discussion CF Tank.

[Rebelervi]

Purchased a plastic 1/16th HL R/C tank, and used as a guide, to fabricate a larger version from CF.
Started with hatch, and layed up 4/5 layers on laminated chipboard, cut ends/sides of lower hull, and some wood flooring to use in makeshift jig.View attachment 313793

 

[Rebelervi]

Used scrap wood, easi sand filler to make pattern/mold for turret, and used around four layers of CF tape, added section for upper surface.
Used wood/filler for pattern, to lay up rear turret box.

 

[Guest]

It took me a bit of thinking to work out that CF is probably carbon fibre … The tank seems to be a Tiger, based on hull and turret shape?

 

[Guest]

Chris.
I will follow this with interest, looks very technical so explanations would be helpful :smiling:
John.

 

[Rebelervi]

Hi, thank you for your interest,yes carbon fibre , cloth, tape and sock. The sock is quite dense compared to cloth Im using, so after laying up sock, three layers? around wood/filler and sprayed pattern, was able to work with grinder to get a reasonable shape for hatch surround (0058) Added disc to top, layed some cf over old tax disc holder, which I hoped would be top layer, for hatch itself. then hoping to get some sealing, cut polo, held onto plastic pattern, and built up with strands to create an edge.

 

[Rebelervi]

After pulling the turret from wood/filler mold, added to front panel, built up alittle inner flats, and worked up sides. (0136)
layed up four layers, using turret mold, for front edge, added, blended in.

 

[Rebelervi]

Build is based on the Tiger, the turret front is alittle wider, hatch surround slightly taller, but lower hull hopefully is as intended. Scale is 1/8th.
After building up ends and sides, in laminated jig, layed up around four layers, to create base(0111)
Pulled, cut front sections, to start upper hull/lid.(0106/ 0139)
Cut some sides, added, epoxied on top surface, which was five layers, but sagged in middle.

 

[Guest]

Hi, thank you for your interest,yes carbon fibre , cloth, tape and sock.

It’s an interesting way to build a model, one I certainly haven’t seen before and will likely follow if you post more about it. However, I think I need to point out that you appear to assume background knowledge on the part of your audience, that most of us probably don’t have I know the basics of carbon-fibre construction (hurrah for How It’s Made ) but I’m certainly not up to speed on the terminology. I think this goes for most of the people reading this thread.

 

[Guest]

Chris.
Think Jakko is right, most of us will have zero knowledge. Looks very technical and very intesresting will follow, but a bit blindly at the moment.
John.

 

[Steve Jones]

Way out of my comfort zone for this build but I will certainly look on with interest. Good luck

 

[Rebelervi]

I'll do my best.
Can go with how it was explained to me....the process is similar to fiberglass. There, to fabricate a FB article, a mold is usually required, for that a plug is needed, a representation of finished article, in size and shape (Pluglast- plug made from wood,filler and spray) once plug is complete, take a mold (Fairingmold3.jpg) Lay up (Build up composite layers, FB = around 1mm of gelcoat, then layers of glass and polyester resin) in finished mold for an article.
CF though doesnt generally like corners, there is a method that can sometimes work, ie, apply epoxy, leave to go sticky, then add cloth, and more epoxy.
The more preferred method is vacuum bagging, which draws all air, and sometimes pulls resin through cloth.
Most surfaces need release wax to prevent sticking, when laying up, although the laminated wood is usually non stick, but to be on safe side give a couple of coats.
With bagging and oven, the panels weigh approx a third lighter than DIY.
If remember correctly, the ratio with CF is 55% Cloth-45% Epoxy, for best strength, so CF ya squeeze, FB ya saturate.
Glass transition temperature (The Glass Transition Temperature (Tg) is one of the most important properties of any epoxy and is the temperature region where the polymer transitions from a hard, glassy material to a soft, rubbery material.) is sometimes a concern, so there are a variety of resins for various apps.
The How its made, feature alot of pre-impregnated cloth http://www.easycomposites.co.uk/#!/prepreg
My efforts are basic, and require no real skills, nor specialised equipment, like ovens and bagging.
The laminated wood provides a great surface to create sheets of CF that can cut with hacksaw and bond together. Use paddle roller http://www.grptools.co.uk/laminating-rollers/paddle-roller/

 

[Guest]

Thanks for that Chris.
Gives a good insight into what you are doing.
John,

 

[Rebelervi]

As the top surface sags, it seemed feasible that a ring would add strength, and be able to blend into sides, for some support.
The hatch system,looked good to seal, with door hinges, to add.
Spotted a container, that raised possibility of mounting turret on bearings.

 

[Rebelervi]

Cut squares of CF cloth, stripped some threads out, and went to work on using "celebrations" lid for pattern.
Guesstimated placing of plastic pot, in centre, built up around four to five layers of scrappy pieces, CF + epoxy, all on a laminated chipboard.
Pulled, trimmed edges lightly, noticed few air bubbles, that will need repairing, once pattern is removed (0199)

 

[Rebelervi]

After repairs to lower bearing surface, and trim, sized up some bearings, purchased silicon sealer, added to lower surface, layed up some scrappy pieces of CF plus.
hopefully have upper and lower bearing surfaces (0244)

 

[Rebelervi]

Gave some thought to hinges, placed two pieces of laminated flooring next to one another, layed up two layers of CF, lined up ally tube, rolled one board, placed and clamped.
Used a brass pattern to fabricate ventilation opening/top of turret.