Hello all

Planning my first project.. I have included some photosbelow of the part to be replicated. Having lurked for a while I was hoping todraw on some experience here.. i have the large mould & high temp laminatekit from EC....

Mould construction

• Would you build up the sides of the mould tomake the shape a complete ‘bowl’ and trim after, or using clay, construct anedge/flange following the contours of the shape..
  

Layup

• ·        I had planned in the first instance to followthe wet lay technique shown on the video. What would be the most pleasing tothe eye to lay the fabric.. i planned to use two pieces of fabric due to theshape, firstly cap the top of the cowing using a circular-ish piece and use aseparate piece of cloth to cover the sides.
• ·        Are there any issues with overlapping the cloth ..any special considerations in doing this,, will it look nasty.
• ·        How many layers of fabric would typically beused to achieve the same thickness at the sample in the photos. this will besubject to vibration and heat
• ·        Can i let each layer cure fully before addingthe next or should it all be laid in one sitting
• ·        Can something of this deep bowl shape be doneusing a Vacuum bagging. Is there anything on the web showing this type of shapebeing made this way.. all i have found is flat or shallow panels.

Thanks

Hi Simon,

Thanks for your post and sorry for the delay in getting back to you. I should have been notified of your post but for some reason didn't see it.

Answers to your questions as follows:

Would you build up the sides of the mould tomake the shape a complete ‘bowl’ and trim after, or using clay, construct anedge/flange following the contours of the shape..

Well, essentially, providing that the flanges were build so that they extend the surface of the part 'flat' out beyond where the trim line currently is then either of the above would amount to the same result in the finished part. You'll need to 'extend' the part all the way around (including at the base) too so I think I would be tempted to get the part raised up slightly and mounted properly to a board and at the same time fill in those missing peices all the way (with some flexible plastic or thin chip board). You might want to use some body filler to smooth the step - when you've got a lot of building up to do you might find that clay/plasticine/yellow wax is a little vulnerable to dropping out.

I had planned in the first instance to followthe wet lay technique shown on the video. What would be the most pleasing tothe eye to lay the fabric.. i planned to use two pieces of fabric due to theshape, firstly cap the top of the cowing using a circular-ish piece and use aseparate piece of cloth to cover the sides. Are there any issues with overlapping the cloth ..any special considerations in doing this,, will it look nasty.

Yes, I think that's a good idea. Make the cap and place that in first then the 'band' that will go all the way round. Make sure there is plenty of overlap when you put the band in. You might want to stiffen the carbon that you use to make the 'cap' using a little hairspray (or use our specially made 'ProFinish' carbon) otherwise you won't be able to cut this disc without it fraying and spoiling the appearance of this join-line.

How many layers of fabric would typically beused to achieve the same thickness at the sample in the photos. this will besubject to vibration and heat

I can't see exactly how thick the laminate is in the part in the photo but here's how to work out what thickness any given laminate would be:

1 layer 200g carbon cloth (or 195-205g really) = approx 0.25mm thickness in a finished laminate.
1 layer 450g carbon cloth = approx 0.57mm thickness in a finished laminate.
1 layer 660g carbon cloth (or 650g really) = approx 0.78mm thickness in a finished laminate.

Kevlar is lower density so will be slightly thicker for a given weight and carbon/kevlar will follow suit slightly, according to its kevlar content.

This means that if the part is 2mm thick you would need 8 layers of 200g carbon or 2 layers of 200g and 2 layers of 660g (=2.06mm)

this will besubject to vibration and heat

The heat tollerence of the part is more down to the resin system you use. The High Temp Laminating Kit you've chosen has an HDT of 180C so you should have no problem there.

   Can i let each layer cure fully before addingthe next or should it all be laid in one sitting

You can do this but it's not good practice. You'll have far more strength if you put down everything in one go. If you do want to do it in multiple sessions then ideally you would add additional layers onto the back of 'partially cured' resin underneith. If you do this then you will get some cross linking and the laminate will be that much stronger for it. If you can't do this then you'll need to 'key up' the layer beneith using coarse abrasive paper.

Can something of this deep bowl shape be doneusing a Vacuum bagging. Is there anything on the web showing this type of shapebeing made this way.. all i have found is flat or shallow panels.

Yes, definately. We don't have any videos at the moment which show it but it could certainly be done. Either vacuum bagging (use SLOW hardener to give yourself time) or resin infusion would be possible. Warren (on this forum) has done some awkward shapes with infusion (a centre console part for a car) which was not too dissimilar. Just try to position the vacuum lines and resin feed lines as far from eachother as possible - the infusion process should take care of the rest.

I hope this helps!

matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Lambretta?

Hi thanks for the replies..

This is indeed a larger engine cowling for a Lambretta...

have a couple of days spare and it sunny outside so I thought Id start.. i have below a few shots of the progress so far


sides & holes filled in.. plug built up.. I used plastacine with some care and patience..



then waxed-polished & PVA



Covered with Gelcoat .. (had to move into the garage before wife came home)



Fibre Putty added.. although the gelcoat was a little further set than i wanted.. still a little tacky though

Will attempt to release the plug tomorrow....

Hey. I made a welding helmet shell and that turned out good. Well, being honest, first try was full of bridging (i did not massage the vacuum bag enough). Epic fail haha.

The second one was ok. And it has what I call "consecutive curves and corners", if it makes any sense to you. I had to increase vacuum pressure slowly while massaging the bag with a rubber rectangle to force fabric and bag in corners. The fabric was laid in one piece, no cut anywhere in the part area. 2 layers of 200 g/sqm 3k 2/2 twill were used.

Notice the vacuum infusion was made without any flow mesh... Yeah in Belgium we crazy people (Matthieu looks profesionnal tho haha)

Infusion was VERY slow, so the slowest hardener was used. I skipped the flow mesh cos it was too difficult to position in tight corners (hence the first part that failed). And it was also too long to do it properly with 100% certitude on how mesh would conform (yeah, in Belgium we lazy people too).

Hope it helps, and dont forget the pics

 



 


    A $1000 electronic device will always protect a 10 cents fuse

How are you getting on with the mold for the TT3?

Hi

Mold for this is done.. and seems good for 1st attempt.. (did an air scoop with the leftovers)... last week i attempted a start.. coated the mould in a layer of resin and allowed it to cure for a couple of hours.. when I returned to it , it lots of what looked like hairline cracks in the resin and bubbles were horrendous.. so decided not to proceed...perhaps it was too cold..?

will now spend some time re-sanding the layer of resin off the mold and try again..

Will update when progress is made

Hi