Wet seams

I always imagined that a fuselage was made this way, using a wet seam type layup, actually making one proved more challenging. My first attempts were with  my flitter hlg, but the mold has had much more use making dynamite's. Making the seams horizontal really payed off, allowing me to adapt the tail configuration and wing seat by just altering the plug and laying up another top rear mold half. The first few goes were not good, not realizing that you had to taper the  fabric and do the whole process wet, doh, wet seam layup. My approach was to lay up the mold with oversized cloth, wetting out the overhanging fabric, then leaving it 4-6 hours to cure to a toffee like state, could then trim one side flush with the edge of the mold and trim the other side 1/4" to 3/8" proud. Apply some more epoxy, thickened to act like glue, then bring the two halves together, bolt up the mold halves and consolidate the fabric on the inside of the mold with a rounded dowel.  I had trouble with the seams, mainly because of the hump I had to get the semi-cured fabric around. and the fabric being half cured, was not sticking together well. They flew well enough, but maybe not quite the beautiful creation I had imagined. After 3-4 fuses, I decided that a gel coat was a waste of time and I would be better off doing them as bare glass, and filling the imperfections before painting them.

My next project was DP2, to replace the DP1 fuselage made of basa and ply which I had then glassed and painted Deep Purple, hence the name. The mold was a better quality, and made from polyester. It is another 3 piece fuselage with slip off nose cone, this gives good access to get into and work on those seams. The first attempt was awful, the fabric pulling away from the purple gel coat and leaving blisters all over the place. Ok, give up on gel coats and try something else. For the 2nd pull I went for an entirely different approach. The fabric was laid into the mold and wetted out to at least 1/4" up from the mold flanges, left for 6-8 hours to cure, then trimmed flush on both sides. Join the two half molds together, then lay tape over the seams and wet out with epoxy, more tape is good, maybe each 1/2" wider than the last, trying to get the same sort of strength as the main layup. This worked well, and filling then painting the fuselage made it pretty and strong.

Backdraft was my next project, based on what I had learned with DP2, it was another polyester mold, and used taped seams. The difference with this plane though was access restriction, a one piece fuse with a canopy makes everything harder, and I really struggled to get the taped seams in there. My solution was to insert the tapes before joining the two halves. So after trimming the fabric flush with the mold flanges at the toffee like stage, I would then add all the tape to one fuse half and wet it out well, with the nose of both halves pointing the same way, I place the seam tapes on the edge nearest me on both halves, then one of them gets flipped over, bolt them together and get in there with a stick to consolidate the fabric seams onto the main fuse layup. I was really chuffed with this approach, it used all the methods I had learnt so far to good effect, however, extreme stress testing proved that my seams were not as strong as I had first thought, if the fuselage broke it was usually along a seam, or at least partly along a seam.

 

 So how can you make it stronger? Time to give up on experimentation and go for research. Information on the internet is a bit thin on this topic, so the seed was planted to do my own web site, uh...that was a couple of years ago, had lots of new skills to learn first. I came acrossRCGroups.com and particularly peoples build threads, more particularly Jart build threads, and started building one the same day that I first read about it. Everything I had learnt up to now was just by experimentation, from here on Rcgroups has had a major influence, it would be very hard to give credit to any one individual for all the things I have learned, so will just say to anyone that has ever posted there, a big collective thankyou thankyou thankyou. If you want to progress your skills, get reading, the site has search tools and you can get all the information you can cope with on moldmaking, (US spelling that I have adopted on this site, I know it has a u in it really) in fact anything to do with Radio Control boats planes or cars.

 

Ok, here is the plan, it is said that a picture paints a thousand words, so pictures and words linked together, its got to be good right? Another steep learning curve and had to throw some money at it but think I am now good to go, this is my way of giving back for all the help and information I have received over the internet. Hope you find them useful.

 

Right click and then save to your hard drive for best results, headphones may also help you to hear the narration better.  If you are going to view them on your browser, give them plenty of time to download as although I  have kept the files small they still take a while.

What is a wet seam layup? 7.83mb mpeg-4 file which hopefully gives you a rough idea of what I am trying to accomplish.

 

Preparation  22.8mb mpeg-4 file explaining how I prepare my templates to cut fabric that fits the mold, making the mold process much simpler and quicker.

 

Lets make something  53.4mb mpeg-4 file bit of a whopper to download, almost real time lay up of a Negus nose cone.

 

Birth  42.4mb mpeg-4 file showing first part removal from Negus nose cone mold. (Not as straight forward as I'd hoped, so details included on getting obstinate parts from molds.