Limitations to infusion thickness

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#1

Is there a theortetical limit to the thickness of a CF layup?

I’m thinking of makeing some structural parts for the boat, backing plates, stern bearings etc. and would need to layup up multiple layers of CF to get the desired thickness, 1/4" to 3/8" thick in most cases. I’ve got some very heavy multi-axial fabric Werks sent me that I guess is about 20 oz/yd and 4 layers of that is 1/4" dry. I’m going to infuse that stack tonight to see how it works. I’ll have to cut it apart to see if the infusion actually gets through all the layers.

#2

I have infused 44 layers of 8.3 carbon twill with 1/2" all at once before. No problem. I’ve seen 1" thick solid fiberglass panels infuse in one shot too.
With the right materials, you should be able to infuse any thickness.

#3

tet , what would those right materilas be that you are referring to? proper resins?

#4

4 layers of the heavy Saertex and 8 layers of 1208 infused really well. I was quite surprised at how quickly it infused, probably 45 mins for the CF. The fiberglass soaked up the resin in about 10 mins. I got a lil’ epoxy in the vacuum line but nowhere near as much as last time. I’ll pop them off the mold when I get home tonight to see how well it actually worked.

I’m guessin’ the right materials Tet refers to is the resin and flow media, they being the two that have the biggest effect on how well the part infuses.

#5

can you post pics, I’m curious. Thanks.

#6

the biggest problem you cuould run into with thick panels/parts is exotherm.
It depends on what resin you are using, don’t even think about doing thicker than 1/2" with poly or VE unless you can control how hot it gets.
Use a long gel time epoxy for thick parts and you should be good

#7

Hey CD

Thnx for the info. I am using a ULV epoxy from Polymer Composites on e-Bay. It has a 5 hr pot life and 24 hr to demolding. Extremely slow and no exotherm. I do have to work inside in the basement so low odour and low toxicity is important.

I’ll be posting pics later on tonight.

Rick

#8

On the left, 4 layers of the heavy multiaxial CF avg. thickness .240" on the right 8 layers of 1208 biaxial F/G avg. thickness .230". Waiting on epoxy mfgr to advice on best temp for post cure. Both are still a little green. The peelply was a real bugger to get off the CF.

Both parts will be cut into sections and machined for bolts to test their respective strengths. I intend to use this or a similar process to make a number of parts for our boat, backing plates for deck hardware, stern bearing holder etc. Probably not any cheaper than buying the parts but much more fun!

Werks, I used the red flow media this time, it worked well but left its impression in the top layer of the laminate. Not a big deal on structural parts but it’d probably be a bugger on cosmetic parts. The peelply I got from you really hung onto the CF. It peeled right off the F/G w/o any problems.

#9

but wouldn’t the flow media be on the inside anyways? or did you do something differently due to thickness?

#10

On the inside? You mean between the layers of fabric? Nope, I put it on top of the peelply.

#11

what I meant was that the good side would be in contact with the plug, and the flow media on as the last layer on top the peel ply …just like you have it in the pic…so how did it get a transfer of pattern on the good finished smooth side in contact with the plug? did I just missunderstand something? are you needing a piece with both sides asthetically apealling?

#12

No sorry, wasn’t thinking that technically. I think I had the “nice” side of the CF up on top and the backside down on the table. Not a big deal, just fooling around with “stuff”. I don’t think I’ll be producing any “cosmetic” parts, most will be underwater or inside the hull out of sight. I’m going to slice this up, drill holes in it, tighten bolts in it till breaks. Next steps will be actually making some viable parts.

#13

ok gottcha

please post and document the cutting and grilling and your outcomes if it’s not too much hassle, I’m interested