Your first issue looks like possible alligatoring. Probably caused by the resin you sprayed being a bit thin and not curing properly, so the styrene in the infusion resin attacked it. Possibly something else but that’s how it appears.
Answered your second and third issues yourself.
Ok thanks.
Just making sure my train of thought was going in the right direction.
I will try again this week sometime after work to make one more.
Hopefully i will improve enough to tackle that 2 part mold of mine.
Ment to ask this earlier.
I used the green partall paste wax. It did ok at releasing.
Had to really pull while using an air gun to get it to release in some spots.
Had about 8 coats applied since it was a fresh mold.
Do you have any type of release wax or chemical you prefer to use?
Yeh I’ve never had a better result than that with wax, I’ve always had to put a lot of effort in.
I only ever use Frekote these days, and have recently started using Zyvax Flex-Z.
You can also give the corners etc a bit of a pushing during the infusion. When all the laminate is wet as everything slides about lubricated by the resin.
Thanks for the info.
Would you recommend also buying their sealer?
I need at some point soon repair two spots on the mold.
Might try and do that after doing a few more parts as the mold sits now.
Might try and order some of the woven flow mesh seems like it might conform to the part a little easier.
Need to do a bit more searching on the stuff first.
I use the sealer, but honestly I don’t think I would recommend it. Not to say that I would recommend AGAINST it, I just don’t find it necessary. I only use it now because I’ve got it, once it’s gone I won’t get more.
The only difference I notice is that you get 2 or 3 more pulls without any additional applications. But for peace of mind, I always do a coat between pulls anyway.
Was cleaning up the mold and noticed that the infusion process caused the fiber imprint into the mold surface.
Which is partly my fault. I had orginally hired a mold guy to help make all the molds. While I was trying to learn from him.
Big mistake as it turns out.
The mold surface is just black gel coat.
After reading up it should have difinetly should have been tooling gel coat instead at a minimum.
Now I’m debating what to do about the mold.
It does need some surface repair work any way to fix a couple of areas.
I’m thinking about respraying the mold.
Would you recommend tooling gel coat or is there something better suited to the task?
If I could get around maybe 30 parts out of this mold after reshoot in tooling gel that probably would be ideal. Then I would remake the mold with correct resins.
Im really thinking of just moving on to epoxy.
Correct me if im wrong.
Since i lay an in mold coat of poly and let cure it has basically preshrunk some.
Then once i infuse the new resin shrinks pulling on the in mold coat causing the fabric texture to appear in the surface of the part.
This is mostly do to the styrene in poly?
I don’t mind using the surfboard resin as it infuses rather nicely with the in-mold coat.
I might just try to infuse with out the in-mold coat to see how the surface turns out.
That should technically reduce the surface texture.
If is pinhole free i might just start 2k clearing it.
It’s not the shrinkage that causes the alligatoring problem that you’ve had. Shrinkage causes the fibre print through, but the alligatoring is likely causes by the resin you sprayed into the mould being a bit too thin and not fully curing. Then the styrene in the resin when you infuse can soften the coating, which makes it expand and wrinkle up.
Ok. It not the alligatoring im concerned with as much since i only had two small spots on the part.
Its more that once the part comes out the mold the fiber print through it very noticeable and the new issue with print through into mold surface as well.
Thats why i might try to infuse without a in mold coat and the spray the part after.
Ok,yes print through is an issue with the ester based resins. Epoxy is much much better, but with high fibre ratio processes like infusion you are always likely to get print through. There’s really only 3 ways to reduce its appearance:
Make the part more resin rich. If you’re doing a purely cosmetic part, making the part more resin rich can help. Unfortunately this doesn’t work so well with the ester based resins, as the more resin you have the more it shrinks, so you can end up getting distortion and other such issues.
Elevated temp cure. Post-curing the part while it’s in the mould really helps a lot. If you need perfect parts straight out of the mould and can’t do any clear coating afterwards then this is the best option.
Clear coat the part after it has been removed from the mould and allowed to sit for a bit of time. This is really the only way I have found to get a long lasting completely flat finish.
I will give post curing the part at elevated temp a try.
Maybe try to run the part a little more resin rich as well.
Still worried about the printing into mold surface.
Thanks for the input.
Temper the mould a few times at higher degrees. Then make few (~3-5) parts and polish the mould surface. That is the only thing that might help.
Even if you respray the problem will still be there.
Ok been busy with life and work going to get back on this project.
I prepped the mold with frekote cleaner, sealer, and release per instructions.
I tried to spray sun-shield as my in mold coat.
That didn’t go so well.
It puddled up like rain on a waxed car.
I did several light mist trying to build it up but it just keep increasing the puddles.
Looks like i will need to try a different in mold coat or not use one.
Any suggestions.
I need to go back and read through that thread on the topic to see if i can find an alternative.
Ok back to finish this project been busy with life and work.
So i prepped the mold with frekote.
Cleaner, sealer, and release as per instructions.
I tried to spray sun-shield as an in-mold coat.
It just started beading up like water on freshly waxed paint.
I sprayed it in list mist coats to start with but the more i sprayed the more it gathered into larger beads of resin on the surface.
Looks like i will need a different type in-mold coat.
Any suggestions?
Going to go reread that in-mold coat thread and see if i can find a alternative unless freekote doesn’t like being in-mold coated.
In that case i can try to infusion with my new thinner epoxy resin and see if i get a good surface to then 2k clear it.
Duratec Sunshield and Frekote work perfectly together, you just haven’t got the technique right yet.
When you spray your first 2 coats, spray them as dust coats as you said you did, but you want to allow these dust coats to set up almost completely before continuing. So as a bit of a walk-through:
2.Set your gun pressure to 50psi. Wind in the fluid control knob on your gun until you can only JUST see any material coming out of the gun at all. Spray your first coat so that you can only just see any material on the mould surface, it shouldn’t appear wet or shiny at all, it should look dusty. Allow this coat to set up for 5-10 minutes (5 minutes in 25-30 degrees, 10 minutes in 20-25 degrees).
Wind out your fluid control knob half a turn, so you can now easily see material coming out of the gun, but still not enough to give a wet coat. Spray your second dust coat in the same manner as the first, the surface should still not appear wet or shiny. Again allow this material to set up for 5-10 minutes (this is why you don’t want to mix a lot of material at the start). Spray some acetone through your gun while you’re waiting for that coat to set up so you don’t get gelling in your gun. Mix the rest of your material (I normally operate in 200ml batches depending on the size of the job).
Drop your gun pressure to 30-35psi and open your fluid control nozzle to ideal flow rate (this is normally 2 and a half turns from fully closed). Spray one quick coat so that it isn’t quite a dust coat, but also isn’t fully wet. Allow that to flash off for 2 minutes before spraying your first full wet coat.
From here you can proceed as normal until you reach your desired build thickness.
Apologies if that seems to come across like you don’t know what you’re doing or how to use a spray gun, but I do find that even experienced spray painters struggle to work with Duratec because it shouldn’t be treated like a regular paint product. Beading up of the material when used as an in-house coating is purely down to not having the right technique and not any fault of the Duratec or the Frekote. It takes a bit of practice, but once you’ve got it then it works wonderfully every time.
This is what you can expect to pull straight from the mould once you’ve got things sussed (you’re looking at the reflection off a 57 Chev dash):
Ok awesome thank you for that.
That is definitely a bit more setup on spraying the sunshield than i thought.
I was treating it to much like paint and doing mist coats and then a heavier coat using a single catalyzed cup of resin.
Breaking it up into smaller batches makes way more sense.
I will give that a go after work today.
Ok so it was a bit tricky spraying the sun-shield.
I think i need to work on my dust coats maybe.
I tried to follow your instructions as best i could.
I did the dust coats and it seemed to be going good.
Had a nice even dusty looking layer.
Its when i had to go to a medium dust coat that i think i should have done it a bit lighter and let it set up longer.
I then sprayed the heavy coat and it started to maintain and even film in some places but others it tended to bead up like before.
Here is some in order shots.
I ended up taking my fingers and smearing all the resin flat till it maintained a nice even film with no holes. I then sprayed a second heavy coat to even things out.
This seemed to save it so i let it cure for a day.
It cured nice a tack free by the next day, which allowed my to drape the carbon the mold.
I proceeded to slowly and carefully push it down into the mold trying to get it to lay perfectly flat. A little tricky but the carbon like to stick the surface so that helped it to stay in place.
Then i do two layers of fiberglass cloth.
I lay down the teflon peelply next. Hard to keep it down since its so slick.
Then goes the mesh. Still not happy with how im laying this stuff in. Abit hard to get it to flow up and down the mold surface.
Part Bagged and infused.
I need to try and use less resin next time.
Seemed like there was to much left in the green mesh layer when i demolded the part.
I used 24 ounces which seems like a lot for a part this size.
The part turned out pretty much perfect!
Thanks for all the advice and help along the way.
The frekote released amazingly easy.
Ill post a picture of the final part as soon as my phone is charged.