Any spray adhesive I’ve used so far shows up on the part. If I do the spray a little in the air and let it settle on the fabric I see it less but it’s still there. I am trying new product this week and will report the results.
I would recommend Nutack-E reactive spray adhesive, it is formulated to react and croslink with epoxy. I use this and there is absolutely no surface imperfections or residue as it becomes part of the epoxy matrix. You can purchase this from Composite Envisions, I even use this as a fabric tackifier allowing me to cut without damaging the weave.
From here i think i will do two layups but both will have the same partall and pva application
on the first i will spray on the sparymax 2k and sand with 180 grit then do a standard carbon twill infusion, mti hose, etc
the second i will spray the duratec sunshield and do the v-weave layup.
do you guys see any issue with applying the 2k or Sunshield directly to the pva??
thanks!
thoughts on how to infuse?
Maybe infuse from the inside out to the MTI hose (which will use a lot of hose) or just across the part? I know the center will infuse very quickly but the bottom end (larger side) wont.
Sorry I can’t provide any help on the best way to infuse this, but I would be interested in seeing pictures of your setup and the final result.
Good luck.
I would infuse from the large end to the small using MTI at the end and a couple inches down each side at the small end. The only issue I have with small amounts of MTI is how slowly it evacuates the air. I usually pull the bag down through both inlet and outlet and then clamp the resin inlet after the bag is sealed thoroughly. If not, the smallest leak will outrun the ability to pull air through the MTI. Not a disadvantage, just a peculiarity.
I do like that idea but i would be concerned that the resin would flow well enough to do it. I could give it a try.
I infuse parts that are about 10" wide and 60" long that way. I use about 4.5" of flow media in the middle of the part and touching the resin spiral, it ends about 2" from the MTI. It takes about 30 minutes to infuse about 170 grams of infusion epoxy from Composite Envisions. My vacuum level is less than 10 mbar before I start the infusion.
I have been using the infusion epoxy from Composite Envisions also, and so far, it has been OK. I have used Soric for a core/flow media, but am thinking about loosing it and making some 1/4" (6mm) thick solid carbon parts. The print thru on the Soric is terrible. The part is fine out of the mold, but after a few weeks/months, the epoxy shrinks a bit and the print thru pops out.
Can I ask you how thick your layup is? Are you using a core? I have some parts that are 12" wide and 30" long, but as I said, I am thinking about making them out of solid CF and concerned about dry spots.
Thank you.
Why not run the infusion media the full length?
Hanaldo,
if you have the mold waxed and spared with a pva, wont the 2k try to slip out if you sand it?
I stop the flow media before the end to slow the resin front. Don’t know if it’s absolutely necessary but the parts have all been very good.
The parts that are that long are .030" thick. I do some other parts that are about .210" thick and they infuse very well also.No core in either part. I do a plain sheet with Soric and two layers of 11oz carbon and no flow media. They come out nicely as well. I always leave a gap between the MTI and flow media.
Thoughts on this?
This method worked out well except for the two tiny holes in the mold that screwed things up. The part came out fine but the were pins holes below the 2k that are trapped now. Everything before the leaks is pinhole free so i am sure that was the issue.
Not a big deal since this was a test part. Now I just need to fix the holes and move on. I doubt I will do another IMC since everything has to go perfect to avoid trapped pin holes which i cant fix afterwards. So now i just need to perfect the Duratec coating to cover them!
i have posted some pics of the process and the part on the car.
Doesn’t look bad at all for a test piece. I don’t extend the flow mesh that close to the sides of the part, don’t know if it matters that much but I leave maybe an inch at the sides to the edges. Never have a problem with resin not filling in those areas. Way to go.
Notice your question for the perfect seam in the layup wasn’t answered. The best method is have the pieces precision patterned and cut for a perfect fit using prepreg. Getting the seam perfect without the slightest fray or errant fiber with dry fabric is exceptionally difficult. If you must use dry fabric, I would recommend first fabricating/laminating a 1/2" wide thin seam cut strip from tightly wound Kevlar to protect the mold. Lay both sides of the fabric in the mold secured with a spray adhesive on top of the cut strip on the seam, then cut through both plies at once. Very carefully remove the strip and excess material, and then lay the plies back in place doing as little disturbing of the fibers as possible. The dry fabric will fray less if you use the spray adhesive on both sides, but be careful to not use too much. I would not recommend attempting to pre apply a topcoat in the mold.
i find the top coat applied to the mold release wax bubbles up and does not stick to the entire surface evenly. I am using Meguiars mold release wax. Is there a way to prevent the clear coat from bubbling up and not laying down evenly?
Thanks,
Brian
mist the first coat lightly, wait 5-1mins until it almost tacked off, then spray as usual
Regarding V pattern, you need to cut one edge of the fabric ideally (for instance left side of V pattern).
In order not to damage pattern cutting line you need to tape it backside with paper tape and then cut.
The right side fabric need to be apply above / over left side (which is ideal cutted) , with efficient radius to fit to the V pattern.
Sorry mate, haven’t checked this topic for awhile.
Short answer is yes, there is a chance of pre-releasing the coating. You need to be very careful and gentle with it, don’t just go at it like you would prep an ordinary panel. If you don’t push too hard or go too aggressively, it’s very possible to scuff up the coating even on a high slip surface like Frekote etc.