Resin infusion for tooling

General Composites Discussions Composites Talk
#1

Hi Lads,

Looking to hear your thoughts here as im planning getting into abit of infusion for tooling.

At the moment I’m very much into pre preg as i have a small setup doing pre preg products but a few of my projects need me to make moulds in the wetlay form depending on the pattern i need to copy and the resin system i need to use. As for wetlay I am the first to admit im not the best at it and my shop isnt really setup for wetlay. But one of the main reasons is, quite frankly I just dont like it. But I have been looking at infusion and although it may take slightly longer in some cases to make moulds and you need to take a few things into consideration, i think it could lend itself well to the products im making and its a good balance between wetlay and autoclave prepreg.
I am new to infusion and although i understand the concept and process( had my head buried in my composite books studying like crazy!), i have never really had much hands on with the process yet. I have been looking at the MTI hose route but any thoughts,pit falls and advice would be brilliant. Also any info on UK suppliers for MTI hose would be much appreciated.

Thanks in advance and any info (positive or negative) would be appreciated

Cheers

#2

Infusion to make tooling is a far superior process than wet lamination. The quality of the tool will be better as it will have no voids to blister. Speed is usually faster as you can for the most part infuse in one shot rather than doing multiple laminations.

MTI hose is a great product and I recommend it. Best advise is to use 2 bags to insure vacuum integrity, that is the key. Lastly I would say, make sure to do test panels first to learn and fully understand how you will infuse your tool.

#3

Cheers Hojo, Thats what i like to hear!

When you say 2 bags, do you mean one single side ( around the flange area for example) then an envelope bag? or just 2 vacuum bags one slightly larger than the other? just to make sure there is no leaks at all? Is there any benefit leaking the material pulled down under vac for a period of time before resin is released? a de-bulk pretty much?

#4

Yes, a “debulk” under full vacuum boils of water that might be in your materials.

Also the resin used is best degassed. Plenty of air and other gasses that you do not want in your mould.

The only drawback of infusion is that you need an airtight plug. This can be troublesome, but it totally depends on what you are making. And as you are prepregging anyway, there is no need telling you about airtightness.

Double bagging indeed is 2 bags over each other, with strips of bleeder in between. All for airtightness.

#5

Hi Herman,

Yes I thought it might be the case a debulk would help. As for air tightness i guess I just need to ensure the flanges and gaps between the flanges and parts are filled successfully. i will also be gel coating the surface to create a good quality tool face so hopefully this will also help create an air tight part for infusing. Also Is double bagging a necessity? I assume the we need to run both under vacuum at all times? Does it need a layer of breather between bags for air flow?

Sorry for all the questions, just want to confirm. :slight_smile:

#6

You should do vacuum checks on your plug first to confirm it is ok. Also, if your plug is leaking, the surface coat you use will more than likely seal it, so the risk is low for a leak in the plug unless you do not use surface coat.

I highly recommend double bagging as if you get a leak during infusion your tool is ruined. Whereas if you have a double bag the risk of a leak is very low.

Either use strips of breather or flow media between the bag. You want to see the resin as it infuses.

#7

Thanks Hojo, Thats really useful information! :slight_smile: