Hi all,
Nash, I’m just curious…which is the final product behind all these tests ?..Maybe something that should fly ?
These are tests for tooling resins, that will allow to reduce our tooling costs. The tooling will indeed be used to make aircraft parts.
Currently our tooling is from epoxy, which is expensive and it still has some shrinkage.
Where are you from in Italy?
N
Hi Nash,
Your tests are very interesting, Will check this formula too (as soon I have time!!) By the way I’ve just finished mould and parts for the new Bentley Mulsanne stretched! I used the VE + 0 shrink polyester resin for a low cost mould ( we could change details after driving tests) That’s true we have NO shrink but the VE I used let some prints in the GC… The product comes from Polyprocess in France. Cheap but could be better. Next time I’ll use a 30gr mat as barrier coat…
Will show you some pics soon.
Steph
PS Do you come to JEC in Paris?
I will be at JEC on tuesday and wednesday.
Hi Steph, Herman,
I usually do prowl the JEC, but this year, I’m not so sure. The zero shrink resin is not yet qualified and I’ll love to do that and get on with the aircraft.
If I do, I’ll ping you folks.
Thanks,
N
Steph,
Bentley Mulsanne stretched sounds hot!
Well, we didn’t get any print through on the gelcoat, but due to a mistake from the tech guy of the vendor, we got a wild exotherm (178degC) that ended up ruining the hard work that was done on the plug, eating into our schedule by at least 3-4 weeks. Is it possible that you have a thin layer of gelcoat? My layer was .8mm of gelcoat followed by one 300gm VE layer and one 450gm VE layer (wet on wet) as barrier coat. I did the infusion on the second day after leaving the barrier on for 36 hours. The recommended time was 24 hours. There was no print through even when many here had warned me of print-through. This being my first polyester mold, I was very careful to stay with specs, except the fiasco in which I listened to the tech rep and not consider the spec sheet.
Thus at this moment, we’re re-machining the plug. Its easy to do it since I’ve got a 4 axis machine with a 4mx1.5mx0.5m bed (this was the largest we could afford). The new part will be ready in a couple of weeks, including polishing. However, we have many parts finished from which molds can be taken. I’m not going to allow that to happen unless we understand fully how the resin behaves. We’re waiting for the vendor to get back to us with parameters which I’ve asked for.
The resin is un-accelerated, thus, they need to give me temperature curves for 10mm thick layer of material and also 400gm resin in beaker, for min accelerator, min catalyst, min accelerator, max catalyst, max accelerator min catalyst, and max accelerator max catalyst. Once we have those, we can interpolate the performance on our molds taking overlaps and edges into account.
I’d also advice anyone using zero shrink resins to do the tests above that will save them valuable time and grief.
Enjoy,
N
I got the mould tool finished. its an interior moulding for an 18ft rowing skiff, bow stern & sidetanks with side floors & frames. I ended up using VE tooling gel & skincoat followed by Optimould tooling resin. Shopped around & got a good price on a batch. Not nice stuff to use as it stinks something awful!, but it did a good job with no shrinkage or distortion.
Spent a good while cutting back & polishing the hell out of the tool.
Anyway after breaking in i laid the first part up last week & it released perfectly, always a good feeling! boat should be on the water in next few weeks.
Show some pictures! Was the smell similar to burnt plexiglass? It might be MMA polymer, which replaces styrene. (usually for UV resistance).
In my experience the polymer used for the low shrink properties does not smell.
Yes it does contain MMA, definate perspex smell, i went through several carbon filtered respirators, dont think i would like to use the stuff without. Will get some pics shortly.
I too use a resin that smells real bad. When its under infusion its ok, but for doing a small test for each batch, wow, that stuff is horrible.
I’ve made a few molds, some very complex, like the seat back of the plane using the zero shrink resin. No markup and a faithful reproduction of the super smooth master plug. The first part from the seat mold was popped out a few days back, and its gorgeous.
Good to hear.