Is it possible to use multiple layers of the Soric locally, to build up a thicker rib in addition to the sandwich that the entire surface will have?
I’ve never tried more than one layer. You could do a little test layup on a sheet of glass to find out.
I was planning on doing some testing with infusion since I’ve never done this before. Here was the plan.
- Small test panel on a sheet of glass, of the same layup schedule as I intend on using. First using a fiberglass twill weave of the same weight, then using carbon.
- Fiberglass version of my sunroof. This will allow me to tweak the infusion process, if necessary. And not incur too much cost doing so. It will also let me test fit my panel in the car. This will also let me know if the part is stiff enough with my layup schedule.
- Make the real part.
Given your experience, do you think 2 layers of 2x2 twill 3k, 6 oz carbon, then one layer of Soric XF, followed by one layer of 2x2 3k, 6 oz carbon will be of sufficient stiffness to span the 30" sunroof? The mounts points are only on the sides, so I’m not sure I’ll have sufficient stiffness w/o adding a thicker rib somewhere. I’ve never worked with composites/cores/etc before so I’m unsure of what to expect. Any thoughts you may have would be much appreciated.
One more random question. What type of glass is typically used to make test panels. I will pick up a 2’x3’ piece of glass on my way home a the glass shop, but need to know what to buy. Tempered, vs plate, what thickness to ensure no breakage when removing the test panel, etc?
Kevin, I would do two layers, core, two layers. This will give you better stability and strength that I talked about in a previous post. The feel of a test panel will be quite revealing in respect to strength…break it, beat on it, stab it, bend it, etc.
For a panel that size you might consider getting 1/4" acrylic/plexi-glass sheet for your tests. Glass may be just fine. I’ve just never done a sandwich layup on glass that large.
Soric Core works really good, it adds rigibility, as wyowindworks says use the same amount of layers before the core and after the core. If I remember correct the thickest you can get is 6mm. If you still want it thicker you can use 2 layers of soric as long as you place a saturated layer of fiberglass or carbon between them. The only problem I had with soric was the print-through of it’s “cubes”.
Where are you US guys buying the Soric? I can’t seem to find any place that carries it besides Fibreglast.com and they’re outrageously priced on everything.
Wyowindworks, I was thinking only one ply on the bottom due to the loading of the panel. It will only be loaded from the top (from either aero or setting something up there). Given that, the sandwich structure would result in the bottom layer in tension and the top layers in compression. Thin laminates are stronger in tension than compression due to the buckling. Given that I was thinking only one layer would be required on the bottom since its so strong in tension.
I went back and re-read your original posting and I think makes a lot of sense. I can certainly accept the additional weight from one additional layer of fabric.
I had to do a spar for a wing once. We used the same logic. Put more carbon on the top to handle compression and prevent buckling. Everything worked great except that it developed a bow along it length and had to go in the garbage dumpster. 
I got mine from Baltek, they had 2mm and 3mm thickness. http://www.corematerials.3acomposites.com/home-emea.html
I’ve seen other people have this problem when they use soric. Even one “pro” shop in Milwaukee did a entire body/interior out of CF on a Lotus and you could see the core in certain location when the light hit it right. :rolleyes: This was a SEMA car too…
Divyncell from DIAB is what you want if you want structural. Here is a nice thread showing infusion with a Diab core from TeT. It’s also the core I used in the MTI hose thread. This core makes your panel XX times stronger then Soric.
http://www.compositescentral.com/showthread.php?t=4243
I’ve never ordered from these guys but they offer it in the small quantity you would need.
http://www.fiberglasssupply.com/Product_Catalog/Core_Materials/core_materials.html
My official cautionary recant:
I must confess that i have only used the Soric SF and never the XF. :o I haven’t noticed any print-thru issues with the SF. It comes in formats that would be too thin for your application.
I think the SF can be combined with XF to prevent the print-thru issues. Don’t quote me on that though.
Maybe Divinymat would be a good choice. I haven’t used that one either.
The advantage with the soric is that its playable- follows contours but the print through and the extra resin needed is a fact. Always wanted to use divynicell but is it easy to follow contours, or is there a trick to soften it? with a heat gun maybe?
Talking about print through
Oh wow nice pic of the Audi hood TnT.
Yup it contours to parts pretty well, depends on the sizing of your “cubes” and it’s machinable too. It can be heated and preformed but I don’t do that much. If I remeber right your supposed to factory 8-10% reduction in strength of the core when preforming it because of cell elongation. But most of the time you can get it to contour to the mould just fine so that’s not a factor, granted I’m not using this on parts like mirrors with tight radi.
Anyways I just ran down and took a couple pics of the one I use alot. I put the roll of bag tape in the pics to try and give a universal gauge of size since most of us are around the world from each other.
The first I tried to show a tight bend, the second I just rolled it up like paper towel roll, then the third is the other side which is scrim to hold it together.
Divynicell also comes in solid sheet, but that is really intended for wet lay-up. I use the H80 from fiberglass supply. I do recall seeing one of their technical specs where they talk about pre-forming the core using elevated temperatures but I think that was assuming you could use your existing mold for the forming and the temperature was +200F so the mold would have to take that.
I’ve done quiet a bit of testing with different types of cores including a new Soric product called LRC. The finish was very good but I’m not sure how it would hold up in such an application. I used to have an FD so I’m familiar with the slight bulges that exist on that panel and I think the soric cores will form into it but depending on the resin system you select print-through might be an issue. Typically resins with more shrinkage will exhibit more print through.
I have a project coming up that will deal with a similar cosmetic issue. So I’ve been wondering if I can lay-up a single layer of carbon with peel-ply and fully cure that layer then as a second step add one layer of carbon, core, then two more carbon layers. The hope here is to end up with perfect finish with no print through. My one major concern with this method is being able to remove peel-ply from just one layer without releasing it from the mold.
Thanks for the photos, Probably Divynicel is the way to go.
I found a video on youtube [ame=“http://www.youtube.com/watch?v=40RbCFL743E”]Vacuum Bagging with EZ~Spray Silicone Reusable Composite Bags 3/3 - YouTube[/ame] check 1.26, is this foam Divyncell 1cm thick, if it is it has enough flexibility even without the “cuts”?
Does anyone know the source for the adhesive film that they are using to adhere the foam to the skin? Is this stuff available in small quantities and different curing temperatures?
It could be but I don’t know… I do know Divinycell comes in all different sizes/shapes, a few colors, and different surface finishes like scored, double cut and grooved/perforated.
I’m planning on buying some 1/4" last-a-foam and perforating it myself. I spoke with a gentleman from General Polymers and he mentioned doing this himself successfully in many applications. I’ll be giving that a try. I am thinking I’ll also buy a small piece of 1/4" divinycell and making a razor blade jig to score it myself. so its flexible in both directions (concave and convex) since my part requires it. It will be basically 1/8" deep scores on both sides, off set to allow for flex. I also ended up buying some Adtech 820 resin and 823 hardner. I think this should give me the best chances at a successful infusion since the viscosity is so low.
One question. I’m doing a low quantity of parts from this mold. Probably 6 or so, so I can’t justify buying expensive semi-perm release. I’m planning on just using wax, specifically Meguiars #8, max mold release. Will this be adequate, when using the Adtech 820 resin system?
I’d test it on a sample or on the flange first.
I did my first infusion yesterday. I did a sample to make sure I understand the process, and work out any issues on a smaller scale.
Here is the setup I did. Its a 4x12" piece, with a 2"x10" piece of 1/8" divinycell. I feed resin from one side, and vac on the other. I put the feed line right at the edge of the fabric, and left ~3" of peel ply on the vac side as a resin brake. Since the part was so small I did not use any flow media. I used 2x2 twill, 8oz glass. 2 layers, core, 2 layers. Then peel ply, then 4 mil polyethylene. I was using Adtech 830 with the medium hardner (45 min).
IMG_5542.jpg by Kevin_Doe, on Flickr
I vac checked the part overnight. I had 29" vac, and lost zero vac over 12 hours. Then I mixed my resin up, and degassed it for ~2 minutes. It was still “boiling” when I removed it. I wasn’t sure if it would boil forever or what, so I figured it was good enough. As you can see in this picture, I don’t think the resin was degassed well enough. There are what looks like air bubbles pulling through, and boiling inside the vac line.
IMG_5548.jpg by Kevin_Doe, on Flickr
Here it is completed. It took about 10 minutes to fully infuse the part. Seems pretty long for a part of this size. For my sunroof project I’ll need to speed up the rate of resin travel, which I think flow media will accomplish.
IMG_5554.jpg by Kevin_Doe, on Flickr
Here are a few of the finished part, trimmed up with a cutoff wheel (not the best tool for a nice edge). The glass is super transparent.
IMG_5557.jpg by Kevin_Doe, on Flickr
In this one you can see the peel ply texture on the surface, as well as what appears to be small voids in the surface of the part. I assume this is from not degassing the resin well enough. I did not see any of those “bubbles” till ~6-8 hours after infusion, then they started to appear. Odd.
IMG_5558.jpg by Kevin_Doe, on Flickr
IMG_5559.jpg by Kevin_Doe, on Flickr
Absolutely perfect surface finish on the mold side.
IMG_5560.jpg by Kevin_Doe, on Flickr
And a short video of the resin boiling/bubbling in the vac line. I am positive I had no vac leaks in the bag, so I assume this is from a poorly degassed resin???
http://www.flickr.com/photos/kevindoe/6698750059/