Hi guys,
I’m working on a 2 piece RTM mold. I’m discovering a resin pump to provide the 4 psi to the resin feed is insanely expensive. Would I get good results if I just run an unpressured resin line in and allow my vacuum to pull the resin through the mold cavity, as if I were infusing?
It is a standard RTM mold, with full resin channel around the entire perimeter of the part, vac dead center.
pressure pot,insanely cheap.
Speaking as someone who has one of those insanely expensive resin pumps, you can’t beat them if you are doing any kind of production. Ours does things that are insanely cool (well, insanely cool if you are a tool geek:D). That being said, I’ve also done it the cheap way.
You can use a pressure pot as cheekybrad suggests. Just make sure you have enough working time. In mass, resin gels much, much quicker. Also, depending on the volume of the part vs the volume of the pot, you may need to open the pot to add additional resin. Make sure you have feed line with enough length to manipulate the lid if that’s the case. A good regulator on the air pressure is a must. Don’t go Harbor Freight on me.:eek:
You can also use head pressure to feed into the cavity if you are set up as a VARTM tool. Just raise the feed bucket above the tool. The higher you go the more pressure is exerted on the feed side. This has the advantage of an open feed bucket that you can add resin to as needed. You still need working time as the feed rate is slower.
The good news is we’re using UV cure vinyl ester, so working time isn’t an issue. Large mold will take almost 4 gallons of resin, eliminating the little pressure pots I’ve seen. Elevation of a 55 gallon drum to achieve 4 psi is 9 1/4’above the mold! Lol, we have an 8’ ceiling.
Has anyone ever pulled resin through one of these molds? I honestly can’t think of a reason it wouldn’t work.
I guess my previous post wasn’t clear enough. I wasn’t really suggesting using head pressure alone hence my comment about having a VARTM (vacuum assisted resin transfer molding) tool. In your case, vacuum would be the prime mover in the system. Using head pressure would assist in getting the resin in the cavity. So, to answer your question, yes, you can do it.
How are you going to UV cure inside an RTM mold cavity? RTM generally is considered to have relatively thick, heavy framed molds. Not something UV is going to penetrate.
LRTM, the b side is a mold of infused uniconform that is absolutely crystal clear.
I have used vacuum only to fill a LRTM mold that was approximately 48 inches in diameter with a 0.25" part thickness, fed from the outer edge towards the center and it filled just fine.
Okay, that makes sense.
I have also done larger (100+ sqft) RTMlight moulds with vacuum only, and although it can be done, it is a lot slower. You will also use less resin, and parts get thinner.