Vacvuum infusion F U # 2

[KnottyBuoyz]

Originally Posted by Fanie

Do you think a thicker shade cloth would improve flow rates ?

The red stuff I used is pretty thick. Holes are probably 1/4", dunno what that is in mm's, metrically challenged!

You're right, the consumables are obsene especially on a boat project. I think some of the benefits outweigh those costs such as:

1. Dry lay up of all your fabrics
2. You can take as long as you want to lay up the fabrics
3. Optomized resin/glass ratios
4. Should result in less fairing

There's probably more.

If you're building a slow trawler and weight isn't an issue it wouldn't really make sense. If you're building a high performance racing boat then it probably makes a lot of sense. Me? I'm building a slow trawler but I'm gonna infuse the hull (S&G Ply) anyways! Ok naysayers have at it!

[Fanie]

This proves to be a bloody expensive exersize so far. I even bought two power generators, one for when we have a power cut (like again Sunday) and a small one that goes on the boat if I can one day get the bloody infusion to work properly ... 650W, may look small but through a step down transformer you can charge up to about 45A... which is ok-ish I think.

The wife is impressed too. She thinks she can run the hair dryer in an emergency

[Fanie]

I have another question.

When the supply goes empty, before it gets air in, will it be ok to block flow while you mix the next bit of resin ? In case one runs a bit short... ?

[KnottyBuoyz]

Originally Posted by Fanie

I have another question.

When the supply goes empty, before it gets air in, will it be ok to block flow while you mix the next bit of resin ? In case one runs a bit short... ?

You should be able to get pretty close on your resin estimate. Weigh all your glass before you start and mix up the same weight of resin. That's a 50/50 glass/resin ratio which is good. You'll actually do better with infusion.

Ideally you'll want to cut off the flow of resin into your layup when the part is about 3/4 finished. The vacuum will continue to pull the resin through the stack. If you get a runaway flow that heads for the resin outlet you can try putting weights on it to force the resin to flow where it's needed. You can even let the wifey go at it with the hair dryer to kick it off quicker. If you get a part that seems to be stubborn you can also squeegee some resin towards the dry parts. All tricks you'll learn as you go.

[Wynand N]

Fanie,

You must use a flow medium to channel the resin to your dry stack otherwise the vacuum will prohibit flow due to the massive pressure on the stack as you had experienced - being there, done that and have a badge.
The peel ply only gives it a smooth finish as can be seen in the photo I posted.

As for the shade cloth - I'm off to the hardware shop this morning to check out the other shade grades than the 40% I'm now experimenting with. If a 70% for instance have more "channels", that is the thick longitudinal strands, it must be better and I will give it a try.
Let me know what is the name of the slow cure hardener you getting and btw, did you received the samples I had sent you?

Fanie, Rubberite in Michelle str, Pta West (about two blocks from where the street starts at Nissan on the right) sells all types of rubber and the have a nice type that slips over the edge (in all sizes) as the one I had used - just bed it with sealer to the canister to prevent leaks between the canister ind rubber seal.

[Fanie]

Haven't received samples yet, will find out from the post today. Thanks, I know rubberrite. It's the drive there...



What is the infusion thickness limit ? If I want to infuse a 20mm thick part will it still work ?

The beams I'm trying to infuse currently is only 3mm thick. I cannot think there should be a problem with thickness... ?

[Wynand N]

Took the infusion laminate of the glass and the average thickness is only 2.3mm for the dry stack consisting 3 x 450g CSM, 1 x 610g WR, 2mm Coremat with a surface tissue.
The hand layup with the same dry stack is an average 5.9mm thick!
In weight the fusion piece weight 30g/cm sq and the hand layup exactly double that at 60g/cm sq.

[Fanie]

Carefull with too light eh Wynand, you don't want the boat to blow off'n the water.

I think the beams I'm trying to infuse is quite difficult to do. The glass and other materials has to be draped tight around it otherwise the glass will deform on the corners and could look yukky.

[Manie B]

Fanie dont feel alone
i am not happy either
going to AMT tomorrow to buy "SP solvent A"
i have scrubbed and sanded and cleaned with all and sundry as well as denatured alcohol - still not right

this heat we are having is also a problem
36 celsius at 3500 meters??? above sea level is something that the other folks havent experienced
they dont even fly aeroplanes at this height or thin air

fu3kit maybe i am looking for excusess
anyway try again tomorrow

this whole flippen week was getting a good second layer
sh1t hey???

[Fanie]

Well, here's the next FU, No 3 is it ?

There's the beam with shade netting as flow medium around it,

Secondly, I've put the resin in ice to cool it down. It gelled after 30 minutes, but I had the same problem. Flow was up to sh1t.

What I have is 9 layers of glass, then peel ply (the peel ply is still on in the photo's), and the shade net that I pulled off.

When I opened the flow, it flowed to the other side through the spiral lacingin about 15 seconds, then started to creep up. 15 minutes flow stopped, and nowhere the resin was meeting at the top, so I still had half the beam dry. Distance is still only 200mm.

I then introduced a second pipe on top which again flowed rapid to the outlet, most of the cloth seemed to wet out with some help and I blocked the supply. It seemed there was only a small slit on the one side that didn't wet out.

Taking the bag off and removing the flow medium is what you see there. I suspect the whiter areas is the glass that didn't get wet out properly.

This vacuum bagging thing begins to look like it stinks with some things. Maybe it's just good to do little panels with. There's no way in hell I'm going to infuse a boat the size I want with this method.

TBH, with the same time, effort and money spent to now, I could have built another boat.

Anybody out there, tell met why this isn't working as it should.

And how thick a glass can you vac ? Seems like 1mm, right ?

[Fanie]

Manie, someone suggested you put peel ply when you epoxy the wood, your problem may come off with the peel ply. I can give you a piece if you want...

[Fanie]

How much is peel ply restricting flow ?

[KnottyBuoyz]

Originally Posted by Fanie

How much is peel ply restricting flow ?

The stuff I've used doesn't restrict flow at all. If I were to venture a guess I'd say your resin is too thick and not a long enough pot life. Cooling it before mixing should help with working time but on the other hand it likely makes it thicker. I don't think any general purpose boatbuilding epoxy will work with infusion. You really need something specially formulated for infusion.

[Fanie]

Aye Rick,

Couple of things bother me about this. I cannot seem to get 200mm of flow in 30 mins, Wynand gets 700mm in 8 mins. My vac is 80, his is 89. If I open the inlet the vac drops immediately so I am getting good air flow. I also use the same resin as Wynand. Cooling it down doesn't make it thicker, remember it is resin, not epoxy.

I have ordered some resin that is designed for vac infusion, they say it's like water, I will hopefully get it tomorrow. Had to crap NCS's boss out, it's 3 days already since I ordered.

[Jimbo1490]

EMI-24 s your friend here. Cures any epoxy with good cured state properties. Room temperature cure is about 1 week @25C if EMI is the only curing agent. So you get like a solid 3 or 4 days of good pot life. But you can cut this time down by adding a tiny bit of TETA, like 1/2 to 1% or so. Or you can add modest heat , say 120F (VERY easy to achieve) and cure time goes down to 4-6 hours. It can be post-cured AT ANY TIME SUBSEQUENTLY to improve hardness and HDT, if needed. Air Products and Chemicals is one seller. Get them to send a sample. They'll send a QT (.946 liter ) just for the asking, which will cure a LOT of resin as the mix ratio is only 1-4%. The mix ratio is not critical, either as EMI is a true catalyst for epoxies, while virtually all the others are 'curing agents'. This is how I built by carbon masts in one shot, and I can tell you the stuff works as advertised.

Jimbo