Help Planning Mold/Part - Sunroof delete panel

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#121

Yea, I see what you mean now…may I ask why the manifold? Just run a spiral line the width of the part on one end and sprial vac on the other…easier that way KD, plus it is a controlled flow in one direction. Your issue with the dry spots was based on saturation, we know you had good vacuum, no holes (even the one mentioned won’t cause that), a slow enough infusion, your lay-up was not an issue, but the resin did not saturate through the laminate skin layers.

It is plausible the manifold method allowed the resin to run quick through the center of the part, only to cause traffic for the subsequent feed of the resin so to speak. The key is maintain an equal and always consistent feed rate that saturates the laminate skins (fabric) at the same rate from the beginning to the end.

On your next one, try just running vacuum from one side, feed line on the other, lay-up as usual, flow media from one side to the other on the entire part (minus the flange), pinch your line 1/4 the way of width and see if it results in a better infusion.

#122

Why feed in the center and draw vac on the perimeter? I’m not sure what exactly lead me to that decision. I was thinking that it would yield a nice even flow front, from center outward.

When you say pinch the line 1/4 of the way of width, what exactly do you mean? You’d pinch off the feed line before the resin reaches the other side?

Would you say it would make sense to feed from one flanged end, across to the other flanged end. That seems like it would be quite a long path for the resin to travel, but maybe that’s better than what I’m currently doing.

#123

Kevin…is there ANY chance that fiberglass has a coating of some kind ? If it did…saturation may be inhibited if the resin of choice is not specified to THAT coating.

Just a thought. Your off to a good start.

Save the part by sand blasting the voids with quartz sand. Clean well and carefully apply resin in the low spots, let dry and flat-stick sand then clear coat the whole exterior with good quality automotive clear. Wetsand and polish to rave reviews !

#124

I think you may be onto something. I looked at it closer and there are undersaturated spots even where there is no core. Seems like the fiberglass just didnt want to wet out like the carbon did. Seems like the carbon is fully saturated but the glass was more resistant to the resin flow. Could be from it being a plain weave or maybe a coating. The glass i used was over 10 years old. I had it leftover from a project i was working on back arould 2000. No idea about any coating applied. I think i will go without it on the next try.

#125

The finish on the glass definitely has a life span. Glass finishes that are “spent” will show a reduction in wet-out ability and a reduction in interface strength between the fibers and the resin. It’s best to store the glass in sealed plastic to extend the shelf-life of the finish.

I don’t know if that was the problem though. :slight_smile:

#126

I sold this carbon one with the blemishes. I’ll get another chance to do it right. I’m happy.

#127

Thats great news! all this work, you deserve a nicely finished piece!

Keep us all posted!

#128

Success!!! Thanks for all the help everyone. I’ll post an update as to what I did different as some point later on.

For now, just a quick camera phone pic. Now one question: Do I need to have it cleared? The Adtech 820 resin says that it is UV stabilized.


Success by Kevin_Doe, on Flickr

#129

Nice! It would probably be best to clear-coat it.

BTW, you were wondering how to calculate the thickness for a given amount of fiber and Vf. Here is a thread where I posted the math.

#130

Here is what I did different.

  1. Holes, 1/8" dia, 1.5" square grid, offset. Previous was 2" square grid.
  2. Grid scored the mold side down surface of the foam, to create flow channels.
  3. Double foam thickness on long edges. This was to stiffen up the part in that direction. 1/4" thick foam on entire top surface, and 1/2" total thickness on edges. I blended them in to help the fabric lay out easier.
  4. No fiberglass cloth on surface.
  5. Degassed resin until no more bubbles, approx 40 minutes (premix).
  6. No spiral distribution on resin inlet. I just used three layers thick flow media as the “manifold” down the middle of the part. This was to avoid the print of the spiral manifold.
  7. Semi perm release, Frekote 770NC.

Infused perfectly, nice slow and even flow. The part came out with extreme ease. Previously I was using all 10 of my wedges and a lot of force. This time one wedge and it nearly fell out of the mold.

I cleared it and wet sanded and buffed it. I’m super happy with how it turned out. I can’t wait to delve into my next project.


IMG_5781.jpg by Kevin_Doe, on Flickr


IMG_5783.jpg by Kevin_Doe, on Flickr


IMG_5862.jpg by Kevin_Doe, on Flickr


IMG_5869.jpg by Kevin_Doe, on Flickr


IMG_5872.jpg by Kevin_Doe, on Flickr

#131

Very nice. Are you guys degassing your epoxy before you add the hardener? Main reason I ask is my epoxy Artech 820 doesn’t give me enough time to degass after mixing.

#132

I am using the medium hardener. I also don’t have time to degas after mixing. I degas the resin and the hardener separately, then mix. I have tried degassing again after mixing, for about 10 minutes and didn’t get any bubbles so I assumed that mixing didn’t really introduce any bubbles. I mix manually with a stir stick and try to avoid creating any bubbles.

#133

And its in the car.

I made some adjustable threaded shims:

IMG_5876.jpg by Kevin_Doe, on Flickr

And also made some stainless washers

IMG_5880.jpg by Kevin_Doe, on Flickr

Installed, and sealed with 3M Windo-Weld.


IMG_5887.jpg by Kevin_Doe, on Flickr


IMG_5889.jpg by Kevin_Doe, on Flickr

#134

How does the epoxy hold up to heat distortion?

#135

Update after the race season.

After a few events in the sun all day the sunroof developed some print through. The HDT of the resin system is 180 deg F. So two theories. One, it post cured on the car and developed the print through. Two, it exceeded the HDT and developed some print through. Potentially both. Nothing huge, just some fabric texture and you can somewhat see the score lines I made in the foam. I may re-clear it and see if it comes back but not really a big priority.

I also sold the mold, and recouped all of my money I put into it. I was pretty happy with that.

#136

I made a carbon kevlar sunroof for an M3 using wet layup last winter. I want to do infusion next time. Nice work. High five.

#137

Great thread! Thanks for posting up all your processes (including the failures!), fantastic info for people doing small projects… it’s good to get a look into potential downfalls. But a great result in the end! Good to know about the eventual print through as well.

What is on the cards as the next project?