How would you make these?

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#1

Firstly, i’m a bit of a newbie, done a few simple infusions so far but that’s it.

I want to make some of these trim pieces

Look’s simple enough right?

On the other side there are these raised sections that the trim clips are mounted to

the easy option would be to make a thin laminated part that sticks onto the original part, but i’m interested in making a part that has this raised section that can incorporate trim clips.

could i put a core within the layup and infuse then drill holes for the clips?

#2

You’d be best making 2 parts - 1 outer and 1 inner with the mouting points and bond them togther. I make something in a similar way for Triumph Speed triple Tank infills.

#3

Do you think the recessed triangle will cause me any problems?

#4

Shouldnt do as this will be rasied in your mould. You might want to add extra flow media to make sure it gets over the bump.

#5

Just polished, up waxed, pva’d and gel coated. Going to back the mould with around 4 layers of glass

#6

What resin are you using to make the moulds?

#7

Easy composites tooling gel coat

#8

Epoxy then. Becarful if you every use polyester as it can damage some plastics and it also attacks painted finishes. I’ve been bitten a couple of times by poly!

#9

Can I back the mould with polyester resin?

#10

Polyester doesnt bond very well to epoxy. But epoxy will bond to a cured polyester.

#11

I noticed that the surface of the cured gel coat feels greasy? is this normal? i usually scuff it with coarse sandpaper and clean with acetone before backing the mould with glass and resin.

#12

Are you sure its cured? If i leave mixed epoxy out over night it feels greasy too.

But you should apply the fibreglass within 24hrs of application to the mould to ensure a decent bond to the gel coat. Then again i use polyester so may be different with epoxy.

Or could be the PVA unless you’ve cleaned it off.

#13

It’s had a good 24 hours to cure, only the epoxy exposed to the air is affected, when I pull the part I’m moulding out, the surface that matters is ok.

#14

Ok iv worked out it’s amine blush from the hardener that’s causing the greasy feeling. I left some mixed epoxy out in the shed and some in the oven. The one left out in the cold feels greasy and is cloudy ( and still a little fexible). The one in the oven i clean and hard as a rock. Amine will wash off.

How warm was the environment it cured in?

#15

It probably goes down to about 10 degrees at night in my workshop so a bit chilly, I guess it just takes a little longer to cure? I’ve got some resin to back it with now so I’ll clean it off before hand.

#16

Mould is made now ready for first infusion, but i can see there will be problems laying the carbon into the radius of the corners, i’m thinking of trying a spray adhesive for the first time, i can get 3M 77 or aerofix 2?
please can someone recommend one of these or something else i can get here in the UK?

#17

It’s a female mold I take it? Try your best to get the fabric in there without any spray. You might have to dart the corners (ie: cut right in the corner, and layer one side over the other) to get the fabric to shear enough. Spray adhesive doesn’t always work well. if you didn’t buy anything, choose one for the resin you are using. Spray VERY VERY light as well!

#18

My bet would be for Aerofix 2 or 3.

The only reason 3M 77 is popular, is its availability. However, many people have problems using it.

#19

When making an epoxy tool we brush on the epoxy gel and just as its gelling we put a coupling coat of resin /cotton fibre/silica (west 403). The gelcoat has a gel time of about 30-40 min and within an hour or so its hard enough to laminate onto it. The fact that we put the coupling coat on means we still have a wet surface to laminate to and a chemical bond between the gelcoat and coupling coat.
The key is not to let the gelcoat cure too far before getting your coupling coat on.
A mold made it one hit!

#20

Rx7 already done these :slight_smile: