Delta Force DF 38" (DF45 MkII) Build - 6S

Intlwaters

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Joined
Jan 24, 2022
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18
Well I bit the bullet and purchased a hull off the back of advice here (thank you).

I plan to run 6S as I already have a motor/ESC/batteries.

The hardware is all on the way from a helpfuly Aussie supplier (RC Boat Bits) but I think my first task is to line the base with a carbon fibre inlay.

The boat has rails so I'm going to use them to mount a 3D printed base for the motor mount, which I'll bolt into the rails. That way the motor mount isn't glued to the hull, and I can easily remove it if I want to run nitro later, which I'd be lying if I said I wasn't interested in.

Can I use a 2 part closed cell foam in the front of the boat (once I know how much room I need for the hardware) as I already have some leftover from another project?

Any hints for closure of the canopy? Should I just buy some locks and tape it shut when it runs?

I'm new to this so any advice would be welcomed.

Excuse the messy bench!
 

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Gary Parker

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Sep 16, 2021
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Hi Michael - a lot of people just use cut-up pool noodles so a waterproof 2 part cell closed foam should be fine for flotation.
 

Wasted wages

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Jan 2, 2006
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I wouldn't suggest using two part foam, even the best will trap water and eventually get waterlogged, it is a mess to deal with if you have to make future repairs to the hull, and it's hard to keep the inside of the boat clean once oil and water get sloshed around inside.

I have also seen the expanding foam warp hulls and even burst seams and blow off deck lids.

Pool noodles work great, if you are worried about them staying in place, a little silicone can glue them down. You can also loop a thin cord thru the noodle and tie it down if concerned that it might get tossed out during a flip.

A 6 ft noodle bent in a V shape and shoved up under the deck with the two legs running
down the insides is usually sufficient to float most hulls...

Make sure to test it with everything in place ready to run and full of fuel for positive buoyancy..
 

RaceMechaniX

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Apr 27, 2007
Messages
2,959
I have a different positive opinion of 2-part foam and use this in all my FE mono's and most nitro mono's too. I am using US composites 3lb 2-part foam. I mix in small batches (2-4oz total) and pour in allowing the foam to spread across surfaces. Compared to pool noodles, 2-part foam adds a lot of strength to the nose of a mono and the side rails. The added weight of an FE plus the higher speeds they are capable of make it easy to cave in a top deck in a crash. In the attached pic you can see the foam in my DF39. I have seen FE mono's crash hard and sink then seconds later half of the pool noodles come to the surface and boat never resurfaces. If you use pool noodles make sure they are secured in the hull.

For the canopy I would use some type of pin in the front and thumb screws in the back for physically securing the canopy and then tape for sealing. Make sure to add 1-2 layers of fiberglass or carbon in the cowl plus some foam to make sure it will float. I use a 1/8" pin on the front and two 6-32 thumb screws in the back corners of the cowl.
 

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Joined
Jan 24, 2022
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Not cheap either I notice! :)

What are you guys using for epoxy to lay carbon fibre? I have tried it in the past with West Systems G-Flex but found it very difficult due to the thickness.
 

Mark Anderson

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Nov 22, 2002
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735
Regular west laminating epoxy will work much better than g-flex and is widely available. I switched to Resin Research products and prefer them to West Systems.
 

Rod Fonda

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Apr 30, 2021
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I also used 2 part foam in both of my cats,,as Tyler mentioned,small batches is the trick,,Its easy to use too much in one go and risk a mess or possibly blow the deck,surprising how much it expands ,I also sealed the foam afterwards with some epoxy resin
 
Joined
Jan 24, 2022
Messages
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Slow going at the moment but I've installed a doubler to the transom and have done the inlay between the engine rails.

Would you do outside the rails also?

The sides are anything but neat, it's not an easy material to work with! It'll annoy the hell out of me, but first try so can't be terribly hard on myself I guess. Needs another coat of epoxy.
 

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Joined
Jan 24, 2022
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I'm having a look at where the motor will mount. It's been recommended I get it back as far as I can but try not to create too much of a bend in the tube.

On the mount as it is, the motor is a good 3/4" from the bottom of the boat. Would you lower it on the mount and flatten it out? That will inform the stuffing tube and then I can make a mount for it.
 

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RaceMechaniX

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Apr 27, 2007
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Michael,
You can cut off the bottom of the rails to lower in the hull and then redrill some of the epoxy holes where appropriate. Alternatively you can use the existing rails as templates and cut some new rails that are lower in height to set the motor deeper in the V. You do want the motor as deep as possible. I use a 1mm or 1/16 strip under the motor as a spacer when mocking up my mono builds.
 

Mark Anderson

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Nov 22, 2002
Messages
735
It appears that you put the carbon in with a 0-90 orientation. If you cut it on the bias (45 degrees), it will be stronger and is much easier to get to lay in. A very lite mist of 3m 77 spray glue before cutting makes bias cut fabrics much easier to deal with.
 
Joined
Jan 24, 2022
Messages
18
Excellent feedback, thank you both!!

I've been building a hydro from scratch, and the amount of things you learn as you go, like the carbon tip above, is huge. I'm forcing myself to finish it, but will probably need to build it again and make it significantly lighter/better with the knowlege I've gained building the first one!
 
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