Props Spartan Laser Metal & Fiberglass Airsoft Prop (Fully Functioning Electronic Replica)


Redshirt

Well-Known Member
Member DIN
S980
By the way, How do you plan on making the front cover slide up and down?

The front shroud will open and close using a modified RC servo, using a DPDT rocker switch that is triggered by the forward handle being opened. This system is based on "The most Useless Machine Ever." Just go check the guy's site on Instructables.com: http://www.instructables.com/id/The-Most-Useless-Machine/ if you want an idea of what I'm looking to do from an electronics standpoint.

From a physical standpoint, I'll either use shrouded cables (also an RC item) to push the shroud up directly, or (more likely) expand on Zarnel's excellent scissor lift system he used on his SPLASER build. My problem is that I have a lot of mechanicals already located in the section of the prop that the scissors would have to straddle.

Redshirt
 
well, if i may make a sugestion, why dont you use magnets? I did a diagram for a guy that was working on a Laser a few years ago. Ill try to dig it up and post it.
 

Redshirt

Well-Known Member
Member DIN
S980
Moldmaking

Well, I got the blanks painted gloss black and rubbed down with five coats of Maguiar's Mold Release Wax. Because I have so many vertical surfaces and nooks and crannies to fill, I needed to start with a thickened resin. If I just used plain resin and glass, it would run off the vertical surfaces, be very brittle in the details, and have lots of air bubbles between the details and the glass layer. I used Cabosil, a silica-based thickener to turn the resin into gel. In lieu of gel-coat, I've painted it on to all surfaces and details, prior to going over it all with traditional resined fiberglass cloth and matt.



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These photos are from while I was finished with the Cabosil layer and getting ready to put on the matt layer. I'll be back when everything is cured.

Redshirt
 

Redshirt

Well-Known Member
Member DIN
S980
So, apparently, I'm working on recovering from Photobucket's betrayal rather than on my build. Images back up very soon.!

Redshirt
 

Redshirt

Well-Known Member
Member DIN
S980
Photobucket Fired--Image Shack Hired

OK Splaser Fans, I'm back in business with all the images replaced except the M3 Grease Gun pics. They'll show in a day or two when my Photobucket ban lifts.

Things are not looking so great, my molds don't want to separate from the blanks without lots of bad sounds. I'm playing with heat, pressurized air, and a few other tricks to get them free. I'll post pics soon.

Redshirt
 

higdog827

Member
Oh god, you did use a release agent before putting the gel on right?? If you dont put some sort of release agent like petroleum jelly on before the mold, youre going to have one hell of a time getting that off (i learned that the hard way a while back with a reach knife that to this day is still encased in silicone caulk). Now i know you are by no means a noob at this redshirt, (heck, your chief build actually inspired me to get into this hobby in the first place!) So i hate to sound condescending. If i do, i apologize. Id just hate to see this amazing piece of work destroyed simply because it wasnt coated in Vaseline before you put the mold on! Best of luck to you man, i hope everything turns out ok.
 

Redshirt

Well-Known Member
Member DIN
S980
Oh god, you did use a release agent before putting the gel on right??

I was assured that the five coats of commercial mold release wax would do the trick. I didn't choose polyvinyl alcohol (PVA) as a release agent because it would cost some detail. I think the real issue is that the Cabosil layer was way under-catalyzed. It took days to set up. I think in that time, it ate my mold release. The NOOB mistake was likely in wanting a little extra working time with the Cabosil. Anyway, I am getting them to separate, just not without damage.

Redshirt
 

Redshirt

Well-Known Member
Member DIN
S980
Epic Fail

OK Folks,
You've heard the rumblings, now it can be told--I got the molds separated with quite a bit of damage to the molds, and extensive damage to my beautiful blanks. Well, I didn't need the blanks to survive and the molds are salvageable. I will do all reasonable repairs to the molds, them pull my parts, expecting that I'll have quite a bit of clean up to do on my final parts. I'll get there.

So here's the rundown: Due to the slow catalytic action, the mold release was corrupted, resulting in the fiberglass resin bonding to the mold blanks. I was able to pull one of the major pieces off without fully destroying the blank, but the mold has micro cracks over most of its surface as well as several cracks through the fiberglass mat. Other pieces would not pull clear. I had to drill though the mold surface to the outer surface of the blank below. Following this, I inserted a high pressure air nozzle and used the air pressure to force the separation. You can see in the pictures just how many holes I had to drill to get the pieces apart. These holes, though ugly, will not be too difficult to repair.


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Here are the molds! Not pretty, but I can make them work.


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Ouch! Sad to see.


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This piece largely survived, though many detail parts remained stuck to the molds (temporarily)



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Yellow paint pen denotes detail that was lost during the mold separation. You can also see the micro cracks in the surface.


Redshirt
 

spartanx360

Active Member
that's a real shame all this has happend, but keep your head up, you learned an important lesson, and those things make us better and stronger.
good luck
 

Redshirt

Well-Known Member
Member DIN
S980
Moving On

Well, the spilled milk has been cried over and it's time to keep moving forward. Today's update shows a little of the repair process getting underway. Before getting to the lost detailing, the basic structure of the molds needed tending to. Any areas that had cracked had to be repaired as well as missing sections replaced. Traditionally, new fiberglass resin doesn't adhere well to cured resin (though the disaster of last week proved that is not an absolute rule). For this reason, I've found that the best way to patch fiberglass or join finished fiberglass parts is to use thick gap filling superglue and fiberglass cloth. It's fast and almost instant if you have an accelerator like Zip-Kicker. Once that's done, you can come back with traditional resin and cloth if you have to build strength, or work the details in Bondo. In these two photos, I'm doing the initial patching of the molds with the super glue and glass cloth. I later built up the details in Bondo on the inside mold surface.

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I've found it is very hard to work up the raised details inside my female molds. It was much easier to cut details into the male blanks. I won't be able to restore all of the detail as crisply as I'd like. The up side is that it won't take nearly as long to get these molds ready for action, but I'll have to do a lot more work to get my finished pieces up to the same level of crispness that my blanks started with.

Redshirt
 

Redshirt

Well-Known Member
Member DIN
S980
More Repairs

Here's some of the work to repair the front shroud molds:

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The blue painter's tape covers the holes I had to drill to get an air nozzle in to separate the molds. I'll come in from the mold side with a little Bondo. Even if I don't totally fill in the holes, they will result in a raised bump on the final piece that can easily be knocked down by a belt or pad sander.



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The super glued on mat will allow me to build up Bondo details that are structurally stable. Look at that jacked-up inside surface--a long way from the way the mold blanks started out.



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Still a long way to go on these parts, but getting there.

Redshirt
 

Redshirt

Well-Known Member
Member DIN
S980
The mold repair continues . . .

I've finished all of the structural repairs and struggle with repairing details as well as the overall quality of the surface of the molds. The molds wil not have as nice of details as the originals, I've accepted that, but neither will this set of molds ever be used to make more than this one set of final parts. If I ever want to cast, I'll be better off to do a new set of molds anyway as I know the final parts will still need altering to mate properly with the metal receiver. Yup, that means big work will be required on the pieces I pull from the molds, but that will take less time than restoring every detail into temporary molds.

This work sucks, so I took some time to look ahead to a different part of the project--metal work! All avenues of CNC of manual milling have been exhausted, so I'll be cutting, routing, and stick welding to make the lower receiver happen. Here are the aluminum pieces I'll salvaged and purchased to start on the lower receiver posed next to my Pep lower receiver (that by now has seen better days). Not shown is a long section of 1 1/4 inch square channel that will be cut in half to make the bottom of the receiver between the two halves.

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This will be a tricky job welding different thicknesses and grades of aluminum. Unlike wire welding, the heat is not localized, and making welds that penetrate into the surface on the metal parts is very hard--anything less is just soldering, i.e., non-structural. I'll get in and explain more when I get started making these parts. For now, this is just a teaser of what I'll be doing. Final, non-structural, details will be grafted onto the surface with JB Weld as it is about the only adhesive sure to hold as well as tolerate the coating process.

Redshirt
 

Redshirt

Well-Known Member
Member DIN
S980
Molds Are Done!!!

For better or worse, I've made as many reasonable repairs as are practical. Everything else will be cleaned up in post production.

I made the repairs using Bondo and scratch filling primer. The filler primer really worked well sealing the porous surfaces left by the micro cracking. I had a nearly full can of gloss blue sitting around blighting my shelf, so I used it to get the final gloss coat on the mold surface.

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Where you see faint circles, that's where I highlighted final repairs that needed done with a Sharpie. After I made those repairs, I put on the blue coat, but the Sharpie bled through. No impact on the mold, just an unexpected result.


Next up, these will receive several layers of mold release wax--yeah, we've been down that road before. After the wax, they'll be sprayed with polyvinyl alcohol (PVA), a water-based mold release film. Following that, they'll be layed up in fiberglass mat and resin.

I'm excited to see this project back on track.

Redshirt
 

Redshirt

Well-Known Member
Member DIN
S980
Casting!

I glassed up the final pieces from my molds. Big sticky job, but I have a lot more confidence in the parts pull than I did for the mold making part of this project. I took my final molds and waxed and buffed them five times with Mequiar's Mold Release Wax. I would have forgone the mold release wax entirely since it failed to spectacularly on the last job, but the truth is, I needed the wax to fill in some of the remaining porosity in my molds. After the wax, I sprayed everything down with a layer of polyvinyl alcohol (PVA) mold release. I applied that with an automotive touch-up gun. The PVA is responsible for the purple tint of the molds. It dries to become like the layer of paper on the outside of an onion. Following that, I layed up the fiberglass mat using the barrel rollers to get out the air bubbles and to force the mast into the contours. This time, I had no catalyzation problems, so I expect the parts will come out just fine.


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This is my mold release wax.


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Using the roller to get out the bubbles


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The new parts cure in the sun while I try to get all the resin off of me.


Next up, removing the parts from the mold and assessing the way ahead.

V/R
Redshirt
 
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