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Lost Mold

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craig.nelson(at)heraeus.c
Guest

Posted: Wed Mar 05, 2008 10:18 am Post subject: Lost Mold

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I do use dry wall plaster in making lost mold techniques along with

paper..on this mold I used gauze and it worked out very well.. I also

use clay to do little fixes-- after the plaster is shaped to the final

contours and ready for composite I seal the surface with a dental

separator used to make dentures and then the residual plaster can easily

be rinsed away with water. After the part is removed from the plaster

and trimmed the surface is smoothed and prepared for paint.



Uncle craig

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craig.nelson(at)heraeus.c
Guest

Posted: Wed Mar 05, 2008 5:02 pm Post subject: Lost mold

<<DSCN1909.JPG>> In a few hours from start to finish custom farings

Uncle craig

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ElleryWeld(at)aol.com
Guest

Posted: Wed Mar 05, 2008 5:48 pm Post subject: Lost mold

 

 Uncle Craig that's not the color I wanted ......Just  Kidding they look like every thing else you make Like Factory  

  

 Ellery 

 do not archive

  

  In a message dated 3/5/2008 8:03:59 P.M. Eastern Standard Time,  craig.nelson(at)heraeus.com writes:

  	  Quote: 	
		  <<DSCN1909.JPG>> In a few hours from start to finish custom    farings

Uncle craig 	




It's Tax Time! Get tips, forms and advice on AOL Money & Finance.

  [quote][b]

Bill Vincent

Joined: 30 Jan 2006
Posts: 84

Posted: Wed Mar 05, 2008 5:57 pm Post subject: Lost mold

wow! It looks great



DO NOT ARCHIVE



<<DSCN1909.JPG>> In a few hours from start to finish custom farings

Uncle craig

_________________
Bill Vincent
Firestar II
Upper Peninsula of Michigan

NeilsenRM(at)comcast.net
Guest

Posted: Thu Mar 06, 2008 8:27 am Post subject: Lost Mold

I'm going to ask a stupid question. Why the extra step of the lost mold? Why 

don't you just form the composite on the plane?



Rick Neilsen

Redrive VW Powered MKIIIC

mdnanwelch7(at)hotmail.co
Guest

Posted: Thu Mar 06, 2008 10:06 am Post subject: Lost Mold

 	  Quote: 	
		   I'm going to ask a stupid question. Why the extra step of the lost mold? Why

 don't you just form the composite on the plane?



 Rick Neilsen

 Redrive VW Powered MKIIIC


	


  Mr. Rick,



  Excellent question.  I guess in some case, especially where outer surface appearance isn't that important, you could do that.



  However, when making most items to be installed on your Kolb airplane, you want them to have the high quality and beauty that Uncle Craig creates.  In order to get that level of perfection, you pretty much need to build that "perfect" part, in position, on your plane......and then copy it (with the "lost mold", and then recreate it.



  Here's why;  If you do all that "rough" build up, like with tape, or wood strips or plaster, or whatever you choose to use, you have is the approximate shape.  Say you go ahead and add some smoothing agent, like the joint compound, or bondo, of carving foam, etc., and you've shaped your fairing....real nice.

Ok, so now you start the fiberglass for the finished piece.  Remember, the really nice surface is on the INSIDE of your layers of fiberglass, not the outside.  But, let's continue.  So if we put a few layers of fiberglass on the outside, and once it's cured, pull it apart.  You will find you have something that is similar in shape as your build-up, but, boy, is the outside in rough shape.  You will have to sand, and sand, and sand, on, and on.  And I'm here to tell you, fiberglass impregnated with resin is darn near rock hard.  Shaping after the fact is a living nightmare!!!!  It will be the same process you just went through, making that "perfect shape" on your plane, only this time you won't be smoothing bondo, or joint compound, you be trying to smooth....well, glass!!!



  Even though making a "lost mold" is a lot of work, and on the face of it, APPEARS to be double the effort, it really isn't.  You will spend much more time trying to enhance the appearance of the shortcut method.



  Another very big difference between the proper mold method, and the quick "lay on some fiberglass layers" method is weight.  Think about it.  If we make our sculptured shape flawless...on the plane...in position, and then make a thick rigid mold, whatever we build on the inside is going to be just as flawless (on its outer surface...the important surface).  We can probably get away with as little as 2-3 coats of glass.  This piece will be virtually perfect, needing only very minor and easy edge trimming.  Lightly sand and then paint.

  But if we try to get away with 2-3 coats of an outside build, the piece will have all kinds of flex and give as we try to make it "perfect".  We'll need 5-7 coats of material, to have the necessary rigidity to sand the heck out of it.



  While I understand your logical question, the industry standard is to build a mold of a "finished product", then recreate that finished product INSIDE the mold.  BTW, not all mold are "lost".  Obviously,  many molds are built to withstand the ability to make hundreds of copies. (bathtubs, , boats, etc)  That is why the release agent is so critical.  It leaves to mold unharmed by trying to pry out your beautiful artwork.



Best regards,  Mike Welch



  

_________________________________________________________________

Helping your favorite cause is as easy as instant messaging. You IM, we give.

craig.nelson(at)heraeus.c
Guest

Posted: Thu Mar 06, 2008 11:07 am Post subject: Lost Mold

I can shape the piece with plaster make the contours perfect. The

plaster sometimes gets up to 1 inch thick. The part ends up one layer of

s glass one layer of carbon and one layer of s glass extremely light and

not much filler to smooth it out.

Uncle craig



--

craig.nelson(at)heraeus.c
Guest

Posted: Thu Mar 06, 2008 11:32 am Post subject: Lost mold

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.Lost mold means just that. The mold is lost when the part is made. I

make a positive mold out of tape to get the basic shape then the plaster

is used to make the mold strong enough to remove from the plane..  More

plaster is used to get the proper contour of the part .. Then I apply

separator to the plaster called Aislar a dental denture material in

dentistry it is call tin foil substitute used to fill the pours plaster

so acrylic does not stick to it. Then I wax the plaster form and apply

the layers of glass and resin, when this sets up I remove the part from

the mold. The plaster brakes up on removal because it is not strong

enough to stay in one piece when removing the part.( lost mold it is

only good for one part) Then I fill the weave of the cloth with filler

and paint it

Uncle craig

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MKIIIX040

Joined: 31 Mar 2006
Posts: 123
Location: Millinocket, Maine

Posted: Fri Mar 07, 2008 8:00 am Post subject: Lost Mold

Mike, Stupid Question # 2

 Would the finished fairing have a larger ID than  the plaster mold (1st build up)?

 Seems like you would have to extend the finished  fairing out beyond the edges so it would meet the strut cover or whatever it  contacts. How is that done if your doing a layup inside your mold?

  

 Note: 10 layers of glass mat ( video), if I used  that much my part would weigh  100 lbs. and be an inch thick.

 Vic

 N740VP

 If you can still see out your house windows you  didn't shovel as fast as you could have.

   [quote][b]

_________________
MKIIIX040
912UL

mdnanwelch7(at)hotmail.co
Guest

Posted: Fri Mar 07, 2008 9:15 am Post subject: Lost Mold

Hi Vic,



  Again, nice observation.  If you shaped a perfect fairing (on your plane), and you took a mold off that perfect fairing, and then you built your part on the inside of that mold, your finished part (fairing) would be slightly smaller, not larger.

  With this understanding, that your part will be slightly smaller (by the width of you glass layers) you may want to build up your sculpted prototype, with extra tape, etc.



  This is especially important if you are building something that has an opening, like our fairing.  Our fairing has two area of interest...the part that fastens to the fuselage.  A tiny bit smaller, or bigger would never be noticed.  But the part that has a hole, that slips up the wing strut, won't fit unless you've made that opening a little oversize".  No doubt, Uncle Craig allowed for this.



  I know it seems to get a little confusing, but if you take into consideration that male, female, male, undersize, oversize, etc., etc. changes, it really isn't hard.



  Example, if I were to make that exact same part as Uncle Craig made, I would wrap the wing strut with...oh, about 3 layers of duct tape, since duct tape is "close" to the thickness of fiberglass cloth.  3 layers of tape gives you room for 3 layers of glass.  So, now, when you build a mold around that wing strut, the hole in your mold will be oversize.  Right?  Therefore, when you start putting in the layers of fiberglass, or carbon fiber, inside your mold....you will be closing in on that original wing strut diameter (prior to the duct tape).



  The portion of the mold near the fuselage doesn't matter if it's 1/6"-3/32" smaller, you'd never know.  But the part of your fairing that needs to slide up and down the wing strut won't fit, unless you accomodate for it.



  The video of mold making was just that....only the mold.  That's why the 10 layers.  He was making a mold, not the finished part.  With this mold he made, he can now apply plenty of mold wax, then gel-coat, and then 3-4 layers of cloth (whether it is carbon fiber, E glass, S glass, etc.)  Because his mold is 10 layers thick of fiberglass, it should last for years, and hundreds of "take-offs".



Mike Welch





Mike, Stupid Question # 2



Would the finished fairing have a larger ID than the plaster mold (1st build up)?



Seems like you would have to extend the finished fairing out beyond the edges so it would meet the strut cover or whatever it contacts. How is that done if your doing a layup inside your mold?



Note: 10 layers of glass mat ( video), if I used that much my part would weigh  100 lbs. and be an inch thick.



Vic



N740VP



If you can still see out your house windows you didn't shovel as fast as you could have.





_________________________________________________________________

Helping your favorite cause is as easy as instant messaging. You IM, we give.

MKIIIX040

Joined: 31 Mar 2006
Posts: 123
Location: Millinocket, Maine

Posted: Fri Mar 07, 2008 11:12 am Post subject: Lost Mold

Thanks Mike. By jove I think I've got it   Finaly

  

 Vic

 N740VP

   [quote][b]

_________________
MKIIIX040
912UL

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