Hanaldo,
Regarding the vtf261. Do you build part thickness with a cheaper material for internal plies or do you use the vtf261 through and through?
Just to clarify in advance, the VTF261 is specifically the surfacing material. Cytec have their VTM264 backing ply material as well.
So to answer your question; no I generally don’t use the VTF261 through-out, I use the VTF261 as the surface layer and then the 400g VTM264 for the bulk. This is more to do with layup time rather than the actual material cost, doing one layer of 400 is just easier than 2 layers of 240.
I have also experimented with using a much cheaper product (completely unrelated to Cytec) for the backing layers, and surprisingly have had quite good success with that. I haven’t played around with it enough to be able to say it works as well as the VTM264, but what I can say is that the 2 different epoxy systems appeared to play well together and cured very strong. The crude testing I did on those panels didn’t reveal any performance issues, with no delimitation or obvious decrease in strength compared to the VTM264. Surface finish was also fine, the VTF261 didn’t appear to have any issues working with the cheaper material.
The main reason I played around with that is because I was interested in using uni-directional pre-pregs to back-up the VTF261.
Thanks for the advice, guys.
I’ll post an update when I get to my office.
So far, I’m using the wring release film (peel ply), at a minimum.
Oh wow… I have never had a part that bad even when I made a huge mistake when I forgot to connect my manifold to the vac pump and the bag lost vacuum over time.
That look like someone sold you a standard HT prepreg as OOA prepreg. I think it is a main problem of temperature over time.
This is what I get from the SHD material.
More power can you please remind me of the spec of material you use from SHD?
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It is the DF212… its the best material I have ever used…
Cheers mate, think I need to give it another go!
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have you tried using teflon tape for your mold surface? Although this can be a expensive solution, it has worked wonders in eliminated surface defects.
If you are getting good surfaces with aluminum but not on gelcoated tools, you probably have vacuum leaks in the gelcoated tools. You cannot get good results with leaky tools.
I can not find enough information about this problem : I have matt surface in all areas where i have to use lot of fixation glue.
MTI hose,no dry spots etc,but those marks…I washed this little area to check if this is 100% the glue influence.
you may need to consider edge damming. you might be drawing out too much resin and/or not enough air.
The prepreg needs to go through a few phases where very important and distinct things need to happen.
1)debulk to remove bulk air and to compact the laminate.
2)temp rise to allow softening of the resin and allow air to escape along the weave of the fabric>for which edge breathing is important (edge damming may also be necessary) whether some tows of glass or breather overlying. This step also at the same time allows the escaping air spaces to be taken up by the flow out of the resin. a certain dwell period may be required at this temp so that enough air/flow out occurs.
3)ramp to cure. all the above have occurred and now it’s time to gel/cure the resin.
in your case either the tool/laminate surface may not be get enough time and/or adequate pathways for the air to escape before curing occurs.
Is it possible that the tool gets more heat on this side the whole time than the rest of the part?
Is it possible that the gel coat is incompatable and off gassing into the laminate?
MTI hose and spray adhesive… You sure you’re in the right thread?
Sorry,you’re right. This is another subject.
I’m having the same issue, Carbon prepreg epoxy mold with a nice glossy surface. No matter what I try when clearing over (Duratec Sunshield) I get like pinholes/fisheye, sand, clear, sand, clear over and over till smooth
I’m still in search of a clear surface coat.
Trying this next.
Our Wonder-Fil is THE SOLUTION to those time consuming, annoying pinholes.x It is a wipe on/wait 15 minutes/wipe off the excess process.x Wonder-Fil shows up in as off-white specks everywhere there are pinholes, and then disappears when the next layer is sprayed on – whether primer, color or clear.
x
This makes it perfect for fiberglass and carbon fiber parts!x Even carbon fiber parts where the weave needs to show through in the clear smooth finish…Wonder-Fil disappears into the clear.x It also works equally well on wooden and fabric surfaces.
Pinholes aren’t a problem with Duratec, it’s as simple as spraying your first wet coat and use a brush to push it into the pinholes, then spraying another coats as per normal. Duratec self-levels so well that 90% of the time it will finish perfectly off the gun and not need any work. The other 10% of the time is normally if it is a bit warm or the Duratec was catalysed a bit too high and it doesn’t have time to flow out before it starts to set up. In which case 20 minutes of sanding will flat the surface.
I’ve heard of Wonder-fil before, but from what I’ve read it doesn’t really work as well as its claimed. I’d get some and give it a go, but honestly I just find the Duratec so easy to use I don’t want to bother with yet another product.
I’ve tryed the Duratec clear top coat, turns yellow can’t handle the 275 degrees.
…
This is straight out of the mould. No pinholes here. Its also not an alloy mould this is just a high temp polyester based tooling from Nord Composites.
