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2013 Mass Build - general chat thread


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It was not my intention to start à "glue" war...

The common denominator is Aliphatic resin, which I hav enever used. Hopefully I can get hold of it in Norway.

I have used a lot of epoxy in boat building, but that is both heavy and too stiff for balsa, thereby creating a weak spot just beside the join. Good for firewalls and ply-balsa seams though.

My limited experience with CA glue is that the gluelike is less elastic than the materials glued, which creates hard spots in the construction. When glueing stiff materials (like carbon rods) this is not an issue. However, the wicking that thin CA does makes it possible, in theory, to position parts in place and then apply glue. With CA hinges this works fine, but I have never tried this with balsa constructions. How do you know if there is glue in the whole glueline?

Great Planes recommend CA glues in their kit manuals though, so it can not be all bad. I will try them all, and will most likely develope a preference after a while, like the builders that responded to my initial post.

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Posted by Lucas Hofman on 26/12/2012 12:54:35:

It was not my intention to start à "glue" war...

It could all come to a sticky end! teeth 2

Seriously though, I think a lot of the issue is down to personal preference, especially mine concerning CA. I'ved used Aliphatic on two airframes and have found it to be a lot easier to work with than PVA, but then again that is just my personal opinion.

Edited By Steve Cornell on 26/12/2012 14:10:20

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I think aliphatic is a generic name, so it would be interesting to know what brand names people use.

Despite what was said before many of the sandable glues are white and not always yellow, for example X100 PVA from Five Star Adhesives ( Starlock ) is sandable yet white.

Evostik Wood Adhesive Resin W ( green bottle )is reasonably sandable in my experience. And of course all these PVA type glues are much better for health ( as far as anyone knows! ) than cyano which is quite hazardous if used a lot. Check out the horror stories of people who have become badly affected by cyano and cannot now use them. Just use cyano occasionally for the very tricky jobs and use PVA for most aeromodelling is my advice.

It's very easy to see whether cyano is as strong as PVA. Just glue a test piece, leave to dry then try breaking the part. High quality PVA if done properly and allowed to dry always breaks the material but not the glued joint. That is to say Evostik Resin W is stronger than hardwood. Some of the cheap supermarket glues are not as strong.

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I use cyano quite a bit and probably will on my Tucano but at the moment I'm completing a model I bought part finished at the Nats swap-meet. It's a Paper Aviation Ezee Pezee which is an 84" trainer constructed largely from Polyboard (a paper covered foam sheet) for which cyano is inappropriate so I'm using Titebond PVA. I get it from Modelfixings.

So two electric models on the go at once. Despite its size the Ezee Peezee is very light (about 3.5 kg) and will be powered with a 5055 700kv motor probably on 4S with a 13x6 prop - I hope!

It's interesting what Phil Winks says about some of the advantages of aliphatic resin, particularly as he is a professional woodworker. I do have some De Luxe materials Super Phatic which is very thin but I haven't used it much. It is very runny almost like water. I wonder if anyone has used it on those slightly hairy plastic hinges intended to be glued with cyano?

I must admit the chemistry of adhesives and paints and their uses is something I have very little knowledge of and even less confidence so I tend to use what I know.

Geoff

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Posted by Lucas Hofman on 26/12/2012 12:54:35:

However, the wicking that thin CA does makes it possible, in theory, to position parts in place and then apply glue. With CA hinges this works fine, but I have never tried this with balsa constructions. How do you know if there is glue in the whole glueline?

Your finger is stuck to the opposite side of the woirk you applied to the Cyano to wink 2.

Actually I'm not joking that much, I've done it a few times. Some people..... smile o smile

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Regarding the health issues - you should use CA in a well ventilated space - the fumes can cause 'flu-like symptomes. Also you would be well advised not to use it for long periods without regular breaks. I don't mean to single CA out - some other adhedsives have their own fume problems, particularly impact style adhedsives - but they smell strong, so there is a natural instinct to be wary. But CA has much less smell, but the fumes can be just as much a problem.

BEB

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Hi, I've just opened the wood pack and have noticed the 9.5 stock is 100 wide yet the wing plan shows the 'main panel' to be 102 wide how is this discrepancy managed?. There are not too many dimensions on the plan, I take it that any required are obtained by measurement of the plan itself - something we were never allowed to do at 'tech'

Mike

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Posted by Mike Hardy on 27/12/2012 16:20:16:

Hi, I've just opened the wood pack and have noticed the 9.5 stock is 100 wide yet the wing plan shows the 'main panel' to be 102 wide how is this discrepancy managed?. There are not too many dimensions on the plan, I take it that any required are obtained by measurement of the plan itself - something we were never allowed to do at 'tech'

Mike

As I understand Mike the wing is made from 3 panels on each side have you takin in to account the 3mm spacers and wing dihedral braces ? also check the build article as there's some mention of shaving the wing down chord wise also check the wing chord on the side view as I believe this shows the intended chord at wing root

Phil

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Right! I've got everything. Plan, wood pack, canopies (2)!, pilots, seats etc. Been watching avidly everyone's contribuitions, toyed with the idea of a built up wing with retracts (tempting) but have decided to stick with the pure original Nigel Hawes concept, although might include the plywood inserts to allow the fitting of a fixed u/c, depending on where I will be flying it. Ordered on-line on Boxing day from Giant Shark an XYH35-42 1250kv 45A motor, Hobbyking Pentium 60A ESC plus various bits and pieces, all arrived this morning! Very good. I have got 3S 25C Lipos in 2200 and 3000 capacities to play with, just need to decide on the colour scheme (dither, chew fingernails, tough decision)!

So,clear the work bench, roll up sleeves and get stuck in. It's just like the Fizza all over again. one thought, on that I used Carbon Fibre tubes for the wing leading edges, it was very successful and I will do it again here.

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Very good Martin - but what are you going to do for the rest of the year (2013). A question for Phil Winks. Your removable wing mod, I notice it is now 3 sections, does this increase the overall wing span by addition of this third section?. Another Question for all you 'master builders' out there, - The fixed undercarriage mod - what method do you use to make the recess in the wing panel to take the 3mm ply reinforcement?

Mike.

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For the U/C recess I made a special tool

Assumming your going to bond in a 3mm ply plate, I cut a smaller (than the size of the trecess) square of 3mm ply and using double sided tape stuck on a piec of sandpaper, and a bit of scrap on the back to act as a handle.

Mark out the recess in the wing, cut round the edge with a scalpel, chisel out a bit of the balsa, use your tool to smooth out the recess, its the same deapth as the ply plate to act as a guide, epoxy on ply plate

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I was going to try using my small router to make the UC recess but that might be a bit over complicated.

Using a template consisting of a hole in some ply just bigger than the size of the recess (to allow for a router bit collar) then set the router end cutter to cut 3mm depth. Use a chisel to square off the slightly rounded corners.
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Posted by Mike Hardy on 29/12/2012 10:50:23:

Very good Martin - but what are you going to do for the rest of the year (2013). A question for Phil Winks. Your removable wing mod, I notice it is now 3 sections, does this increase the overall wing span by addition of this third section?. Another Question for all you 'master builders' out there, - The fixed undercarriage mod - what method do you use to make the recess in the wing panel to take the 3mm ply reinforcement?

Mike.

Mike the centre section for my removable wing is made by cutting that section from the origanal wing so no extra wing span the new dihedral braces should be made from the same material as the originals and the rest of the wing construction is then as per Nigels build article

Phil

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Posted by david fillingham 1 on 30/12/2012 18:55:17:

Can I ask what you used for the cockpit trim around the sides and over the middle? Is this tape or solar film / trim? Looks very neat.

David

David are you aware that "solatrim" is simply coloured tape sold at a huge markup. fablon is another name lol

Phil

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Hi Chaps!

well the "official" start date is 1st Jan - so for the rest of us taking part, time to put a new blade in the scalpel, dust off the building board, break out the PVA and get ready for the off!

I think its great of these guys to have ventured out ahead and sorted out all the problems for us! wink 2

BEB

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Hi David,

It is not trim but just narrow strips of Profilm ironed on with a very cool iron otherwise the canopy will be distorted. Don`t ask me how I know this! Sticky Protrim would be much easier but the cost would be even further through the roof. These lines are not very scale-like and have been enlarged a bit just to emphasise them. I used Profilm only because the rest of the model is done in this and not much else will stick to it.

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