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Affordable vacuum pump for epoxy?

Started by eriksen, November 13, 2018, 02:08:01 PM

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eriksen

How strong vacuum pump do I need in order to get rid of air bubbles in epoxy. I plan to start producing burl/epoxy spheres up to 100mm in diam. Are there any cheap ebay pumps I can use for that purpose?




ronwood

Welcome to the forum. Sorry I can not help you with your question.

ronwood
Sawing part time mostly urban logs -St. Louis/Warrenton, Mo.
LT40HG25 Woodmizer Sawmill
LX885 New Holland Skidsteer

FLPINERAT

People I know who do epoxy casting and that stuff use pressure pots.

They use a faster set epoxy and vacuum can create more bubbles as the mix sets.

Is there a specific reason you chose the vacuum route?

I use a Robinair (15310) VacuMaster Single Stage Vacuum Pump - Single-Stage, 3 CFM for stabilizing and here at 2' above sea level it pulls darn near to 30hg

**just saw your project**

Have you ever seen how much air is pulled out of a burl piece under vacuum?

https://www.facebook.com/RedHillsTurkeyCalls/videos/2506767929549001/

This is probably 10 mins into a pulldown, at the start there's a 3 inch froth you have to control with the valve!

Burls create way more air than this....and you'll be dealing with them as the mix sets

Now I don't cast, but seeing what my buddies create and knowing how they do it, I'd choose pressure. But I do know there's two camps on this :)

low_48

If you aren't going to run for a day at a time, get one from Harbor Freight. You can get a little oil mist from the pump, but I put a clear hose on the exhaust and run it to inside a can with paper towel to absorb anything that comes through.

Brad_bb

I built the V2 vacuum press pump shown here for a project I was working on a few years ago.
Do-It-Yourself Vacuum Veneer Press
Here is the kit I bought
Project: V2? Air-Powered Vacuum Press Kit ::On Sale!::
Here's a video of a guy building a different pump from joewoodworker, but it's very similar to the build for the V2 pump.
Making a Vacuum Pump System: Andrew Pitts ~ FurnitureMaker - YouTube

The pump works really well.  I don't see why you couldn't use it for a vacuum chamber like FLPinerat shows. In fact, I'd like to get a pot to do some Mallet heads.

One thing I don't understand about those vacuum chambers...does the resin set up in the chamber?  That would be a problem.  Must not, but how do you clean it out?  Is the resin used catalyzed or not?  So do you recover the unused resin for later use?  I saw one guy in a video using a resin called cactus juice.
Anything someone can design, I can sure figure out how to fix!
If I say it\\\\\\\'s going to take so long, multiply that by at least 3!

btulloh

Looks like the same one I made.  I used a Robinair HVAC pump I got used.  Works.  

I'm curious about this use for epoxy though.  Brad_bb asked me questions already.  

Standing by . . . . . . . . . . . . . . . . . .
HM126

FLPINERAT

Cactus juice resin is used for stabilizing. That's what I use.

It can be reused, I leave it in the chamber until I can't submerge what I'm stabilizing. Just add more.

Soap and water cleanup...before the activation!

It does have a catalyst mix but does not activate until around 180 deg.

After the vacuum, the resin is pulled into the wood upon equalization. Then the pieces are heated. I use an electric smoker.

But again, for casting...I'd use pressure.

TKehl

How cheap?  A vac pump can be made out of an old AC compressor.  There are also real cheap venturi type ones, but cost a lot of $ in compressed air to run.  

I haven't done wood yet, but do a lot of metallurgical samples with porous coatings in epoxy under vacuum.  The vacuum level will depend a lot on your epoxy.

For absolute fewest bubbles, best option is to pour while under vacuum, then put under pressure.  However, just pouring in air then pulling vacuum followed by releasing to atmosphere will pull out or shrink a lot of bubbles.

Curing under vacuum has not been good in my experience.
In the long run, you make your own luck – good, bad, or indifferent. Loretta Lynn

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