Scratch type 17 project begins

[anonymous]

Thanks Sam, you beat me

Thanks Sam, you beat me to it!

Steve

[mylo]

Steve,

How do you post

Steve,

How do you post such nice big pics ? I've been messing around with this for ......a long time. (See my photos to the forum post).

Myles.

[anonymous]

Myles,

I have a server I

Myles,

I have a server I use for my web site ( www.sneill.com ) and an FTP program. This allows me to upload to my server my pictures.

Then I create a link from the file strusture of my site. Such as

http://www.sneill.com/type17/appendagesmolds1.jpg

This is placed into the box that comes up when your posting. there's a box to the right that says image. Click on that and place the link into that box and hit return. That establishes a direct open link to the post rather than something you have to click on to see.

On the server the www.sneill.com folder. And the appendagesmolds1.jpg is the file or image that is to be seen that is in the type17 folder.

Sounds hard at first but after you do it a few times it becomes second nature.

You'll need a server to do this. There are many out there. I use www.thehostpros.com long time old friend runs it and gives great deals on server space and service.

hope that helps Myles. Man this thread has everything in it! LOL!

Steve



Edited By U812 on 1126305368

[mylo]

Steve,

Thanks for that. I

Steve,

Thanks for that. I was able to get photos posted but I was just wondering how to get the images bigger.

Yes, this is a COMPLETE thread for all your R/C sub modelling needs.

Myles.

[anonymous]

More progress. Being that I

More progress. Being that I have never work with BJB RTV before I learned a lesson here tonight. Merriman warned me I'd have trouble without a vacuum chamber to evac the air out of this very thick material. These molds will be ok for a few pulls. Same with the hull.

But until I get the chamber and the pressure pot for pouring the appendages and urethane parts properly I will be sending the tools themselves to David to re mold and produce the kits.

But for now I will be able to make a few and build one for the instructions and finish this thread.

The process you will see to make the molds and do the lay ups is correct though so you can continue to learn and see a finished sub.

Here you see the tools in the clay lay up. I dammed it up with water based clay known as EM 210.

Then I mixed the RTV and poured it in. Tomorrow I'll do the other sides to these molds. By Sunday I can pour the parts and move on to the hull lay-up.

Steve

[Guest]

Hi Steve,

Your U-boot is looking

Hi Steve,

Your U-boot is looking so good! I still can't believe how quickly it's all come together (though it may not have seemed so quick to you, since you were doing all the work! LOL).
I've got a few questions...

You mentioned making the appendages from PVC sheet-
Was it difficult to carve/sand them?

Where did you find sheets of PVC? I suppose a plastics supply type place???

You mentioned making the walls of your mold forms from that clay, but what is the white material you used for the "floors" of your mold forms?

Hope you're not getting overwhelmed with questions, since I can't wait to see more of your boat!

Thank you!
Darryl

[mylo]

Darryl,

I'm just glad someone

Darryl,

I'm just glad someone else is asking a few questions. I had the same ones in mind.

Myles.

[anonymous]

Darryl,

the PVC comes from that

Darryl,

the PVC comes from that Evergreen rack at your local hobby store. Easy to cut on a skill saw. Didn't have to carve it and it sands easy like hard balsa.

The clay comes in 25 pound bricks from art supply stores. Known as EM 210 from Westwood Ceramics. It's for lay up purposes rather than sculpting.

The white stuff is Leisure Craft modeling clay which comes in many colors form a art supply store.

Thanks for you kind comments Darryl

Steve

[Guest]

Steve,

Thanks so much for the

Steve,

Thanks so much for the answers. I know Myles and I appreciate it!

Seriously, I'm used to building models from a box. So making everything from scratch is a new and exciting change for me.
Your tutorial has answered so many questions and doubts for a lot of us I'm sure!

Keep it up!,
Darryl

[anonymous]

Darryl,

You are so welcome. Can't

Darryl,

You are so welcome. Can't wait to see what you do after this.


Well here's some more progress. All the molds with the exception of the hull are done. I start that tomorrow.

What I did is build a box around the sail rather that slop this stuff up on it again and again until it gels. Wastes a bit of RTV but saves the arm.

I applied the silicone mold release to the inside and on the tool. The too is glued down to a board so it doesn't float and stay put. I also added a raiser out of would to it raising it up 3/16 off the table and it also leaves a line to flat sand down to on the sail once I lay up one.

I then filled the box with RTV and let it sit over night. Then I removed the box. Leaving the tool inside I then laid up the RTV mold with some water based EM 210 clay. Added the little keys you see that were shaped using a knife and cutting at angles so as not to create any draft.

Once that's done you mix up the Ultracal 30 just like plaster and brush on a surface coat followed by more of the mix. I allow it to start to gel and then with tools shape it and build it up to an even thickness.

Once the first side hardens (about 30 mins.) I remove the clay, grease it up with Vaseline on the parting seam and repeat the whole process for the other side. Once it sets up and cools you can tap it with a hammer and open it up.

Now you have a two piece mother mold that fits back together nicely keep the RTV's shape.

It's at this time you can remove the tool and put away for the day you may need to make a new mold.

Pretty simple stuff really. Just time consuming.

Now it's ready to lay up with epoxy and glass for a light weight sail that's easy to cut out.

You will notice also the sail before casting and how well using the tape and primer works to make the depressions.

The hull starts next. But this gives you and idea of how that will work as well.

Steve
















Edited By U812 on 1126589874

[anonymous]

Continued

http://www.sneill.com/type17/sailmolding8.jpg

http://www.sneill.com/type17/sailmolding9.jpg

http://www.sneill.com/type17/sailmolding10.jpg

http://www.sneill.com/type17/sailmolding11.jpg

http://www.sneill.com/type17/sailmolding12.jpg

h

Continued

[anonymous]

Started the first side of

Started the first side of the mold for the hull today. I used the old parting plane board that I had saved from the GW project.

It fit well and I just filled in the gaps with the modeling clay. Now this parting plane is about a 1/4 of an inch below the hulls scribed separation line. This is done this way for both sides. This way when you cast up the to halves they both have the line present so you can flat sand them both to the line and they will fit perfectly back together.

Now I would have never thought of this being an old epoxy glass mold guy. When I made my jet kits I would mold the plug as we called it of the fuselage in two pieces with no scribe line as we didn't need it.

The parting board and the seam had to be perfectly flat and even. Cast the top or side, then the bottom and the two halves would fit back together again. When you laid up the glass you would cut the flash off flush to the seam on both halves of the mold. Then place fiber glass tape that you soaked with epoxy resin butter and put the two halves together. Then I would go in through the opening for the tail cone and blend everything together. When you opened the mold the fuselage would come out in one piece.

So when I watched David Merriman's excellent video on molding a sub this method of the scribe line and casting slightly past it was a revelation! Especially since subs are usually in two halves anyway for the obvious reasons.

This is where I also learned of the BJB 5040. And much more. With all my years doing this stuff for the film biz I quickly learned my watching David's videos that there was so much more to learn. All good too.

So moving on. You don't have to worry about the clay seam being perfect either as your just going to flat sand away to the scribe line you are well below.

Some silicone spray on the master and your ready to go. The first coat of RTV is on and will sit over night. Tomorrow I'll do another coat and maybe a third. This is not fast but worth the time investment. Once I'm satisfied with the thickness of about 1/4 of an inch I will make the mother mold out of Ultracal 30 much like I did for the sail.

You can see in these pictures as a result of leaving the trim tape on too long that in the limber holes it pulled out some material. Looks sloppy but you are just going to drill these out anyway so I kept it as is. It wouldn't be worth the time to go back and fix it so you have nice looking limber holes out of the box that get drilled out.

More tomorrow.

Steve

[mylo]

Steve,


.....must.......have.........more.........*collaps es to the ground like

Steve,


.....must.......have.........more.........*collaps es to the ground like in the movies*

Mylo

[anonymous]

Well I put three coats

Well I put three coats on 500 grams each and I think it's thick enough now. So on to the mother mold next.

Steve







Edited By U812 on 1126942697

[anonymous]

First the surface coat of

First the surface coat of Ultracal 30. When that gels you can cut strips of burlap. Soak them with water. And apply to the mold and cover with more Ultracal 30. Done.

Now to wait for it to cure and I can open this mold.

Next I will do the same procedure for the bottom.

Steve