X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 19 Jan 2010 06:19:03 -0500 Message-ID: X-Original-Return-Path: Received: from mail960c35.nsolutionszone.com ([209.235.152.150] verified) by logan.com (CommuniGate Pro SMTP 5.3.1) with ESMTPS id 4087132 for lml@lancaironline.net; Mon, 18 Jan 2010 17:33:07 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.235.152.150; envelope-from=rsmiley2@centurytel.net X-POP-User: rsmiley2.centurytel.net Received: from QS4 ([98.125.184.180]) by mail960c35.nsolutionszone.com (8.13.6/8.13.1) with ESMTP id o0IMWS6w007015 for ; Mon, 18 Jan 2010 22:32:29 GMT From: "Bob Smiley" X-Original-To: "'Lancair Mailing List'" References: Subject: RE: [LML] Tips on working with Glass, carbon and kevlar X-Original-Date: Mon, 18 Jan 2010 14:32:14 -0800 X-Original-Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0003_01CA984B.08749E30" X-Mailer: Microsoft Office Outlook 11 Thread-Index: AcqYg9es/nm08AQnRa+YSEuBqrViHwACdTrg In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_0003_01CA984B.08749E30 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit It has been ten years since I built my 360 and am now into APBA stock outboard racing. The following post on Hydroracer.net is very informative and should be useful to you guys pertaining to tips and techniques working with glass, carbon and Kevlar layups. Enjoy. "Working with Kevlar _____ I'm not quite sure where all the mystery of working with Kevlar has come from. It simply isn't nearly as bad as everyone seems to make it out to be. Here are some hints and observations that I have learned by using it for quite a while now. 1. Scissors: You don't need to buy the expensive special Kevlar shears that are out there. I've used the same pairs of cheapo scissors to cut glass, carbon and kevlar. I used to build inboard safety cells. Between those and regular outboard stuff I've probably gone through close to 100yd of Kevlar and it will still cut just fine. A neat trick that really helps is to give them a light sharpening on a grinding wheel. Run the blades perpendicular to the wheel and leave the slight burr that is created. They should feel "gritty" when you work them now. This will help hold the fibers and keep them from "squirting" forward away from the cut. The other thing I do is to pull them back as I'm doing each cut. It is like using 4" of blade to cut 2" of material. Sort of hard to explain, but I think you will figure it out. 2. Surface prep: I have seen many times where people talk about pouring epoxy over the bare wood and then laying on whatever fiber they are using. Next time you epoxy coat something pay attention to how some spots wind up glossy and others look dry when it is cured. This same thing will happen when there is fiber over it. The dry looking spots are now resin starved layups where the part will have far less strength. It is better to coat the part, let it cure and then clean it, and scuff sand it. This primer coat ensures that your fiber will maintain the resin content you want and not be too lean in some spots and too rich in others. 3. Bagging: Kevlar doesn't need to be bagged. While I say this, also bear in mind that it is lighter than you resin and will actually float. If you keep putting on resin, it will just keep floating up. I simply put on the pre-cut kevlar on my prepped panel and pour resin down the middle of the part. Gently work the resin through the fiber with a body filler squeege. The more of it you get wet out, the more aggresively you can work the resin through. You don't want to squeege fast or you will induce a lot of tiny air bubbles to the resin. Just work with gradually harder pressure and you will see the color change slightly. You will also be able to see any spots that need more resin by the way they have a flat look rather than glossy. Let is set for 10 minutes or so and then add resin where necessary and squeege one more time for uniformity. Remember to only put enough resin to wet it out completely and then quit. Any more is just extra weight and wasted money. 4. Peel ply: Dave hit this one in another post. My test at the fabric store is to try to blow through the cloth. If you get one that is very hard to blow through, it will peel off easily. I just get 100% polyester cloth with a very fine weave. There is alway something on sale in the bargain corner. Usually the only problem is getting the cashier to believe that the small stain or whatever put it in the sale rack won't affect my use of it. Don't even try to get into that discussion at the store! Once my layup is wet out evenly, I put a piece of the peel ply over it and squeege again. I use a good bit of pressure here. If you have the right amount of resin, you will see the pattern on the peel ply change from just the dots at each high point of contact with the weave to one solid color. any excess resin will work up through the tiny holes in the peel ply and come off when it is removed. The peel ply can even be used to hold things in corners much like bagging. What happens is that between the surface tension and the difficulty with which air passes through it, it will hold the fibers in some fairly complex shapes with no vaccuum. A hint when peeling it is to pull it off 45 degrees to the weave direction. This way, just like gaining strength by laying up gusset strips on the bias, you are pulling on tiny strings in two directions rather than one. It should pull up without too much effort if you work slowly and work from side to side. 5. Green trimming: I alway time the lay up the Kevlar so that I will be able to come back later and trim the parts when it is say 80% cured. I don't mean to full cure, but rather when it is no longer tacky, but still pliable. At this point the peel ply will come off very easily. Don't try this too soon, or it can actually lift the fibers you are keeping down. After you have the peel ply removed and you are done admiring your very flat surface, trim the edges with a new utility knife blade, You will quickly find the ideal angle to hold it by experimentation. I always have all the cuts made in the wood first so that this becomes a simple tracing step of following the lines. 6. Dry trimming: If you need to make any cuts after the stuff is cured, make the cuts however you normally would. Use carbide tools or you may as well throw them away. It is very hard on cutting edges. You will see the edges fuzz up like crazy. Don't sand them or they will only get worse. A lot of this can be cut off with a brand new utility knife blade. It won't get it all though. You will need to wet out the fuzz, and trim it in the green state or let it cure and sand and repeat a time or two. With patience it will all come out with no ragged edges. 7. Flat straight cuts: If you have an edge that you want straight across a panel that extends beyond the fiber, here is a neat trick. Put down a piece of 2" wide tape that butts up to the desired edge. Lay the fiber so that it extends on to the tape. When it is in the trimming state of part 5 above, simply come back 2" from the exposed edge of the tape, and cut it. Peel up the bottom layer of tape and all the wierd little stuff that happens at the raw edge of cloth is gone and you are left with a perfect crisp edge that looks great. 8. Not quite a vaccuum bag: A neat trick for holding any fiber into complex shapes is to use a garbage bag with water in it. Put down the peel ply and then use a garbage bag with some water in it. As long as there is slack in the bag and it isn't bridging over any shape detail you will get modest pressure in all directions to hold the cloth to the more complex shapes. You will be amazed at just how little water it can take to accomplish this. To make this method one better use warm water and accelerate the cure! That is about all that I can think of right now. I probably have photos somewhere that show some of this if anyone needs more to go on. Steve Roskowski " Submitted by Bob Smiley 94RJ 360 ------=_NextPart_000_0003_01CA984B.08749E30 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

It has been ten years since I built = my 360 and am now into APBA stock outboard racing.  The following post on Hydroracer.net is very informative and should be useful to you guys = pertaining to tips and techniques working with glass, carbon and Kevlar = layups.  Enjoy.

 

 

“Wor= king with Kevlar

I'm not quite sure where all the mystery of = working with Kevlar has come from. It simply isn't nearly as bad as everyone = seems to make it out to be. Here are some hints and observations that I have learned = by using it for quite a while now.

1. Scissors: You don't need to buy the expensive special Kevlar shears = that are out there. I've used the same pairs of cheapo scissors to cut glass, = carbon and kevlar. I used to build inboard safety cells. Between those and regular outboard stuff I've probably gone through close to 100yd of Kevlar and = it will still cut just fine. A neat trick that really helps is to give them a = light sharpening on a grinding wheel. Run the blades perpendicular to the = wheel and leave the slight burr that is created. They should feel = "gritty" when you work them now. This will help hold the fibers and keep them from "squirting" forward away from the cut. The other thing I do is = to pull them back as I'm doing each cut. It is like using 4" of blade = to cut 2" of material. Sort of hard to explain, but I think you will = figure it out.

2. Surface prep: I have seen many times where people talk about pouring = epoxy over the bare wood and then laying on whatever fiber they are using. = Next time you epoxy coat something pay attention to how some spots wind up glossy = and others look dry when it is cured. This same thing will happen when there = is fiber over it. The dry looking spots are now resin starved layups where = the part will have far less strength. It is better to coat the part, let it = cure and then clean it, and scuff sand it. This primer coat ensures that your = fiber will maintain the resin content you want and not be too lean in some = spots and too rich in others.

3. Bagging: Kevlar doesn't need to be bagged. While I say this, also = bear in mind that it is lighter than you resin and will actually float. If you = keep putting on resin, it will just keep floating up. I simply put on the = pre-cut kevlar on my prepped panel and pour resin down the middle of the part. = Gently work the resin through the fiber with a body filler squeege. The more of = it you get wet out, the more aggresively you can work the resin through. You = don't want to squeege fast or you will induce a lot of tiny air bubbles to the = resin. Just work with gradually harder pressure and you will see the color = change slightly. You will also be able to see any spots that need more resin by = the way they have a flat look rather than glossy. Let is set for 10 minutes = or so and then add resin where necessary and squeege one more time for = uniformity. Remember to only put enough resin to wet it out completely and then = quit. Any more is just extra weight and wasted money.

4. Peel ply: Dave hit this one in another post. My test at the fabric = store is to try to blow through the cloth. If you get one that is very hard to = blow through, it will peel off easily. I just get 100% polyester cloth with a = very fine weave. There is alway something on sale in the bargain corner. = Usually the only problem is getting the cashier to believe that the small stain or = whatever put it in the sale rack won't affect my use of it. Don't even try to get = into that discussion at the store! Once my layup is wet out evenly, I put a = piece of the peel ply over it and squeege again. I use a good bit of pressure = here. If you have the right amount of resin, you will see the pattern on the peel = ply change from just the dots at each high point of contact with the weave to one solid = color. any excess resin will work up through the tiny holes in the peel ply and = come off when it is removed. The peel ply can even be used to hold things in = corners much like bagging. What happens is that between the surface tension and = the difficulty with which air passes through it, it will hold the fibers in some fairly complex shapes with no vaccuum. A hint when peeling it is to pull it off = 45 degrees to the weave direction. This way, just like gaining strength by = laying up gusset strips on the bias, you are pulling on tiny strings in two = directions rather than one. It should pull up without too much effort if you work = slowly and work from side to side.

5. Green trimming: I alway time the lay up the Kevlar so that I will be = able to come back later and trim the parts when it is say 80% cured. I don't = mean to full cure, but rather when it is no longer tacky, but still pliable. At = this point the peel ply will come off very easily. Don't try this too soon, = or it can actually lift the fibers you are keeping down. After you have the = peel ply removed and you are done admiring your very flat surface, trim the edges = with a new utility knife blade, You will quickly find the ideal angle to hold = it by experimentation. I always have all the cuts made in the wood first so = that this becomes a simple tracing step of following the lines.

6. Dry trimming: If you need to make any cuts after the stuff is cured, = make the cuts however you normally would. Use carbide tools or you may as = well throw them away. It is very hard on cutting edges. You will see the edges fuzz = up like crazy. Don't sand them or they will only get worse. A lot of this = can be cut off with a brand new utility knife blade. It won't get it all = though. You will need to wet out the fuzz, and trim it in the green state or let it = cure and sand and repeat a time or two. With patience it will all come out = with no ragged edges.

7. Flat straight cuts: If you have an edge that you want straight across = a panel that extends beyond the fiber, here is a neat trick. Put down a = piece of 2" wide tape that butts up to the desired edge. Lay the fiber so = that it extends on to the tape. When it is in the trimming state of part 5 = above, simply come back 2" from the exposed edge of the tape, and cut it. = Peel up the bottom layer of tape and all the wierd little stuff that happens at = the raw edge of cloth is gone and you are left with a perfect crisp edge that = looks great.

8. Not quite a vaccuum bag: A neat trick for holding any fiber into = complex shapes is to use a garbage bag with water in it. Put down the peel ply = and then use a garbage bag with some water in it. As long as there is slack in = the bag and it isn't bridging over any shape detail you will get modest pressure = in all directions to hold the cloth to the more complex shapes. You will be = amazed at just how little water it can take to accomplish this. To make this = method one better use warm water and accelerate the cure!

That is about all that I can think of right now. I probably have photos somewhere that show some of this if anyone needs more to go on.

Steve Roskowski “

 

Submitted by Bob Smiley 94RJ  = 360

 

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