Custom body, How do I achieve this, cheaply!

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Apologies for duplicating it here but I thought I would finish off this thread with a picture of the form for my car body cut and sanded from insulation foam. Next I need some GRP.

IMG_5450.jpeg


I will continue the body build in the ‘Scratch build tethered race car’ thread.
 
Apologies for duplicating it here but I thought I would finish off this thread with a picture of the form for my car body cut and sanded from insulation foam. Next I need some GRP.

View attachment 181977

I will continue the body build in the ‘Scratch build tethered race car’ thread.
It fits in here. Maybe @WoodiE can move this thread to the Paint and Body forum, as I would suggest you go ahead and keep updating both threads simply because it's relevent for each forum 😉
 
Ok man. I found a solution for you 😉

Not seen one of those pens used like that, some people have real commitment to a technology, it is anmzing what they anchive given its limitations.

I am always on the look out to repurpose stuff especially things which are not intended to be used in a particular way, IKEA being one of my favourite places to source pre bent plywood, aluminium and stainless steel rods , small pieces of acrylic, thin steel sheet, tubes and mounting brackets!

‘Any-road-up’ my GRP kit arrived yesterday, we shall see what kind of mess I can make with 1960’s tech. :0)
 
Not seen one of those pens used like that, some people have real commitment to a technology, it is anmzing what they anchive given its limitations.

I am always on the look out to repurpose stuff especially things which are not intended to be used in a particular way, IKEA being one of my favourite places to source pre bent plywood, aluminium and stainless steel rods , small pieces of acrylic, thin steel sheet, tubes and mounting brackets!

‘Any-road-up’ my GRP kit arrived yesterday, we shall see what kind of mess I can make with 1960’s tech. :0)
I thought the same thing when I saw some of that guy's videos. Really creative ideas. He does a pair of Converse sneakers that is really cool too.
 
Well the kit of GRP bits included tools, gloves and acetone, warmed my shed up with an electric heater and set to work.

I decided to try the chop strand mat because I remember it was better at going* around corners. I have some fine woven mat for the top layer. The buck/plug is screwed onto a bit of 21/2” x 2” with feet so that I could lift it well clear of the bench top, then drape the glass fibre mat over it. Never tried this inside out approach before, it’s fast but clearly the finish will never be great, but hey no one’s gonna see it when it’s on the move.

One layer down with a second to go, now all I can smell is resin.

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Image above is as seen from the rear, I stopped taking photos because everything was getting sticky and there was a risk that my phone might become part of the moulding. Finish is as anticipated rough, it’s going to need a fair bit of sanding, then the woven layer and more sanding.

Well at least it still resembles the original shape and not a giant sticky ball of chop strand fibres.

Later this afternoon I put the second layer of chop strand on, hopefully it will have sufficient thickness to take a light sanding, I will see if it’s hardened sufficiently tomorrow otherwise it could be another week before I get to smooth the lines and put the last layer on of woven material.

I am not looking forward to trimming it, I have an engineers scribing block I should be able to use that to get a reliable level all around.

I might have a look for a rattle can of paint, I like signal red.
 
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Some progress today, I marked the edge to cut and trimmed it with a Dremel, sanded it down to expose fibres and applied a coat of resin by brush. The trimmed edges were of the order of 2mm to 2.5mm thick so I decided not to add the third woven layer, may be next time, one layer of chop strand and a top layer of woven.

IMG_5463.jpeg


Plan is to give it a light sanding and for this to provide a key for the paint, plenty more chances to sand it although it is never going to have a super smooth finish that you could expect from doing it properly with a mold.
 
The GRP 'loaf' is currently sitting along side me in my home office and has cured very well. I get to pat it like a dog in between moments of actual work!
It now has a nice smooth semi matt finish and feels quite tough when tapped. I am not looking forward to the further sanding that is required.

It should do a reasonable job of keeping the flys off the car during a run and maybe affording the motor and battery some protection in the event of a mishap?

I have decided to cut it shorter to reduce the overall length. I am no aerodynamicist, but I might leave the back open, I have a gut feel that closing it off won't help anything.
 
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I am thinking about how to fasten the GRP body down to my car chassis, I was thinking of making a couple of 'U' brackets fastened to the underside of the chassis rail one at the front another at the rear, think of them like they were each made from a 6" steel rule with the ends 1/2" bent up so that i can screw through the sides of the body shell in four places in to the bent up ends. This might be discrete, but seems a bit clumsy, 4 screws to undo each time.

So I thought about using a couple of thumb screws through the top of the body shell which could screw into 2 angle brackets mounted on top of the chassis rail, neater and lighter, but fewer fixing points. However this would allow me good adjustment of mounting height in case it needs to be tweaked. The down side is that the thumb screws, (I could make some custom knurled ones) will be very visible sticking out of the top of the body shell.

Thumb screw.JPG


Which got me wondering what is available for this application that already exists? I have found some nice 'flush' motorcycle cowling quater turn fasteners but they are understandably quite big.

Any ideas? BTW cheap is good, I've blown the budget on this project already, Ooops!

I wonder if car plastic panel fasteners would do? (The reusable type) Might not be secure enough?

panel rivet.JPG
 
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Ok so a female version of the thumb screw, I like the O-ring presumably to protect the car body?
I can see how this might be an improvement as it would be easier to locate the body over the protruding screw threads.

Thinks,.....this has been done before hasn't it!

These could look quite swish, countersunk body washers, who knew? Albeit I'd need to use a hex key to open it each time.

washer.JPG
 
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Ok so a female version of the thumb screw, I like the O-ring presumably to protect the car body?
I can see how this might be an improvement as it would be easier to locate the body over the protruding screw threads.

Thinks,.....this has been done before hasn't it!
I used them on our drag build. You would thread the studs into a standoff then put the o-ring on, then the body, then the nut. Since you're painting the body on the outside I presume, you would want some body washers under the nuts.
https://www.amainhobbies.com/search?cID=&s=body+washers
Here they are installed in the Pro-Line body post. So your mount - you'd probably want to put about a .020"-.030" counterbore for the o-ring to rest in. You would want to locktite the studs in if going into aluminum, and use a blind hole, or drill and tap through and locktight a jam nut on the back side.
20211215_153813.jpg
 
I used them on our drag build. You would thread the studs into a standoff then put the o-ring on, then the body, then the nut. Since you're painting the body on the outside I presume, you would want some body washers under the nuts.
https://www.amainhobbies.com/search?cID=&s=body+washers
Here they are installed in the Pro-Line body post. So your mount - you'd probably want to put about a .020"-.030" counterbore for the o-ring to rest in. You would want to locktite the studs in if going into aluminum, and use a blind hole, or drill and tap through and locktight a jam nut on the back side.
View attachment 183382
Hm
Made me think.
I have an extra pair of those for my slash. Wondering if I can use one for my buggy battery strap. To replace having to unscrew a screw. To take / put in the battery.
 
Hm
Made me think.
I have an extra pair of those for my slash. Wondering if I can use one for my buggy battery strap. To replace having to unscrew a screw. To take / put in the battery.
Yup. They should work there as long as the set screw is the correct size for that pin hole. I can't remember what size that is.
 
I like the thinking, studs to help location of the body and a rubber washer/O-ring to help stop the nut undoing.

I might go for shallow profile aluminum in red seeing as the colour of the body is to be red.

CThumb nuts red.JPG
 
built conveyers for years they dont have kevlar in them.nylon sure..I would have went with a solid aluminum wheel myself..I'm going out to Bonnyville salt flats to see Aussie invader try to break the land speed record ...


https://aussieinvader.com/the-challenge/
 
built conveyers for years they dont have kevlar in them.nylon sure..I would have went with a solid aluminum wheel myself..I'm going out to Bonnyville salt flats to see Aussie invader try to break the land speed record ...


https://aussieinvader.com/the-challenge/

Solid aluminum wheels, you make an interesting point, i chose to follow the wheel design of one of the established members at the club who runs IC engine 'driven wheel' vehicles, they are push started and rely on the rubber for traction during the start. My IC car followed this design, but you are right on my electric car I could consider solid aluminum wheels. It would reduce my angst with regard to the risks from 'out of balance' wheels.

Thank you for the thought.
 
I sanded to body shell on the plug until I got fed up sanding and the fibres started to show!

IMG_5467.jpeg

It’s shiny because I’ve just wiped it down with white sprit

Then released it to trim the edges

Finally I gave the shell a coat of primer, as usual I got impatient and put too much on in one go and now have runs!

IMG_5472.jpeg
 

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You're doing a helluva job man. Runs can be dealt with easy enough with a sanding block. Especially if it's sandable primer. It's getting so close man. Dying to see the finale.
 
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