Well we made a part as I have before same layup but this time a bit cooler maybe 65 degrees, well we infused and long story short the infusion really slowed down at the end and the bag on the in side was loose and getting full of resin. I’m assuming the epoxy was to thick and needed to be heated up to thin out before infuson. Anybody have anything like this happen to them.btw I was pulling 27 in vac
Won’t be the last time it happens… I think it’s happened to everyone if it makes you feel any better. I know, it sucks!
Having a few different feed lines on a larger part may be helpful, even if they aren’t all opened at the start of the infusion but rather in sequence as the front creeps along. You can even time a fresh batch of resin if you are potentially risking it kicking due to a slow infusion…
Very bad vacuum is probably the problem, a infusion with 27 Hg is a no go. Also can be a leak somewere.
Working with composites means bad experiences. I can cry sometimes out of frustration, I have ruined for around €75 on material today because I had a leak that I couldn’t find.
If the person is running a piston type vacuum pump 27inHg may be the max.
Show us pictures and detailes of your layup and the materials you used.
That doesn’t matter it is still not enough for a good infusion.
No bag leaks I have got pretty good at that, I did a viscosity test on the epoxy and seems pretty thick. I’m using huntman 8605 high tg room temp cure. Two things I’m thinking here is I buy 5 gallons at a time so ether the reson is going bad as I have had this can for about three months or it was just to cold. This is not a full time job so I don’t go through a ton of resin but the parts I make are racecar body parts so there pretty good size.also I ran pump today and it seems like its losing it vac strengh as it was only pulling 26in this morning.
On the good side we salvaged the parts. I’ll post pics of what I bulid
That is good enough for infusion. I don’t think you understand what I am trying to say, if you have a piston pump 27 is the max vacuum the pump can deliver, and that is sufficient for infusion as you do not need 29 inHg to infuse. If you have a diaphragm pump you can easily reach 29.
Looking forward to seeing the car part pictures. 
I understand what you are saying, but what you are saying is incorrect. A good piston vacuumpump can pull a deaper vac then 27 inHg easy. For a good infusion you need less then 20 mbar, that’s 29,… something inHg.
Look I’m not going to get into a back and forth with you. I have piston pumps and some of the largest ones that I have are rated at a max of 27 inHg—they are not rated at 29. I used them for infusion, and I do it fine. We can disagree, but I’m not going to do a back and forth. Lets not have our disagreement take this thread off topic.
You’re not going back and forth but you’re doing it :rolleyes:.
But apparantly the problem has been found in the pump. For a good infusion it is criticle to have a good vacuum less then 20 mbar. If you don’t have that you can run into some problems that you’re experiencing. And yes you can infuse some nice optical products with a vacuum of 27 inHg.
Yeh there’s no way a part infused at 27in/Hg is going to be as good as the same part infused at 29.9in/Hg. Might be able to produce a part that looks good, but there will be more voids within the laminate. Not saying that would make the part total junk, just not AS good.
The problem in the States is that they still use inHg. It is a relative measuring method. But you should always measure absolute.
So do not say I pull 29 inHg vacuum, say 0.006inHg pressure left in the part. Or absolute pressure below 20mbar.
You can infuse a small part with 27 inHg and it can come out great without voids. The change that it will be the case is small but as we need to believe Wildcard it’s no problem :D. The product properties will be another story when you infuse with 27 inHg or 29.9… inHg or as DDCompound told less then 20 mbar.
Here’s some pictures of some work I’ve have done all 1 year experience.
I would suggest correcting your infusion setup. Your vacuum line is hook directly to the flow media and part. You should either use peel ply as a break, or can use MTI hose directly on the laminate. Also you should end your flow media short of the laminate by 1-2" so that the resin flow front has time to equalize and infuse the remaining laminate correctly.
Thanks, I will give it a try I’m always learning.
No problem, by the way, I ran the composite shop at Tim McAmis Race Car for 5 years prior to moving out here 3 years ago. Perhaps you are familiar with them?