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Ok, I want to reinforce all my corners with fiberglass tape. Aircraft
Spruce sells a 50 yard 8.7 oz tape to do this job. Can anyone tell me why I shouldn't use cut strips of my 1.4 oz cloth instead of this very heavy tape? Lou |
#2
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Earlier, Lou wrote:
Ok, I want to reinforce all my corners with fiberglass tape. Aircraft Spruce sells a 50 yard 8.7 oz tape to do this job. Can anyone tell me why I shouldn't use cut strips of my 1.4 oz cloth instead of this very heavy tape? For one, I don't think of 9 oz tape as being particularly "heavy" for corner reinforcement. I find it's a relatively convenient weight; two to five plies (depending on application) of it are about right for most taped-in bulkheads and such. I don't know what you're building, but 1.4 ounce is lighter than anything I use except for veil cloth. The thing about the prefab tapes is that the edges are hemmed (or whatever you call it) so they aren't always unraveling at the edges. That's a huge advantage when you're putting down a lot of the stuff. Here's another thing to consider, though: If you cut your own tapes you can cut them on the bias for easier draping and better shear strength. Such tapes also don't unravel as much at the edges, since there are no fibers parallel with the cut edge. The disadvantages to bias tapes are that they are hard to keep of consistent width (they keep doing the "Chinese handcuffs" thing), and that you can't have lengths greater than about 1.4 times the width of the roll. I guess the best thing to do is whatever it says in the plans you're working from. Thanks, Bob K. http://www.hpaircraft.com |
#3
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One really big advantage to a bias tape is its ability to conform to
complex shapes. It will also stay in the corner better and all the fibers are NOT crossing a right angles. Old Vari-Eze builder. "Lou" wrote in message ps.com... Ok, I want to reinforce all my corners with fiberglass tape. Aircraft Spruce sells a 50 yard 8.7 oz tape to do this job. Can anyone tell me why I shouldn't use cut strips of my 1.4 oz cloth instead of this very heavy tape? Lou |
#4
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One way to keep your hand cut,45 deg, bias tapes neat and uniform
is to lay them up on clear poly (Home Depot plastic sheeting) then after you get them worked to your best epoxy / glass ratio, cut the assembly to your needed width & length and cary the layup with the nonstretching poly backing , flip over and apply to the joint. Peal the backing off , finish and inspect. Reggie |
#5
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![]() Reggie wrote: One way to keep your hand cut,45 deg, bias tapes neat and uniform is to lay them up on clear poly (Home Depot plastic sheeting) then after you get them worked to your best epoxy / glass ratio, cut the assembly to your needed width & length and cary the layup with the nonstretching poly backing , flip over and apply to the joint. Peal the backing off , finish and inspect. Reggie While the tape may be more convenient, the extra thickness of the edge sticks out. What I like to do is roll out a piece of plastic wrap, roll a piece of peel ply on top, paint on a little resin, roll out the bias tape, saturate with resin, roll out the narrower hemmed tape, apply a light coat of resin in the corners, apply the whole works. You can run your fingers against the plastic to insure good contact. Then get a piece of foam rubber with a wood backing, press against the plastic with weights, clamps, etc. to keep pressure on. The peel ply will absorb excess resin and when cured and peeled off, the joint will look great. Spray on some light grey primer and finish with spatter paint. Ed |
#6
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On 20 Oct 2006 13:03:09 -0700, "Reggie" wrote:
One way to keep your hand cut,45 deg, bias tapes neat and uniform is to lay them up on clear poly (Home Depot plastic sheeting) then after you get them worked to your best epoxy / glass ratio, cut the assembly to your needed width & length and cary the layup with the nonstretching poly backing , flip over and apply to the joint. Peal the backing off , finish and inspect. That's one of the methods they show for doing multiple lay-ups such as the wing attach points on the G-III. I've wasted more fiberglass and resin trying to do that than on any other approachsigh It sounds good in theory and I've seen guys do it successfully, but not me. It depends on the surface, but if I can lay the tape on top: I use a cloth marking pen (marks disappear in an hour or so) to mark the cloth on the cutting table, roll the tap up, mark the surface on which the lay-up will be done for the proper width, wet the surface with a light coat of resin, lay the tape out as I unroll it (push to widen, or pull the narrow - do the same while stippling) then using a one inch paint brush, stipple the resin into the tape. I use vinyl ester resin which has a much lower viscosity than most epoxies although the West System is fairly low. Reggie Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair) www.rogerhalstead.com |
#7
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![]() One way to keep your hand cut,45 deg, bias tapes neat and uniform is to lay them up on clear poly (Home Depot plastic sheeting) SNIP Peel the backing off , finish and inspect. Reggie ************************************************* ****************************** "ED" While the tape may be more convenient, the extra thickness of the edge sticks out. What I like to do is roll out a piece of plastic wrap, roll a piece of peel ply on top, paint on a little resin, roll out the bias tape, saturate with resin, roll out the narrower hemmed tape, apply a light coat of resin in the corners, apply the whole works.Snip Ed ************************************************* *************** Roger (K8RI) wrote: SNIP It depends on the surface, but if I can lay the tape on top: I use a cloth marking pen (marks disappear in an hour or so) to mark the cloth on the cutting table, roll the tap up, mark the surface on which the lay-up will be done for the proper width, wet the surface with a light coat of resin, lay the tape out as I unroll it (push to widen, or pull the narrow - do the same while stippling) then using a one inch paint brush, stipple the resin into the tape. Roger Halstead (K8RI & ARRL life member) ************************************************* **************************** While each of these systems works,most stippled corner tapes that I have seen come in heavier than they need to be. Ed's method of placing a slightly narrower tape under the final tape gives a thinner edge, and is what I do, but the peel ply can hide inspection and makes the joint smother but also heavier. Most scratch built composite airframes that do not pay close attention to these small weight increases ending up weighing more than necessary. That straight tape edge adds points at Oshkosh and less weight allows one to climb faster. Reggie ************* ALSO ******************* "Lou" wrote: Ok, I want to reinforce all my corners with fiberglass tape. Aircraft Spruce sells a 50 yard 8.7 oz tape to do this job. Can anyone tell me why I shouldn't use cut strips of my 1.4 oz cloth instead of this very heavy tape? Lou ************************************************* ***** If you use enough plys so that the strength exceeds the peel strength of the joint and is as strong as the skins you are joining ,go for it. It may take a few layers and will use more epoxy. Reggie |
#8
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On 21 Oct 2006 17:22:07 -0700, "Reggie" wrote:
One way to keep your hand cut,45 deg, bias tapes neat and uniform is to lay them up on clear poly (Home Depot plastic sheeting) SNIP Peel the backing off , finish and inspect. Reggie ************************************************ ******************************* "ED" While the tape may be more convenient, the extra thickness of the edge sticks out. What I like to do is roll out a piece of plastic wrap, roll a piece of peel ply on top, paint on a little resin, roll out the bias tape, saturate with resin, roll out the narrower hemmed tape, apply a light coat of resin in the corners, apply the whole works.Snip Ed ************************************************ **************** Roger (K8RI) wrote: SNIP It depends on the surface, but if I can lay the tape on top: I use a cloth marking pen (marks disappear in an hour or so) to mark the cloth on the cutting table, roll the tap up, mark the surface on which the lay-up will be done for the proper width, wet the surface with a light coat of resin, lay the tape out as I unroll it (push to widen, or pull the narrow - do the same while stippling) then using a one inch paint brush, stipple the resin into the tape. Roger Halstead (K8RI & ARRL life member) ************************************************ ***************************** While each of these systems works,most stippled corner tapes that I have seen come in heavier than they need to be. Ed's method of On the G-III with the Vinyl Ester resin the cloth is quite a bit more dense than that used with epoxy. I just cut the corner reinforcement out of regular cloth on the 45 bias. Glasair used to use a bias tape, but they have eliminated that and have gone to using the regular cloth cut on the 45. With a reference mark you can get a pretty straight edge. placing a slightly narrower tape under the final tape gives a thinner edge, and is what I do, but the peel ply can hide inspection and Squeezing out the peel ply (I use Dacron it's cheaper and works just as well) will give tapered edges and tends to spread the fibers at the edge of the cloth as well. makes the joint smother but also heavier. Most scratch built composite Done correctly the peel ply should remove the excess resin giving a lay up without excess resin or weight. At least the stuff I'm using sure does wick off the excess. The biggest problem is learning how much "excess" resin to put on depending on the weave of the peel ply during the lay-up so the peel ply doesn't make it too dry. A normal lay-up with the coarse weave will come out almost white which is too dry. We have one guy building a Glasair Super II whose plain lay-ups look better than mine using peel ply. He is good! airframes that do not pay close attention to these small weight increases ending up weighing more than necessary. That straight tape edge adds points at Oshkosh and less weight allows I don't have any tape edges that show. For peel ply I have four different Dacron weaves that give me finishes from smooth to those that look almost dry depending on what comes next. one to climb faster. Reggie ************* ALSO ******************* "Lou" wrote: Ok, I want to reinforce all my corners with fiberglass tape. Aircraft Spruce sells a 50 yard 8.7 oz tape to do this job. Can anyone tell me why I shouldn't use cut strips of my 1.4 oz cloth instead of this very heavy tape? Lou ************************************************ ****** If you use enough plys so that the strength exceeds the peel strength of the joint and is as strong as the skins you are joining ,go for it. It may take a few layers and will use more epoxy. Reggie Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair) www.rogerhalstead.com |
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