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Jul 08, 2010, 01:47 AM
Need 4 Speed!
pdawg's Avatar

Splitter box

Its been a long day of building but my least favorite part of any molding project is done....the splitter box. The splitter box is very critical but IMO boring to construct. Its also a step where the completed plug risks getting dinged on accident. I always cross my fingers that nothing happens.

There are many ways to do the splitter box but here is the technique I've refined over the years. Its pretty straight forward and results in a very tight fit with a minimum amount of fuss. In the past I've tried other techniques which use spackle or clay with success but I prefer using bondo since it gives a very sharp molding line. Please check out the images...hopefully they tell the story. If not, please don't hesitate to ask and I'll do my best to clarify the process.

If everything goes smooth there is a good chance this mold will be completed by the end of the weekend.
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Jul 08, 2010, 03:25 AM
Team30 Micro EDF
NitroCharged's Avatar
All class Bret! Very nice and very easy to follow.
Jul 08, 2010, 05:17 AM
Life begins at transition
Is that bondo polyester resin? The stuff that sets in around 10min?
Why pull it out when the resin's green?
Jul 08, 2010, 06:29 AM
Tom Bass Park RC Nonconformist
Cdr.Instigator's Avatar
Pdawg, That looks freaking SWEET!!!
Jul 08, 2010, 11:10 AM
fly like an EAGLE ;)
corsair nut's Avatar
very well done bro!
Jul 08, 2010, 02:13 PM
Bret,thanks for taking the time to show the molding process..great photos and explanation. I think I could make a plug,a splitter box,and correctly place the plug in the splitter box now. Keep up the good work and photos too!!
Jul 08, 2010, 03:05 PM
Registered User
stegla's Avatar
Pdawg.............. I have a project in mind that could use a moulded fuse.

Watching and learning!

Jul 08, 2010, 03:17 PM
Need 4 Speed!
pdawg's Avatar
I'm glad that those pics make sense. To answer Odysis's question, there are 2 important reasons for removing the plug while the bondo is rubbery. The first is that at this stage the bondo releases from the tape easier than if it was given more time to harden. Additionally if there are any negative draft angle issues (for example the pointy nose or the radius around the turtle deck) the flexibility of the bondo still allows the plug to be easily removed.

Thanks for the feedback...its the same technique that was used on the Micro Stinger. Maybe thats why this feels a bit like deja vu. Its the same size...but this time its a jet

This pic is for you since I can already guess what you would do with an Electrolyte fuse. It could be pretty close to an F-20 with a few mods.
Jul 08, 2010, 05:58 PM
fly like an EAGLE ;)
corsair nut's Avatar
pretty close, but ill probably do my own thang...inspired by the F-20 of course think you can get a 50mm in there??? i bet a kyosho 45mm would be sweet too....

man that F-20 is down right SEXY.
Jul 08, 2010, 06:31 PM
Need 4 Speed!
pdawg's Avatar
Originally Posted by corsair nut View Post
pretty close, but ill probably do my own thang...inspired by the F-20 of course think you can get a 50mm in there??? i bet a kyosho 45mm would be sweet too....

man that F-20 is down right SEXY.
Thats cool. Actually I'm not 100% positive at this point that a 40mm fan is going to fit in there. Its going to be close but I really won't know until the first fuselage is popped out of the mold.
Jul 08, 2010, 10:59 PM
fly like an EAGLE ;)
corsair nut's Avatar
i meant, once i get one of those fuses...ill make up my own wing/tail design

well, there are some kiler 40's out there for sure.
Jul 09, 2010, 06:44 PM
Need 4 Speed!
pdawg's Avatar

waxed and PVA'd

4-7 layers of wax plus a layer of PVA and the Electrolyte plug is ready to be molded. The plug was waxed and polished so many times yesterday I honestly don't know exactly how many layers of wax it has at this point. The PVA is applied over the numerous layers of wax but it did not turn out perfectly uniform as expected. Since I usually polish the mold anyways I'm just going to live with the current layer of PVA and push ahead. Tomorrow is going to be a long day of mixing epoxy and dabbing fiberglass but I'm honestly looking forward to it.
Jul 09, 2010, 08:35 PM
Team30 Micro EDF
NitroCharged's Avatar
Exactly what is PVA and how did you apply it Bret?
Jul 09, 2010, 10:58 PM
fly like an EAGLE ;)
corsair nut's Avatar
PVA is a mold release, it can either be brushed or sprayed on. its water based, and after you apply it, it dries and creates a protective, film over your plug, it also acts as a release agent. after the mold is layed up and cured, you pop the mold off, and rinse your plug and mold off with water, which removes the PVA. pretty cool stuff. we use it at work all the time, and thats what my dad uses for doing ducts ect.

looking great bret. good luck tommorow, and keep us updated
Jul 09, 2010, 11:03 PM
I don't want to land yet!
Nitro... PVA is a release agent which forms a skin(spray or brush on), helps heaps and is easy to clean off... you can blast it with air even and it peels off in most cases and water will get it off. But best to use both like pdawg has, the wax makes it slippery and will release away from the plug...
Try to avoid creating heat in the process as much as possible, less chance of having problems.
I have done heaps of this sort of stuff as a patternmaker/modelmaker in the automotive industry and marine fields. Of course that was a few years ago now, just an office CAD monkey these days...

I have used a blue PVA mostly... makes it easy to see where it is on the mould.

Very nice job there pdawg... looking real sweet!

Last edited by Strike3; Jul 09, 2010 at 11:06 PM. Reason: corsairnut beat me to it!

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