Print through using Divinycell H with infusion?

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#1

I’m doing a small infusion project that calls for the part th have some thickness. I’ll be using a foam core sandwich. I’ve selected Divinycell H60 for the core because I can get it in 4’ x 8’ sheets to accommodate the 3’ x 7’ part I’m making.

I’m curious about what kind of print through I’m going to get from all the scoring and groves and if there is anyway that I can mask them? I can get the non grooved version as well but it comes in smaller sheets that I will need to butt up tightly and glue together, which will also cause some print through, no doubt.

Any tips or thoughts would be helpful.

#2

I used to score sheets of normal divinycell to use in infusion, and even with just the shallow scores that I made there was quite visible print through. I was only using one layer of carbon fibre on each side though, so I’m not sure if having a print-blocker layer would prevent it?

#3

I recently did a large job with 10mm thick 2 x 2mm grooved H80 infusion core.

This had a gelcoat finish and we skinned (and cured) on top the gelcoat with 225g CSM and vinylester before doing the infusion job. This seemed fine for print through but then the laminate was also reasonably thick, 650g quad fglass.

#4

Thank gents. I ordered some up yesterday to do a test run. I kinda figured there was going to be some print through and it would need some treatment. Weight isnt very key here but it has to be fairly durable so I may try some 1mm Coremat that I’ll lay up with the CF laminate to hide the print through.

#5

I did a 12’ boat with H60 and did have a lot of print thru. My next boat will be gel coat then 3/4 oz skin coat.

#6

The Divinycell product that arrived from the supplier came unscored and without any perforations. It’s a 3 x 4’ panel that I’ll cut to make 3 different tests with. I’m using 6mm H45 (3lbs per cu.ft). Does anyone know if I need to make small pinhole perforations for resin infusion process (or is it semi permeable) and if so, what is a good starting placement for the perforations (1/2" ?)

Appreciate any help. Thanks

#7

So no luck on my last attempt. Totally bummed out.

I tried a test panel of 2 layers of 2x2 CF twill, 3mm thick Divinycell H45 (non scored) and I made 1.5mm perforations every 2cm in the 60cm x 60cm panel, followed by 2mm coremat, 2 layers of 2x2 CF twill, peel ply, red flow media, followed by bagging.

Pulled vacuum for 15 min on test panel, clamped off and did a 30 minute vacuum drop test. No leaks. Mercury read 29.1" Hg.

Mixed some Mia 100 Epoxy and 97 hardener (47min pot life) and pulled resin for about an hour and had to stop as the flow front didnt advance more than 10cm during that time. I’ll extend my flow media to my vacuum inlet next time to draw resin quicker but go with green mesh instead.

What has me bummed out is the fact that the top had 10cm of resin that flowed, but the underneath only had 1.75cm of resin.

What went so terribly wrong? Do I need more or larger perforations?

Any help would be appreciated.