Vac-forms, these days

[JamesP]

I do indeed, Rene and have already started the master.

I have a selection of drawings from some highly detailed large scales from R/C Canada to the beautifully crisp rendering in Ralph Pegram's new book.

Thankyou for the tip about this book! It sounds excellent. I have the Robert Hirsch book, but this is slanted to the US aircraft and I spotted a couple of errors compared to photos in his otherwise excellent drawings of the the Sea LionII when building the Karaya model.

[Scratchbuilder]

James,

the Pegram book is the result of 30 years of deep research, a remarkable achievement. It is beautifully presented and every drawing is to the same style and standard, many with sections and framework info. All with a scale.

I hope you enjoy it.

Cheers,

Martin

[Paolo]

also I liked a lot vacuform planes.

have some kilos to sell around, but mostly military planes, not civil.

Think they were much more better to work with than any resin...

[rbeach84]

Good Quality vacform epoxy/aluminium resin moulds material cost around £30.00 a kilo, anything else will cause problems. A high vacuum pump is essential for sharpness. Drilling holes-no I don't, I have my own method and if I have to drill I don't use twist drills. Use of a female mould does mean material thickness will change, quite markedly so in narrow deep draws. Pre cut vacforms have been the holy grail for a long time, it is very difficult. If a hi speed rotary tool is used then styrene quickly heats and deforms and burrs also the parts need to be held securely and that's not easy (there are ways such as vacuum but vibration of the model shell can release the vac with an instant change of shape the result). If a horizontal band saw is used blade/ material vibration and bounce causes an uneven surface and posible mould damage unless a slave mould is used and that can be problematical.

A vac pulled at start of work will be different in size to one at close of work.

John

John, I believe Scratchbuilder's point was that the external surface dimensions of a female molded part will exactly match the master whereas a male molded part is made from an undersized master with allowance for the thickness of the molded material. In a way, male masters would be a candidate for some very serious computational analysis to accurately "model" the flow and stress/deformation behaviors of the plastic sheet (pun intended.)

Considering how having the parts integral with the 'sheet' has benefits with packaging, protection and providing raw material for supporting structures for little cost in weight, not to mention the savings from *not* having to remove the parts, I just don't know how 'pre-cut parts' make sense. Getting the parts ready for use is not hard - just different!

I once again propose that a state of the art 'vac, multi-media kit' as achieved by you (Aeroclub), Bill Koster and the (early) MPM folks is the perfect model (again with the pun!) for targeted, low production kits. The fact that Bill could produce a beautifully engineered, fully boxed, *complete* (with resin, decals, metal AND photoetch) 1:48 Fw200 kit for US $70 when the Trumpeter kit was selling for over US $100 proves just what is possible. (This is to say nothing of the fact that the Koster kit is more accurate, too!) The lower cost & lower tech of vacuform kit production is perfect to meet the mature, craftsman modeler's need (or 'desire' as the wife rightly asserts) for the esoteric or out-sized subjects (aka, the 'wishful thinking' subjects.) Further, fine detail need not suffer if the maker has the requisite skills and if 3D CAD modeling is part of the in-house skillset, then mastering finely detailed "bits" comes down to a 3D printer (or 3D printing services) followed by resin production. Production is not really the issue, it is distribution.

This pro-vac argument has been an up hill battle for years, but now that the Chinese injection kit makers have adopted a low production, fast ROI (return on investment) business model, lower tooling cost production methods definitely stand a chance. Also, if they continue to 'half-bottom' their research (can I get a "Vampire"? Hallelujah!), their target market will sour on them - if it hasn't already. I still dread scratchbuilding a hull for my USS Hornet, but I can't ignore it and Doolittle demands better anyway. More and more, I see mates switching to the 'old kit' or 'second hand' kit market - or even looking at paper modeling (now, THAT is a challenge!) in light of these ZONKS kit prices. Our local club used to run a raffle for fun and fund-raising but no more. Too expensive for our crowd.

Now seems to be the time for a maker to adopt the WingNut Wings business model with some quality no-holds barred multi-media kits. The fact we are hashing about on this forum tends to prove how connected we have become so it is actually viable to work solely via the web, foregoing traditional distribution houses and in effect, meeting the customer head-on. Would require a different allocation of resources when you must manage your own distribution, but with all the automation tools floating about it *should* be feasible. I seriously doubt it could be a 'one man operation' anymore without being grueling. I suppose you are well aware of that point...

Brave new world for the modeling hobbyist!

Time for dinner. Cheers!

Robert

Edited March 26, 2013 by rbeach84

[Scratchbuilder]

Hi Robert,

sorry, I seemed to miss your post somehow. Thanks for your thoughts.

I'm sure you have many points there that are very valid, but only for a "business" model type of company.

I am not, however, a company or even a business, really. I AM an ex business owner from way back, who was a one man band and yes, it was gruelling, which is why I packed it in. Fumes from casting white metal, unreliable suppliers and worst of all packing very fiddly model car kits brought it all to an end. But in that time I sold a LOT of models, both kits and builts and my old kits now appear on ebay, etc. for the kind of money I wish I could have got then!

No, this time around it is purely a little scheme to help my son get some use out of his home-made vac-former and make a few bob away from his dull day job.

Whilst I do see CAD and 3D printing making some inroads into "my" world of handmade masters, it's not for me. I can't make Turbo CAD work, even with a DVD How-To, so it's brass and files for me, which I can put to equally good use fortunately.

Certainly the internet is now a force to be reckoned with from a publicity point of view, not to mention information, which used to be a pain and require a huge library of books and magazines and a lot of travelling. Fuel prices have knocked that on the head too.

So very small time is where I shall be staying this time, but that does not mean any compromise in accuracy or quality. Decals and p/e are far more difficult to get done than they used to be, with only one etcher that I know of accepting pen artwork and heaven knows what the increasingly rare decal producers ask for these days. Technology has not altogether meant improved choice.

I do everything by hand, because I can and have done so with complete success.

My aim is to keep these vac-form kits down to a reasonable price and so vac-forming fits there as well, though plastic prices are constantly on the rise and w/m has jumped three fold in 18 months, but I do have a reliable man there. But, he's no youngster. If he chucks it in, I really will be stuffed!

Cheers,

Martin

[rbeach84]

Martin, I understand; nature of being a 'cottage industry' maker, I wager. As I said elsewhere, I for one am pulling for you & your 'mini-me' to have a good go at it as far as you wish to take it. Does bite when it isn't fun anymore... so I hope it stays such!

Your words re: CAD ,etc were mirrored not too long ago by my friend David Merriman, who works much as you do. He feels a modeler needs to have draftman's skills. I took a CAD course in college and it has proven very useful - but it followed the square & pencil basics that allowed me to understand what I was doing as well as knowing the how. In the end, it is all tools for the 'job' so if it works, bully.

Not to mention the satisfaction of working with one's hands!

Regards, Robert

[JOCKNEY]

Hi Martin

As a flying boat fan, often as not vacform is the only way to obtain some aircraft hence my collection of Contrail kits. As a builder the later ones that also had injection parts and decal make life simpler, apologies to the purists !

What seaplane / flying boats / float planes have you manufactured ?

Cheers Pat

Edited April 11, 2013 by JOCKNEY

[Scratchbuilder]

I haven't manufactured any yet, Pat, but the Waco will be offered with a float or ski option as well as the wheels. Lars Opland furnished me with excellent reference on floats and skis, including all the Edo and Fairchild float drawings.

Any a/c I do that ever had floats will be offered with them.

I also rather fancy the SR53 jet flying boat in the Experimental series.

Cheers,

Martin