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Aug 08, 2019, 07:25 PM
A dream will find you
StevenSeim's Avatar

Matched set...


Arriving Monday.

Decided to re-do the left half. The plywood base on it was too thin. I'm not going to mess around with scraps and surplus I have lying around. That ship has sailed.

Though I cannot speak directly on behalf of Killer, myself and he very likely would like to follow your conversion of these plugs to molds.

Thinking on converting these myself, I would not even touch the MDF. Just treat the epoxy/ATH inserts. Only my first thought. On sealing the part, I would think 2k primer will make everything butter smooth. Once the primer is on, finish sand. When you can just barely see the witness lines, you know you have it right. Paint, then cast. Again only my approach. Given your skill(s), I personally would want to follow your build closely.
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Aug 11, 2019, 08:01 PM
pnc
pnc
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Me toooooooo
Aug 12, 2019, 06:16 PM
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I got the electric Chubby fuse plugs from Steven today and raced home with them. A brush and a little heat gun action was all it took to get them to soak up 150 grams of epoxy.. a little light sanding and epoxy primer to come!
Aug 18, 2019, 09:47 PM
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attacking on two fronts


The corian blocks have been glued up and shipped to Steven for final milling and I spent the last few days priming and painting the fuse plugs to perfection so molds can be made. On my end things have gone very well but by the time Steven received the corian blocks they we warped even though I took every precaution to see that it wouldn't happen. Being the genius that he is though he has already figured out a fix for the problem. One of the blocks even got delammed a little but he has already fixed that.

Corian:
I started by sanding the individual pieces or corian with 220 on an orbital then cleaning them with laquer thinner as directed by my local corian guy. Corian glue was then squeezed onto the first block and evenly spread. The second block was placed on this and vacuum bagged down for an hour. The third layer was done the same way. After this was done to both blocks I took them to work and squared them up on our cnc machine. They were both then shipped to Steven.

As stated when Steven got them they were both warped. When I asked my corian buy about this he told me, well after the fact, that when you glue big pieces of corian together as the glue sets it imparts internal stresses in the corian that cause it to warp. The more layers the worse the effect. In the counter top industry this is no big deal as they rarely glue in this manner and tops are usually supported with plywood or steel before being installed. Steven came up with the idea of turning the block upside down on his machine and tickling off and 1/8 or so to make the bottom flat. That should leave more than enough flange to clamp them down once they are turned over on his machine and the real magic begins.

Plugs:
I started by priming the resin coated mdf plugs with 4 coats of 2K primer. They were then sanded back to the witness lines and the priming process was repeated until I had two buttery smooth plugs. It took a total of 20 coats of primer. Today I sprayed them with 3 light coats and 2 wet coats of blue 2K paint and they look spectacular. After they cure completely I will fill the milled channel surrounding the plug with either wax or clay. Still deciding which way to go here.

and now some pics:
Aug 18, 2019, 09:51 PM
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fuse plug pics


BASF Limco products used to prep the plugs
Aug 18, 2019, 10:10 PM
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Nice work guys. I dont think I would use paraffin again to profile groove. Remember if grooves is a hair low, you can block sand the parting plane flat

20 coats, yahoo!

Lee
Aug 18, 2019, 10:59 PM
A dream will find you
StevenSeim's Avatar

Nice work...


To correct the block warp, I first tried to draw the block down to the vacuum gallery. This flattened the block, which is actually a good thing, but not at this point. Had the block been planed, the warp would remain when the vacuum was removed.

I moved the vacuum gallery out of the way and just braced the block against the registration pins using clamps and furniture. No downforce from vertical clamps. Great cut, removing only about an eighth. On flipping the block over, it now lies flat on its own. Good news in that the block can be drawn down dead flat by vacuum for the surface cut.

In repairing the delam, I may have stumbled into a technique to bond Corian sheet to begin with. Aaron reports the glue he used has a short working time, and generates heat. It's also a bit spendy if my understanding is correct.

Scribing a Sharpie line at the base of the delam, I propped the block on an angle with scrap 4x4. I wedged the sheets open and worked epoxy/ATH (fairly thin) into the separated sheets with 1/32" music wire as far down as could be had. While doing that, I soaked untreated heavy brown construction paper with untreated epoxy applied with a gift card. The paper was fully saturated and a bit shiny with excess epoxy. Plenty of working time. Taking time, I worked the soaked paper into the delam all the way to point where the delam started. I then squished the hell out of it.

I just finished planing the block flat a few minutes ago. I slid the (rather heavy) block off the table to the start of the delam and levered it on and off the table briskly. Rock solid bond. No issues.

The bond is so solid I think it's worth a test to carve a surface that penetrates both layers. Unlike the Sheer wing molds that did not have brown paper between the layers, I'd bet a block so treated will not see an irregular transition between the layers, specifically if the layup is bagged under vacuum and weights. The paper would wick out any air between the layers, at least I think it would. Plenty of working time. No rush. A roll of brown construction paper is cheap. One could use shopping bag paper for smaller length molds.

Surfacing starts right away.
Last edited by StevenSeim; Aug 18, 2019 at 11:11 PM.
Aug 18, 2019, 11:00 PM
Loving Lee's Slope Slut
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This particular primer is not a high build primer. It is thin and meant to penetrate well into very fine nooks and crannys. A high build primer would have taken fewer coats but I don't know how well it would have "bit" into mdf. Some of the mdf was surely opened back up after I sanded off the high parts after the first round of epoxy so I decided to go with this one. I am glad I did because it all turned out very well.
Aug 18, 2019, 11:15 PM
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FPS tail


Lee, are you still needing an FPS tail? I have this one that is flouro yellow and white on top with white stripes on the bottom. This pic does not do the color justice and it only weighs 35 grams. Working on a green one now for me.
Aug 18, 2019, 11:33 PM
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StevenSeim's Avatar

Yes...


The plugs really look terrific Aaron. Oh man.

The contours, transitions and profile lines look great. The final fuselage is going to be very smart looking.

Your spray booth is a converted bus?
Aug 18, 2019, 11:35 PM
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Of course it is! you designed it
Aug 19, 2019, 10:37 PM
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Chavant around the edges, deleon for the trailing edge dam.
Aug 19, 2019, 10:53 PM
A dream will find you
StevenSeim's Avatar

Super nice...


Surfacing starts tomorrow am first thing. Both top and bottom have been coded. All good.

Will post photos to this post.
Aug 19, 2019, 10:54 PM
A dream will find you
StevenSeim's Avatar

Super nice...


Surfacing starts tomorrow am first thing. Both top and bottom have been coded. All good.

Why did you fill in the mounting screw guides, or am I missing something?

Will post photos to this post.
Aug 19, 2019, 11:43 PM
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The guides are only temporarily filled. I will press in the solid brass rod and then carefully re-scrape the chavant. More pics to come


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