Vacuum and resin for infusion questions

General Composites Discussions Equipment Talk
#1

I want to try doing some vacuum infusion and found a robinair 15600 for a pretty decent price, stats are 6cfm, 2 stage pump, posting for the pump says 1/2 hp but robinair website says 1/3hp, this is a airco unit but it can pull 29"hg vacuum. Will this work for infusion I like that it’s a 2 stage capable of 29" since lightweight and strength are priorities.

Also what kind of resin do you guys use for infusion, I searched for infusion resin and found mas infusion resin, but want to know what others use. Needs to be room temp cure, can I use any epoxy resin with low enough viscosity? If so how low?

#2

I have been using Adtech 820 resin. Its a epoxy resin, room temp cure. 350 cps, flows very nice for infusions. I’m new to infusions, but I’ve been having excellent results with it.

#3

I use hydrex100LV. Great stuff :).

#4

You can use epoxy resin with low viscosity, but its not all about viscosity , its how well you wet out the fabric, need samples let me know. RESIN333@aol.com

#5

i use a Gast dual rocking piston pump, 2cfm, 29" rated. Resin is Derakane VER (510-a, 8084), and API’s SC-15, SC-79, and CCMFCS-2. I also have various Composite Polymer Design resins, and Huntsman Araldite MY721, which has to be heated to 150f just to infuse.

#6

Bit of a side track but who is your distributor for huntsman resins? There’s a huntsman system I’ve been trying to get but the distributors I’ve been communicating with won’t do single pail volumes.

#7

snocutt: that is becoming a larger and larger problem. Many times the larger epoxy companies only accept pallet-size orders PER PRODUCT (resin and hardener are 2 different products). This is really thinning the options out, as you need a certain amount of sales to justify the purchase of such quantities. Buying too large can cause problems in warehousing, cashflow and profit.

I believe Huntsman has not been biten by that virus (yet) but many others have. Which actually creates a market for sub-distributors who create their own resins and hardeners by mixing and modifying basic systems.

Anyhow, your pump may work for a while, but keep in mind that most airco units smoke like nothing else if they do not reach their vacuum. Keep some spare oil at hand.

As for resins, both polyesters, vinylesters and epoxies are available in infusion qualities.
Polyesters and vinylesters should be largely unmodified (non thixotropic) and can have the cobalt added or not (check it, read the datasheet!).
Epoxy resins should be low viscosity, mixed viscosity up to 700 mPa.s works well. Keep in mind infusion speed is lineair with the viscosity. So a viscosity drop of 50% will speed up the infusion time by 2.

Also keep in mind that infusion is not a NASCAR race. Quality is more important than speed.

#8

I use IVEXC410 Vinyl Ester/DCPD Blend Infusion Resin.

#9

The bucket shipping label says Huntsman directly. I was not part of ordering.

#10

Hi E20:

Well, I am on same situation, I have read a lot, and I have bougth the robinair 15600 just two weeks ago. It was the best for my project and $.

I also have done some research about resins, but at this moment I guees I would like to go for the MAS infures, but I still dobious about mix rates, how many accelerator on this?

Other it seems to be an option for me are the uscomposites 635 thin epoxy resin, but I really I have not find if it is good for infusion.

I have also a question, it looks the first choise to use with cf and infusion are the epoxyes, but some people uses other resins, but I would like to know the proper aplication of each. I would like to use cf and an infusion resin on a medium to small body automotive parts.

Regards.

Antonio

#11

Temperature can have a very large effect on resins and how they infuse. Its well worth spending time looking at data sheets and seeing how the mixed viscosity and cure rates change with temperature. You can save a lot of moulding time and money on expensive infusion resins by doing some research.

#12

The Robin air will work perect, obviously it’s not a Industrial pump for composites but with the proper maintance (oil changes) you should get 1000’s of infusions. You should look into building a vacuum system with storage tanks and vac switch to reduce run time and prolong the life even more. For epoxy you will want 600 cps or lower. You “can” go higher but I don’t suggest it.

The US composites 635 thin epoxy is not for automotive body panels. You can use it if you want, but they mention on their web site that it isn’t suggested. This is because of the low tg. (works great for learning the process since it’s price is so low)
Check out PTM&W resins if you want something to handle automotive applications. Something like the Epoxy-n-fusion system http://www.ptm-w.com/index.asp?pgid=180

#13

Hello , I am new to this forum and to tell you the truth this is the first time I have tried this. I am wonering is there anyone on here that can help me with understanding vacuum moulding inside a vacuum chamber? I would try and infuse resin into a mould inside of a vacuum chamber.
Any help on this subject would be great.

Cheers Barry

#14

We can help you, but you should tell us a little more. What do you want to infuse, how big, wich material, layup…

#15

If I am not mistaken, you cannot infuse inside of a vacuum chamber, it defeats the purpose of vacuum infusion, the mould inside the vacuum bag has to be under full vacuum… in other words, the vacuum bag is the vacuum chamber. This question was posted in another forum and it wont work because if the whole mould is inside a chamber then there wont be any atmospheric pressure pushing on the bagging stack. hope that kind of explains it.

#16

Hi Thanks for the reply, I want to infuse polyester resin into a mould filled with fiberglass.

I am thinking If I take a mould and make an inlet for the resin and an outlet for the air to be evacuated from the mould. Then take a sealed cannister for the resin and attach it to the inlet port on the mould and leave the outlet open to the inside of the vacuum chamber. Then make a hole in the vacuum chamber wall and insert a length of tubing and attach the end that pertrudes in the chamber to the top of the sealed resin cannister and leave the end of the tubing that is outside the vaccum chamber open to the normal atmospheric pressure. I am thinking that so long as we stop the vacuum before the resin runs dry it will infuse. I know your probaly thinking why not just connect direstly to the mould with the vacuum pump and leave an open container with resin in to infuse. The reason we are trying to do it a different way is our workers cannot be relied upon to ensure a leak free mould , so I thought that if we could do it all in a vacuum then we take away the risk .

Any suggestion would be much appreciated.
Barry

#17

Sorry I forgot to mention the size of the item.

Its mass is about 150 grams
Thickness of the part at its thickest is about 10mm
Thinnest is abour 3 mm
Infusion resin Polyester
Gel time about 15 mins

Cheers thanks Barry

#18

I’d like to find a resin that will be durable enough to use on a piece of luggage and still thin enough to infuse. Also, can you apply a coat of the epoxy just like you would a gel coat? Maybe someone could inform me, but I’m afraid a gel coat would not hold up to bumps and bruises.

Daniel