Andy Hat Posted July 12, 2019 Share Posted July 12, 2019 OK, I've built a large number of planes in my time but there's one part I always dread - sanding wings. My building is not as neat as some construction I've seen here. It would be great if everything lined up but in reality, my stuff needs some 'adjustment' after gluing, i.e. ribs need sanding down to match the spar height, drips of glue need removing etc. A lot of the time, I'll catch the top of a rib (and break it off) when I'm sanding a spar, or take a groove out of a spar when I'm sanding along the top of a rib. One of problem I have is holding down a wing (usually over a table edge) whist sanding it. Occasionally, I've had bad breaks because I'm applying too much force. I use my Permagrit block a lot but also a rubber sanding block (paper attached by spikes over the top. I also use those sponge sanding blocks. Even with the softer tools, I can still cause damage to the delicate structures! My models look OK in the end (covering can hide a multitude of sins/repair) but any expert-tips on sanding would be great to hear. Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted July 12, 2019 Share Posted July 12, 2019 It doesn't start with the end Andy, sanding misaligned bits Preparation for sanding starts at the beginning, with a flat building board Parts trimmed and dry fitted, to take up the space accurately. Parts may take on slight deviations, but care along the build will reduce sanding Sanding across wing ribs will break them easily Sand along the line of the rib, forward and aft Also, consider the grit size of the paper, against the softness of the balsa Consider also making sanding shapes which fit the lines you are trying to level e.g. Wing leading edge Just tailor your parts as closely as possible, glued square, with enough glue to " wet " each surface Edited By Denis Watkins on 12/07/2019 15:19:22 Quote Link to comment Share on other sites More sharing options...
Don Fry Posted July 12, 2019 Share Posted July 12, 2019 Chuck out the rubber sander with the nails. As Denis says you can make custom blocks. Also look at the Axminster catalogue, they do very good Velcro backed abrasive, and foam rubber, one hard face, one soft face. And if you are using force, you will break or mis-sand. The abrasive does the cutting by you moving it as you want it. No real force, but always with your eyes on the work. When the paper starts to lose efficiency, replace. BTW, I once knew a master builder, proper job, did expensive jobs for top rates, if you could wait for him to be free, if he thought he would get on with the client, otherwise he would not work for you. "Don, best to get it right, but as long as it looks OK when you finish. Never worry about what don't get seen." Quote Link to comment Share on other sites More sharing options...
Andy Hat Posted July 12, 2019 Author Share Posted July 12, 2019 My current project is a Ben Buckle Playboy Senior kit. It's a perfect example of pre-cut parts that are not accurately cut. You are meant to fettle six wing-tip ribs from the standard size, but its not actually possible because the drawn ribs don't fit into the standard ones. I don't think the drawn ribs are correct either, since my copies (cut using photocopies as a template) didn't fit too well. The pre-cut wing tip and tail parts were approximations of plan parts. I'm not complaining, I knew what to expect from making other BB kits. I'm not sure how old the kit was when I got it but I hope some new templates were made after mine was made... Anyway, here's a pic, you might be able to see where I've accidentally marked the soft wing spars when sanding the ribs - doh! The Axminster stuff looks good - particularly the detail sanders - cheers. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted July 12, 2019 Share Posted July 12, 2019 Protect the parts you don't want sanded with a couple of layers of tape and use the longest sanding bar you can find or make. Aluminium extrusions and box sections are good if you can find suitable straight pieces, 2' is a good length, 12"/300mm I'd consider the minimum. I buy abrasives on a roll and attach it to the bar/blocks/shapes with double sided carpet tape. Aluminium oxide abrasives last for years, though not as long as a Permagrit tool. Quote Link to comment Share on other sites More sharing options...
Bill Reed Posted July 12, 2019 Share Posted July 12, 2019 Andy, 100% with you there, everything you say I do to. Quote Link to comment Share on other sites More sharing options...
Don Fry Posted July 12, 2019 Share Posted July 12, 2019 Bob, good tip. Also Mick Reeves on his website suggests painting surfaces to be sanded, so you can see the surface going a thou at a time. But lads, to reiterate, sanding is not easy. Clue, why does lightweight balsa filler come in balsa colour. Cock it up, build it back. Quote Link to comment Share on other sites More sharing options...
Former Member Posted July 13, 2019 Share Posted July 13, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
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