Vacvuum infusion F U # 2

[Fanie]

Ok, now tell me what's wrong.

That is how far the infusion went in 12 mins before the resin gelled.

No leaks in the bag this time. It took the resin about 20 seconds to flow through the length of the spiral and then everything seems to block up.

If I opened the inlet prior to the resin then the vacuum dropped.

Size is 100mm x 100mm 2 meter long

[Fanie]

There are 9 layers of WR glass 450g.

I have opened the bag on the inlet side and poured a liter of resin in it, then closed up again. It has made a big clump on the one side, but did not flow to the out let

Why not ? Isn't the resin capable of flowing through glass or what is going on

[KnottyBuoyz]

What kind of resin are you using Fanie? The stuff I use for infusion has a 100 minute working time. It's ultra thin (viscosity <500 CPS). It flows well through most materials (doesn't like CSM though).

Others will correct me if I'm wrong but it's better to infuse from the bottom up. This will help prevent clogging your vacuum lines with excess resin.

The use of a flow media will help distribute the resin in the part. Multiple vacuum outlets will help. Three along the top would work on a part like that or use your spiral wrap as a vacuum manifold inside the bag. I think having a single point of vacuum at the far end of the part is part of the problem.

Is the beam hollow? Did you get any resin puddling inside it?

[Fanie]

Hi Knotty,

It is normal resin I have. The distance the resin has to flow is only 200mm !!

I am infusing from the bottom up, I turned the beam upside down to take the picture else I have to lie on the floor and take the pic upwards.

What flow media ? Peel ply ? If it doesn't flow through the glass, what would be the purpose of having it flow over the glass. It's not going to wet it out on the inner layers then.

[Fanie]

I have ordered other resin I should get tomorrow, the guy told me it has a cure time of 45 mins if hot else 1 hour.

If this doesn't flow then I can tell you that isn't going to work either.

[Fanie]

The beam is solid foam, so there is no puddling. I can try multiple outlets.

Rick, if I cannot infuse this small a thing, how am I going to infuse a 10m thing many times this size in width

[KnottyBuoyz]

Solid is good Fanie. My first attempt at a shaft log ended up with a solid chunk of epoxy inside it. Duh!

Infusion resins are extremely thin almost the consistency of water when mixed. They'll flow very easily through a stack. Regular epoxies won't do this at all, I've tried (and failed).

Flow media is a screen mesh material that'll allow the resin to flow over the top of the fabric then down into the layup. It looks like plastic screening.

If you look close at this pic you can see the red mesh covering the layup.



Some people substitute "shade cloth" for flow media with good success. Sometimes you have to improvise when necessary. You normally put the flow media overtop of the peelply so that it doesn't bond to the layup. If worse comes to worse you can probably get some plastic screen at the hardware store.

Nine layers of glass might be too much for a single infusion. You might have to do it in two shots, dunno, maybe someone else knows.

[Fanie]

You know, the list of consumables and their cost is already past the 'saving' one would make in the resin. The time it takes also begins to look like it would take much longer that a hand layup.

Seems the actual glass and resin cost is going to be neglectable compared to the consumables

What are the advantages of vacuum infusion again ?

[Manie B]

Jeez - pity hey
starting to look very problematic and complicated

[Landlubber]

Infusion processes are basically simplke, but yes there is a lot of mucking about to get to the end product. The flow media is also essential to allow movement of the resin mate, otherwise the flow is restricted by the resin itself as it blocks the exit towards the output sides of your tubes.
The main advantage of resin infusion is the compactness that is the result. No other system can compact the glass as tight without using moulds to do so, very expensive. We do fairly large boats in one shot, but always hace a flow medium, the peel ply is optional, we only use it where extra work is going to be required.
Another thing, the gelcoat and the first tie layer are already in the moulds, we only infuse the actual laminate schedule.

[Fanie]

Damn Manie, and then you look so bloody serious and sympathetic on your avatar

I'll get some shade cloth tomorrow and if it doesn't work you guys are in so much trouble

Still don't know why the resin would flow down into the fiberglass instead of just over it and out.

[Wynand N]

Fanie,

Also done an infusion today with a complete layup schedule as follows with my polyester resin to see how it would go.

1 x surface tissue
4 x 450g CSM
1 x 610g WR
1 x 2mm Coremat in between

It was a typical scorching hot Free State day with the temperature about 38C in the workshop. I used a 1.2% hardener mix and it gelled out in 8 minutes flat The vacuum was at 87-88Kpa through out the infusion.
Total length of infusion was 700mm and you will notice I put the resin feed in the centre and the vacuum lines at the ends with no connectors at this stage yet.
Will see if I can get a slow cure hardener from my resin pimp

The last photo is of my improvised peel coat and you can see the smooth finish and the patterned top side the shade cloth (flow media) was laid on. This is the same peel ply as the samples I sent you and it works like magic.

You will notice my resin trap is an old Cadac gas cylinder cut open and a rubber edge trim fitted and the Perspex is only hold down by the vacuum - easy to open in an emergency...

[Wynand N]

Btw, will take the laminate off the glass plate tomorrow and check the thickness and stiffness wit the hand laid sample next to it on the board...

[Fanie]

Seven friggin hundred mm I wish.

I only got two inches. As frustrated as a woman

I ordered 2 pieces of perspex for my resin traps and got some 5mm rubber for sealing it off.

Thanks for the pictures there Wynand

[Fanie]

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