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  #41  
Old 06-11-2015, 01:35 AM
Yen Yen is offline
 
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Location: Benaraby Queensland. Australia
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I found that PVA woodworking glue works well with tha foam I use. That is old broccoli boxes. Even laying the weave at 45 deg to sharp corners I still have a less than perfect lay down. I have used an external form at times to get a corner down tight.
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  #42  
Old 06-11-2015, 09:14 AM
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DanH DanH is offline
 
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Quote:
Originally Posted by sblack View Post
I have to disagree that wax should not be buffed. If I recall the mould release wax instructions are to buff it out and I always do. Pva can be tricky to apply on top of buffed wax. I spray a mist coat and let it flash, then I can build it up with no fish eye.
Works for me. For years I used the same old can of Turtle Wax, and it worked better unbuffed. When it ran out I switched to real mold release wax, and indeed, it works great using several buffed coats.

http://www.aircraftspruce.com/catalo...clickkey=11425

BTW, the green Fiber Glast brand PVA sprays on buffed Meguiars without fisheye:

http://www.aircraftspruce.com/catalo...clickkey=11425

Quote:
Originally Posted by C5Engineer View Post
I'm working on making a bubble to clean up my cowling...I was wondering if you had any recommendations on the best way to do a nice cover over the big hole in my cowl. The kicker is the cowling splits right down the middle left to right with fastners so the bubble needs to be removable or...... open to ideas/designs.
Sometimes, when all you need is a blister, the easy thing is to find an ordinary kitchen bowl with the right size and dish shape. Wax the inside, spray some PVA, lay up four plies of 8 harness satin. Pop it out when cured and trim to fit your cowl.

After trim, I'd attached it to the assembled cowl with a flox filet and a few filet plies, then cut the split line after cure. Clean up the edges, wax and PVA one side, sand the other side rough, re-asssemble the cowl, and lay up a flange using some two inch tape. Same basic flange process here:

http://www.vansairforce.com/communit...28&postcount=1

Quote:
Originally Posted by Yen View Post
Even laying the weave at 45 deg to sharp corners I still have a less than perfect lay down. I have used an external form at times to get a corner down tight.
Whatever works! I've seen nice external "clamp" forms made from cast rubber. Try Reynolds Advanced Materials.

I vacuum bag layups over complex forms, like this one for composite VW cooling baffles, as good 'ole atmospheric pressure will push the layup down into the concave places pretty well:





Yes, this approach should work for an ECI cylinder. The trick is making the mold form. The actual baffle parts are four plies of 8.9 8-harness, with HTR-212 resin, a room-temp cure epoxy with a fairly high heat distortion temperature:

http://www.aircraftspruce.com/catalo...tr212resin.php

In any case, I'm not real worried about temperature, as these will have a gasket strip of silicone-impregnated glass cloth between them and the cooling fin tips.
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  #43  
Old 09-15-2015, 10:06 AM
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AAflyer AAflyer is offline
 
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Default Hair spray?

Can anyone comment on the suggested use of hair spray as a release agent? I saw this mentioned on a Hints for Homebuilders video.
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  #44  
Old 09-15-2015, 02:55 PM
BillL BillL is offline
 
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I have not tried the hairspray, but I find there is some hours invested in the bucks or molds and why risk it when PVA is pretty cheap. I read to add a wax application on top of three coats of PVA, and it worked pretty well.

I use 5 wax applications and 3 sprayed layers of pva. PVA comes off most easily with water after parts are separated.

PS. I was looking at DanH's VW picture above. It's upside down! I know the VW's pretty well, and was thinking "what the heck is that boss on the bottom" ??? Having looked at Lyc's so much the pushrod tubes seemed natural!
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Last edited by BillL : 09-15-2015 at 02:57 PM.
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  #45  
Old 08-08-2017, 05:36 PM
dtw_rv6 dtw_rv6 is offline
 
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Location: Martinsville, IN
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Old thread, I know. Dan - are there any learnings from your FAB that you would pass on to anyone duplicating your effort? I'm considering something similar for my RV6. I'm planning to print this for my mold:



Don
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  #46  
Old 08-08-2017, 09:40 PM
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DanH DanH is offline
 
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Quote:
Originally Posted by dtw_rv6 View Post
Old thread, I know. Dan - are there any learnings from your FAB that you would pass on to anyone duplicating your effort?
Don
Nope. 704 hours, working fine.
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  #47  
Old 11-22-2017, 01:55 PM
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humptybump humptybump is offline
 
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Default PDF of DanH's valuable work

I've been making reference to DanH's fiberglass work and was bummed when I realized (1) I had lost the PDF I had created from this thread, and (2) the photos fell victim to the PhotoBucket EUA.

I took a little time today to do my best to recreate a usable PDF for anyone looking for this material. I found all but 2 or 3 photos (the ones showing the fabrication of the alternate air door).

Here is the PDF - link.
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Last edited by humptybump : 11-22-2017 at 07:16 PM.
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  #48  
Old 11-22-2017, 01:59 PM
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humptybump humptybump is offline
 
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Quote:
Originally Posted by dtw_rv6 View Post
Old thread, I know. Dan - are there any learnings from your FAB that you would pass on to anyone duplicating your effort? I'm considering something similar for my RV6. I'm planning to print this for my mold:



Don
Don - I can not see the image but you said "print" a mold. Depending on the complexity of you mold, you may have real issues. (I just went down this path.) If you can display the image, I can provide more useful commentary.
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  #49  
Old 11-28-2017, 06:29 PM
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johnbright johnbright is offline
 
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Quote:
Originally Posted by humptybump View Post
... I took a little time today to do my best to recreate a usable PDF for anyone looking for this material. I found all but 2 or 3 photos (the ones showing the fabrication of the alternate air door).

Here is the PDF - link.
Thank you sir!
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  #50  
Old 11-28-2017, 09:18 PM
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vernon smith vernon smith is offline
 
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Location: Naples FL
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Being blesses with a nasty respiratory allergy to two part epoxy products doing custom molds for myself is a non starter. Three D printing is coming into it's own but I realize the headlines from GE and the like are for machines that cost over a million bucks and powdered materials that run in the thousands of dollars a pound.

There are a couple topics currently on the forum featuring machines that can be considered reasonable affordable. My question is will the plastic based materials they use hold up as well as the current run of the mill fiberglass creations?
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