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Started by lastvautour, January 08, 2010, 01:44:59 AM

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lastvautour

Nice series of planes you have there Barry.  Are they all 2009?

Lou

Balsabasher

Yes they are Lou,been trying to get the gallery models up to date as I have a backlog to put on.
Barry.

dave_t

Barry, are all of your recent models made from balsa? If so, do you have a local supplier? I don't see big blocks of it at the shops locally, but maybe I go to the wrong places.

Balsabasher

Dave interesting question,just recently I have been made aware of the distinct lack of block balsa on the shelves of what model shops there are left here in the UK at least,at one time you could buy block balsa off the shelf alongside the ordinary sheet wood but alas no more,the only way to buy block is to send your request to a good balsa supplier who should be able to fulfill your needs,I know of quite a few home builders of light aircraft who have ordered block balsa for wingtips and fillets on their creations so it is available to special order.
Sadly the introduction of ARTF ( Almost ready to fly-rattle the box ) models has deprived us of decent balsa,wire,tube,covering materials etc etc,every time my local hardware shop has balsa delivered which is far and few between months I grab the best stock even if at that time it is not needed,the best source of readily obtainable block is those balsa bundles which contain rougher offcuts but ideal for solid models built from balsa.
What I do if block is required then I laminate it with PVA adhesive and lay those old cast irons that are sold in Antique shops and can be found on car boot sales etc on top.
I divide my models between balsa creations for domestic building ( sanding into a large plastic bag in the lounge ! ) this stops the lightweight dust from flying everywhere,to workshop models built from any surplus pine,Jelutong etc that I can get my hands on,those heavier models such as the Blackburn Botha that was built recently are heavyweight creations  that an be whittled with chisel and Surform.
Thanks for your question Dave,whilst many consider balsa too soft I still think that it commands a good easily worked material for small solids,fine you need to spend more time rubbing down but that is half the fun,most of those old American plans mentions the new wonder wood 'Balsa' I love it and have proved that with care a good result can be achieved with simple tools ie scalpal,razor plane and a selection of abrasive papers.
Barry.

Oceaneer99

Barry,

You've been able to achieve a very nice finish with your balsa models.  I think most of us have had mixed results with balsa, so it's nice to see some have such success.  My son is still working on a balsa Spitfire model.  For him, balsa seemed less threatening to work with than harder woods.

Garet

Balsabasher

Basic method is-

1/ Sanding Sealer.
2/ Sand down the furry bits really well.
3/ Spray can high build car primer.
4/ Wet sand & desludge,wash well.
5/ Another coat of standard primer ( ie low build )
6/ Sand down well.
7/ Check over for any blemishes,rectify with Squadron putty.
8/ Acrylic rattle can spray 1st coat.
9/ wet and dry key sand down.
10/ Acrylic rattle can 2nd coat.
11/ Second colour application/trim.
12/ Brush coat of Johnsons Kleer.

Barry.

Joe

Barry,

Awhile back I noted that I had found a Cadet Aeronautics B-29, a vintage balsa model.  It is a lovely model that cries for restoration (photo attached).  Ken, Ray, and Lou all added to my ideas as to how to restore it without doing fatal damage.  Ken mentioned a high-build primer that he uses and your method provides me a second example of such service.  Excellent!

I think your complete method will work just fine for the restoration and I plan to use it or a minor modification of it.  Thanks for the advise and counsel.

Joe

cliff strachan

But Barry what do you think of the old tried and true Dope and Telcom Powder mix used as a sanding sealer/ grain filler for balsa? I've become quite reliant on this mix.

Cliff

Balsabasher

You bet Cliff,the time tried method is excellent and the beauty is that you can vary the amount of talc to do the job.
Just recently I have been experimenting with the cling film method,for anyone who has not tried this then give it a go,better to do parts on their own ie wing before assembly etc,basically what you do is add a generous layer of sealer or even white artists acrylic paint from a tube,this can be spread like butter with a palette knife keep everything wet and sticky,then take your cling film and stretch it tightly across the sufrace of the wing,dont worry about any surplus  as you can trim that off when dry,the film pulls the filler thinly across the grain both spanwise and chordwise and you merely wrap the ends around the surface.leave overnight and enjoy the sight of a beautiful surface appear as you pull away the cling film ! you can do the same with fuselages in sections by placing the cling film over the back of the model and pulling downwards,the film happily clings to itself which is a bonus.
This method would work well with those spackling fillers but as yet I have not had chance to try those out as they are not available here in the UK.
There is also scope for wood rot injection fillers which literally soak into the wood and make it turn into rock,I first saw this being used on a De Havilland Vampire pod in a museum,the balsa/ply construction needed restoration so the wood rot system was used,it took some sanding down ! all food for thought,use the system that suits you best personally and never be afraid to experiment on a piece of scrap timber.
Barry.

Balsabasher

This one is for Joe and his B-29 Restoration-
Joe I  have been looking at this lovely old model closely,what you need to do is get rid of that aluminium paint which is going to give you problems if left on the surface,what I would do is to dismantle the model into sections first,then rub away as much of the aluminium as possible with fine abrasive paper,once this is done you can then seal what is left of that finish by applying a coat of Johnsons Kleer ( now obsolete but still available on the polish sections of supermarkets ) this will seal the finish and then you can spray a coat of acrylic grey car filler over the top ready to add the final silver.
I would be wary of going near it with any cellulose based products as it may lift the silver,as an alternative to the above you could seal it with thinned down PVA adhesive 50/50 instead of the Johnsons,then you can add a spray finish on the top,it is all about shielding what is underneath ! they use a similar system on old cars that need a shield shim of something before the respray is done,that is polyvinyl based.
Barry.

Joe

Barry,

Thanks for the note.  As you probably know, I have restored a number of Strombeckers, a task made easier, in general, because water soluble casein glue was provided with the models and often used by the vintage builders.  Since Strombecker used pine for their models, very little damage is done when dismantling an old model. 

However, Cadet's use of balsa scares me and if a glue more substantial than casein were used, my concern about damage to the model rises to a higher level.  Thus, I am sorely tempted to use your approach in regard to removing the Al paint, but with the model intact.  I would hazard a guess that your concern with that approach is the possibilty of leaving some Al paint on and said paint eventually bleeding through.  I would hope that a careful, pre-priming exam would preclude that.

There is another experiment that I am pondering.  On this side of the pond we have a product called ZINSSER's 1.2.3, a stain blocking primer.  I have used it with complete success for covering materials such as lacquer, shellac, and modern water-borne stains/paint.  It has a solid content that makes it behave like a high-build primer, but it can be diluted, as well.  I think I will experiment with it to see if it will "block" Al paint.  According to a sales rep, it will.  However, sales reps can sometimes stretch the truth...  I will report back to the gang regarding the results of my experiment later in this Anno Domini MMX.

Again, thanks for your advise and counsel: it is invaluable!


Joe


Balsabasher

Yes Joe I can understand the problems with balsa as opposed to hardwood restorations,best keep it in one piece and handle carefully,never done a Strombecker but have done numerous ID models in the past and they come apart fairly readily.
Golden rule here it seems due to the fugative nature of that silver is to keep to neautral finishes ie acrylic based,you may find a good idea with that pool solution,give it a try on an inconspicuous area first.
Best of luck and look forward to seeing the end product.
Barry.