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Old Jan 20, 2013, 03:08 PM
Entropy is happening!
Jim.Thompson's Avatar
Australia, NSW, Bellingen
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Quote:
Originally Posted by josh18 View Post
Shane and Ant from down my way (rcjunkie and anthonyd) have had some great results infusing soric. They do say its heavier though.
I have read their postings Josh!
To the best of my knowledge, they have not done destructive strength testing (yet).
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Old Jan 20, 2013, 03:14 PM
R.I.P
josh18's Avatar
Australia, QLD, Toowoomba
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Sounds to me like the soric really needs a bit of a thicker layup to work propperly. Im sure you'll find some use for it sometime down the track.
Cheers mate
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Old Jan 20, 2013, 04:18 PM
Entropy is happening!
Jim.Thompson's Avatar
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Soric.

Quote:
Originally Posted by josh18 View Post
Sounds to me like the soric really needs a bit of a thicker layup to work propperly. Im sure you'll find some use for it sometime down the track.
Cheers mate
Josh,

My conclusion is that the Soric is working properly for what it is designed for. That is for static parts that don't need to be built to a weight limit, and for parts like car or boat hatch covers etc. that can be made under production efficient methods.
It acts like a sponge and soaks up a lot of resin. Also, it has structural weakness along the hexagonal divisions.
I have done samples with thicker skin layup like you suggest. Sure, it is stronger, but extremely heavy! So much so that I did not even bother weighing it. It has 285 gsm glass fabric either side. I might end up using it for servo trays or such. Even so, it will be not nearly as good as more conventional glass/ply or just glass/carbon etc.

Just to re-iterate what I've reported on my blog. The Soric cored sample was close to 40% heavier than an equivalent (and stronger) balsa cored sample.

As I said somewhere before, I would love someone to do some test to prove otherwise. Untill then, I'll avoid using Soric.

Jim.

edit: If you would like to try a small sample Josh, PM me your address and I'll send you some along with some infusion mesh. What do you think?
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Old Jan 20, 2013, 04:32 PM
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Thanks Jim, I might take you up on that.
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Old Jan 21, 2013, 04:42 AM
Entropy is happening!
Jim.Thompson's Avatar
Australia, NSW, Bellingen
Joined Aug 2008
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Steel backing frame - second side.

I cut out and welded the backing frame for the second side tonight after work. It looks like a bit of an overkill with two rows of RHS steel, but the second smaller one is to build up the height to clear the wing fillets etc. so that I can use purpose made sliding clamps. This is a variation of what I first saw on one of Adam's threads.

I scored some very suitable 1.6mm Ferrocraft electrodes. Really nice to weld the thin walled RHS. The welder in the picture is an old oil cooled single phase welder that came from the tip about 35 years ago. It is almost as smooth to weld with as a DC welder.

I just might be to splitting stage of this mould at the weekend! The moment of truth.

Jim.
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Old Jan 22, 2013, 06:42 PM
Entropy is happening!
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Plug stuck again!

I split the two mould halves this morning with much difficulty. The plug stuck!
More to the point, much of the paint and primer stuck to both halves. The pictures tell the story. The plug is destroyed (again).
The first pic is of the steel backing frame preparation.

I've lost count of my stuck plugs! I don't think I have pulled one successfully. I'm putting these in the car this afternoon and taking a drive up to Woolgoolga (Woopi) where I know a helpful proffessional fibreglasser who has shown me how to apply wax and PVA. Maybe he will see what I might have done wrong again.

Jim.
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Old Jan 22, 2013, 07:04 PM
ERS....Energy Retention System
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gold coast australia
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[QUOTE=timbuck;23425597]Use 2k hi build primer as well. Always ends up in tears.
It will be worth it in the end.
...

Very sorry to hear that Jim..

How stuck it the paint to the molds ???
Looks to me you didn't have much bonding between primer and paint.... The bond between 2k black and mold was more than the primer and paint.

What was the last sandpaper size on the primer ??

Tim
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Old Jan 22, 2013, 07:50 PM
Entropy is happening!
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[QUOTE=timbuck;23897219]
Quote:
Originally Posted by timbuck View Post
Use 2k hi build primer as well. Always ends up in tears.
It will be worth it in the end.
...

Very sorry to hear that Jim..

How stuck it the paint to the molds ???
Looks to me you didn't have much bonding between primer and paint.... The bond between 2k black and mold was more than the primer and paint.

What was the last sandpaper size on the primer ??

Tim
Tim,

The paint and primer is stuck well enough to the moulds to be a real pain to remove. The two halves split with great effort too! See the wedging required in the pictures to split them.
The primer to paint bond is good. Better than the bond of the primer to the substrate. It was the primer/substrate bond that finally failed in the visible patches. There is no stuck remnants in the mould of the black paint only. All remnants have primer as well.
I appreciate your re-statement of the original post. While this might have helped, it still does not explain why the 2 pack is sticking so hard and fast to the release system on the surface of the mould.

The problem that I had about using 2 pack primer is that I would have to mix very small quantites, and wash the gun, countless times. Maybe that is just the price I have to pay. However, while that might have helped, that is not the full explanation here. The results indicate that I'm still not applying the wax/PVA correctly. The wing plugs on my moulded plank pulled very nicely; they were primed with acrylic lacquer primer and finished with 2 pack paint.

The only possible explanation in my head is that I used a slightly different method to apply the PVA compared to what I did the with wings mentioned above. For them, I used what I call the "flood and drain method". Self explanatory?
For this fuse, I used a method of sponging it on, which my local proff. bloke showed me by examples. The sponging off of the PVA might have removed too much.
But............ successfull builders like Kevin Bennett tell they use only wax.

So, nothing is entirely conclusive about this string of failures to me. Still............

Jim.
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Old Jan 22, 2013, 08:20 PM
ERS....Energy Retention System
timbuck's Avatar
gold coast australia
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Alot of successful builders only us wax. I wonder which introduced him to wax.

Bond between plug and primer....
thats why I asked paper size..
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Old Jan 22, 2013, 11:28 PM
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Ah bugger!

Moulds should look great once they are cleaned up. Can't wait to see that first part!
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Old Jan 22, 2013, 11:48 PM
Entropy is happening!
Jim.Thompson's Avatar
Australia, NSW, Bellingen
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Quote:
Originally Posted by timbuck View Post
Alot of successful builders only us wax. I wonder which introduced him to wax.

Bond between plug and primer....
thats why I asked paper size..
Ok Tim.
Paper grade was 180 & 240 throughout. Sorry I did not answer this previously. See later note below.

It's just as well that I did use single pack primer in this case actually! (this is not an argument that it is better than 2 pack, clearly 2 pack is better!).
If it didn't fail in the primer/filler stage(s), it might have been impossible to split the two halves at all! I might have had a good canoe mooring anchor! There had to be a failure point. Normally, the designed failure point is the release system. That is where I went wrong, I am convinced. My pro pals at Woopi agree.
Why I did not answer the grit size in previous post is because clearly that is not the problem. Some of the epoxy splooge fill also came off with the paint/primer, itself indicating a very strong stick up. A 2 pack primer would have only pulled off more epoxy, if the mould could have been split at all!

I just been to Woopi and back to talk to my pro friends and presented the evidence. It seems that I came unstuck (no, actually the opposite), by applying the PVA in high temperatures. It was 42 deg. C when I applied it to the first half, which is the most stuck! The material was evaporating while I was applying it!

John, my friend at Woopi, assure me the paint will come out ok with a bit of work. I'm trying now to soak it in Acetone.

Better days ahead?

Jim.
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Old Jan 22, 2013, 11:52 PM
Entropy is happening!
Jim.Thompson's Avatar
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Quote:
Originally Posted by Hamburglar View Post
Ah bugger!

Moulds should look great once they are cleaned up. Can't wait to see that first part!
Thanks for the words of encouragement Jordan!
The 1 hour + trip up and back to Woopi was worth it. I was feeling pretty despondent about this mornings results untill I drove up and talked with my friends up there.

It will be interesting to see just how hard or easy it is to get the stuck paint out.

Jim.
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Old Jan 23, 2013, 12:52 AM
ERS....Energy Retention System
timbuck's Avatar
gold coast australia
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Ahhhh..
That was my next question, how hot was it when applyied.

I know other people who have had and done the same with acrylic paint that has come off in the mold.
Once socked in thinners the acrylic melts leaving the 2k... Which was easy to remove with a piece of timber laminate...

I agree with Jordan , a bit of elbow grease and your molds will be perfect.
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Old Jan 23, 2013, 01:11 AM
Entropy is happening!
Jim.Thompson's Avatar
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Quote:
Originally Posted by timbuck View Post
Ahhhh..
That was my next question, how hot was it when applyied.

I know other people who have had and done the same with acrylic paint that has come off in the mold.
Once socked in thinners the acrylic melts leaving the 2k... Which was easy to remove with a piece of timber laminate...

I agree with Jordan , a bit of elbow grease and your molds will be perfect.
Yes Tim and Jordan! I have already mostly removed the stuck paint from one half!
The day is saved.

Thanks,

Jim.
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Old Jan 23, 2013, 01:26 AM
Entropy is happening!
Jim.Thompson's Avatar
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Originally Posted by timbuck View Post
............From Woolworth....you can get white very skinny home brand straws.
.....................
http://www.moroday.com/product-range...ls/mini-spools

Tim
I have got some of these ready for the control surface spars. I also begged some of Macca's thick ones for the drag spars.

I have yet to chase up the foam noodles though. I might end up using conventional end grain balsa for this model though.

Jim.
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