Thread: Make A Fibreglass Warbird Mould - 1/7th Scale P-40E Warhawk

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    Ready for Clay

    ...well I guess that says it...




    Dime-in-clay corner fillets will form upper, outer radiused edge of mould face once all white board formers have been removed later.

    The parting plane along the trailing edge of the flap bay has turned out quite well and has been carefully positioned to fall precisely at half thickness. This will give the best case scenario for trimming along the mould edges prior to joining.

    This clay work isn't finished yet. Stay tuned, there's still plenty of work to do before we paint on that silicon carbide tooling coat.


    Don't forget to identify your tools for the day when they're here and you're not....


    Ongoing clay you can see that there are still a lot of little cracks and crevices to fill - one day at a time - this stuff is worth the extra effort later on


    WOW! That is a lot of work! but it is looking good.

    Somewhere to Pry

    I will leave the clay in these pry locations when I flip it over and mould the upper flanges. This will give a nice spot to get the crows foot into when separating the finished upper and lower mould sections. I've tried to target potential problem areas while placing them around the periphery.


    1/4"-20 Flange Bolt Thread Inserts

    Be careful not to over tighten the screws. Just pull them down flush.


    Bring it on...if you've got clay, I've got all dang day!


    Yes folks, it was absolutely free afterall!

    I'll post a link to the iso file once I get it ripped...

    ...and here's a supplies link that looks pretty good too


    Every time I go to use this mould and I don't have tighten a hundred nuts and washers onto all those bolts, I'm gonna grin from ear to friggin' ear! Just set the clutch nice and loose on the driver and give those 1/4" bolts hell. These thread inserts are going to save so much time it's not even funny.


    These are garage door hinges. I had them laying around from a past project and won't be needing them. I thought this might be a good opportunity to try something new and hinge the two main sections of my wing mould. If it doesn't work out, I will simply remove the hinge pins. I will align their axes with the laser level to give it the best shot at working since they can't simply be mounted flat against the angled back wall.

    It's the classic risk vs reward. The question is - are yours big enough to get an angle grinder that close to 3 years work?

    I'm not finished cleaning up yet but I needed a break, so here's some pics for today.


    These hardwood blocks were $0.50 ea at the woodshop supply store.

    Here's their website. They have lightweight ply too...

    Notice that I've set the hinge pins to level when the blocks are placed on the mould face where they will become part of the finished mould base.


    So the hinge pins are level, at the same height, and in the same plane. Hopefully this will work because it will take what is really an awkward two person job and make joining the bulky clam sections a one handed operation. There's still some play in the end because I can shim the hinge plates on the hardwood should need be to get things finalized.


    So this is pretty much the mould form completed and ready to cast. I will now go over everything with a fine tooth comb and make sure all the clay is finished off properly.

    Once I've laid the main lower section in the formers, they will need to be removed. The clay blocks around the top will just give me somewhere to get between the newly cast mould face and the white board. The formers are very close to the finished plug and we don't want to be trying to force something in the seam to pry the board away from the plug in order to carry on to the second mould section. (main upper) Just dig out the clay and there'll be a nice place to GENTLY pry off these white board formers.

    The recesses around the perimeter of the base will also provide a little rigidity but that's not really why I did it.

    I've also added two air ports in the wheel bays. They're held in place with clay. Just before laying up a part in the mould I will fill the hole with some clay and glass over them. Once the part has cured I'm hoping that a short blast of air in this location will free the part from the mould. It's the deepest spot in the mould, and it's a flat face at the bottom of a tightly controlled cylindrical form....we'll see....


    Almost forgot to fill the wing mounting holes...added cavities in the mould at the aileron trailing edges too. The empty cavity just outboard of the inboard hinge (hmm...clear as mud eh?) will provide a place to feed the control rods from the bellcranks during assembly.

    Oh, and a quick pic from the couch of all the pieces that I have moulds for, all duct taped together - motivation....


    Once I have progressed to some of the heavier cloth layers in the layup of this main lower mould section, I will lay this straw conduit down on a tacky surface and continue to lay cloth up on top of it. All of the joints have been sealed with clear tape to keep the resin out. I will mould a pipe union into the end faces so that I can screw taps onto each end of the mould.

    By running hot tap water through the mould face, I hope to have a means for controlling the time/temp curve for the cure and tool cycles. I should be able to reduce the cure time to some noticeable effect with only tap water to a maximum of about 140 deg. fahrenheit or about 60 Celcius.

    To my estimation, this would represent the home hobbiest's best chance of approaching any sort of idealized tool utilization rate while maintaining a moderate capital investment.


    The lowest cost solution seemed to be a hose repair kit. It cost me just under $5 for both the male and female brass fittings. I now have a couple of spare 1/2" gear clamps in the top drawer of my tool chest.

    I've positioned the hose hookups on the rear face of the mould section so that the potential exists to hook the upper and lower sections together in a series configuration during final assembly with two small lengths of hose.

    Normally I would wait an additional 24 hrs to demould the joined wing assembly. With heat to aid in reducing cure times and improving wing rigidity, I'm hoping to take a mould cycle from a tiresome 3 day operation to an easy 2 days per wing.


    One of the first places to wear on a multi-piece mould like this, is the edge along which you trim semi-green parts just prior to joining. As a result, it's a very slow and tedious process to try and freehand.

    This aluminum insert in the mould face will help to provide a nice durable trimming edge face. Notice the external grooving to aid in bonding with the tool surface coat.

    It will also form an overflow channel to give excess resin during joining a place to go.

    It might also provide a calibrated groove in which a custom trimming blade jig might ride...

    Here's a source link (for future reference, 36" weighed in at 205 g)

    ...and here's the idea...


    OK, first of all - thank you for your patience - I know that this takes forever, and now I've gone and switched things all around on you....

    We still have the semi-spherical registration keys - but there are fewer of them. Fewer means less effort in keeping them clean and free from build-up. In an effort to maximize their effect however, they are placed at the extremes of the mould sections.

    We still have the 1/4"-20 thread inserts for joining. There are a couple new ones. You can also see that I've countersunk the two on the end faces so that they will not interfere with removing the leading edge section.

    The new bits are the extruded aluminum T-slot ways. I've filled them with clay, and then screwed them down to the parting board.

    They will provide a nice flat, and wear-resistant face to trim against.

    They will also act as an overflow channel during assembly.

    But mostly, they give me the option of speeding things up considerably if needed at some time down the road. By vacuum sealing across the flange face and controlling resin flow into each of the nine overflow channels, while drawing vaccum from the underside through the gear bays it will be possible to infuse parts rather quickly.

    I left the conduit for the heating circuit on top just for the sake of the picture: of course it will be embedded in the layup.


    Join Date
    New Milford, CT
    Wow, you've really have made a great project here. Lots of great information! Hope it continues. Good job!
    Favorite Quote: Passions once set in motion, move themselves... Unknown author.

    I agree, I never knew how much work it is to create a mold for making our aircraft. B1hegh54 has been doing an outstanding job on this.

    #98 let's see...where was I ?? Oh yes, let's build a fuselage !!

    It often seems that life has a way of pulling us away from things. This is exceptionally true with a project of sufficient scope to impress. lol
    The trick, is to make your way back home....

    I've been to the local school supply store in my ongoing efforts to stock my shelves with goodies that I can use to itch my constructive itch from time to time. I came away with I think what you will agree is the cheapest method for pigmenting your epoxies.

    Now, as regards effectiveness, this test will serve to establish a rather subjective pass, or fail grade to the candidate in question. In support of my somewhat educated guess, I will attempt to attach supporting documentation of related adhesion test results for various common pigmenting approaches; one of which I was rather impressed to discover was tempera powder.

    If I'm unable to attach the aforementioned article, I will suggest that a google search of the terms "West Systems, tempera, adhesion, results" will also provide a quick link.

    For this one, I intend to incorporate a 1/4" 5 ply firewall and I also have what I think you will find to be an interesting idea for applying camouflage in the mould with my new tempera powders.


    First things first; we're gonna need patterns for our camouflage design. I've taken a few liberties in the name of artistic impression here with regards to symmetry and the like, but hey, it's my fuselage afterall isn't it. (??)

    I've used an old pair of pants here to drape and tape. Taped in place with duct tape, and marked with a sharpie.


    ...and we're gonna need a firewall...
    - don't forget to take a minute to identify your templates for later when you don't know what the heck it was anymore
    - and don't forget to cleanup and put your tools away as you go (took me a good 40+ years to learn this one, but building in your kitchen helps...)


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