How can I speed up my clear coat process.

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#1

Hi guys,

I’m chasing any hints and tips when it comes to clear coating my finished carbon parts. Now some parts are infused, some wet lay vacuumed and others dress layers but as time is of the essence and I’m flying solo in my workshop I really need to speed up the process and pin holes seem to be a part of life in the shop.

At the moment once a part is trimmed, I will wet rub with 320 grit, brush 2-3 coats of Nason high solids clear rubbing in between coats and finish with a spray coat of DuPont and still have pin holes :frowning:

Any tips would be great, I was also thinking if the quality of RC200 twill that I’m using has anything to do with the pin holes…I don’t think it’s the best as it was purchased a few years back at sub $30 per yard (so I’ve been told)

Cheers, Jase

#2

Try Bascofill

It’s available from: www.basler-lacke.ch

It’s a black paste you apply over the product after wet sanding to fill the remaining pin holes.
After its cured, abrade with some scotch brite and water - that is all that is required to knock off the excess…

#3

Same product as MAP Yachting “Bouche-Pores” (pore filler).

Basicly a 1K PU paint with carbon black mixed in, up to a paste.

Also see if you can purchase some higher weight 3K fabric, for instance 245 gr/m2 (7 oz/ft2 or so) instead of 200 gr/m2 (5.7 oz/ft2), which helps getting rid of the large-ish openings in the weave.

#4

Thanks for that guys. The basler-lacke system sounds great, but after something that is easily sourced in the USA.

#5

You can make your own compounds. Mix up a batch of high velocity 2K urethane and mix in a little graphite powder (West Systems 423 for example). Dip a cloth into the compound and rub the surface with a swirling motion. This will fill the pin holes. Once cured you can wet sand with 320/400 and shot the clear.

#6

I use the PTM&W Poly Filler HT. Its a black paste as well and its fairly cheap. It has the curing time and sandability of bondo.

#7

The fastest finish system is to spray the mold surface with a clear-coat before infusion.

#8

What clear coat would you use? Does it need to be tacky before infusing? If cured, what needs to be done to the surface of the clear prior to infusing behind it?

#9

This goes without saying but your part will be an exact replica of your mold. If your mold has pin holes in it, then your part will either have a pin hole (unlucky) or a small spike that you can sand off (if you are lucky). Either way, you will have this issue every time you lay up. PU fillers will work as an engineered bandaid but it should be repaired just like any other crack, or defect in the mold surface. Sand defect out, fill hole with mold repair (something like Duratec mold repair) block sanded down, wet sanded, buffed, and sealed. In my experience the only time that fillers have failed is when you need them to work. This is a perfect example of the need to realize that only perfect molds make perfect parts. Take great effort in getting the mold perfect and much success will come.