george 53 Posted November 3, 2009 Posted November 3, 2009 Guys, I'm wantin to try my hand at casting some resin, but not the little stuff, I wanna try to do larger stuff like MAYBE a customed out body. Harbor Freight has an air vacuum pump for R134A and R12 auto systems. Is this sufficient to pull the right amount of vacuum in a pressure pot? I can get both of them at a reasonable price, but I don't wanna waste my money if it won't work. Can anybody who does this help me out? Who knows MAYBE I can be the next Holthaus!
Guest Gramps-xrds Posted November 4, 2009 Posted November 4, 2009 George the 1st thing you need to do is find out how many inches of water or mercury it takes when casting resin. Then see what those pumps will pull. I doubt it'll take more than 5in. and 10 at most. Most shop vacs will pull 3 to 4 inches of water. I'm sure this totally confuses you
rattlehead71 Posted November 4, 2009 Posted November 4, 2009 I work for a Mopar dealer and back when R-12 was king, we would have to use a vacuum pump to clear the a/c system of water. The pump would pull up to 29" of vacuum which is high enough to boil the moisture out of the system. The a/c machine we use now is a recycle machine with a built in vac pump that still pulls 0up to 29'. My guess is that if the Harbor pump will pull 29 then that should be suffecient, but I don't know what resin vac formers pull down to.
envious8420 Posted November 4, 2009 Posted November 4, 2009 pumps for a/c work need to pull at least 20-30 inches of water, but the seem to take awhile to get there. i would think you would need to pull pretty quick because of the speed of resin. i thought resin was done under positive pressure??
E St. Kruiser50 Posted November 4, 2009 Posted November 4, 2009 George the 1st thing you need to do is find out how many inches of water or mercury it takes when casting resin. Then see what those pumps will pull. I doubt it'll take more than 5in. and 10 at most. Most shop vacs will pull 3 to 4 inches of water. I'm sure this totally confuses you INCHES OF MERCURY BILL 29 inches of mercury is an almost perfect vacuum. NOW YOU'RE MORE CONFUSED . I was in the vacuum forming industry for nearly 40 years. Besides the guys here that'll help you George, research will help a lot too. GOOGLE "resin casting pumps", and other related topics and you'll be surprised at all the cool info that'll come up. Because I was an engineer, and a research kinda guy ( I love doing research - Information = knowledge), doing this kinda stuff has always been fascinating and fun to me. Good luck on your search .
george 53 Posted November 4, 2009 Author Posted November 4, 2009 Oh HOW WELL you know me Bill! Yeah it's all greek to me so far, but I'm sure the box it comes in would have that kinda info. I've never done anything like this, I've casted small stuff like valve covers an mags but never anything larger than that. I'd like ta try it with larger stuff. The machine is only 11.00 bucks, the dam POT is like 60 Bucks! but I got a 20% off coupon, an I'm willing to try it. Jeff Ballard is a member of our club, but I don't know if he'd help the"Competition" Anyways, since I got so much time on my hands I thought I MIGHT give it a shot. Like I said, maybe someday you guys'll be talkin about MY flawless,bubble free,PERFECT resin castings! Hey, din't one of the guys once mention a website where they sell resin an give advice about casting?
jeffb Posted November 4, 2009 Posted November 4, 2009 george..shoot me an email..ill be able to save you a ton of time
george 53 Posted November 4, 2009 Author Posted November 4, 2009 Jeff My MAN! Thanks You better beleive I'll be doin that! Thanks Bro! If any of you guys have any more/other advice, PLEASE feel free to chime in! ALL of it will help! Thanks!
Modelmartin Posted November 4, 2009 Posted November 4, 2009 Vacuum Sucks! I have said it before and I will say it many times. I started out in 1980 with a vacuum pump and tank and produced a lot of ######. A few years later I discovered the pressure casting technique that others were using. It was a 180 degree turn in quality! It is easier, too! I will bet you already have a compressor somewhere so you don't need to spend more money on a vacumm pump. You will need a paint pressure pot which you can get anywhere. I pump it up to 40 psi for both the mold making and the casting. It works really well and it is easy. If you want more info from me just send a PM.
george 53 Posted November 4, 2009 Author Posted November 4, 2009 THANKS Andy, This is the kinda stuff I NEED ta know! You'll be gettin a PM soon! THANKS again!!!
Guest Gramps-xrds Posted November 4, 2009 Posted November 4, 2009 INCHES OF MERCURY BILL 29 inches of mercury is an almost perfect vacuum. NOW YOU'RE MORE CONFUSED . No Dave I'm not confused. I know 29 in of mercury in as close to perfect vacuum as you can get. I spent 29 yrs working with vacuum systems and pumps and a'm quite familiar with mercury manometers and how to use them. If you go back up and really read what I said, I made no mention of tryin to pull that much vacuum. I merely stated inches of water or mercury is how vacuum is measured. Having worked that 29 yrs in the chemical industry. I have always said "Before they give someone a degree in engineering they should have to work with a mechanic for 2 yrs for free to learn something"
RyanSilva Posted November 4, 2009 Posted November 4, 2009 Jeff and Andy have you covered with the details..but I'll say this... Don't go vacuum! it's much much more trouble. Using pressure is the way to go and much much much easier.
Eshaver Posted November 4, 2009 Posted November 4, 2009 O K , now that i'm more confused as ever , I will now go back to pouring resin into ONE PIECE MOLDS and hoping for the best ! Whew !!!!!!!!!!!!!!!!!!! Ed Shaver
george 53 Posted November 4, 2009 Author Posted November 4, 2009 Ed, that's all I know how to make! But I figgered it might be worth learning caz to me, it'd be EASIER for ME to learn than the picture posting thing! Like I said, I can do easy stuff, Valve covers,Rims, one peice mold stuff, but I'd LIKE to be able to MAKE stuff an cast it. I know if I ask the right questions, you guys'll know the right answers!
Porky Posted November 4, 2009 Posted November 4, 2009 Hey Hey, They are steerin ya in the right direction,,,vacuum your mold rubber and pressure cast your parts and you will be headed on the right path to those bubble free parts you are wanting. Eric Jones "Porky" P&P Resin Works
george 53 Posted November 4, 2009 Author Posted November 4, 2009 Thanks Eric, I figger the guys here would know better than ANYONE, so when your in a knowledgeable group like this one, who better to ask???
lonewolf01 Posted November 4, 2009 Posted November 4, 2009 hey george how about doing a wip this sounds interesting
george 53 Posted November 4, 2009 Author Posted November 4, 2009 Oh I'm SURE it would be Jere, BUT we DON'T wanna over tax my poor ol brain! IF i can get the casting thing down,The NEXT step is tryin to POST the pics!!! I'm hopein I can get THAT down before Clay comes home,so I can surprise his ol Jarhead a$$!!!!!
Guest promodmerc Posted November 4, 2009 Posted November 4, 2009 (edited) George, You can't figure out how to post pics but you're going to try csating resin? I'm just glad you are a states away from me incsase something goes BOOM Including your brain Edited November 4, 2009 by promodmerc
george 53 Posted November 4, 2009 Author Posted November 4, 2009 Welp Danner, they's ALOTTA left click,right click,IMGing stuff to do when postin, but I'm lucky to have a Club member who JUST happens ta OWN his own resin casting buisness,(Jeff Ballard)an he's offered to TRY an show my feeble minded self how it's done!. IF I could get someone to sit down with me to teach me how to post properly, I could PROBABLY get it, But Joy don't got much patience with her ol Dad, an she gets REAL frustrated when I DON'T get it down RIGHT NOW!!! Havein TWO wimmins on my case,is NOT what I call a fun expireince,Life in general can be hard enuff!!! BUT if ya do see a mushroom cloud in the direction of "The Mitt" Do me a favor an check on me!!!
Aaronw Posted November 4, 2009 Posted November 4, 2009 George, setting up the part right for the mold is more important than vacuum or pressure. If you do it right the air can escape and you get very few bubbles. The guys on this site were a great help for me figuring out what I was doing. I got a pressure pot and one of those cheap harbor freight vacuum things, but have not found the need for either, although admittedly I just don't use the pressure pot because that is just one more thing to do and I've had good results without it.
RyanSilva Posted November 4, 2009 Posted November 4, 2009 I always found it much easier to pressure cast my silicone molds rather than vacuum.
george 53 Posted November 4, 2009 Author Posted November 4, 2009 Aaron, COOL, That just might save me some bucks to use on somethin else. But HOW do YOU do it if ya don't use the stuff that usually used? May I PM you on how YOU do it? Both Jeff and Andy have offered to help, and I'm open to ALL suggestions!!! Like they say, The more ya know, The more ya know! Thanks!
Aaronw Posted November 4, 2009 Posted November 4, 2009 Sure you can PM me, but you are already getting advice from two of the guys that helped me. I haven't seen him on the site for awhile but there is a poster who goes by Monkeyclaw who was also quite helpful. Just think like an air bubble when you plan your molds.
BKIN10SECS Posted November 4, 2009 Posted November 4, 2009 I always found it much easier to pressure cast my silicone molds rather than vacuum. If I may, so are you saying rather then degas your silicone at 29"...you should place the silicone and turn on the pressure. I can see why this would be easier but could you go into further detail as to psi and time under pressure. And then, would you still pressure cast the resin, for how long and what psi. Thanks
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