Cleaning/Flushing Agent RTM Machine

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#1

I am rebuilding a resin transfer molding machine we have at the shop. The machine uses two cylinders that draw resin and hardener from a vat and then injects it using a static mixer. The machine was stored improperly and I’ve noticed all the seals in the cylinders for the hardener have perished, probably from the amines in the hardener. The material used was EPDM rubber.

I’ve found a supplier for Viton seals which I hope will hold up better to the hardener. However, I also want to start flushing the cylinders when they aren’t going to be used for a few days. So I’m looking for a flushing agent. I would like to use the piston in the cylinder to force the agent through and cycle this a few times.

I’ve done a lot of research and found multiple commercial products but am unsure of the “price/effectiveness” ratio. Many of these companies are in the US and I’m in the Netherlands so shipping is an issue.

Options:

[ul]
[li] Acetone is a no go for Viton seals;[/li][li]I’ve been recommended Ethyl Acetate but am still waiting on a quote;[/li][li]I’ve read about Vinegar on the forum;[/li][/ul]
I’de like to ask any experts on the forum if they have recommendations for fluids which are commonly used to flush equipment that has contained epoxy.

Thanks!

#2

Hi Alex,

By far most machines are flushed with acetone. What kind of machine are you working on?

Unless heated, flushing with water based materials is a no-go, so I suggest forgetting that. Especially if the machine is not in a daily routine production. (and when it is, it already creates enough problems for people to revert to acetone).

I would need to check what kind of seals we use in the Plastech and Composite Integration machines. I believe many are viton. When you flush the machine with air after flushing with acetone, you are OK in general.

Normal flushing is done with 2 buckets of acetone. First flush the machine with air (pump dry). Then put the pickup and recirculation hose in a bucket of acetone, and recirculate. This will clean the machine.

Then use the second bucket to flush a second time.

#3

Herman, thanks for your elaborate reply. The machine is custom built so there is no supplier I can turn to for more information.

Viton has a high chemical resistance however, it is not suited for ketones such as acetone and MEK. I believe the Composite Integration o-rings are silicone.

Is the concerns with waterbased fluids that it will not evaporate quickly like solvents such as acetone do? Are specially formulated fluids such as GEF1000(http://www.glenmarc.com/GEF1000.pdf) or Thermaclean EP(www.ccponline.com/includes/PDFs/095-0049.pdf)out of the question too?