Infusion resin feed lines

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#1

Hi there, im trying to find a good resin feed line material as i want to get away from using spiral wrap. The spiral wrap leaves a resin rich blob on the part which is annoying to grind off afterwards, so im looking for a material thats cheap, easy to lay, and is flat so theres no mark off - similar to the enka channel or resintrak products designed for this purpose.

So why not use the purpose designed products? Because theyre too expensive… ive managed to cut my infusion consumables cost by 300% by using other materials that are designed for other purposes, not resin infusion consumables. The resin feed channels is the last thing i need to figure out.

To give an idea on consumables savings, i am now using the following;

Vac bag film = polyethylene shrink wrap film, no holes, rolls 4m wide x 100m long = $100 per roll = 400m^2;

Flow media = ive used everything from bird netting @ $100 per 450m^2, to shade cloth @ $0.30c m^2 to plastic mesh/netting depending on the required flow speeds. Many fabrics and plastics are available.

Under bag Vacuum lines = Hessian Webbing for tieing plant saplings @ 20c linear meter.

Hoses and plumbing, all has been adapted to use std PE irrigation tubing and fittings hardware - no it doesnt leak or collapse under vacuum.

So does anyone have a solution for low cost resin feed lines that will not mark off? Ive tried a few things and they work, but they do not flow fast enough to suit my purposes. I typically infuse parts between 20-40kgs of epoxy over 10-20m^2.

#2

It is one of the things that I haven’t sourced yet.

The 9/12mm spiral is already 2x faster than Enkachannel, which is a factor to keep in mind.

I am having my own PE tube made, own infusion mesh, sealant tape, etc. Curious to see what you come up with.

I have a customer that uses PE angle strip, laid with the corner pointing up. When the resin exotherms (after infusion) the heat collapses the PE, and there is no mark-off.

#3

hi Groper. Is there a reason you don’t lift the spiral wrap off the part after it is filled?

#4

Well i cant lift the spiral off until its cured as i cannot get inside the bag to remove it without breaking the vacuum seal… how is this possible?

Herman, good to see you here… next thing i will try is PVC jointing molding which is used by carpenters to butt join fibre cement sheets when building houses etc… this is the stuff;

It comes in 3m lengths for about $1 linear meter - so its still a bit expensive but i think the mark off should be ok… it will create 5mmx8mm resin path on each side of the center, so double this for each strip which should flow a decent amount of resin. its readily available and most hardware stores and building supplies should have it. I havnt tested it yet, but its the next on my list…

#5

If there is peel ply below the spiral the excess resin is removed with the peel ply.That’s how I do it and never had resin blobs around there.
Polyethylene shrink wrap film is it the plastic packaging film?

#6

I am not a fan of using “cheap alternatives” because most of them are not cheaper in the end.
For example bagging films, all cheap alternatives are not tight because most of them have holes because of the cheap material or are microporous like all PE films. There are multilayer alternatives from the food industry, but they are only cheaper if you can get a rest roll. But they work perfect( It’s the same than bagging films)
Flow media. The cheap alternatives are most time not ideal in flow managment. If you take a alternative that is similar to a prefessional flow media it is not more expansive. The higher price most depends on the weight of the fabric. Even if you make big parts like you I would not try saving a few $ and risk a part that is damaged. That is expansive.
If you don’t want a print ob the backside from the spiral wrap it seems that you produce quality parts.
Place 3 layers of flow media below the spiral and there will not be a print through. Or work with a “flying feed line”.
Hessian webbings work but not perfect, they have a too big inner friction for the air and if saturated there is no further airflow possible. Than better work with a spiral hose and a resin trap.

@herman: tge idea with the PE angle strip is great.

#7

Typically im happy to pay more for something that works better. However, i produce excellent results with cheap alternatives so i choose to reduce costs where possible and maintain quality at the same time. The cheap vacuum film i use, has no pinholes in it - however it took me some time to find this quality film at a good price - like you said, i discovered most cheap films have pinholes - but not all of them, just have to find it.

The hessian webbing - you are correct, but depending on your process, the problem you speak of is not an issue for me. Products like MTI hose etc are great for what they can do, but i think its like compensation for poor strategy design - you should not need the ability MTI hose gives with proper design. Likewise, with proper resin quantity calculation and control, little resin ever gets into my vacuum line unless i make a mistake.

I agree the extra layers of flow media stops the mark off, but its time consuming cutting up strips and placing it, hell ive even used multiple layer strips as the resin feed itself, but its all too labor intensive.

I hear the same defence of the high price of infusion consumables from the people invested in selling the stuff. Like “how much is the part worth” and “why risk it” etc… its all bunk, if you do your own appropriate testing, and develop a system that works, you can save heaps of money, you only need to prove it to yourself… When the market starts to realize this, we will all be 1 step closer to more competitive pricing on the stuff we want.

#8

If you will understand the MTI process you will see that it is more than only a compensation of a poor strategie. But that’s not we want to discuss here. If you are interested you can read the MTI thread.
You can always save money, abd I am a friebd of saving money. The things you do may work in your case an if you do the job. But what happens if other people wirk with your materials or you produce other parts?
And about how much money are we talking? The flow media for example, I pay about 0.60€/m². On a 20m² part we talk about 6€ difference to your mesh. At such a big part that should not make a difference. And for the vac bag I pay about 0.50€/m².
And I am sure your PE film is microporous. Espacially shrink films have a porousity. Do you have airbubbles after a while in the flow media?
Maybe you can post a picture of a part so that we can understand what you do. I often here that people produce parts with a great quality, but most of them are wrong. They only produce parts.
But for some cases you don’t need that quality I mean.

#9

WOW, perhaps i should move to europe your prices are much better than here in australia… infusion mesh over here costs way more than that, i was quoted $7.30 per m^2, and the proper laminated nylon vacuum bag film costs around double what im paying for the PE film - which im sure is micro porous as you say, but it doesnt cause me any problems within a 2 hour gel period.

I do get air bubbles forming in the flow media after the resin line is clamped off and the laminate Vf evens out, however i was getting the same thing using the proper film, so this must be caused by something else in my process. I use the method of clamping early and maintaining 99.9% vacuum to acheive highest Vf possible without resin wastage back into the pot. I do not degass resin either, i would like to but i need a method of degassing upto 40kgs per pot. Despite this, the air bubbles are not visible in the part and do not cause me any concern, the tool side of the parts are shiney smooth and pinhole free, they can be taken directly to paint without filling, which is what i do.

#10

Ok, than you don’t have a good laminate quality in my mind. If it is ok for you that’s fine.
The price for the flow media is hhmmmm :eek::eek::eek:
Degasing the resin should be possible, but that only makes sence if your other parameters will enable a erfect result too.
Have you looked for Omega profiles? They are often used in the wind energy as flow channel.

#11

You lift the spiral wrap off the job as soon as the part is filled. BEFORE the resin gels.
Put a pleat in the bag directly over the spiral wrap. When that area is fully wet out, roll the spiral wrap between your thumb and index finger. With a bit of manipulation you can push the spiral up into the pleat. This can be done under full vacuum. If you are running multiple feed lines you can lift each line off the part as soon as that area is filled.

DDCompond I just paid $2240 Australian for a 220m roll of bagging film, and that is with my bulk buying discount. And the Australian dollar is worth more than the American dollar at the moment.

Omega profiles cost an arm and a leg here. I pay for quality when neccesary and cost effective. For what I do Omega isn’t neccesary or cost effective.

#12

:eek::eek::eek::eek: bagging film! Must surely be a VERY wide roll for that price no? Or is it a super high temp autoclave compatible or other super exotic? :confused:

And ok i see ASB… why not simply bunch up the spiral into the pleat with excess flow media before opening the lines then? same thing really? Yes its doable and ive done it before, but still a hassle IMHO… i think everything just gets easier with a nice lay flat resin feed material. Im confident the fibre cement jointing moldings will work well, but its still $1 per linear meter…

Agree on the omega lines, very expensive and even the silicon ones dont last very long before you end up wrecking them.

#13

I do the same…much faster infusion without signs on the piece

#14

Groper, I am very curious on what you got offered in terms of film and mesh, and at what place.

#15

You mean the prices i got for mesh and film, here in australia? The mesh @ $7.30 per m^2 was the Airtech resin flow 60.

The bagging film was Wrightlon 5400 nylon film… its about $1 per m^2…

id rather not say where from, other than a reputable australian composites supplier… the prices are all similar no matter where you shop here, its all too expensive - which is why i contacted you some time ago about supply of foam core materials - its also about triple the european price over here…

#16

On the foam: We just did a full stock inventory, and I will generate a list of what can go cheap to cheap(ish)

And I will check on the Resinflow 60 price. Sounds steep to me. Make sure you contact the Airtech distributor in your area.

#17

Three metres wide.
It isn’t a hassle. Quite the opposite when you get the knack .
Flow media and spiral in the pleat is a hassle on large jobs though. Time consuming and more consumables in the bin.