Back at the building board and repairs are underway.
Fuse and nose
cut two layers of glass fibre to start off
Wetted out and using the fuse as a plug
cured and removed
checking fit prior to gluing into place
The wing has now been glued back together using PVA. The fit wasn't perfect but all things considered it was a good 90% joint (if that makes sense). After the glue had cured the wing appeared reasonably stiff but after a bit of fairly hard manipulation a crack appeared along the joint. Obviously, this wasn't a very good sign! I then bent the wing just enough to introduce a bead of CA into the gap and left it to harden. I noticed on a recent P6 wing that CA can melt the foam core so perhaps this wont be the best solution in this instance.
The wing was then prepared with 120 grade sand paper to receive on layer of 200g/m2 woven fibre glass on both elevations starting with the underside.
light filler over damaged laminate
After sanding and brushing off the dust the wing receives a medium thickness coat of resin prior to the laying and smoothing out of the fibre glass.
If I'm working on an area of multiple curves I'd use 3M spray mount to attach the FG cloth first prior to wetting out. However, in this instance and a flat surface it's just as easy to coat the surface first with resin and then lay and wet out.the FG cloth after. I leave at least a 10mm overhang on any loose edges.
Whilst wetting out less is definitely more. Trust me! Do not try and flood the job with resin in order to try and achieve a glass finish in one coat. The first coat need only turn the cloth from white to clear, filling the twill to half thickness. I think this could apply to any weight cloth if practical. The next coat of resin will just about fill the above textured finish. If I leave it too long which is quite normal then a light sanding is required to remove the wax from the surface which is a natural occurrence. But if caught at the right time 5hrs approx and just ever so slightly tacky another coat can be applied direct without any surface preparation. Often the third coat is all that is required to provide a really near professional finish but of course personnel tastes differ so a lot depends on what you really want the end result to look like.
Back to the fuse and the collar has now been glued into place with a 5 min 2 pack glue as laminating resin isn't strictly an adhesive.
Here's a contradiction. A carbon sheave has now been glued inside the GF collar using laminating resin! As a side note the 2012 London Olympic Games were to leave a lasting legacy. In my case they will! At the sailing event. Weymouth had a little forest of roughly 40 flags planted all around the boat park. The long, narrow, tall curved tipped flags. Each flag was hung from telescopic carbon fibre rod with a 50mm dia at the base diminishing to 10 mm at the tip over 3m. After the games they were being thrown away so I acquired two and recycle them.
The Fuse is now glued back together and appears solid enough, a little paint touch up is required at the nose cone joint and the re-fitting of the hardware will be the icing on the cake.
Once the second coat of resin has cured and rubbed over to remove the wax there is virtually no evidence of the fibre glass cloth. A part from the odd bump in the underlying original surface. Now, applying the next coat of resin is what I consider to be the hardest! There are little to no visual or sound aids to help provide just the right amount of resin over the job. This is where a bit of past experience comes into play. Too little resin will run out fairly well and there wont be any runs etc but be prepared to apply yet another coat. This is still better than too much which will run, drip and contour quite badly which inevitably result in a lot of elbow grease being applied in the future. So I think the secret is just to apply the thinnest most even coat possible after the surface is initially properly covered. I do spend some time going back over completed areas to ensure an equal level layer of resin.
This photo was taken just after the third coat was applied so hopefully should flatten off quite nicely. A rub over with wet or dry should be all that is required to remove the wax.
I use West Resin for most of my modelling (bought in junior packs) with a mix ratio of 1:5. I use kitchen measuring (1.25ml-15ml) spoons to attain the right amounts as I'm only using small quantities at a time. If I was to use in excess of 20ml then a wide bottom glass jar is required for mixing to prevent premature curing. This almost occurred during the last mix as the plastic tub was a little small and the heat built up quite quick. I just managed to spread the last of resin over the wing in time where it cools down and becomes fluid rather than treacle like in consistency. That is a 50p brush which has lasted a long time and numerous acetone cleans. After which it is always rinsed with a soapy and then fresh water.
The Fuse is now glued back together and appears solid enough, a little paint touch up is required at the nose cone joint and the re-fitting of the hardware will be the icing on the cake.
The wing is also coming along nicely. Yesterday after a little light rub with 120 sand paper it received it's second coat of resin. This time I was aiming just to fill what was left of the woven twill texture. The sound of the brush during the stokes is as helpful as your sight during this process. As soon as the strokes became quiet I knew there was resin in a particular area, the original sound being as if you're running your finger nails over denim cloth.
This photo was taken just after the third coat was applied so hopefully should flatten off quite nicely. A rub over with wet or dry should be all that is required to remove the wax.
I use West Resin for most of my modelling (bought in junior packs) with a mix ratio of 1:5. I use kitchen measuring (1.25ml-15ml) spoons to attain the right amounts as I'm only using small quantities at a time. If I was to use in excess of 20ml then a wide bottom glass jar is required for mixing to prevent premature curing. This almost occurred during the last mix as the plastic tub was a little small and the heat built up quite quick. I just managed to spread the last of resin over the wing in time where it cools down and becomes fluid rather than treacle like in consistency. That is a 50p brush which has lasted a long time and numerous acetone cleans. After which it is always rinsed with a soapy and then fresh water.
Today's post repair flight:
The conditions were near perfect, blue sky, Sun and 20mph warm wind blowing directly onto the slope. I was looking forward to shredding the sky. However, shredding was going to be the wrong adjective, sedate would have been more appropriate! I was a little gutted, thinking the extra weight would equate to additional speed and snappier manoeuvres but this just wasn't the case she laboured in all departments and was no longer the spring chicken she once was.
I doubt the weight is the main cause of this difference so can only assume it's this alteration in wing section perhaps. Maybe more flying in a stronger breeze will help cheer me up a bit. Or could it be the changing of the Tx? The initial accident and subsequent flight today have been with a JR Tx where as before she was extremely responsive when I was using a Futaba Tx. Do differing Tx's affect a planes flying characteristics? I guess Tx latency is fairly important then.