Carbon V Style Layup

General Composites Discussions Composites Talk
#1

So I dont know the name exactly but i am looking for suggestions on the best way to “V” the carbon from the center out. I have attached a pic of the part I am trying to make and the pattern as well.

Question 2
Since I am having so many issues with clear coats after molding, i was thinking of doing a either a 2k spray or Duratec Sun-shield application in the mold first. Is one better than then other for this type of work? I assume you would apply the mold wax and pva as you would normally be for spraying in the clear coat?

http://www.expresscomposites.com/?product=polyester-top-coats

#2

2k clear for me is clearer slightly. Duratec sprayed in the mold seems to darken and tint but maybe I’m loading it on to heavy. I find that spraying the part with duratec vs regular 2k clear has very little difference when looking side by side.

Pick your poison. There’s no perfect solution since I’ve been told 2k needs to be scuffed for mechanic bonding in the mold. I experienced delamination on parts when trimming with 2k clear so had to strip and reclear.

#3

Why would you want the 2k to bond to the mold. From what i understand you just need to spray it right over the PVA, let it dry and then do the layup.

#4

Why PVA? Is your mould a mess?

#5

He doesn’t mean bond to the mould, he means you need to spray the 2k clear and then scuff it for the laminate to bond to the clear coat.

2k clear isn’t formulated to be open to bonding, it’s formulated as a final topcoat. So as you would when repairing or respraying a panel, you need to give it a mechanical key for the resin to stick to, otherwise it will delaminate. This isn’t necessarily true of ALL 2k coatings, some of them may be open to bonding without prep, however it is an unknown so it’s a chance you take.

This is the advantage of the Duratec. It is formulated for use as both a final topcoat as well as to be open to bonding, so it can be sprayed in the mould and then simply laminated onto without any other prep-work at all.

Infused, the Duratec certainly shouldn’t appear any different when sprayed into the mould. It does have a slight colour to it, and the Sunshield is slightly more so due to the presence of UV inhibitors, but this shouldn’t affected the appearance of the final part in the slightest.

#6

Yeah I think I’m laying it on to thick on my molds. I’m going to pay closer attention and only do 2 full coats. Sometimes it may be 2 or 3.

#7

So you have to spray the 2k (I would be using spray max) then lightly sand it? how do you do that without breaking through? Guess its sunshield for now!

I am just trying to figure out something that will work. I had no luck with the German advance IMC and clear coating the parts after has been a major issue. I am not body guy by any means so spraying things etc is like voodo to me.

Any tips on doing the “V” pattern? Like this one in this pic

#8

Late Reply…

No the mold is fine. Generally I wax the mold then apply a pva to surface before doing the layup. Is there a better way?

#9

Soller composites used to sell the fiber you show pictured. It is exact. As far as in mold coatings I like the 2K method but it is difficult and takes some experimenting.

#10

Composite envisions and solar both carry it!! Ordering it!

Do you sand the 2k before doing the layup?

#11

If the wax is good, PVA shouldn’t be required.

#12

You should be spraying your coating thick enough to not break through. It’s the same as prepping a panel for paint, you just scuff it up until all the gloss is gone. 180 grit is fine for adhesion.

V-pattern is very easy, nothing to it.

#13

What method are you using, pre-preg, infusion, wet preg?

#14

that is how i have always done it, not that it isnt right. I read somewhere that wax doesn’t actually create a barrier between the mold and epoxy so you can easily damage the mold on removal.

#15

infusion with MTI hose

#16

I picked up some duratec sunshield. A few questions on it though…

  1. does it need to be sprayed in or can it be brushed in?

  2. should it be at a tacky state when doing the layup or can it be dry. Meaning can I apply it and let it sit a few days before doing the layup??

#17

It can be brushed, but I would only recommend doing this if you aren’t vacuum bagging. If you are vac bagging or infusing then this will push the fibres into the brush strokes of the Duratec and cause a strange optical effect on the final part. If the parts are just wet-laid then the fibres simply ‘float’ on the surface and it isn’t a problem.

If you are using polyester or vinyl ester then the layup should be completed when the Duratec is at a tack stage. If you are using epoxy then it needs to be fully cured, minimum of 24 hours before layup. There is theoretically no problem with letting it sit for a few days if you are using epoxy, the bond is purely mechanical so there is no open time to observe. The longer it sits though, the more likely it is to be exposed to dust and contamination that may affect the bond or appearance of the final part.

#18

i always use epoxy and darn on the brushing. Rolled maybe? I also have ot figure out a way to apply the Feather fill as well.

It i cannot figure out a different method I will just need to figure out a way to spray the parts. Cant do it in the garage (too cold) and the wife would shoot me if i did it in the basement.

#19

fancy new carbon fiber showed up. Any thoughts on how to keep the v centered down the length of the part??

will spraying airtac on the 2k or Sunshied cause issues??

#20

any one have any thoughts on the above questions???