What grit to sand with prior to clear coat?

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#1

I have been clear coating my parts since it’s less labor intensive with simple spray can stuff. I’ve been sanding prior to clearing with 400 grit or 600 girt. So far it’s been good, I’m jsut wondering…

What is the grit that I should be sanding with prior to clearing?

#2

thats what I always sanded up to, too high the clear may not stick well, and two low may show scratches. you can gelcoat your mold with clear then infuse to save the steps of sanding ans spraying after

#3

i’m not sure I understand what you mean by “gelcoat my mold with clear” ?

do you mean spray the gelcoat in there to act as a clear…

or

spray the clear coat in there as if it were glecoat?

#4

Both! Buy clear gel coat, and spray it in the mold before laying up.

#5

using clear coat as a gel coat layer seems a bit complicated.

wouldn’t spraying the clear in there and then placing it under vacuum cause the clear to gas off some volatiles and cause bubbles?

wouldn’t the clear turn cloudy when it’s under an entire stack of reinforcements and resin during the time which the resin is curing?

How long should I wait until the clear coat has been sprayed in before I start infusion?

if clear coat can infact be used as a make-shift gel coat layer then I would be really curious to try that…

#6

let it tack off. then continue as normal

#7

I think I will do a test run tomorrow. thanks

#8

I wet sand with 400 grit prior to clearcoating. If i’m going to do an epoxy surface coat after the part is pulled from the mold, then i use 320 grit dry. Just be sure to wash your parts with acetone or soapy water prior to painting or clear coating. You can also buy a special wash soap that auto body shops use prior to painting cars… sells by the gallon and works awesome. They have waterborne or solvent base. I want to buy some. Try a local auto paint supply store for it.

#9

Spraying mould surface with something like Duratec clear coat, would probably work very wel…but obviously quite impossible using rattle cans!

#10

I think you’re confused. Nothing is makeshift here. Companies actually make/sell CLEAR gel coat. Just like white, black, and orange gel coat, but this one is CLEAR.

#11

I thought I was talking about spraying a automotive clear coat not a gel coat?

#12

Here is a new question.

If I want to spray several layers of clear coat do I have to sand the previous one? what grit do I sand with?

#13

Im currently testing out HOK Kosmic Kleer UC-35 on carbon plates.

Clean very well first (make sure any pits are totally free of sanding dust) 91% isopropyl alcohol worked much better than hot soapy water.

Then sprayed light coat wait about 10min then flood coats X3 every 10 min or so.

Dry a day just to be sure its cured then - “buffin’ the clear”

http://www.youtube.com/watch?v=KdHofsKFVmk

That worked VERY WELL.