1/10th scale Blackburn Beverley.

[MalcolmDouglasPorter]

Had a frustrating couple of days. Did I say this was the fun stuff? These are seriously compound curves. I will be needing to use a bit more filler than I had anticipated in a couple of areas, as you can see from the picture.

Talking of filler, can any of you tell me which are the preferred filler types for the balsa skin. Perhaps I can get away with ordinary car bodging P38 or similar?

[Alan Cantwell 1131]

P38 is heavy, and OTT, there are a few fillers out there, i dare say guys will be along with their favorites, I just googled balsa filler, and found some,
About the shape of the balsa for the doors, did you just bend the wood, or did you get some assistance, I used to use ammonia, make a poly bag, long as your wood, seal one end, put the wood in, add ammonia , seal the bag, leave a few hours, you can then even tie a knot into it, when the ammonia dissipates, the structure of the balsa returns, leaving the bend in place,

[Phil Clark]

P-38 and the other polyester based car body fillers are way to heavy & also way to hard......when used in this application, you'll sand away the surrounding (soft) balsa before sanding the filler fully to profile. Only use P-38 (very sparingly) once the balsa is glassed, hard & fully protected.

There are several light weight balsa filler available (Deluxe Materials etc....)......there is even a very light weight ready mixed polyfiller available (One Fill)

I can also vouch for Alan suggestion re:- ammonia.........it works beautifully.

Phil

[Karl mander]

Hi Malcolm

Cracking work on the Beverley. I have the upmost respect for the fact that you are designing the model all yourself, this is more than I have dared to do.

I'm a keen builder and have used various methods of covering. I've had good results with glass cloth and pond sealer, however mindful of the fumes, I now use water based floor varnish.

In relation to filler do not use car body filler, it's far too hard compared to the balsa. I use West systems microlight balloon filler and there quick epoxy. However I mix in vast amounts of the microlight filler to the epoxy, thus only a small amount of epoxy in the filler makes it easy to sand, plus it's light., I mix up a ratio of filler that ends up having a consistency of whipped cream, the instructions give a ratio that ends up like smooth peanut butter which is hard to sand.

Karl

[Keith Mitchell]

PolyFilla Lightweight - the best of the lot. Used it for years; easy sanding and light weight, water soluble.

http://www.wickes.co.uk/Polycell-Polyfi ... /p/228110#

[MalcolmDouglasPorter]

Thank you guys for all the info. I have some lightweight Polyfilla, and believe it or not, I had wondered about using this, so I'm glad that a couple of you pointed to this. I had to do a bit of glassing inside the cam shell to support the balsa where the filler is most needed. I had to feather the balsa to a very thin profile in one place to get the correct shape. I am hoping that this little glassing patch will help support it. When I continue with the other side of the cam shell, perhaps I will adjust my methodology a little to prevent the bulge from happening. It is extremely difficult to get the wood to bend to the exact shape in a couple of areas as there is a change of direction and a twist in the other direction. Instead of using one strip all the way along, I will terminate it at the problem area and scarf in another piece to continue the run. This could produce a small lump that will easily sand off. The photo shows an acceptable job so far!

I could do with some more info on the ammonia? Do we fix the wood in place whilst the ammonia is still active, or do we bend the wood then wait till the ammonia has worn off before gluing in place. How long is the working time once taken out of the bag. Oh, one last thing, where can we buy ammonia?

[Alan Cantwell 1131]

Treat the wood in the bag, as i said, fit the piece, glue and pin it in place, ammonia will evaporate, job done, Ammonia, i havnt done any serious building for quite a while, i used to get ammonia from a local supply, but H&S have spolied that, i do believe some cleaners are rich in ammonia, and some use these

[Nigel Cox]

Amonia http://www.ebay.co.uk/itm/Max-500ml-Str ... 4d11a98358 not sure if this is strong enough ?

[Alan Cantwell 1131]

Nice one Nigel, thatl do nicely

[MalcolmDouglasPorter]

Thanks for the link Nigel, I have ordered some.

I have been planking the other side of the cam shell in a slightly different pattern and am getting much better curves. Instead of the alternate side/bottom method, I have feathered the bottom planks as needed, terminating them in a more natural position rather than forcing the twist which causes the plank to belly outwards and distort the intended shape. I am currently planking from the top (the assembly is upside down on the bench) until I reach a point where alternate planking is viable to complete the side. This side will require much less attention with filler etc. I think, based on advice given by you lot, that I will complete the shaping corrections after the glassing is done. I will just fill to enable a reasonable shape for the glassing, then use a slightly harder filler for the final finish followed by an extra coat of G4 and prepped for primer coat.

Talk about learning curves! (No pun intended)

[Alan Cantwell 1131]

Groan

[Ben Catley]

Malcolm ,

Those doors ... Clam Shell , Not Cam

Been enjoying from day 1 , Keep it up.

[Stephen Jefferies]

Malcolm ,

Those doors ... Clam Shell , Not Cam

Been enjoying from day 1 , Keep it up.

Ditto - looking forward to seeing your colour scheme...hope it's the desert camo...

[Alan Cantwell 1131]

One thing about using ammonia, protect the airways and your hands, marigolds and a face mask are the norm, H&S has some uses

[MalcolmDouglasPorter]

Who feels a proper prat! CLAM SHELL!

The colour scheme I have decided on is the original 84 Squadron Grey / White. This is the scheme that was in use when I worked with these aircraft. I do not recall them being in camo at any time in my service. What I have not yet decided is the aircraft identity, any suggestions welcome (84 Squadron of course).

As you can see from the pictures, I have completed the planking on the CLAM SHELL doors. I have applied some lightweight filler and when this is dry (in the morning) I will coat the inside with some G4 to consolidate the small nooks and crannies, and give a better adhesion for the skin balsa. I may well glass this sooner rather than later to solidify the structure.

[Stephen Jefferies]

Who feels a proper prat! CLAM SHELL!

The colour scheme I have decided on is the original 84 Squadron Grey / White. This is the scheme that was in use when I worked with these aircraft. I do not recall them being in camo at any time in my service. What I have not yet decided is the aircraft identity, any suggestions welcome (84 Squadron of course).

Nice scheme the great and white - just FYI here's a link to the desert camo scheme as used by 84 Sqn in Aden.

http://www.hu17.net/2010/03/09/blackbur ... ort-plane/

Interestingly I found earlier that some design genius put the lavs outboard of the paratrooper drop doors in the bottom of the boom and some poor sod fell to his death after exiting the bog without knowing the doors were open...what a way to go...

[John Greenfield]

Malcolm

Please understand that G4 does not work like epoxy and painting it onto the inside of the model to "fill nooks and crannies" will not work too well if they are of any size. G4 is a single component substance what will not cure properly if applied in any thickness. It is ideal for applying glass cloth to the model but if as I suspect you want to add something to the inside to strengthen it up and add support to the sheeting joins you would be better off using some of the epoxy you have already purchased. This will fill the joints better and cure properly so giving the structure support. Just be careful not to apply too much as it is heavy.

John

[Alan Cantwell 1131]

Would this mix with micro ballons John, To fill it out sort of thing?

[MalcolmDouglasPorter]

Yes indeed John, I accept fully what you are saying. As part of my recent research to learn about these things, I discovered nature of the various types of resin etc, and one of the important aspects (for me) was that ideally it should not be high viscosity, which G4 is not. So it occurred to me that this stuff would be ideal for reaching into the smallest of nooks and crannies and assist in the structure of the skin. If there was a residue, I tilted the assembly from side to side, back and forth until the G4 was dispersed in a satisfactory manner. What I can say with absolute certainty is that this application has worked brilliantly. The photograph does not really show this too well, but I am very happy with it. There will be circumstances where the use of the West System stuff will be useful, or indeed preferable, I'm sure.

One thing I have learned about G4. When replacing the tin cap, please be sure to remove any excess gunge from the threads. I had the take a mole wrench to it!

[John Greenfield]

Alan

G4 does not work with micro ballons. If you need to create a "filler" there are better things to use.

John