Hello. I use IMC and i can not fix this problem even after 2 layers.
I use Rexco wax and im not sure what is better to apply on it before IMC.PVA is it the best solution Frecote?
That’s an issue with whatever release agent you have on your mold. I get that sometimes when I frekote a new mold or an entire mold again and don’t use enough wax to create a high surface tension for the in mold clear coat to bind too.
You can either do these things.
- Make sure you wax your mold more to prevent this.
Or - Follow hanaldo’ steps precisely and make sure the first coat is a very fine mist coat and let that tack up.
Or - If you want to fix whatever you have you can let the entire mold tack up then go back to step 2 I suggested and then spray the tack coat dusting, once that tacks up you can spray another full coat.
Or
For spots like that and I’m impatient I take a blow drier or heat gun since I had a larger mold do this recently in one spot so I just helped it along so I wouldn’t need to mix up another batch of gel coat since if I let it air dry it would have kicked in my gun, which is a nightmare…
Fine, thin mist coat, wait until almost fully tack and spray medium coat. sometimes you will need to do 2 fine mist coats waiting 10-20mins between coats on new or freshly coated moulds.
Thank you for your answers. Problem is that i made it with a brush…I believed that it is possible and heard about positive results with brush.
As for wax and surface: I have 4 wax layers here…
Brushing it is always going to be difficult, it isn’t really designed to be applied by brush. You may be better off with Scott Bader Crystic Glosscoat if you can get it, as it is a bit thicker and will suit brushing better. Otherwise, your only real solution will be to keep brushing the coating flat until it starts to set up and no longer separates.
Another potential issue to be aware of is that if you are infusing or vacuum bagging then your brush marks will distort the carbon and cause a strange appearance to the final part. If you are just wet laying with no form of consolidation then this won’t happen, but with any sort of pressure consolidating the carbon then it will.
ok, I’m about to fly someone out here to show me what an idiot I am, because I can’t figure out what I’m doing.
So, going back to Sunshield. I applied a mist coat, then two heavy coats, then mixed another batch, and applied 3 more heavy coats all 4 minutes apart. Let it dry for a week in Texas summer. I took 1000 grit to it lightly today for a minute and I think I went right through it somehow. The picture below is just a minute of light sanding, even the high spots from the orange peel are still there. The problem is, the dull area is easily scratchable with my fingernail, so that has to be the epoxy, right?
1000 grit is pretty aggressive. For in mold coatings I’m able to get away with 1 most coat and 2 full wet coats seem to do the job. That way I can pop out the parts, hit with 2000 grit and buff.
If you put 5 coats on then that’s pretty thick. How much can you scratch into it? Maybe your mekp was bad? Usually the stuff is pretty hard after a full 24 hours in my experience.
double post sorry.
I’m not sure I see the issue, it looks to me you haven’t sanded far enough. When you have gone through the clear coat, it tends to show up more like this:
Right, that’s what it looks like. I haven’t even gotten through the high spots on the orange peel. The issue is, I had a scratch-resistant surface before sanding. Now, on the sanded part, I can easily make marks with my fingernail. So in my brain, either I somehow went through the clear even though there’s still high spots, or clear coat is easily scratchable before it’s polished. Neither one makes sense to me.
Is that what your photo is showing? Because if so, I still don’t think you have gone through. Especially knowing Duratec Sunshield, it would take a very very long time to rub through with 1000 grit. There’s just no way.
In fact, the proper procedure with Duratec products is to DRY sand the surface with 400 grit before allowing it to sit for 8 hours before wet sanding through the stages and then compounding. This is supposed to prevent the coatings absorbing water and dulling the finish, however I haven’t done this for quite some time and haven’t had any issues what-so-ever. My point is more that even with only 2 wet-coats, one should be able to sand from 400 grit through to compounding without going through the coating at all (depending on how good your surface was). I just can’t see it being possible that you have sprayed an adequate coating and rubbed through it with 1000 grit.
Out of interest, can you give me a rough idea of the surface area of your part, as well as how much of the Duratec you mixed up and applied?
I’ll have to look when I get home, but I think I mixed 4 ounces up each time, and probably had 1 to 2 ounces left each batch before it kicked. The piece is about 12" x 16".
Just to make sure I’m not nuts, you shouldn’t be able to easily make marks in dull, sanded Duratec, right?
See that is bucket loads of coating as well. By my measurements, your piece is about 0.12sqm. Duratec Sunshield takes around 550g to cover 1sqm, so your piece should only have needed 65g or so to build adequate coverage. Factor in a bit of wastage, and 100g would have been plenty.
Unless you have thinned the coating by 50 or 60%, I just can’t see how it’s possible you could have sanded that off without rubbing for hours, especially on a flat piece. And ESPECIALLY seeing you haven’t rubbed out the orange peel yet, it’s just impossible.
It’s hard to comment on the surface marking issue as I don’t know how much effort you are putting into it etc. It’s certainly possible to mark the surface, but I wouldn’t describe it as easy. It’s a tough coating.
What gun settings is better to have for IMC ?
hi … i’m new to composites central …
i’m new to composites but not paint … i’ve been an autobody painter 10years …
clear coat is layed down in 1 coat … with a tack up coat always running ahead of your shoot … paint panels … not whole sides … and don’t tack up a whole large surface all at once …
always move 1/2 panel ahead of where your wetting your coat … lay it thin … then go back and fully wet the previous thin 1/2 pannel you laid … get it started then move on then come back to wet it out … move ahead light … come back wet … move ahead light … come back wet … but it’s 1 coat it’s just spread out over a few minutes so that it doesn’t run …
if you lay any more coats it just makes for orange peel … can always sand it out … but when i lay a shot down i wan’t it nice and smoothe and use the least material possible … also layers of clear just make more time that dust can get on the surface … and makes for possible solvent pop if there’s thick enough that the solvent hasn’t flashed off between coats …
just 1 coat … time it right … use a hvlp gun and dessicant filter … and tack rag the base off
… Leroy