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Old Dec 12, 2008, 03:41 PM
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So far the blocks seem to be holding fine.
For the next plane was thinking about cutting out the whole servo pocket and tack glue it back in place. This way I could adjust the blocks before bagging the whole wing.
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Old Dec 13, 2008, 02:31 AM
Festina lente
Berrie's Avatar
Schoonhoven, the Netherlands
Joined May 2006
242 Posts
Thanks for posting your pic's. I learned things from them that make my next wings even better.

It is indeed a kind of dejavu


Very nice to see the same kind of struggle. For example, the servomount. I have decided to do the "fiddly internal measuring and fitting".

Mainly because I dont believe I can find back, after bagging, the location of the "pre-cut-out-foamblocks"...
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Old Dec 17, 2008, 03:32 PM
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Have received most of the composite material from ACP so just finishing a repair on an Espada RL which literally broke in half after a mid air and some house work before starting the new Supras.

More pictures of the old one.

Two part epoxy paint like Klasslote are a pain to clean the equipment but the result is always nice. This is supposedly an HVLP gun but the results were inconsistent. I seem to have trouble adjusting it since once I find a perfect setting it needs to be disassembled for cleaning and copying the previous setting never results in the same paint quality.
So I have been using a cheap airbrush with good results. We don't want to apply to much paint anyway.
Also Dolphin Wax (not made out of Dolphins but for Dolphins ) is the best way to avoid fish eyes. This is a tip from Phil Barnes and you can find this wax here .
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Old Dec 18, 2008, 11:53 AM
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USA, CA, Aptos
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Has anybody actually been able to get any Dolphin Wax out of H&M lately? I've been wanting to try it but they're not very responsive. Lately have been using Finish Kare from Aircraft Spruce, prior to that Meguiars #88.

CG.
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Old Dec 18, 2008, 12:28 PM
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Hi Craig.

Got the Dolphin wax about two years ago so can't say what is happening now.
It was $20 for an 8 oz can plus $6 for shipping from Canada. Couple of weeks for delivery.
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Old Dec 18, 2008, 05:48 PM
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United States, VA, Falls Church
Joined Mar 2007
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Is there a reason nobody uses PVA on their mylars. I have, and it works great.
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Old Dec 18, 2008, 06:00 PM
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United States, CA, Folsom
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Quote:
Originally Posted by Daryl Perkins
Is there a reason nobody uses PVA on their mylars. I have, and it works great.
Perhaps you like those chemical odors. I knew there was hope for ya...
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Old Dec 18, 2008, 07:36 PM
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Vancouver, Canada
Joined Jan 2008
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"Is there a reason nobody uses PVA on their mylars."

I've tried it on painted mylars but I found that if I had to reposition the layup (or parts thereof) the PVA/paint lifted locally.

T.D.
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Old Dec 18, 2008, 07:53 PM
Daryl Perkins's Avatar
United States, VA, Falls Church
Joined Mar 2007
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That's a good reason. It does release REALLY well. I've used it on painted pieces as well, but that never happened to me. Guess I got lucky.

Thx

D
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Old Dec 19, 2008, 10:57 AM
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How do you apply the PVA to Mylars, with a paint gun?

Waxing is really easy. I just clean the Mylars with Alcohol and then one single application of wax. Don't even use the power buffer.

By the way PVA is nasty stuff but last time I went to West Marine they had this "new formula" which is not actually PVA. JT can help us here but the main component is Ethene Homopolymer. VOC is .08 lb/gal compared to 2.71 lb/gal for PVA. Have used it at some fuse molding at it worked as well as PVA and you can almost drink it according to the label.
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Old Dec 19, 2008, 11:06 AM
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Quote:
Originally Posted by Glauco
How do you apply the PVA to Mylars, with a paint gun?

Waxing is really easy. I just clean the Mylars with Alcohol and then one single application of wax. Don't even use the power buffer.

By the way PVA is nasty stuff but last time I went to West Marine they had this "new formula" which is not actually PVA. JT can help us here but the main component is Ethene Homopolymer. VOC is .08 lb/gal compared to 2.71 lb/gal for PVA. Have used it at some fuse molding at it worked as well as PVA and you can almost drink it according to the label.
Glauco,
Take a pic of the label with the ingredients, and post it. I can tell you what it is from that.
JT (Chemistry-boy)
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Old Dec 19, 2008, 11:19 AM
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Nasty how Glauco? I use tons of it....


Quote:
Originally Posted by Glauco
How do you apply the PVA to Mylars, with a paint gun?

Waxing is really easy. I just clean the Mylars with Alcohol and then one single application of wax. Don't even use the power buffer.

By the way PVA is nasty stuff but last time I went to West Marine they had this "new formula" which is not actually PVA. JT can help us here but the main component is Ethene Homopolymer. VOC is .08 lb/gal compared to 2.71 lb/gal for PVA. Have used it at some fuse molding at it worked as well as PVA and you can almost drink it according to the label.
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Old Dec 19, 2008, 11:41 AM
I'm all about that bass
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United States, IN, Indianapolis
Joined Feb 2004
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Hey guys,

OK, for starters, I'm no expert... On anything. But have you all tried Crown mold release for waxing the mylars? It comes in a spray can and you just spray it on.

I have been using it on the wings I bag, but then I don't do any painting on those wings. And, I'm clearly an amateur compared to the work of Glauco.

Ryan
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Old Dec 19, 2008, 01:51 PM
TEAM FUTABA TEAM DURALITE
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Joined Nov 2004
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Hmmmm... I have used regular old Carnuba wax..like for cars.... the trick with the paint is to preheat the painted items a little bit.... though mylar doesnt have much thermal mass...

But.. if you put down a very light coat... almost like overspray density.. let it tack for a few minutes.. then do another overspray coat... and repeat.. the "Fish Eye" comes if the paint is applied thickly enuff to flow.... if the coats are thinly done and the volatiles allowed to escape... there is no flowing.
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Old Dec 19, 2008, 02:22 PM
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Some PVA Info

I did a little checking on PVA mold release agents. The most common formulas seem to be about 7% in butanol/ethanol/water, or 7% in isopropanol/water. There was very little acute toxicity data on PVA, but most MSDS's suggest that it is a skin irritant, and a potential carcinogen.

Before anyone freaks out, the potential carcinogenicity is based on dosing rats with pretty large amounts (around 2500 mg/Kg of body wt.) but this did lead to problems. This kind of result is no big surprise, but it suggests that some precautions should be taken when using it, because there is no difinitive information to say its absolutely safe, or actually methyl-ethyl death. Its somewhere between, likely closer to safe than deadly.

My recommendation: this stuff is water based, so very little possibility of inhalation. Take precautions based on how you use it. At the least safety glasses and gloves. If you are going to spray it, use a filter mask (HEPA type cartridges are best and a plain dust mask is better than nothing since the mist is a particulate, not a gas).

Glauco, don't buy into the advertising hype. Ethene homopolymer is a fancy way to say polyvinyl alcohol. "New" formula means it uses different solvents and diluents.

Dr. JT
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