Projects in process, peel ply and other tricks
2001-11-24 by Mike Denman
Three new photos today(Mike Denman's project album). The first is the rear end with peel ply applied. What is peel ply I hear you asking? Peel ply is dacron and it is applied over the last layer of fiberglass and resin (while the resin is still wet). The peel ply is applied just like another layer of fiberglass. Lay the peel ply on top of the wet resin and saturate the peel ply like another layer of fiberglass. Let the resin cure till it is hard and then you can peel off the peel ply. Why doesn't the resin stick to the peel ply? I don't know... it just doesn't. Whether you are using epoxy or polyester resin the effect is the same. Photo #2 shows the peel ply being removed. Neat trick, I hear you saying, but why would you want to do it (other than to amaze your friends). Well, there are a couple of reasons to use peel ply. The first is that it provides a surface that you can apply additional layers of fiberglass/resin to with out sanding between coats (even if you are using "surfacing resin" (resin with wax in it to promote curing) You can leave the peel ply on indefinitely and when you are ready for another coat of fiberglass, peel off the peel ply and the surface is ready for additional coats of fiberglass/resin. The peel ply takes the layer of wax off with it and leaves a clean, wax free surface that is smooth (as in flat) finely textured like the weave in the dacron which makes it very easy to bond to with additional layers of fiberglass. The peel ply also blends any transitions beautifully. Are there any disadvantages to peel ply? Yes, there are at least two. Peel ply doesn't conform to compound curves so it is only useful on relatively flat surfaces. The peel ply leaves a "resin rich" surface. This is a problem if you are working on composite aircraft because resin is heavy and you want to keep everything light. On cars, the extra weight is not a good thing but the amount of extra weight is relatively insignificant. Why did I use peel ply over the last layer of fiberglass? I used the peel ply because I wanted a smooth, resin rich surface which is difficult to achieve on a verticle surface like the rear end. I wanted the resin rich surface to insure that the last layer of fiberglass had enough resin on the surface to allow a final sanding and to blend in the edges next to the areas that hadn't been disturbed. Photo #3 shows the final sanding of the top panel. The bottom panel will have a final layer of fiberglass/peel ply applied on Monday. After a final sanding of the bottom panel I will be ready to tackle the final detail sanding and filling of pin holes etc. Mike Denman 1966 Marcos 1800 Chassis #4079