26 replies to this topic

[Aaronw]

I'm looking for a good fairly inexpensive vacuum pump, I undersatnd refrigerators are a good source for these pumps, rebuilts being fairly cheap.

I built a vaccuum chamber and have a blow by vaccuum thingy (metal box you hook an air compressor too) but it does not seem to have the needed suction to de-air the silicone so I'm looking at plan B. I live in the middle of nowhere (2 1/2 hours from Fresno) so I think online is going to be my best bet but if someone knows a good place in Fresno feel free to mention it.

Thanks

[CAL]

I'm looking for a good fairly inexpensive vacuum pump, I undersatnd refrigerators are a good source for these pumps, rebuilts being fairly cheap.

I built a vaccuum chamber and have a blow by vaccuum thingy (metal box you hook an air compressor too) but it does not seem to have the needed suction to de-air the silicone so I'm looking at plan B. I live in the middle of nowhere (2 1/2 hours from Fresno) so I think online is going to be my best bet but if someone knows a good place in Fresno feel free to mention it.

Thanks

You can build a vacuum pump from a refer compressor. Understand that it's a compressor and not a vacuum pump. You do have to do some modifications and build a few things to convert a refer compress.


you'll need to pull roughly 29 inches of mercury.

Evilbay is a pretty good source. Thomas pumps? IIRC. and medical equipment sales. $100-$200 range.

[Reliable Resin]

Google > Robinair


Setting up a proper functioning Resin Casting shop, will not come cheap

Then there's the learning curve .........

Good Luck

[Modelmartin]

Forget Vacuum. Vacuum sucks. Pressure casting is the best and much cheaper and easier way to do it. All you need is a paint pressure pot which can be found at any good hardware or industrial supply store and an air compressor. When you pour your silicon for molds and when you fill your molds with resin just put them in the pot and pressurise to 30-40 psi. Do not remove either until they have cured. This is by far the easiest and cheapest way to reliably cast resin. I have been using pressure casting for 20 years and can not recommend anything else. Fell free to e-mail me if you have more questions about the process.

[Aaronw]

Google > Robinair
Setting up a proper functioning Resin Casting shop, will not come cheap

Then there's the learning curve .........

Good Luck

Vacuum pump and chamber are my last additions (except perhaps the centrifugal thingy if the plans look easy enough and I figure out what its used for). I've been casting for a couple of years and slowly adding new gizmos to improve quality as I learn to use the ones I have. I agree with you there is a learning curve, I have some funky resin and silicone to remind me of that.

Forget Vacuum. Vacuum sucks. Pressure casting is the best and much cheaper and easier way to do it. All you need is a paint pressure pot which can be found at any good hardware or industrial supply store and an air compressor. When you pour your silicon for molds and when you fill your molds with resin just put them in the pot and pressurise to 30-40 psi. Do not remove either until they have cured. This is by far the easiest and cheapest way to reliably cast resin. I have been using pressure casting for 20 years and can not recommend anything else. Fell free to e-mail me if you have more questions about the process.

I have a pressure pot and I remember you mentioning this before. My problem is getting an uncured mold into the pot. I'm not quite sure how I'd manage that. It would also limit me to only one mold at a time.

[Reliable Resin]

Forget Vacuum. Vacuum sucks. Pressure casting is the best and much cheaper and easier way to do it. All you need is a paint pressure pot which can be found at any good hardware or industrial supply store and an air compressor. When you pour your silicon for molds and when you fill your molds with resin just put them in the pot and pressurise to 30-40 psi. Do not remove either until they have cured. This is by far the easiest and cheapest way to reliably cast resin. I have been using pressure casting for 20 years and can not recommend anything else. Fell free to e-mail me if you have more questions about the process.

Maybe it's me , & I didn't read what he was looking for however .........
Don't you Vacuum the Rubber prior to Pouring the Mold ?

We do !

If you do not VACUUM the Rubber, PRIOR to pouring the Mold , one would have serious problem casting w/ pressure

What do I know ......................

[Zoom Zoom]

Forget Vacuum. Vacuum sucks. Pressure casting is the best and much cheaper and easier way to do it. All you need is a paint pressure pot which can be found at any good hardware or industrial supply store and an air compressor. When you pour your silicon for molds and when you fill your molds with resin just put them in the pot and pressurise to 30-40 psi. Do not remove either until they have cured. This is by far the easiest and cheapest way to reliably cast resin. I have been using pressure casting for 20 years and can not recommend anything else. Fell free to e-mail me if you have more questions about the process.

I had not thought of doing the rubber molds under pressure as well as the parts, sounds plausible to me, and the Firebird III I have shows no signs of being cast under pressure in a mold that wasn't de-aired. But now you don't get to see the giant expanding marshmallow anymore

[Modelmartin]

What do I know ......................

No comment!

If pressurising is good for the resin which cures in minutes why wouldn't it do the same for the rubber which is still pourable after 3-4 hours? I may not know the exact reason why it works so well but I do know this; After I did it the first time I parked the vacuum pump permanently and have never used it again. That was in 1987! I would have converted to a vac-former but it was too bulky and my shop vac works just fine.

Aaron - you just need to get a bigger tank. I have a tall 15 gallon and I am doing several 1/12 scale bodies in it. I also have a 2, a 4, and a 10. The 4 is the same diameter as the 2 and twice as tall. I lay it down and now I can put any 1/24-5 body mold in it. If you look around you can find old ones that may need sandblasting and a new seal. Check out Ebay, Craig's List, used industrial supplies, painting contractors, etc.

Bob - The marshmallow sucks too! What a mess that USED to be!

Setting up a properly functioning resin casting shop is cheap and simple. All you need is a compressor, pressure tank, a pile of legos and sheet plastic to make pour boxes, some clay, a cup, and a stir stick! The toughest part is the one between the ears - figuring out how the resin will flow in and air out.

[CAL]

Forget Vacuum. Vacuum sucks. Pressure casting is the best and much cheaper and easier way to do it. All you need is a paint pressure pot which can be found at any good hardware or industrial supply store and an air compressor. When you pour your silicon for molds and when you fill your molds with resin just put them in the pot and pressurise to 30-40 psi. Do not remove either until they have cured. This is by far the easiest and cheapest way to reliably cast resin. I have been using pressure casting for 20 years and can not recommend anything else. Fell free to e-mail me if you have more questions about the process.

Vacuum is for the rubber not for the resin. I vacuum my rubber, too.

[Modelmartin]

Vacuum is for the rubber not for the resin. I vacuum my rubber, too.

You guys can suck on your RTV all you want.

Please re-read my posts. Perhaps my language was unclear. Pressure is for everything - rubber and resin!!!! Vacuum for RTV moldmaking is a waste of time, equipment, and effort. The results from pressurizing the mold while it is curing are far superior than vacuuming it. I do not understand why one would go out and buy an extra piece of equipment that does an inferior job. I have made thousands of molds since I starting doing resin casting in 1980. I hesitate to try to estimate the number of castings since then - certainly in the many tens of thousands.

Edited by Modelmartin, 01 December 2007 - 11:23 AM.

[Reliable Resin]

Hey Andy , lighten up there Big Guy

We're just trying to help out a fellow Modeler get the Rubber / Resin process correct
& we're simply sharing our own methods / experiences & tips

Just an FYI,
I use a 10 / 1 Industrial Rubber which REQUIRES vacuuming for at least 20 / 30 mintues,
at 20 > 30 CFM ( ? ) Inches of Mercury ( on the gauge ) depending on the amount ,
I think it's recommended / suggested 20 / 30 mins per pound of Rubber

The Only Rubber ( that I'm aware of ) that doesn't require vacuuming is the Micro Mart 1/1 mix

As far as the "pot Life" > pour time , I'm not aware of any that has
a pot life / pour time over 1/2 hr > 1 hr

The Mirco Mart 1/1 has ( I think ) 20 minute , before it starts setting up

The Industrial RTV 10/1 Rubber I use , depending on the
Temps & Humidity ( at best ) has a 1 hour Pot Life / Pour Time

I'm not sure what brand / type rubber that you use , I'm interested in knowing more about it

As far as your process , or your instructions > your making it sound as if Making Molds & Pouring Resin is as easy as making a batch of Cup Cakes .....

If it was that easy , wouldn't there be more individuals doing it ?


Just my thoughts & input ......... we all have our own method ,
what ever method works for you GOD Bless ......... we all have our own Technique'

Lets do the math on this /

Cost Effectiness :

A decent compessor ...............................................................................$100
Misc Fixing / Gauages & Air Lines..............................................................$25 / $30
2.5 gal Paint Pot ................................................................................
....$50>$100
10 lbs of Rubber ................................................................................
.. $100 ( or more w/ S/H )
1 gal Resin kit ................................................................................
.......$130 > $150
( again Gas or S/H @ $1 > $2 per lb ....etc....)
Mold release , Pattern release ( defferent for either Resin or the Rubber ).... $20 Plus (?)
Clay , Rubber Gloves > ...........................................................................$20 ( ? )
Mold Box / Tape / etc.............................................................................
.$10
Cups / Plasic spoons / Popsicel stick ..........................................................$10 ( ? )

( low end ) $400 > $500 ........Plus * give or take *


*None of the above calculates : Time / the creation of Master / increased Electric Bill / Learning Curve or the Vaccum Pump !


Making an absloute mess in your Shop :

PRICELESS !

[Modelmartin]

For the humour-impaired, the first line in my last post was meant to be tongue in cheek with a slight edge to it. Apparently Don was offended. I can't help that. I have an attitude and people who know me know that.

One can spew all the little technical data you want in an attempt to sound like a big shot but resin casting is not very hard as far as equipment and materials. As I already stated the learning curve applies to laying out molds and figuring out resin and air flow. Most people don't do it professionally because they have real jobs which 98% of the time pay better!! I do it because I like working for myself and enjoy the process of creating a complete product from research to patternmaking, molding, instruction sheets, contracting out for P/E, etc. etc. I am willing to make less money for this independence. There have been dozens of people who have attempted resin casting over the years and I guarantee that some who are casting now will quit within the next 1 year, 5 years, etc. It is inevitable and will happen for many reasons.

Now before anyone gets snippy with me for anything I have written in this thread I say to go back and read it all again and try to comprehend what I have said. Try really hard!! I know I may have used some big words but that is just me. I actually use bigger words in private!

Edited by Modelmartin, 01 December 2007 - 01:26 PM.

[Reliable Resin]

Hey Buddy ,, what's w/ the neg. attitude ?

Just tying to help others out here

Happy Holidays

[Modelmartin]

Hey Buddy ,, what's w/ the neg. attitude ?

Just tying to help others out here

Happy Holidays

Help? Ha!

I have vastly more experience resin casting and was presenting ideas for others to use which simplify the process. I was actually being helpful for those willing to listen and try new ideas. All you offered were platitudes about how tough it is and how expensive it is. Give me a break!

I am NOT your buddy and am NOT "Big Guy". Spare me your overfamiliarity and attempted condesencion. You know what the score is between us.

[CAL]

I guess Modelmartin is the pro then.... who is this guy?


BTW 20-30 CFM on a vacuum pump is roughly 22-28 -In. Hg on most pumps.

[Reliable Resin]

Help? Ha!

I have vastly more experience resin casting and was presenting ideas for others to use which simplify the process. I was actually being helpful for those willing to listen and try new ideas. All you offered were platitudes about how tough it is and how expensive it is. Give me a break!

I am NOT your buddy and am NOT "Big Guy". Spare me your overfamiliarity and attempted condesencion. You know what the score is between us.

Well, "Andy" ... if You Read Back to the begining org Post ...

All this guy wanted to know was "simply" where to get a Vaccum pump

I / we don't recall him asking :

#1 > How do I make molds w/o pump pour rubber / cast resin ?

#2 > Did he specificaly ask for your advise ?

#3 > I don't care what score ( you seem to be keeping ) , that seems to have made you sore

I'm just a Resin Caster / Model Builder .............. not a GOD

........... But I did sleep at a Holiday Inn Express last night

Happy Holidays
Don

[Modelmartin]

Well, "Andy" ... if You Read Back to the begining org Post ...

All this guy wanted to know was "simply" where to get a Vaccum pump

I / we don't recall him asking :

#1 > How do I make molds w/o pump pour rubber / cast resin ?

#2 > Did he specificaly ask for your advise ?

Did he specifically ask for anyone's advice?

#3 > I don't care what score ( you seem to be keeping ) , that seems to have made you sore

Score is a figurative term here. It means the situation, the state of our relationship. Get it?

I'm just a Resin Caster / Model Builder .............. not a GOD

........... But I did sleep at a Holiday Inn Express last night

Happy Holidays

Don

Wow! I am truly sorry you got the wrong impression. I am not sore. I actually enjoy these exchanges with you and look forward to them. It's good sport. A little unfair, but still sport. You too are a god! You know it. We know it. The world knows it. All hail Don!!! Huzzah! Premier model car builder to the stars! Intelligent designer of the model car universe! Ruler of resin! Patriarch of plastic! Sultan of Styrene! Lord of lacquer! Envoy of enamel! Primate of putty! Master of models! I bow before you!

[Modelmartin]

I apologize to everyone else on this forum for the preceding unpleasantness. It is completely undignified and truly annoying and has no place in polite society. Please forgive me.

Aaron - I was actually trying to offer useful advice. I am sorry the thread went bad. I know that is not what you wanted when you posted your question.

Edited by Modelmartin, 01 December 2007 - 07:39 PM.

[Darin Bastedo]

I apologize to everyone else on this forum for the preceding unpleasantness. It is completely undignified and truly annoying and has no place in polite society. Please forgive me.

Aaron - I was trying to offer useful advice to you.

Andy,

Both you and Don have given some good advice, I feel that you may have taken his differnce of opinion just a wee bit too personally. I Realise that you and Don have had problems in the past, but he simply does things differently than you do. I have seen & bought products from both of you, and everything I've bought was top notch. That tells me that both of the methods you guys use works and works well. I've studied Fluid dynamics, and when it comes to removing air from a liquid (uncured RTV in this instance) you have two choices Squeeze it out (pressure) or suck it out (Vacuum).

The only difference between the two is that there is a limit to how much air you can remove from a chamber (all of it) but you can pump as much air in as the strength of the chamber and the power of your pump will allow. Niether matters as either situation will remove the air from the rubber. Regardless, is this issue really important enough for you two to get into a snit over.

the way I see it you guys have two other choices. You can man-up and bury the hatchet (preferably not in each others heads) or you can continue to be two grown men argueing over whose toy cars are best. It's your choice but I know I'm getting tired of the drama.

[CAL]

Just an observation from an outsider who doesn't know either one of you from Adam or what ever the past problems were, and not to take anyone’s side, but the display that Modelmartin put on was a real turn off from anything he had to say, anything he had to offer, and thing he is doing or done, or any of his products. Trust me, I am not going to police any boards but he might want to think about it the next time he puts on a show. Someone who doesn't know him or what is going on might get the wrong impression of him. If it wasn't for Darin's explanation I would have wrote him and his product off for being a complete egotistical A.H., which is too bad because Modelmartin has something that I would like to get; however, I was left with such a bad taste in my mouth I am not sure I would ever give him a dime. And it has absolutely nothing to do with different opinions, just the way it was presented and came across. Completely unprofessional, sometimes it doesn't mater how good a product is if the one selling it is a turd.

I will at least take his apology under advisement.