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Old Sep 29, 2011, 04:22 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
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Originally Posted by kgfly View Post
The plugs are works of art by themselves, and they are just to make two pods for one model!

I have seen others create surface details such as rivets and panel lines on their plugs so that they will be inherent in the molds and hence part of the finished parts. You did not want to go down that path?
At this point I still don't know the level of detail I will show on the plane, I did not want to show too much on the pods and then have to sand it off.

I have some ideas on how the finish will look, but need to experiment more to see what will work on over 16,000 square inches of airframe.

Thanks, DAG
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Old Sep 29, 2011, 04:31 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
5,820 Posts
Well here is the $330.00 mess that in the end will work great.

Somewhere I really screwed up my calcs on volume. This liquid mold stuff is more expensive than molten gold. I should have had enough to make 3 molds, top/bottom, front. a gallon is about $160.00, and it took it all for just 1 mold. This is why this plane is so freaking $$$$$$. I had blocked of the un-used parts of the mold, but still was way off, but not a total surprise with everything I am trying to do right now in life.

I am 110% happy with the results, but my budget on this plane is getting scary, and it is not even Halloween yet.

Oh well...... At least if I ever build a 168" B47 I will have the jet pods, oh wait? No it won't because even though they came from the B47 in the 50's they were modified to be more sleek.... So all of this for 2 pods???? Now I really need to be put in a rubber room.

DAG
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Old Sep 29, 2011, 05:14 AM
Joined Jul 2007
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Originally Posted by Bob Snedegar View Post
In case this hasn't been posted earlier in the thread, there is a 1950's USAF SAC film on youtube showcasing the Peacemaker - startup, taxiing and takeoff with good interior views of flight deck and crew stations - shows how really enormous the aircraft was. A truly incredible machine!
Dag, when you do the maiden flight you WILL have to play the music in the video!! You will make many grown men cry. LOL
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Old Sep 29, 2011, 05:59 AM
Hey Guys, Watch This.......
mike2663's Avatar
USA, TX, El Paso
Joined Dec 2003
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Originally Posted by dag214 View Post
Well here is the $330.00 mess that in the end will work great.

Somewhere I really screwed up my calcs on volume. This liquid mold stuff is more expensive than molten gold. I should have had enough to make 3 molds, top/bottom, front. a gallon is about $160.00, and it took it all for just 1 mold. This is why this plane is so freaking $$$$$$. I had blocked of the un-used parts of the mold, but still was way off, but not a total surprise with everything I am trying to do right now in life.

I am 110% happy with the results, but my budget on this plane is getting scary, and it is not even Halloween yet.

Oh well...... At least if I ever build a 168" B47 I will have the jet pods, oh wait? Know it won't because even though they came from the B47 in the 50's they were modified to be more sleek.... So all of this for 2 pods???? Now I really need to be put in a rubber room.

DAG
Use the old home repair method of calculating cost. Take your original estimate and triple it. This way you'll never freak out over cost overruns. Seems to work around my place on all my projects.
Mike
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Old Sep 29, 2011, 08:01 AM
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Liverpool, England
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Hi Dag,

This is my first post on this thread so first off I would like to say how awesome this all is, I have followed over the last couple of years and love watching progress absolutely fantastic

Anyway what I wanted to comment on was the technique you are using to produce the flexible moulds. Whilst most people (including myself) use this technique because it is easy to do it isnt the best method for larger items such as the pods.

The best method is to place the item on a parting board and cover evenly with 3/8" > 1/2" of clay building a ring around the outer edge of the item. This is then covered with plaster of paris and hessian for low use moulds or fibreglass for high use. The outer position of the case is marked for reference use. When set the case is removed together with the clay. Holes are drilled in the case at high points to prevent any air traps then a funnel is attached in a convenient location but not at the top of the mould.

The case and funnel is then re-aligned over the plug using the reference marks and fixed in position temporarily (I use plaster and hessian) with the outer edge sealed with clay.

You can then pour the liquid mould into the funnel to fill the gap where the clay was sealing the air holes with clay as you fill. Allow to set, remove parting board and repeat for the other side.

It is more long winded but you can imagine uses a fraction of the liquid mold and has two specific advantages, the first being the case acts as a support for the flexible mould and the second prevents any differential shrinkage due to the unfirm thickness of the mould

Sorry for the long winded post, hope this helps at all
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Old Sep 29, 2011, 08:12 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
5,820 Posts
Quote:
Originally Posted by heli_madken View Post
Hi Dag,

This is my first post on this thread so first off I would like to say how awesome this all is, I have followed over the last couple of years and love watching progress absolutely fantastic

Anyway what I wanted to comment on was the technique you are using to produce the flexible moulds. Whilst most people (including myself) use this technique because it is easy to do it isnt the best method for larger items such as the pods.

The best method is to place the item on a parting board and cover evenly with 3/8" > 1/2" of clay building a ring around the outer edge of the item. This is then covered with plaster of paris and hessian for low use moulds or fibreglass for high use. The outer position of the case is marked for reference use. When set the case is removed together with the clay. Holes are drilled in the case at high points to prevent any air traps then a funnel is attached in a convenient location but not at the top of the mould.

The case and funnel is then re-aligned over the plug using the reference marks and fixed in position temporarily (I use plaster and hessian) with the outer edge sealed with clay.

You can then pour the liquid mould into the funnel to fill the gap where the clay was sealing the air holes with clay as you fill. Allow to set, remove parting board and repeat for the other side.

It is more long winded but you can imagine uses a fraction of the liquid mold and has two specific advantages, the first being the case acts as a support for the flexible mould and the second prevents any differential shrinkage due to the unfirm thickness of the mould

Sorry for the long winded post, hope this helps at all
I think I am following you, any pictures for my slow mind to see this?

Thanks, DAG
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Old Sep 29, 2011, 09:16 AM
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RiBell's Avatar
Canada, BC, Abbotsford
Joined Jan 2003
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Quote:
Originally Posted by heli_madken View Post
Hi Dag,


The best method is to place the item on a parting board and cover evenly with 3/8" > 1/2" of clay building a ring around the outer edge of the item. This is then covered with plaster of paris and hessian for low use moulds or fibreglass for high use. The outer position of the case is marked for reference use. When set the case is removed together with the clay. Holes are drilled in the case at high points to prevent any air traps then a funnel is attached in a convenient location but not at the top of the mould.


You can then pour the liquid mould into the funnel to fill the gap where the clay was sealing the air holes with clay as you fill. Allow to set, remove parting board and repeat for the other side.


Sorry for the long winded post, hope this helps at all
I've re-read you post a couple of times. Think I sorta get it. But as Dag said pictures?
So did I get it?
What you end up with is a solid mould that has between 3/8 and 1/2 thick layer of the liquid mold stuff against which the part will be made.
Rick
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Old Sep 29, 2011, 10:24 AM
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Liverpool, England
Joined Jan 2005
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Hi,

Hope this helps, section through, the technique is called 'case moulding' and certainly not my idea so you should be able to find more info on the net, its actually a technique I learnt as a fibrous plasterer.

Notice how the fill line of the moulding compound in the funnel is higher than the highest point of the model, this applies a head of pressure to the mould and helps prevent the formation of bubbles. During filling you allow some of the compound to spill out through the airholes to also allow bubbles to escape before plugging with clay.

Also note the upstand around the perimeter of the mould to locate the flexible in the case whilst taking casts.

Thats exactly right Rick 3/8" to 1/2" thick mould uniform across the entire surface, you can actually get away with a 1/4" on the majority of low profile stuff

Ken
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Old Sep 29, 2011, 02:15 PM
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Aurora, Ontario, Canada
Joined Mar 2002
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Quote:
Originally Posted by Bob Snedegar View Post
In case this hasn't been posted earlier in the thread, there is a 1950's USAF SAC film on youtube showcasing the Peacemaker - startup, taxiing and takeoff with good interior views of flight deck and crew stations - shows how really enormous the aircraft was. A truly incredible machine!
Bob, now one's pointed it out yet, but this is a cut from "Strategic Air Command", a commercial movie from the big studios back in the 1950's starring Jimmie Stewart and Harry Morgan (aka Colonel Harry Potter from MASH).

Not a USAF film, but certainly shows the ability of the studios to get the Air Force to co-operate.

However, as a document covering flight operations (one take-off, one landing), I agree, "incredible".
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Old Sep 29, 2011, 07:50 PM
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Chantilly, Virginia, United States
Joined Jul 2004
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Originally Posted by byrocat View Post
Bob, now one's pointed it out yet, but this is a cut from "Strategic Air Command", a commercial movie from the big studios back in the 1950's starring Jimmie Stewart and Harry Morgan (aka Colonel Harry Potter from MASH).

Not a USAF film, but certainly shows the ability of the studios to get the Air Force to co-operate.

However, as a document covering flight operations (one take-off, one landing), I agree, "incredible".
I thought some of the crew looked and sounded familiar! Will definitely rent the movie.
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Old Sep 29, 2011, 10:24 PM
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Somewhere in central Oklahoma
Joined Oct 2007
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Quote:
Originally Posted by Bob Snedegar View Post
I thought some of the crew looked and sounded familiar! Will definitely rent the movie.
Its amazing how many folks do not know that movie exists. A friend here at work is a big Jimmy Stewart fan, and he'd never heard of it. I ordered it online and loaned it to him to watch. He liked it enough to get a copy for himself.

Always been a fan of the Magnesium Overcast. I am right now wearing a B-36 tee shirt that says "Six turning, four burning". Also have a six foot scratch built control line model hanging up in my garage, that I built 30 years ago when I was a young 20 year old. Powered by six Cox Tee-Dee .051s, so it was only ever flown twice due to difficulty getting started. What a racket those things make! I think I lost the hearing in my right ear fooling around with that beast.

I scaled up the three views from a Squadron Signals book, made my own plans and built it in about a years worth of time. You bug me enough, I'll take it down, clean it up and get some picures. Far as I'm concerned, anyone who scratch builds a flying model B-36 has got the bug BAD.

Your project is awesome, and I've been following it for some time. Cannot wait to see it done.

That clip from Strategic Air Command is my all-time favorite short clip, watch it all the time.

Carry on.

ps: here is the one photo I do have showing the clean side. ;-)


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Old Sep 29, 2011, 10:58 PM
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United States, Mt, Belgrade
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Movie Question

Let's see what people ring in on this one. While watching that clip again ( have to watch it again even though I own the movie and have watched it several times) I noticed that the rudder seems to be exactly opposite of nose wheel control.

Why is that? Were the nose wheel and rudder directly inverse or were they seperate controls that happened to be working against each other for the movie .

Curious and thanks.... Great progress on the 36. Thanks for letting us ride along and spending the time to document.

Don
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Old Sep 30, 2011, 12:33 AM
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Anyone who is enough of a glutton for punishment to deal with half a dozen TD's at the same time deserves something! New padding for his cell? (never had any luck with TD's, that is one reason I quit flying gas a lot of years ago)

Model looks great, I for one, would love to see a few more pics of her.
Foo
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Old Sep 30, 2011, 01:35 AM
I fly, therefore, I crash!!!
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San Jose, CA
Joined Jan 2008
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Quote:
Originally Posted by doonbt13 View Post
Let's see what people ring in on this one. While watching that clip again ( have to watch it again even though I own the movie and have watched it several times) I noticed that the rudder seems to be exactly opposite of nose wheel control.

Why is that? Were the nose wheel and rudder directly inverse or were they seperate controls that happened to be working against each other for the movie .

Curious and thanks.... Great progress on the 36. Thanks for letting us ride along and spending the time to document.

Don
Yes, separate wheel controlled the steering while taxiing... I had to ask that myself....

SteveT
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Old Sep 30, 2011, 05:50 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
5,820 Posts
Hey all,

Well the plug is ready for the top mold to be poured, the liquid mold will be here next Tuesday. Which is good as I will be out of commission for the next 3 days. Finally getting my shoulder surgery done today I have been needing since I was a kid. Rotator cuff fix, and some bone to cut away stuff. So don't let the thread go to hell about the price of beans...... I hope by tomorrow afternoon I can at least be back in the shop messing with some little things. Still need to build another aileron, and 4 more flaps.

Also....... A rumor started at one of the fly-ins that I was writing a book about my aviation life. I know that it was discussed here about a year ago and I thought it might be a good idea, but as I am not a great writer I just let it die. But I met with a guy that had written a few books about things outside this hobby. We spent a afternoon talking just about everything I have done since I was about 9. He really thinks it would be a great story to tell, but even he is not sure we could do it justice. So before this rumor gets to big, and I get to many people e-mailing me telling me they want to buy one.... I have to say 110% there is no book, and I have no idea if I ever will be. I guess what seems important to me, and what others would like to read could be miles apart. This guy thought all the stuff I did between 9 and 20 was really cool, while I think it is the last 12 years, B-36, C-130, T-28, 50% Pitts designs.

So for now I am just trying to get this bird in the air, and figure out my next project. It is going to be either 250" C130, 195" Mosquito, 150" T-28. The A7 is just to aggressive for my next project (at least my ADHD says that this week)

Thanks all,
DAG
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