wax below frekote and sanding duratec topcoat

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#1

Hey,
So I’m having a bit of trouble getting my Duratec Black VE topcoat to come out with a good mirror finish. I sprayed it, let it cure for longer than necessary and then stepped upwards from 1000 to 1500 and finally to 2000 before using a wool pad and a heavy cutting compound. I still can’t get a mirror finish because there appears to be pretty heavy sanding marks left from other steps (the duratec was sprayed on top of a primer layer that was sanded to 600; the coat was quite thick so it should’ve flooded out everything below it).

So any recommendations on what I could do to help with my wet sanding process? Or do I just suck at the easiest and most basic form of labor in our industry?

Anyways, I was wondering there was some sort of wax I could apply before sealing the pattern up with Frekote FMS and then applying my 770nc release. If I can’t get the sanding marks to disappear I would be totally fine with just applying some sort of wax to fill in the cut lines and then applying the sealing agents on top of that. Is there any sort of specialty wax out there that can sit below frekote… or, rather, frekote can be applied on top of?

Thanks!

#2

So was your plug mirror finished? Whatever surface you end up with on your plug, you’ll end up with on your part. I’ve used the orange duratec on a plug then, sanded and polished to a high gloss finish and the molds ended up the same.

Sound like you just need to fully prep your plug.

And freekote should be applied to a clean mold, no other release is necessary.

#3

I’m actually referring to my plug in this post. My plug is sprayed with a duratec top coat. For my molds I typically use a random PE gel coat diluted with duratec hi gloss.

Really I’m just trying to figure out what my normal sanding technique that has never failed me before is leaving me with poor results on my pattern. I’m doing a normal wetsand and washing the entire thing between grits, new water in my cup, etc. Still not able to get rid of the heavy sanding marks.

#4

Sound to me your doing everything right , just not starting low enough in your paper size.
The scratch marks sound to me that they are sink back of the primer. You need to slice the top off the coat with heavier paper. Think of them a corrugated iron roofing. 1000 paper is never going to get to the bottom of the valley’s easy. If you go with 600 , it will knock the tops off flat and then you can polish.
I’ve had similar in the past and used guide coat between paper sizes to see where in at.
Do a small test patch if possible and see if you get your desired result.

Tim

#5

Ya I think that has to be it, because I did a very thorough sanding but only started at 1000. I figured I laid the top coat on thick enough to hide whatever marks were left on the primer coat below, and thought I did a good job because after the shoot there was a great gloss surface on it, but I guess it was just some sort of illusion. I’ll go back in today and start with 600 and see where that leaves me.

Do you guys ever just seal the thing up with a 2k clear coat? I’m considering taking that route for future patterns because I could then just give it to my local painter who could shoot it in a booth and it wouldn’t require any finishing work to get rid of dust nibs.

#6

I’ve sealed with 2k, but I still ended up wet sanding and polishing to get a mirror finish. Plus, there’s always that 1 spec of trash that somehow makes it in and it kills me! Maybe I’m just not a great painter. :slight_smile: The duratec gets just as smooth once polished out and IMO is all that’s necessary to finish with.

#7

Shot another round of duratec and tried buffing it again today, and it just won’t get up to a gloss. Not sure if my rubbing/cutting compound is bad, my duratec is bad, or maybe the lacquer thinner im using the thin the stuff is reacting with it in some way. It cures to a perfect gloss out of the gun but won’t return to one after sanding to 2000 and buffing with microfiber or wool. Really not sure what’s going on :confused:

#8

I just buffed some duratec up today. What I do is go from 500, 800, 1000, 1200, 2000, and 2500, and then I switch to color sanding and buffing: 3m rubbing compound, machine polish, and then hand glaze.

The rubbing compound will immeadtely start to give it a shine and wet look. Once I’m done it shines.

I’ve never done steel wool and microfiber, by try some rubbing and polishing compound and see if it shines up.

#9

I went to 2000 and then used a rubbing/cutting compound. heaviest cut Meguairs that’s available. It’s given me a good shine immediately after I start buffing before, so I think something has happened to either my duratec or the thinner that I’m using to shoot it. I was originally using a lacquer thinner from a specialty paint shop but am now using one that I picked up from Home Depot. I added 15pct by weight of the thinner which is my standard setup. I’m going to go pick up a can of the good stuff on Monday and do a test panel and see if it’s the problem.

If anyone else has any suggestions please let me know!
Thanks

#10

Are you dry sanding with 400 before compounding? You need to ‘break the skin’ and allow the solvents trapped below the surface to flash off for 8 hours before starting to wet sand, otherwise it absorbs water and won’t go glossy.

#11

Am I reading this correctly…you mix the Duratec top coat with the resin system and then spray this on as your top coat/ gelcoat?

#12

No, the hi gloss is an additive to the pe gelcoat

#13

So is ‘Duratec’ just a brand of pigment paste then that is used to tint the resin?

#14

Duratec is a coating manufacturer who makes polyester primers, top coats and other coatings.

http://www.duratec1.com/hawkeye/

#15

This is interesting, never heard of it. I am waiting 24 hrs at a minimum of 70F before doing any sanding. I usually start at around 600 (but I have started at 1000 before) so this could be a problem.

Anyways, problem solved(ish). I think either my rubbing compound of my sand paper was bad. I took it to 1000 and then went over to my local auto body painter who hit it for like 20 seconds at 1500 and then used a DA sander with a 3000 pad on it. It started buffing to a gloss within seconds of putting the wool pad on it. I used Gator brand sand paper for the final 2000 grit finish (from Lowes) and was using Meguairs Heavy cutting compound. I know the compound has worked well enough before, so either it went bad or the paper was bad.

Thanks for all the input! What a waste of time… :frowning: as with all things in like, I got screwed by trying to save a couple of bucks by buying fine grit paper from lowes instead of an auto or auto-paint store.

#16

No, I’m using the Duratec top coat as a finishing surface for my pattern. Once it’s sealed and release treated I’ll spray it with a normal PE gelcoat and then build a mold off of it. The gloss surface on the duratec will hopefully be imparted onto the PE gelcoat.

#17

As per the official Duratec application instructions:

“After curing, dry sand with 400-grit sandpaper,
then allow to cure overnight prior to further sanding, compounding and polishing.”