Resin infusion for a CF pocket board

[SonnyRider]

First time board builder.

Yes, I am aware it would be much easier to not do infusion on my first board

I've vacuumed a couple layers of 210gr 3k CF on the hull and the deck. Now looking to do a couple of 12k layers top and bottom. Top is to be finished off with cork. I was thinking 2 x 12k layers on the hull and three on the deck.

Trying to get my head around the process. All I can work out is, you do a dry layup of both sides and pull the resin through both sides. Makes it tricky for sure. I'm assuming you can't really do the hull first then the deck or vice versa? Like 'normal' vacuuming process. I was hoping I could infuse the deck first, followed by the hull, then hiding the lap under the cork.

Anyone out there managed it from a DiY standpoint?

[BWD]

Seems like your lamination schedule is a bit heavy. Are you using lght eps as core?
If using a stronger core like divynicel etc you could be ok with 600gsm total + local reinforcements, or 400 if you are light or gentle.
There is no reason you cannot infuse in stages, btw.
A one shot infusion saves time but is harder to pull off. If your goal is a great result, consider just infusing one side at a time, or merely infusing reinforcement patches - easier to grind off if it screws up.
If your goal is to learn process and board doesn’t matter too much, go for the one shot infusion. I have never bothered with infusion due to extra consumeables etc.
If you get good at wet layup you can have results that match most vacuum jobs in strength and weight, btw but that’s another story

[kostantin]

First time board builder.

Yes, I am aware it would be much easier to not do infusion on my first board

I've vacuumed a couple layers of 210gr 3k CF on the hull and the deck. Now looking to do a couple of 12k layers top and bottom. Top is to be finished off with cork. I was thinking 2 x 12k layers on the hull and three on the deck.

Trying to get my head around the process. All I can work out is, you do a dry layup of both sides and pull the resin through both sides. Makes it tricky for sure. I'm assuming you can't really do the hull first then the deck or vice versa? Like 'normal' vacuuming process. I was hoping I could infuse the deck first, followed by the hull, then hiding the lap under the cork.

Anyone out there managed it from a DiY standpoint?

Greetings,

you are trying one of the most difficult things in "plastics" as first home build. No offense, but from your questions I understand there might be some serious problems on the horizon.

tks

Kosta

[downunder]

First time board builder.

Yes, I am aware it would be much easier to not do infusion on my first board

I've vacuumed a couple layers of 210gr 3k CF on the hull and the deck. Now looking to do a couple of 12k layers top and bottom. Top is to be finished off with cork. I was thinking 2 x 12k layers on the hull and three on the deck.

Trying to get my head around the process. All I can work out is, you do a dry layup of both sides and pull the resin through both sides. Makes it tricky for sure. I'm assuming you can't really do the hull first then the deck or vice versa? Like 'normal' vacuuming process. I was hoping I could infuse the deck first, followed by the hull, then hiding the lap under the cork.

Anyone out there managed it from a DiY standpoint?

No.

2.1kg for now. Target is 2.4.

Why complicating?

[fluidity]

SonnyRider, I've done it.
Not a lot of experience so far but some really important things: You should use infusion mesh (normally above peel ply) and a really low viscosity infusion resin. A slow hardener because you don't want the resin going off in the mixing pot before it's even in the vacuumed layup.
Check for leaks by vacuuming and sealing off the pipes, wait 10min + and then recheck your vacuum-Before doing any mixing!

The function of the infusion mesh is to significantly extend the available infusion distance while creating turbulence to drive resin under the peel ply in place of the vacuum voids between fibres.

I haven't done any jobs bigger than a kiteboard (which can be done with just one infusion line running along an edge) but from videos I've watched they are like BWD says, you can infuse in stages. Use peel ply without fibres or infusion mesh at the edge like a brake, infusion is fast through the mesh but when it hits the peel ply only it will really struggle to pass the resin, however the peel ply will will let the last air out.

If you are vacum bagging against a surface, if you can't absolutely guarantee that the surface won't leak air into your wet layup then bag right around the other side too.

Make sure that your resin inflow pipe has a good clean entry into your spiral tube and that vacuuming won't shut the flow down! It's good practise to put a bit of peel ply or infusion mesh around the pipe to assist the bleed spirals to release flow into the composites when the bag snugs up against the tube, you don't want anything to slow the infusion on the input side.

Before you pull the bag fully tight to the piece, be sure that you have checked that you can work it snug into any depressions and around any protuberances.

Running multiple infusion pipes in means that you can get a time extension from an initial mix if you take care to not share mixed pots between pipes- You can block off all but one at a time and let it run until it's close to the neighbour pipes and then clamp that pipe off, unclamp another one. The resin will be nowhere near final cure when it gets too viscous to flow but you can then open another flow pipe to a pot of fresh resin and let that flow instead. Remember that your gap between fibres is super miniscule due to the vacuum and mostly the resin seems to find it's way into the unwetted gaps to long as there is resin availability and vacuume available at the moving front of resin. If a bottle neck forms then the resin will still want to creep in and close the fat part of the bottle because there is vacuum there still.

You will probably need to post-cure your part with heat after the initial cure because that's easier than bollixing a part by being impatient and getting too fast a hardener. An hour gel time at ambient temperature is a good ballpark for kiteboard sized things.

Spend plenty of time on your fibre layup and peel ply, infusion mesh, it only takes getting one underneath or top set of fabrics in the wrong order and your project will be a write off.

I use a short length of hose from my ear to all the seals to check for leaks under vacuum however keep an eye on the infusion and sealant patches ready in case a leak develops during the infusion and you need to work quickly.

Try to eliminate sharp things inside the bag and if you must have them, protect them with some cloth and tape or allow plenty of excess bag around them to conform without pressure on the sharp piece.

I don't have a catch pot so I create a buffer zone for any resin which gets past the peel ply, I put paper towels around the vacuum pipe with some length for the resin to have to travel though before it can go into the vacuum hose on the pump side. With only a flat end to the suction pipe end it can easily suck the vacum bag in and not suck the air out of the bag at all.

[SonnyRider]

Thanks BWD & Fuidity.

I am using 15mm thick T90 airex for the core. Hence, the different laminates. I hear what you're saying regarding the weight. Hence, why I'm looking at infusion to save a little weight

I've got all the kit/hardware I need for the infusion process, I just haven't found a video showing the process for hull and deck as a separate process. eg. trying to get my head around stopping the infusion from going to far over the 'other side' of the board (deck/hull), I don't want to spend an age grinding all the resin off the other side. All the videos I find on the infusion process is in a mould, which clearly is no good for a one off pocket board

I know it'll be a difficult task to do it all in one, but I wouldn't say it's not do-able, it's just going to need lots of tack spray, I do have a couple of cans

[tomtom]

As one off infusion is overkill and you have like 5:1 chance it goes wrong. Infusion is very easy process theoretically but very demanding for execution. Its very unlikely you pull it on your first time. It take some trial and error to get it right. Carbon is especially problematic because there is 7x less space for resin flow than glass. There is absolutely NO weight saving at all vs vacuum laminating. Contrary there is good chance you end up with more saturated laminate with infusion. I made like 20 boards with infusion. My current position is that for thin laminates carbon /less than 400g/m2/ and small project /which pocket board is/ is not worth hassle. Infusion is big help for bigger structures boat hulls , kayaks, wings etc... Thicker laminates are naturally more permeable and labour saving vs hand impregnation here are clear.

[kostantin]

On the picture, this is one of in total 4 / 70 meter molds made out of carbon.

Trust me, for mold injection you need shitloads of knowledge and you will not find it on youtube.

tks

Kosta

[fluidity]

Thanks BWD & Fuidity.

I am using 15mm thick T90 airex for the core. Hence, the different laminates. I hear what you're saying regarding the weight. Hence, why I'm looking at infusion to save a little weight

I've got all the kit/hardware I need for the infusion process, I just haven't found a video showing the process for hull and deck as a separate process. eg. trying to get my head around stopping the infusion from going to far over the 'other side' of the board (deck/hull), I don't want to spend an age grinding all the resin off the other side. All the videos I find on the infusion process is in a mould, which clearly is no good for a one off pocket board

I know it'll be a difficult task to do it all in one, but I wouldn't say it's not do-able, it's just going to need lots of tack spray, I do have a couple of cans

If you want to do only a side at a time then mask the edges of the area you don't want to infuse with some low tack masking tape to about 80mm wide. Run the composites past the edge and finish the peel ply before the unmasked part.
When cured slice with a dremel to make tidy edges of your composite fabrics and lift off the edges with the low tack masking tape.

[SonnyRider]

If you want to do only a side at a time then mask the edges of the area you don't want to infuse with some low tack masking tape to about 80mm wide. Run the composites past the edge and finish the peel ply before the unmasked part.
When cured slice with a dremel to make tidy edges of your composite fabrics and lift off the edges with the low tack masking tape.

Thanks, makes sense. So, if I wanted to have the fibre wrap around the rail, to enable lapping, I would do the same. But on the underside/topside.
Sounds tricky