Tim Ballinger

Mike , Many thanks for the update. Two Questions if I may. From what I have read this issue is not directly connected to the LBT feature or is it? Presumably the packet validation check does not fail each and every time there is some interference on the Tx/ Rx as that would presumably not be a rare occurrence or does it? The RC group chat seems full of reports of hardware incompatibility issues with the latest firmware that makes most of us reluctant to implement the upgrade atm. Are we right to be waiting? ( yep that’s 3 questions) Tim. Edited By Tim Ballinger on 25/01/2020 16:38:23

Firstly, where is Levanter when you need him, he was a professional in composites I seem to remember and would give a better answer than me I am sure. You do not have to use a gel coat. However if you use a gel coat you have a thicker layer of resin protecting the laminate which is the important structural element and any damage to the fibre is bad news. Cosmetically this looks better and it is easier to achieve a high gloss finish. (I am beginning to get out of my depth without doing some reading but in using a polyester gel you get a more flexible finish than if you used an epoxy gel . If you want a good clean hard edge/surface than epoxy gel is I believe the way to go.) The bond between polyester and epoxy is not as easily achieved and even with special formulations will not work well after the polyester is fully cured. However if you have a polyester gel between the laminate and the mould , which probably has an epoxy resin surface you protect the mould if you penetrate the release agent or wax when laminating with your epoxy. Finally if you add pigment you can to some extent protect against UV damage. So as you suggest adding a gel coat for our purposes might seem overkill and not worth the effort, especially when it does not go well. To some extent having made a useable cowl (with clear gel coat) I am now just experimenting while trying to also make a spare. i have just tried again and made sure the gel coat application was not too thick and I let it cure for longer. I did not see the gel coat pull away from the mould this time but it was very difficult to get an even coat . It was almost like the effect you get in paint if you have mixed in the wrong thinners it just seems to separate out. i did use a different manufacturer for the pigment paste but it was sold as polyester compatible and seemed to mix ok. Sorry may have got carried away there but I have been thinking a lot about the whys and wherefor’s as you can probably imagine. Tim

Cowl no 2 now cured. Complete disaster! As I suspected I messed up and the gel coat had indeed come away from the mould when I had started to lay the cloth. I hate to show it but the result is below. It is now in the bin. So my enthusiasm for using coloured gel coat where I could see what I was doing was obviously part of my undoing. In an effort not to get it not too thin I brushed way too much on and it sagged . I saw the ripples on the inside of the mould but had assumed the mould face side would be ok. Wrong. Second error I think was starting to work the cloth layer too early in the gel coat cure. Guidance says best adhesion is to start when still tacky. Although my over thick coating clearly did not help I think I went too early and as I suspected pulled the still rubbery gel coat away from the mould. Despite stippling it all as flat as I could the result was inevitable. Great bond just looks like a frozen lake. Glad I have 1 decent cowl in the bank as it were. So hopefully with a lesson learnt I will try cowl no 3. Tim

Colin , you are correct about the incompatibility but this poly gel is advertised as being specifically epoxy compatible so as to get the benefits of both compounds. It seemed ok on the first cowl out of the mould but just not sure it feels right this time but we will see in due course. Tim

Well added the 3 layers of cloth and the final job looks ok. However when I started to apply the first layer it seemed as though the gel, by now a semi cured skin , was coming away from the mould as I stippled the cloth. Now I’ve never used coloured gel coat before and I am not sure I would have seen this with the clear gel coat. However I am nervous I either got the gel too thick or went with the cloth layer too soon . Anyone noticed this or had it happen to them? Guess I will find out on Saturday morning when I release the cowl from the mould. If it’s gone wrong then I’ll be on cowl no 3 ! 🤞 Edited By Tim Ballinger on 23/01/2020 17:33:19

Colin , Forgive the nostalgia trip guys but that reminds me when my dad and I used to go down the boat builders on the local canal for our poly resin supplies. Mind you most of it used to go into car repairs. In a similar vein we used to go down the speedway track at monmore green to get our gallon bottles of methanol, Castrol R and nitromethane filled up . They kept it in loads of 5 gallon drums and relatively speaking charged a pittance. While Killing time here waiting for the correct degree of tackiness in the gel would you believe a large fly came in through the open window and decided to try backstroke on the new gel coat! Must be the first fly ive seen in months and it had to target my wet gel coat. Great use for long nosed forceps in ensuring minimal damage. Only satisfaction was that poly resin seemed to finish him off pretty dam quick. Anyway back to the mould. Tim

Clearly the weight goes up the heavier the cloth you use but with the relatively small amounts of cloth in an average size cowl I am not sure it matters a great deal as even an extra ounce in the nose , at least for electric setups, is generally beneficial. However..... Added a drop of epoxy to cover the missing bit of gel coat on cowl number 1, feathered it in and all is well. Cowl number 2 with white gel coat to hopefully ensure full and even coverage is now underway. Certainly easier. The pigment comes ready mixed as a paste so mixing in with the clear resin is easy and uniform. Now waiting for the optimum time to start laying up the glass cloth.

What a stunning model, Thanks for sharing. Tim

Andy, Thanks for that. Since I am still using FrOS its the OS update for me and ignore the specific IXJT firmware update . Tim

David, Many users are trying to get their heads round the implications for the many permutations of Frsky kit so you are not alone. Mike Blandford , is our resident guru and is generally quick to correct us when we go wrong However as I understand it. Frsky has not yet released the firmware upgrades for the ACCESS protocol radios such as your x10 Express, so you can do nothing yet. the ISRM module is however expected to need this upgrade so you will more than likely feel the pain in due course. ( I have only quickly scanned the RC groups forum but there seem to compatibility issues with several flavours of the Taranis radios too.) For the moment do nothing especially do not try upgrading rxrs until your specific Tx upgrade is released or you will end up with a mismatch that will not work. Perhaps not surprisingly I see several users on RC groups now suspecting they have experienced the actual issues that are being addressed by these upgrades and are a little agitated. For my part my horus X10 and Rx series Rxs all have firmware upgrades released and while not actually doing anything yet I am preparing for the inevitable. For my part I am a little confused as to why there is a separate firmware upgrade file for the IXJT module as I thought the internal RF module on the HORUS could only be updated with the Fros firmware update. Perhaps the IJXT firmware is actually for the external module? Can Anyone put me right here ? Tim

Chris, Thanks for the kind words. The wine is indeed mine, a reward for walking round part of a very,very muddy half marathon at Doynton near bath. My other half ran the full distance , mad woman so I just do my own walk for an hour or so,. I thought about buying some pigment when I bought the gel coat so I will revisit and colour before my next attempt. Thanks Tim

I’ve become a real fan of slow cure, not only 90 min pot time but no obvious heat at all in its 30 hour cure time. At least that’s how long I had left it when I released it from the mould. I am actually pretty pleased with the result . It weighs in at 32g or 1.12 oz ( 15cmx15cmx12cm) and feels rigid enough to me, certainly pretty much the same as the original. Surface finish I am also pleased with , its picked up a few whitish spots from the bits of filler I used on the mould but that’s ok. I can see a trapped air bubble in the nose but it’s in the solidest part so would be ok. That said I am going to make another. Reason? I commented it was difficult to see where I had painted on the gel coat and I obviously got a bit thin on one corner right on the edge of the mould and as a result there is about a 2cmx 1 cm bit missing it’s gel coat. Again not a real show stopper but my personal mission was to do the best I could so I will have another go. I am wandering if putting some pigment in the gel coat might help ensure a more even coverage. Chris your cowl looks to have colour , did you use a coloured gel coat? Anyway pictures below including a close up of the offending bit of missing gel coat.

It took me 80 minutes to lay up 3 layers of cloth and having mixed up 78 g of resin at 30% ratio I have about 40g unused. After 100 mins the remainder is just starting to thicken . It was so much easier having all that time to work with. You could actually spend time working the resin into the cloth without having to spoon it on in a race to beat it curing in the middle of the job.( slight exaggeration but those that have tried this will know what I mean). I used 2 layers of 20g and 1 of 200g cloth as planned. I used large oval shapes to cover the bottom or nose of the cowl and then just overlapping rectangles to go round the sides. A couple of small discs of 200g cloth right at the front to make sure of strength where it will be drilled out for the prop shaft. Currently no pools of resin and no heat but then it is only just starting the long cure. Of course I have 30 hours to wait before I find out if it even comes out of the mould let alone what sort of finish I will get. Any way this is what it currently looks like.

Well gel coat is on. Biggest issue is seeing that everywhere is covered. You really only need about a 20g mix but to make sure I mixed the correct ratio (2% by weight) I started with 100g of resin and added the requisite 2g by pipette. You can not see anything in the pic really except for the excess resin in the tray alongside. (It’s shallow to stop any heat build up and premature curing) .Started to go thick bang on it’s quoted 15 min pot life.) Plan is start the lay up in around 4 hours time. Should be tough enough but still a bit sticky. Instructions reckon adhesion is excellent even after 24 hrs.  Piers I hear your thought about upside down but I reckon I would be asking for laminates to sag if I tried that so I’ll stay the right way up. Edited By Tim Ballinger on 18/01/2020 11:07:54