PRESSURE POT

[knowltoh]

I am going to experiment with casting some blanks. I have the mold, Silmar 41 resin, and dyes. I have read cautions about using a pressure pot. I get the impression that a pressure pot is not needed for a resin blanks, but how about "worthless wood" casting? I really like experimenting and probably won't use pressure unless necessary for decent results. Seems 25-30psi is enough to do the job. Just how much trouble can I get into with the pressure pot?

Thanks for the help,

 

[PenMan1]

Herb:
You are correct that with PR, pressure is generally not needed. An ultra sonic cleaner with heat is a better option for me. I use the USC to thin resin and after vibrating the filled, curing molds, I almost never have bubbles.

On "Worthless Wood" ( tm TurnTex wood) type blanks. I have a very difficult time getting PR to adhere to the wood, even at 80 - 90 psi. IMHO, Alumalite is the better solution here.

One bit of advice here. The cheap, Chinese made paint pots WILL NOT constantly hold the pressure needed to adhere Alumalite to wood. It was just a plain miracle that I was not killed when my "altered paint pot" exploded. Be careful and get a pot rated for at least 150 psi.

 

[lorbay]

pressure poy

I am going to experiment with casting some blanks. I have the mold, Silmar 41 resin, and dyes. I have read cautions about using a pressure pot. I get the impression that a pressure pot is not needed for a resin blanks, but how about "worthless wood" casting? I really like experimenting and probably won't use pressure unless necessary for decent results. Seems 25-30psi is enough to do the job. Just how much trouble can I get into with the pressure pot?

Thanks for the help,

You can get into a whole bunch of trouble if you use to much pressure just ask Curtis aka (MesquiteMan ) and you will need higher pressure for worthless wood casting.

Lin.

 

[jd99]

Herb:
One bit of advice here. The cheap, Chinese made paint pots WILL NOT constantly hold the pressure needed to adhere Alumalite to wood. It was just a plain miracle that I was not killed when my "altered paint pot" exploded. Be careful and get a pot rated for at least 150 psi.

Where do you get a pot rated to 150psi? all the ones I've seen are either 60psi like the HF model, or 80 psi max.

Thanks
Danny

 

[JD Combs Sr]

Will the opposite, a vacuum chamber not work. Seems to me that if you pull a vacuum on a casting to remove bubbles it would also work to pull the casting material into the "worthless wood" once you release the vacuum. Then you are not working with dangerous pressures. I have not done any casting but I have the materials and am planning on casting some soon and I am going to use a vacuum chamber. Just looking around for a good vacuum pump. I have the chamber, its a big old canning type pressure cooker. It will hold a vacuum as easily as it holds pressure.

The only issue I can thank of that might occur with vacuum is the casting resin might boil at low vacuum then it would foam out all over everything.

 

[Padre]

Why in the world would you need to cast at 150 psi? 40 psi pretty much covers it.

 

[MesquiteMan]

I cast everything I make at 75 psi with great results. My pots are Binks pots that are ASME rated working pressure of 80psi. Working pressure, according to the techs at Binks, means the pressure you can use day in and day out, not max pressure. Binks does not state a max pressure but the tech told me there is at least a 3x safety factor built into their pots.

As for Harbor Freight...do you really want to trust the Chinese, who brought us bad drywall, bad children's toy paint, and bad dog food, to name others, to rate their pressure pots at 80 psi?! I would not trust a HF pot over about 35 psi but then again, I would not trust a HF pot if you gave it to me free as a flower pot! BTW, the 2 HF pots I own are now just trash cans in my shop!

 

[PenMan1]

Curtis:
I have been doing a good bit of research and my findings align exactly with what your reps said. To have a WORKING load of 80 psi, the max psi would need to be TWICE working load. I.e. A pot used for loads of 75 - 80 would need a max pressure rating of 150 - 160.

The HF pot has a max rating of 80 psi, according to my sources that would make a safe working rate of less than 40 psi. My HF pot turned into shrapnel at about that pressure.

 

[PenMan1]

Herb:
One bit of advice here. The cheap, Chinese made paint pots WILL NOT constantly hold the pressure needed to adhere Alumalite to wood. It was just a plain miracle that I was not killed when my "altered paint pot" exploded. Be careful and get a pot rated for at least 150 psi.

Where do you get a pot rated to 150psi? all the ones I've seen are either 60psi like the HF model, or 80 psi max.

Thanks
Danny

Binks and Devillbis both make pots with ASME WORKING pressures of 80 PSI. That means their MAX Pressure ratings are at least 150 PSI.


Think of tire ratings here. A tire that has a max pressure rating of 80 usually has a run pressure of about 40 psi. You can put as much as 80 Psi to seal the tire to the rim. If you put said tire under a load with 80 psi, it will quickly explode.