up or the next coat will peel off quicker than a bikini top in a strip club. I prefer to use a medium grit/grade scotch brite pad to rough up the surface before going with a second/third coat of epoxy. 120 grit seems a little too abbrasive to me but wood is a different animal than fiberglass and kevlar. ------------- "Morfoot; He can ski. He can wakeboard.He can cook chicken.He can create his own self-named beverage, & can also apparently fly. A man of many talents."72 Mustang "Kermit",88 SN Miss Scarlett, 99 SN "Sherman" |
Posted By: Waterdog
Date Posted: December-04-2012 at 12:20pm
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We use 220 grit and lightly sand to a "uniform flat finnish" After surface prep compressed air or an acetone swipe and bond. Bonding should be done within 8 hours of surface prep. If the surface has a greasy feel it's amine blush, wash it off with soap and hot water let dry then sand. ------------- - waterdog - http://www.correctcraftfan.com/diaries/details.asp?ID=3896&sort=&pagenum=2&yrstart=1978&yrend=1978" rel="nofollow - 78 Ski Tique |
Posted By: 8122pbrainard
Date Posted: December-04-2012 at 8:53pm
I agree on the amine blush. A solvent will not do the job since it is a water soluble. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Waterdog wrote:Posted By: Gary S
Date Posted: December-04-2012 at 9:24pm
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I do think in the context of this thread ie cpes to epoxy that this is not a concern.The cpes I used from the rot doctor never felt at all slippery or greasy. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: 8122pbrainard
Date Posted: December-04-2012 at 9:36pm
Gary, I agree with the CPES not having a amine blush issue. It is so thinned down and really doesn't build up on the surface even after multiple coats. However, I think the blush comment was a general statement with epoxy's. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Waterdog
Date Posted: December-04-2012 at 10:01pm
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Lots of papers on amine blush out there. If you heat or cure with gas/oil heat it's an issue Heat or cure with electricity (heat lamps) not an issue. It's funny I just layed up 2 Harley bat wing fairings. (Epoxy and carbon fiber) The first one cured at 150* under a heat lamp cured perfect in 1 hour and 15 minutes. The second after I layed it up and put it under the heat lamps I pulled my 2 motorcycles into the garage and shut them off. You could smell the exhaust and monday after work I popped it out of the mold - And - amine blush. just sayin'  ------------- - waterdog - http://www.correctcraftfan.com/diaries/details.asp?ID=3896&sort=&pagenum=2&yrstart=1978&yrend=1978" rel="nofollow - 78 Ski Tique |