So Ive been trying my hand at vacuum infusion for a couple attempts now. I had issues with vacuum but figured what I was doing wrong with the molding process. That being said I have a 3cfm dual stage pump and it will only pull -29.5 to -29.75 psi (thats only connected to the catch pot) as well I dont think thats an issue my other problem is that I cant seem to get the resin to pull through the part before it fully cures. I know the resin is a 'low viscosity' but it will get about halfway through the part and then the resin will just crawl through with me ending up wasting quite a few ounces of resin because it will harden in the container. This part is an interior a-pillar part for an Acura so its a small part but it takes at least an hour to pull the resin through. Am I using too much hardener or should I go with a slow cure time? My concern is that ive pulled what resin I could get into the part through and so its thinner than it should be. To add, what is the resin to Carbon fiber ratio in ounces for vacuum infusion? 

29in/Hg is enough as long as it holds, 29.75 is damn close to as perfect a vacuum as you can get with a vacuum pump. Mine pulls 29.85, and that's bugger all difference in terms of what is actually left in there. As long as it holds, you're sweet. 

ok lemme see if I can remember. 

Also I've noticed that when I pull the part out of the mold the surface finish is flat and not shiny. Is that from not enough resin? Or is it the surface finish of the mold? I'm using a carnauba type wax as a mold release and it seems to work well, not as easy as the easy lease but it still pops out ok. I will see if I can provide a pick but another question. If there is a spot that had a large bubble that I was able to exacto knife out the bubble how could I go about filling it in? Should I mix a small amount of resin and wait for it to begin solidifying and fill in the hole or what. 

You should always draw the resin the shortest distance. 40" is a metre, that's a massive distance to try to draw the resin so I'm not at all surprised it took an hour. It can of course be done, but depending on the pot-life of your resin you may have to adjust the setup to suit. 

Hanaldo, thank you very much for the info that helps me out ALOT! Though im confused regarding the draw regards length. Watching the video on EC's website the infusion video seems like that part is a fairly good size but they said it only takes a few minutes to pull that. Maybe its the pump I have? its a 3CFM dual stage pump by Pittsburg Automotive, their specs says they pull down to 22.5 microns. FYI my above post I added the materials im using (specific brand names) Only thing I dont have is the Epoxy, its sold by Revchem locally in the U.S. in a few states, I believe its a vinyl epoxy..they said its used for bagging.

•  Can I add multiple resin draw points to a part if its too long. (ie: Resin pot>feed line#1>part>feed line#2>part>feedline#3>part>pump line>catch pot>pump) just so long as I make sure the resin will pass a certain point before I unclamp the next line.....or is that just crazy talk?
• You said to use Acetone, but what if I just did a scuff up and used compressed air & a tack cloth to wipe off the dust before recoating? which leads me to getting rid of micro bubbles when I use an applicator, I know you use a heat gun but how long to you hit it with heat for?
• My mold has a few little imperfections that I need to 'fill in' so the final part is smooth. Can I use clay or wax (do I need to wax or ez lease it?) or should I just let the resin fill in the imperfection and sand it out? (fyi these imperfections will be raised points on the part, though not by 'much')
• Lastly, if I run into a large part in the future how do I get around the issue of too large an area for the pump? my above idea or a slower cure resin?

Thanks again all your help, this I feel will get me past this little hump I cant get over in my learning curve.

edit: I think I get what you were talking about regarding the draw distance being too long. If the part width that im pulling the resin into is smaller than the length of the part then im basically like trying to quickly fill up a 12x40 ft room with people only coming in 1 door on the 12 foot side, even though its the same amount of space overall if I instead let people into the room via the 40ft side I will have more entrance space and thus fill it faster with less work. So feed on 40inch side and exit on 40inch side should net me much better results. Now to figure out why I keep getting bubbles on the gauge pod part I molded into the pillar. it is a deep part of the mold so maybe there is a bubble pulled from somewhere and it just sits there, that or its because of the way I was pulling resin that started to 'thin out' the resin to create gaps in spots.

 

Your analogy isn't totally correct, but it's sort of the same principal. It also isn't because of the size of your vacuum pump. It's a bit of a tricky thing to understand because you need to know how the physics of infusion work, but I'll try to explain it because it's quite useful to know. 

Ok that makes more sense. However what did you mean by bridging?

Correct, same surface area. The spiral hose simply extends the flow front, it doesn't slow the resin at all. You could theoretically accomplish the same thing infusing the length of the part by running your spiral hose from the entry point to the exit point. This would mean that your resin reaches the end very quickly, but for one you will waste resin as the resin that has already reached the exit will flow out of the part again before the rest of the part has fully wet out. Secondly, infusing at this speed would likely create voids as it doesn't give the resin time to wet the material out evenly; and third you will likely end up with the spiral tube 'printing' through onto the surface of the part. 

Ok, thats what I figured you meant by bridging. That seems likely to be happening, its difficult to get the bag to suck down into the gauge pod dip in the mold. I think more bag and maybe better pleating will allow it to get down deeper and keep the carbon against the mold surface. Ive learned alot from your help thank you. I still am having alittle trouble with the 'science' of it but this helps me with figuring out a good balance in what im doing. I know for sure the next mold I make will have a larger flange area than the last 2 molds I made.