1/32nd Scale Russian WWII SHCH "Pike" Series X Build

[thor]

One note I would like to add here; this is not being done in real time. The beautiful CNC work was performed by Tom Anderson in his incredible wood shop in the Bay Area of California in 2008. At the time I did not have a CNC machine large enough to handle a 72" long hull, so Tom graciously offered to machine the parts out for me. He does beautiful work!

Today, I now have the ability to machine a very large pattern in my shop, and I have the 3D printers as well to assist with the smaller detailed parts along with parts for the WTCs. Tom machined the patterns for my original Sturgeon, LA, & Seawolf kits back in the early to mid 2,000s.

I am bringing this project up to speed from the very beginning, and going through the entire process so you get a feel for the work that goes into a scratch built project of this magnitude. We will get to where the project is at in 2020 in a couple of months.

[thor]

The joined Conning tower halves are coated with a thin layer of epoxy; making certain to force the epoxy into the grain and pores of the wood with your fingers. Make certain to wear gloves! Then, after a light sanding, spray successive coats of lacquer primer onto the surface of the conning tower. Sand lightly between coats to obtain a nice smooth finish. Use spot putty and fairing compound as needed to get a nice, smooth result. Expect around 20-30 coats to get a finish suitable for molding.



Work your way down to 1200 grit emory paper to get a nice mirror finish. Wet sand only at this point! After that, polish with a dry paper towel

[thor]

I took a bit of a diversion this last week to pursue the design of periscope mechanism for the Observation and Attack scopes on Pike. I've decided to use a hydraulic system to drive the scopes the scale 8.5" vertical travel for both scope. A small, machined piston will be driven in a 13/32" O.D. brass cylinder. The scope mechanisms will be nested in a cylindrical penetration into the ballast tank which will pass completely through.

[thor]

Over the last fifteen years I have trained many individuals to create epoxy glass molds and parts. The methods I use were taught to me many years ago by one of the very best in the business. It works without fail for me, and it will for you -- IF you take your time, IF you spend the money and buy the right stuff, and IF you are willing to practice a bit before you get overly ambitious. This tutorial will use easily obtainable, off the shelf products that anyone can order over the internet. If you are going to use the following information to produce your own molds and parts, please do not substitute inferior products. You will end up with an expensive gooey mess in your lap!

Materials
I use all Fiberglast Epoxy resins, cloth, thickeners, and surface coats. Yes, their products are expensive. Yes, you will get the very finest resins available in the business. And no, you will never have to worry about having a second cut, filled resin, or an expired shelf life product. Go on the cheap and you are rolling the dice. Be careful! Lots of the discount resin depots sell expired, cut or filled products. System 2000 Epoxy Resin System 2000 Epoxy Resin is a medium viscosity, light amber laminating resin that is designed for fabricating parts and other demanding structural applications. Use this system to maximize the physical properties of carbon fiber, Kevlar®, and glass laminates. Test results have proven superiority over other room temperature epoxies. Its low viscosity and great handling characteristics make it a favorite in the shop too.

Three high performance hardener systems are available for the System 2000 resin: 20 minute, 60 minute and 120 minute pot life versions. This allows the fabricator to select the system best suited to the size, complexity, or time-frame of the project. Simple parts which need to be demolded quickly should use the 20 minute hardener. Larger and more complex parts can use either of the other hardeners. Vacuum bagging applications would typically warrant the longest 2 hour working time. As with any epoxy system adhere to the proper mix ratios and maintain an adequate curing temperature of at least 70 degrees F. The cure time will be cut in half for every 10 degrees F that the temperature is raised above 70 degrees F. Purchase a single cure, or buy resin in bulk and order a variety of hardeners to keep on hand for any project. Chopped strand mat contains a binder which prevents proper bonding with epoxy resins. Use polyester or vinylester resins with chopped strand mat.

The hardener I use for construction of molds and parts is 2020 Epoxy Hardener. Its short 20 minute pot life is quite versatile and its mix ratio is 4:1 by volume. It works well for repairs, simple fabrications, or those parts requiring a quick de-mold time. For the inner surface of my molds I apply the BJB Enterprises High Temperature Surface coat TC-1611 A/B. The Fiberglast Resin systems are 100% compatible with this system. Do not use this product as a surface coat for production parts. With a service temperature to 350°F (177°C), this product produces a hard black finish that can be drilled or machined if desired. This stuff is awesome. It provides an extremely durable inner mold surface that can be post cured to provide additional durability.

Epoxy Surface Coat

For production part surface coats, I like to use standard high buff white #1099 Surfacing Resin System from Fiberglast. It does an excellent job of picking up and retaining the most minute details from the mold surface. It provides a very durable surface for your epoxy glass components. It can be brushed on as thick as 1/8-inch at a time without developing runs or sags. It is specially formulated to provide strong interlaminar bonds with the reinforcing materials, even if it is left unsupported overnight. #1099 resists chipping and cracking, and retains its high gloss.

Thickeners
Do not use micro-balloons as a thickening agent! Micro-balloons are tiny glass spheres that are meant to be used as a filler only. It is typically used to form fillets and other nonstructural shapes. A micro-balloon filled joint will be brittle and weak. Micro-balloons are also very difficult to sand. To properly thicken use talc and/or Thixotropic (fumed) silica. I use both materials depending upon the specific application.

Talc
Talc is the major component of any body filler. #131 is a sandable filler added for fairing and smoothing the finish of fiberglass laminations. The recommended filler ratio is 2 parts #131 to 1 part resin to result in a smooth, creamy semi-paste. The exact filler portion will vary by application depending on the desired consistency. Allow to stand one hour before adding hardener and using.

Thixotropic Silica
#23 is a fine grade fumed silica thickening agent similar to Cab-O-Sil and is added to resin systems to prevent run-off and sags on vertical surfaces. Mix in the ratio of 1 part by volume #23 to 2 parts resin for general use. Cab-O-Sil is a registered trademark of Cabot Corporation. Thixotropic Silica sands just like the base material.

[thor]

The Part
Those of you who have been following my previous build thread of the 1/32 Russian WWII SHCH Series X Fleetboat Pike will remember that I have been working on this project, mostly research, since June of 1991. So you can imagine I have really been chomping at the bit to get this boat under construction. I am more excited about building this boat than any other sub I’ve built from scratch. The part for which this mold will be created is the boat’s conning tower fairwater.

The Mold
All accurately produced parts start with a properly constructed mold. A proper mold is constructed from using the finest materials, processes, and support equipment. There are places where you can go cheap, but this is certainly not the place to do it. I am a stickler for straight and true molds that index well. That is easily accomplished by using a nice, straight parting board with mold indexing keys of the proper size and shape. To provide a nice, smooth surface to act as a parting board

I like to use melamine covered MHD particle board. This material is easily obtained at any big box home supply store like Lowes. The one shown is a 24 inch x 8 inch melamine covered shelf. It is 1/2-inch thick. It runs about $10.00. Along with the melamine parting board you will need a fine line sharpie marker, mold keys, 600 grit and 1000 gritsand paper. If you look at the small bag in the photo you will see what I use for mold keys. I use stuffed animal eyes (15mm) with the mounting stem. They are half-spheres, and are very smooth. They are also about 1/10 the cost of professional mold keys and are identical with the exception of the painted eye ball on them. A bag runs $0.99 versus the $12 I normally spend. The small stem on the back allows them to be mounted quickly and easily with a small hole drilled after mounting the part to be molded.

After you are happy with the shape and contour of the part you are going to mold, you need to prep it for the molding process. First, the part needs to be primed. I like to use PPG polyurethane primers, but they are a pain to mix and apply. So, for this project I will stick with plain old “in the can” automotive primers that you can get down the street at your local automotive parts supplier or body shop supply house. I will use a lacquer based primer for this application due to the overall ease of use. If you live in one of the states that outlaw the use of this primer then you will have to resort to one of the more expensive and inferior enamels or another alternative. Coat and sand the part as necessary to achieve a smooth and uniform surface as shown in the photo. The finish is dull and flat, but it is ready to be wet sanded to produce the required mirror finish that will define the surface finish of the mold cavity.

First I start with 600 grit wet/dry paper. You will go through several small sheets of sand paper before you are ready to go to 1000 grit. Be careful not to sand through the primer. Keep a nice moist coating on the part while sanding, but do not drench the surface with water. Sand for 1-2 minutes. Dry the surface with a paper towel. Now, here is the little secret to getting a mirror finish: take a wad of very dry paper towel and buff the surface of the pattern.

You must move in a rapid circular motion while applying pressure to the surface. You will see the shine come to the part after a few seconds of buffing with the paper towel. It will reveal the defects in your surface which will make it easier for you to re-sand those areas. It will take several iterations of the sand-dry-buff-inspect process before you will have a flawless part. This is the finish that you will want to achieve to obtain a superb surface on your production part. It is hard to see in this photo, but I can see my own reflection on the side of the conning tower pattern...Yikes!

I like to use Duplicolor High Build Primer #DPP104. You can purchase this fine primer on Amazon.com and ebay.com.





After the part is completely sanded and looks great we need to wax the part thoroughly with a good release wax. I use Partall wax for shining up the pattern and as part of the release process. Release wax not only makes mold separation from the part a breeze, but also increases the shine of the part which, again, improves the surface finish of the parts you will be pulling from the mold. Next, we will install the conning tower pattern on the parting board and install the mold keys.

The first step is to trace the outline of the part on the parting board with a sharpie or other permanent marking pen. After you are happy with the outline, cut the area inside the tracing out with a scroll saw. You will need to drill holes in each corner to allow the saw blade to be inserted into the board to facilitate removal. After that is complete, insert the part into the parting board. Make sure you have at least 1/32-inch clearance all the way around the part. If the gap is too big, don’t worry about it. That is really easy to fix. There are no points for a pretty parting board, just pretty molds! Mark the centerline of the part all the way around. Insert the part into the parting board up to the centerline. Using modeling clay to keep the part in place. Press the clay in from the back in several areas to secure the part to the parting board. Place masking tape all around the part where it intersects the parting board.

Mix up a nice batch of Bondo or other suitable quick cure body filler. Trowel the body filler into the gaps. Remember the part needs to have several coats of Partall wax on it before you insert it into the parting board. If you do not have wax on the part, the Bondo will keep it there forever and ruin your part. You will end up with chips in the parting board where the sharp corners of the part reside. No problem. They will be filled with Bondo. Simply trowel more Bondo over the damaged areas of the parting board and trim off with a single edged razor blade while it is still soft. Do not wait until the Bondo is cured. If you look close, you will notice that I have spread a bit of Klean Clay over the Bondo in areas. This is a quick and easy way to address any small pits in the Bondo. When you are happy with the smoothness of the surface of the parting board, it is time to install the mold keys. That, along with the first epoxy layup, will be handled in the next update in a couple of weeks.












You can purchase the supplies used in this article from the
following websites:
Fiberglast: www.fiberglast.com
BJB Enterprises: http://www.bjbenterprises.com

[Ben Brigham]

Very much looking forward to the results of the CnC machining job!!

[salmon]

Matt,
It is like Christmas every time you post! I watch and learn, so thank you for doing this! someday, I will try to make my own hull.
Peace,
Tom

[thor]

We last prepped the conning tower fairwater pattern for a 1/32 scale Russian WWII SHCH Pike fleetboat, and mounted it in the parting board. Here you can see it on the bench surrounded by the wide range of materials that will be utilized to fabricate the intermediate mold for the Pike conning tower. All of the items were purchased from BJB Enterprises and Fibre Glast. On the surface of the parting board you will notice a series of raised, small, hemispherical objects. These are the mold keys. The keys allow the final glass parts to be joined while they are aligned properly in the mold. Joining parts by hand can be tricky and often ends up with an angry user and a discarded part. Always join your parts in the mold when you can. You can purchase 3/8 inch half-sphere keys at any fiberglass supply store. To save a bit of money you can use 3/8 inch stuffed animal eyeballs purchased from your local Hobby Lobby as I do. They are the exact dimensions of the professional mold making keys at 1/10 the cost. They are easily mounted by drilling a 3/16-inch hole through the parting board to accept the mounting shaft. Secure with a small dab of silicone sealant. They can be easily removed for future use.



To prepare the parting board for mold creation, apply and polish out several coats of Partall wax. Over this spray three to four light coats of PVA parting film. PVA provides a protective barrier coat for your pattern against the corrosive nature of the epoxy resin. It also provides a back up release for the two surfaces. Do NOT rely on the wax or PVA by themselves. These two products are designed to work together to provide an (almost) fool proof combination to assure your pattern is not stuck forever in a mass of epoxy and cloth. It is now time to cut our surface cloth, an initial layer of 2 ounce fiberglass cloth weave that will cover the pattern. I do not like to use scissors for this process. The light surface cloth is very difficult to cut without snagging the fabric and pulling the weave out. Instead, I use a razor wheel to cut it. Razor wheels can be purchased at any fabrics store. Be sure to get several spare razor wheels as glass cloth dulls the edge very quickly. I have found that if you cut the surface cloth in small 4-6 inch circles the surface in the mold turns out much better. The disks move and slide against each other and have no sharp edges that are prone to cloth and weave separation that would be found on a square patch or a long strip. These small defects show up easily and ‘print through’ in the surface coat after a few pulls. Your part will pick up these tiny defects.



I apply the surface coat (2 ounce) and the backing layer, a second glass layer of 4 oz. cloth, as disks. In the image you can see the 4 ounce cloth on the left and 2 ounce cloth on the right. Additional layers can be applied with larger rectangular strips of glass. With the cloth cut, it is time to apply the BJB Enterprises Tooling resin TC-1611 A/B. This is a fantastic resin system for creating molds, but it is NOT intended as a surface coat for production components. It is much too heavy and brittle for this use. TC 1611 A/B is a very thick resin system. It will break your average mixing stick right in half during mixing. I have resorted to using spruce sticks to mix this product. Please note it is critical to add the two components properly by weight. If you do not have a scale with a resolution of at least +/- 1 gram, then do not bother using this resin system. It is very sensitive to mix ratios. Mix the A and B components together for at least two minutes to assure a complete mix. If not thoroughly mixed, you will end up with soft spots or uncured areas in your mold. If the resin is a bit thick for your liking, it can be heated with a hair dryer to reduce the viscosity. However, be warned this will accelerate the curing of the resin. Work very quickly if you chose to pre-heat your mix. Use a 1-inch stiff brush to apply the tooling resin. Push the material around the part and parting board to get it leveled out before you start to really brush it to a nice even coat. Take your time and pay special attention to applying an even coat over the entire surface of the part and parting board. The tooling resin may be applied up to 1/8 inch thick, but try to keep the film thickness less than that. The thicker the tooling resin coat, the more brittle your mold will be.





Do not be alarmed if you see brush streaks on the surface of your tooling resin. They will not show on the inner surface of the mold when complete. Let the tooling resin rest until it comes to a heavy tack. You will know it has reached this point when you touch the resin and it still feels sticky but it leaves nothing on your finger. This usually occurs after 30 minutes at 70° F. When you reach this point it is time to start laying down the first layer of cloth. DO NOT let your tooling resin cure beyond a heavy tack without laying up the rest of the layers of glass to the mold. You will have to start over if you do as the tooling resin will pull and lift off the parting board as it goes to final cure. Before you apply the first layer of glass to the mold we must apply a bead of thickened resin into every sharp corner and shape transition. One thing to remember about glass work is that glass does not like sharp corners or rapidly changing geometry. Thickened resin must be used as a transition volume to carry the glass over the sharp corners by providing a smoothing effect. To prepare the thickened resin, begin by mixing a small batch of epoxy as normal. I make thickened resin up in batches of 50 grams for small jobs like this. Next, Cab-O-Sil is added to the epoxy as a thickening agent. A good rule of thumb for mixing the resin with thickening agent is to add equal volumes of catalyzed resin and Cab-O-Sil. Mix completely so there are no small globs of thickener floating in the mix. You want a nice, even, whitish appearance with the physical consistency of toothpaste. If it runs off your mixing stick, it is too thin. Add a bit more thickener. A little practice will be needed to get it just right. A side effect of the Cab-O-Sil is it significantly accelerates the cure time of the resin, so move fast.

[thor]

To apply the thickener to the mold, I use newspaper cones, pre-rolled and taped. Simply fill the top of the cone with the thickened resin and roll it down tight to force it into the tip. Cut the tip off with scissors. You only need a tip of about 3/16 inch. Quickly lay an even bead of thickened resin around all of the changing contours and sharp edges on the part and mold surface. Squeeze lightly. It is just like frosting a cake. Do not forget to apply a bead around each key. When the cloth is applied, the thickened resin will level out and assume its own shape to fill all of the gaps that may occur between the glass and the tooling resin outer surface. Once application of the thickened resin is complete it is time to jump right into applying the first layers of glass cloth. With a small mold like this I use only two cloth weights: 2 ounce surface cloth, and 4 ounce cloth. A good, lightweight surface cloth is required to prevent ‘print through’ from the following heavier layers of backup cloth. If you do not use a surface cloth the surface of the part will have the imprint of the cloth weave from the proceeding layers of mold build up.







It is very important to apply just enough resin to ‘wet’ the cloth completely. If you see a shiny surface on the cloth you just laid down with resin, then you applied too much resin. Do not be surprised if you are able to apply a complete layer of cloth without the application of additional resin. You want to soak up all of the excess. Too much resin causes the cloth to float, sag, wrinkle, and move. A properly filled weave assumes a dull, green, almost dry looking surface. After applying the 2 ounce surface cloth it is time to continue with six more layers of 4 ounce structural cloth. For molding larger pieces I would cut the number of 4 ounce layers down to three and add two layers of 10 ounce tooling cloth. I don’t use any 18 or 20 ounce tooling cloth until I get into hull molds for stability and mass. When application of all layers is complete, let the mold stand for 24 hours in a temperature of 70-85° F. Once the epoxy has cured, the next step is to separate the mold from the parting board. This is easily done by driving a small Teflon wedge around the edges of the mold. Do NOT drive the wedge in so far that it lifts the mold from the part. You must retain the part in the mold for proper creation of the second mold half. If the part comes out of the mold it is time to start over with a new mold. Gently and evenly push the part through the parting board from the back side so it remains in the newly created mold. Be patient and don’t get too manly with it. If you properly applied the wax and PVA release agents, then it should push through quite easily.





The next step is to trim the dry glass away from the mold and define the mold’s hard edges with a grinding tool. I use a pneumatic sanding tool to remove the dry glass and to define the edge of the mold. If done properly the mold thickness should be fairly uniform all the way around the part. It should have some flexibility, but not too much. After trimming the mold to shape, flip it over and grind the back glassed surface smooth to get rid of any sharp edges. If you don’t, the little shards of glass will cut you like a razorblade during handling. It is cheap insurance to keep the stitches out of your hands.





Flip the mold back over and you are ready to proceed with laying up the second mold half. We will tackle that, and finished parts production, in the continuation of this project.






The supplies used in this article can be purchased from the following websites:
Fiber Glast: www.fibreglast.com
BJB Enterprises: http://www.bjbenterprises.com