# Pressure Pot Set Up



## BRobbins629 (Jun 28, 2006)

Can someone please post some photos or description of how they plumbed the HF pressure pot.  Do you remove the tube? Do you cap off the air outtake?  Will a bike pump work to fill it up?

Thanks


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## its_virgil (Jun 28, 2006)

Do not use the tube. Plug that hole. Use the other hole for inlet and guage. Can't help with the bicycle pump..haven't tried one. Maybe a pump (elec) for airing auto tires. Here are some pictures of mine. I know one guy who has an air tank that is a little larger than the paint pot. He stops by the gas station and air it to 80 or 90 psi and hooks it to the pot and the air equalizes at 40 psi or so...25 psi is enougn and some even cast at 20 psi. I cast at 40 psi but will be trying less pressure after last nites chat.
Do a good turn daily!
Don





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> _Originally posted by BRobbins629_
> <br />Can someone please post some photos or description of how they plumbed the HF pressure pot.  Do you remove the tube? Do you cap of the air outtake?  Will a bike pump work to fill it up?
> 
> Thanks



edited to remove duplicate pictures


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## BRobbins629 (Jun 28, 2006)

Thanks - I'm on my way to Home Depot tomorrow!


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## its_virgil (Jun 28, 2006)

If you have a Harbor Freight they have been $39.99 on the website.
Do a good turn daily!
Don


> _Originally posted by BRobbins629_
> <br />Thanks - I'm on my way to Home Depot tomorrow!


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## Randy_ (Jun 29, 2006)

I air up my bicycle tires to 50 PSI all of the time.  Can't see any reason why a good bicycle pump wouldn't work??


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## BRobbins629 (Jun 29, 2006)

One more thought after looking at the picture. I don't see the pressure relief valve.  Anytime you have a pressure vessel, it's a good idea to put that in.  Just want you to be aafe!


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## Mudder (Jun 29, 2006)

> _Originally posted by Randy__
> <br />I air up my bicycle tires to 50 PSI all of the time.  Can't see any reason why a good bicycle pump wouldn't work??



Itâ€™s quite probable, but you must remember that the volume of air to be compressed in that pot is much much more than the average bicycle tire so you better be ready to pump like crazy for quite some time. Of course you might find a way to add it to the exercise routine to decrease the size of the midriff (if you know what I mean) [][] Think deep knee bends or situps [}]


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## its_virgil (Jun 29, 2006)

I agree and the one that came with the pressure pot is now installed. I was so anxious to get this thing configured and to try it out that I forgot to add it in. But the relief valve was put in soon after the pictures were made. Safe casting.
Do a good turn daily!
Don


> _Originally posted by BRobbins629_
> <br />One more thought after looking at the picture. I don't see the pressure relief valve.  Anytime you have a pressure vessel, it's a good idea to put that in.  Just want you to be aafe!


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## bonefish (Jun 29, 2006)

I have never seen this before. What type of casting do you use the pressure pot for? Do you use pressure to stabilize wood, instead of vacuum?

bonefish


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## Jerryconn (Jun 30, 2006)

bonefish
They were talking about this on the chat Tuesday night,  Although I haven't done any PR casting yet I am wanting to get into it.  They were explaining that using pressure when casting PR especially with snakeskin blanks or I guess for any PR, the pressure keeps bubbles from forming in the blank as they are curing.  I thiink that is the jest of it but if I am wrong someone please correct me.


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## hombre4 (Jun 30, 2006)

Am I correct in thinking this is nothing more than a pressure cooker used for canning? Add a valve to pressurize and that's it.


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## its_virgil (Jun 30, 2006)

It looks my grandmother's pressure canner also, but it is actually a pot used by painters, at least it was  until Mr. Wagner invented the airless sprayer and the painters swithced. Safe casting.
Do a good turn daily!
Don


> _Originally posted by hombre4_
> <br />Am I correct in thinking this is nothing more than a pressure cooker used for canning? Add a valve to pressurize and that's it.


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## its_virgil (Jun 30, 2006)

This is basically correct. Actually the bubbles that are already there are crushed or squeezed by the pressure, and they become so small that they can't be seen. It has really improved the quality (clarity) of my own personal snake blanks. The colored castings I do don't have voids any more either.
Do a good turn daily!
Don


> _Originally posted by Jerryconn_
> <br />bonefish
> They were talking about this on the chat Tuesday night,  Although I haven't done any PR casting yet I am wanting to get into it.  They were explaining that using pressure when casting PR especially with snakeskin blanks or I guess for any PR, the pressure keeps bubbles from forming in the blank as they are curing.  I thiink that is the jest of it but if I am wrong someone please correct me.


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## Randy_ (Jul 1, 2006)

> _Originally posted by hombre4_
> <br />Am I correct in thinking this is nothing more than a pressure cooker used for canning? Add a valve to pressurize and that's it.



Archie:  Answer is yes and no and probably more no than yes.  I don't know exactly how canning pressure cookers work or what pressures they are designed to operate at; but there was a question not too long ago about using a standard home kitchen type pressure cooker for doing PR casting and the answer is definitely not!!!  Pressure cookers(and probably the canning ones, too) are designed to operate at 10-15 PSI and no more.  The paint pots are designed to work around 60 PSI(IIRC) and I think most guys operate at around 40 PSI or a little less.  There is a good chance that using a pressure cooker would be unsafe and I would advise the you thoroughly research the issue if you are thinking about going in that direction.


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## Rifleman1776 (Jul 1, 2006)

I recall the earlier discussions about pressure cookers but have to wonder if the conclusion(s) reached are based on fact or speculation. Pressure cookers often are made of 1/4" to 3/8" thick aluminum and have rubber seals for the lid. Considering that many use glass pickle jars for vacuum stabilizing, I wonder why the fear of pressure cookers. Seems to me they would be plenty strong enough for stable work. I know their pressure limits are set by a safety blow-out valve but that is for home use and I'll bet the built-in safety factor is, at least 5 or more.


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## its_virgil (Jul 1, 2006)

I would NOT use a home pressure cooker or canner for pressure casting PR. I've seen two that were "rounded" from the pressure and was really suprprised that they did not "blow". They were being used at 40psi and pressure cookers (not canners) usually work at 15psi or less..the safety valve is either set higher or "DID NOT WORK". Why, there was even some who had a lively discussion about using these pressure paint pots. Search for the thread...
do a good turn daily!
Don


> _Originally posted by Rifleman1776_
> <br />I recall the earlier discussions about pressure cookers but have to wonder if the conclusion(s) reached are based on fact or speculation. Pressure cookers often are made of 1/4" to 3/8" thick aluminum and have rubber seals for the lid. Considering that many use glass pickle jars for vacuum stabilizing, I wonder why the fear of pressure cookers. Seems to me they would be plenty strong enough for stable work. I know their pressure limits are set by a safety blow-out valve but that is for home use and I'll bet the built-in safety factor is, at least 5 or more.


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## BRobbins629 (Jul 1, 2006)

There is a big difference between operating a glass vacuum chamber where it will implode if it breaks and a pressure vessel which could explode.  I think the Harbor Freight unit is more robust than the pressure cookers, but the most important feature with either is a releif valve.  The one that comes with the HF unit also acts as a valve to reduce the pressure when you are ready to open it.  If you do use a pressure cooker, be sure to include a releif valve that will open below the maximun pressure rating of the pot and you should be okay.


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## its_virgil (Jul 1, 2006)

DO NOT USE A PRESSURE COOKER
DO NOT USE A PRESSURE COOKER
DO NOT USE A PRESSURE COOKER

OH YEA, ONE MORE THING: DO NOT USE A PRESSURE COOKER!!!

Do a good turn daily!
Don


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## melogic (Jul 1, 2006)

Speaking of which.... does anyone have a good setup for stabilizing blanks using a glass pickle jar and whatever else goes with it? And also what to use to stabilize the wood? I would be interested. []


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## its_virgil (Jul 1, 2006)

seems that quite a few are having good results with plexiglass dissolved in acetone. Maybe some of those guys will fill us in, so to speak.

do a good turn daily!
Don
[guote]_Originally posted by melogic_
<br />Speaking of which.... does anyone have a good setup for stabilizing blanks using a glass pickle jar and whatever else goes with it? And also what to use to stabilize the wood? I would be interested. []
[/quote]


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## Rifleman1776 (Jul 1, 2006)

Again, my post reference VACUUM for stable work.
And, I asked (asking again) are any of the conclusion reached based on observed fact or just speculation?


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## its_virgil (Jul 1, 2006)

Maybe a new thread needs to be started to get the attention of those who are stabilizing. They may not be reading this casting thread. I'm not interested in stabilizing...I think $1 per blank is a fair price to pay the professionals to do mine...so I'll not be starting the thread. 
Do a good turn daily!
Don


> _Originally posted by Rifleman1776_
> <br />Again, my post reference VACUUM for stable work.
> And, I asked (asking again) are any of the conclusion reached based on observed fact or just speculation?


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## joeatact (Jul 1, 2006)

Speaking of Pickle Jars! This is what I use to stablize blanks:

http://www.trade80.com/JCP/Pen_Images/Shop/vaccumpump.jpg

And here is some info

http://www.trade80.com/JCP/projects/project_1.htm


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## Blind_Squirrel (Jul 1, 2006)

Has anyone tried to cast PR in a vacuum?  In theory wouldn't that pull all of the air bubbles out of the PR?


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## its_virgil (Jul 1, 2006)

I'm sure some have tried vacuum. Maybe they will report their results. I wanted to get rid of the bubbles that seem to cling to the embedded snake skins. Draw our the air bubbles or squeeze them, didn't matter to me. I had no vacuum pump but I did have a compressor, so I squeezed those suckers too small to see....and I do think the PR turns better than it did before pressure casting. Can't comment on vacuum castng.
Do a good turn daily!
Don


> _Originally posted by Blind_Squirrel_
> <br />Has anyone tried to cast PR in a vacuum?  In theory wouldn't that pull all of the air bubbles out of the PR?


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## cozee (Jul 2, 2006)

Vacuum or pressure, end results in each process have a few related important factors which one should consider. First, the consistentcy of a resin would allow it to yeild more favorable results using the pressure process since it is easier to compress the air molecules as opposed to attempting to pull them out with vaccum. As stated eariler, with a pressurized process, air is not removed, simply compressed, or crushed to the point of being invisable. It is still there, just no longer a problem for turning as it no longer forms a viable void.

With vacuum process, the air is withdrawn as long as the casting/stabilizing media has a consistentcy which is compatible. Resins are thick enough to hinder the extraction and may even casuse problems by trapping air in the hardening resin before it can reach the surface. When stablizing, most do not use a resin or epoxy but instead a urethane and urethanes have a less dense consitentcy which yields itself to easy extraction of trapped air, especially since they do not set-up and cure, or as easily with air. Epoxies and resins set due to a chemical reaction which usually does not require air/oxygen to catalize.

With either process, the consistentcy of the media used will determine the amount of pressure or vacuum needed factored in with the set-up time. Heavier consitentcy coupled with short set-up/cure times will require more pressure/vacuum to extract/compress the trapped air.


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## Daniel (Jul 2, 2006)

Frank,
 there is actually a big difference in the forces of pressure and vacume. I havn't done any studies on it, but from what I know about how glass withstands pressure a glass jar under vacume and a metal pot under pressure are not really comparable. just a short comment on this is that glass under vacume actually gets stronger to a point. the metal pot would start to bulge under pressure right from the get go basically loosing entegrity with each pound of added pressure.
I remember seeing something about deep sea exploration years ago. they used a glass bubble to reach depths that steel or Iron unmaned machines could not go. the shape of the bubble as well as being made of glass actually made it able to withstand greater pressure the deeper it went. this sumbmersable worked so well they where able to send men where machines where not able to go.


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## Daniel (Jul 2, 2006)

> _Originally posted by Rifleman1776_
> <br />Again, my post reference VACUUM for stable work.
> And, I asked (asking again) are any of the conclusion reached based on observed fact or just speculation?



Sorry, I missed a turn in your post as well.
I do recall a conversation in the past that the presure cooker is designed for pressure and that the seals are not designed to hold against a vacume. I don't recall for sure if anyone actually put a vacume to a pot to make sure but it seems they did and the O ring or seal just sucked into the pot. this was followed by descussions on how to modify the pressure cooker to withstand the vacume, and walla the pickle jar idea was born.


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## Jerryconn (Jul 3, 2006)

This may a little long so please bear with me:
It's important to keep in mind that pressure and vacuum have to seperate measurments.  Pressure is measured in pounds per square inch (PSI) Vacuum is measured in inches of Mercury (inHg). The two are really not related.  But below is a bit of a comparison. Everything is based on Atmospheric pressure.
1 atmosphere is = to 14.7 PSI and is also = to 29.92 inHg <b>AT Sea level</b>.
When you pull a vacuum you are taking away pressure (so to speak) for example the vacuum pump from Harbor Freight that eveyone uses to pull a vacuum for stabilizing is capable of 28.3 in Hg at sea level. So what you are left with, again at <b>"sea level"</b> is 1.62 inHg.  If you tried to convert this to pressure you would be left with .8 PSI in the inside of the container, <b>But</b> you have 13.9 PSI trying to get back in the vessel. The important thing to remember is the when you are working with a vacuum you are NEVER working with more than 15psi. So vessels (pickle jars) that are designed to have a vacuum in them are set up to deal with this kind of pressure (or vacuum). But when you are working with pressure the sky is the limit.  
Hope this helps and doesn't really confuse anyone too bad.[]


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## elody21 (Jul 24, 2006)

UPDATE!!!!!!!!!!  I called Harbor freight today to see how long my pressure pot would take to come in.  They said it had beed shipped already!!!!!!! on the 18th. from California. Well I'll believe it when I see it but it is supposed to be here soon!?
I'll keep you updated. Alice


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## JimGo (Jul 24, 2006)

Good luck Alice!  It will take another 6 weeks using their shipping methods!!!! []


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## elody21 (Jul 25, 2006)

Guess what I got in the mail today!!!!!!!?????????? Yes my pressure pot! So now I need to go back through everything and find out just what and how to use it. For those who have had it on back order I suppose you will be getting yours too. I suppose I just ordered mine as they got more in. Alice


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## Jeff-in-Indiana (Jul 26, 2006)

I, too, received my HF pressure pot on Tuesday.  I went home excited about crushing some air bubbles, that is, until my neighbor who is a college professor with a PhD in Physics ... He started out by saying that the pressure pot would not work to eliminate the bubbles, or even crush them so small ... I know that all the folks here cannot be wrong, so I ignored him. Again, until he pointed out that the bubbles which DO exist, however small they might be, will consist of super-compressed air, and might continue to exert pressure from within the microscopic bubble. My feeling is that the polyresin is so much stronger than a little air pressure that I just do not think it is worth worrying about.

Shall I tell him, " ... take your PhD. and get lost, and stop spoiling my fun with all of your RULES .. "    []  []

Jeff in Indiana


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## JimGo (Jul 26, 2006)

Actually Jeff, your neightbor's arguments are the same as I've been presenting all along.  It seems to me that a vacuum would be the better way to go (as far as removing bubbles is concerned), but vacuum casting poses its own problems from what I understand.

All that being said, it's tough to argue with the results Don Ward and others have had!  The big thing to remember is that even the bigger bubbles in standard castings are only 1/64" or smaller.  If we can further reduce their size, and take other steps to reduce their formation in the first place, then the couple of microscopic bubbles, even under the relatively high pressure that may exist once cast, are not likely to create enough pressure to crack the pen.  This is especially true when you consider the relative strength of the material (as you pointed out).  You'll also note that many people have reduced the overall pressure used - while this may lead to larger bubbles, it also means less pressure in each bubble.


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## elody21 (Jul 26, 2006)

Good for you Jeff!!! There is always someone that has to try to "burst one's bubble"  Ha! Ha! It will be a while before I can get around to playing with mine. Let us know if you make anything! Alice


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## melogic (Jul 26, 2006)

I got mine yesterday in the mail also![][]
I'm leaving for Myrtle Beach in the morning, so it will be late next week before I get to mess with it. [^][!]


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## BRobbins629 (Jul 26, 2006)

True only if the plastic was a barrier to air.  If the professor looked at the gas permeation rate of polyester and styrene, he would soon figure out that in a relatively short time, the gas would difuse through the plastic and the pressure inside the bubble would be atmospheric. While I can't prove it, I believe that the pressure pot not only makes the bubbles smaller, but also helps them diffuse through the plastic during the curing process (if we only had a see through presure pot!)[[].  I do know that before I used pressure pot I had bubbles and now I don't.  Thats all the physics I need. quote]_Originally posted by dishripjlt_
<br />I, too, received my HF pressure pot on Tuesday.  I went home excited about crushing some air bubbles, that is, until my neighbor who is a college professor with a PhD in Physics ... He started out by saying that the pressure pot would not work to eliminate the bubbles, or even crush them so small ... I know that all the folks here cannot be wrong, so I ignored him. Again, until he pointed out that the bubbles which DO exist, however small they might be, will consist of super-compressed air, and might continue to exert pressure from within the microscopic bubble. My feeling is that the polyresin is so much stronger than a little air pressure that I just do not think it is worth worrying about.

Shall I tell him, " ... take your PhD. and get lost, and stop spoiling my fun with all of your RULES .. "    []  []

Jeff in Indiana
[/quote]


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## Ron Mc (Jul 26, 2006)

The pressure pot blanks look so much better it's amazing! I have some of Don's snake blanks that were done before his discovery of the pressure pot method and I have recently turned a blank that was blessed with the pressure pot. It's like night and day! Absolutely NO bubbles of any kind anywhere on the skin or in the blank at all.
I'm not saying that someone with a PHD is wrong but I am saying if you try Don's method you will be overwhelmed with the results![]


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## rgundersen (Jul 26, 2006)

A Ph D means your neighbor has lots of knowledge, but on this one results of what people are doing seem to pseak for themselves.  

Lots of knowledge does not mean he knows all the variables in the problem or that everything he is expecting holds true.  Heck for a long time (and still as far as I know) according to the rules of aerodynamics bublebees can't fly yet there they go doing it anyway.

Experimentation ends up doing many things that in theory are impossible.


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## its_virgil (Jul 26, 2006)

Thanks Ron...I'm glad you like my snake blanks. Ron has the benefit, as he mentioned, of seeing pre and post pressure pot casting. And whether the bubbles are pushed out of the resin, crushed so small they are unseen, or just somehow magically vanish, it doesn't matter to me 'cause my castings have no more bubbles clinging to the skin and that makes me []


I have three pens that were from the first pressure casting...the little crushed bubbles are crushed with 50psi and none of them have caused the blank to explode[)] or even crack.

This past weekend I used a vacuum pump to degass the resin and I pulled 28 inHG and the resin bubbled for about 12-15 minutes. I use very little catalyst, so I was not concerned with the PR gelling or seting up....my castings take over an hour to jell. After degassing I slowly poured the resin over the skinned tubes and cast at 30psi. Here is the resulting casting. I will turn one of these later in the week and report on how this new process (for me at least) compares to the pre-vacuum pressure only casting.
Happy casting and ...
Do a good turn daily!
Don




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> _Originally posted by Ron Mc_
> <br />The pressure pot blanks look so much better it's amazing! I have some of Don's snake blanks that were done before his discovery of the pressure pot method and I have recently turned a blank that was blessed with the pressure pot. It's like night and day! Absolutely NO bubbles of any kind anywhere on the skin or in the blank at all.
> I'm not saying that someone with a PHD is wrong but I am saying if you try Don's method you will be overwhelmed with the results![]


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## johncrane (Jul 26, 2006)

they look real good Don the only bubbles l can see are on the edge of the mold. maybe there not bubbles


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## Jeff-in-Indiana (Jul 27, 2006)

Many great responses, and all seem to agree with me ... other people are doing the pressure casting and it works so well, AND they have not lost an eye ... thanks to everyone ...


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## elody21 (Jul 27, 2006)

This thread has been fun! Listening to all the reasons why this should not work. As with most, we do not really care why is works, just that it does. When my older son comes home for a visit I am going to bring up the subject at the dinner table. It will be fun to listen to the heated discusion that will insue. For when both my sons and my husband get together it sounds like a physics think tank. I can't wait for their responses. Finally I came up with a subject to talk about!!! Alice


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## Gadget (Jul 28, 2006)

I have a couple of questions: 
First what kind of resin were you using and how much catalyst did you use? 
Second how did you know that the resin was bubbling if they were in a pressure pot?
Third where can you buy the resin?

I have a pressure pot and i am currently experimenting with stabilizing wood with vaccum/pressure.


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## its_virgil (Jul 28, 2006)

(1)I use polyester resin and 3 drops of catalyst per ounce of resin.

(2)I know that the resin is bubbling because I can see it bubbling[][}] . Actually, I made a lid for the pot from a piece of corian and cut a hole in it and glued a piece of Lexan on the top so I could see the resin and the bubbling.

(3) I purchase my resin from http://www.mrfiberglass.com and I get the Silmar 41 Clear Casting Polyester Resin. Some purchase from http://www.artstuf.com, but it is more expensive. 

I could post a picture of the lid I made for the pot if you would like to see it. Let me know.

Do a good turn daily!
Don


> _Originally posted by Gadget_
> <br />I have a couple of questions:
> First what kind of resin were you using and how much catalyst did you use?
> Second how did you know that the resin was bubbling if they were in a pressure pot?
> ...


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## Gadget (Jul 28, 2006)

1)I use polyester resin and 3 drops of catalyst per ounce of resin.

(2)I know that the resin is bubbling because I can see it bubbling[][}] . Actually, I made a lid for the pot from a piece of corian and cut a hole in it and glued a piece of Lexan on the top so I could see the resin and the bubbling.

(3) I purchase my resin from http://www.mrfiberglass.com and I get the Silmar 41 Clear Casting Polyester Resin. Some purchase from http://www.artstuf.com, but it is more expensive. 

I could post a picture of the lid I made for the pot if you would like to see it. Let me know.

Do a good turn daily!
Don

Yes i would like to see the lid I have some 1in thick plexi to make a lid out of.
Thanks


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## its_virgil (Jul 28, 2006)

Here it is. I drilled a hole just smaller than the pipe and screwed the pipe into the hole using epoxy.





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> _Originally posted by Gadget_
> Yes i would like to see the lid I have some 1in thick plexi to make a lid out of.
> Thanks


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