Home made pressure pot / resin trap

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#1

i was asked by gtfour to show this cheap simple pressure pot and how it was made so here it is. Most of these materials i had lying around so it actually cost me about £10 to make which was a lot cheaper than £100 or more for one of the shelf. I have been using the one pictured below for two years now and there is absolutely no vac leak.

As you can see the main part is a 4inch soil pipe section with end caps, the bottom one is bonded to a piece of mdf to give stability. The top part the working section is just made from normal get anywhere plumbing fittings, i`ve added a few notes pointing to the various parts. When i first made this i tested it for 24 hours under full vacuum and it lost nothing.

So there you go a cheap pressure pot / resin trap.

#2

I just use a pressure pot for paint from HARBOR FRIEGHT. I got the vac gauge from GRAINGER and the hose barb from LOWES

TOTAL COST

PRESSURE POT $80
VACUUM GAUGE $15
HOSE BARB $2

$105 with all taxes and the gas to drive to get it.

I can open it and pour paint stripper in it if I get any resin in it. It hangs up on my wall with its handle built in to the lid and I know that if it can handle pressure it can really handle vacuum.

#3

hybrid, on this side of the pond what you can buy in dollars we have to pay pounds so your $105 is £105 over here, this has cost me £10 to make as i had most of the fittings anyway. Not that im a skin flint as i have spent thousands doing this, its just the way my mind works, i see a problem and find a cheap solution.

Baz

#4

exactly right on the £-$ conversion :frowning: cheers for the pic m8,do you have a pic of the inside of the lid so i can see how its all secured?

#5

right,first attempt lol.it seems to hold full vacuum after i pinch the vac pump pipe and switch the pump off,still a very slight leak though.i think i picked up the wrong kind of endcaps as i have had to epoxy both ends on as they were threaded and leaked loads?obviously now i cant get into the chamber lol though im not sure if this is a problem or not? should i have some wire wool or something in there for the resin fumes to collect on as surely they will just get sucked straight thru the chamber and into the pump as it is?

#6

Not bad at all gtfour, it must hold full vacuum though.You need a valve to the vac pump so you can isolate the system and a bleed valve to release the vacuum so you can move the bag material around. I can pull a vacuum any number of times before i`m happy that the bagging material is okay and not bridging.

Baz

#7

yeah i noticed i need some kind of tap :slight_smile: do you think it will be ok the fact that i can never get into it? i suppose its cheap enough to build a new one anyway.

#8

No mate it doesnt matter, i checked mine the other day and there was about 2 inches of resin in the bottom, thats nothing consider how much it gets used. Saying that though get your vac/resin lines right and you shouldn`t get any in there. Make sure the resin trap is above the part your infusing it makes it harder for any resin to reach the trap. I try to judge when to clamp the resin line so i get nothing entering the vac line but it cant always work.

Good luck, are you going to have a go soon then.

Baz

#9

Oh I was just saying what I used.

And a hundred “pounds” is like a hundred and fifty dollars US I believe. Or really close to that.

I like the idea, I just wanted easy and done.

#10

£100 is nearer $190 now!
im going to try my first test infusion hopefully at the weekend,just doing dru runs at the mo so i can get everything right and have a figting chance of getting it right.im trying it with no gelcoat/duratec first of all with 3 layers of carbon,the mold is basically a flat plate but recessed 1mm,its not the best mold in the world but i figure its best to practise on my easiest mold.size wise the part is about 10"x8",its a plate for the top of a chargecooler- http://www.gt4oc.net/album_pic.php?pic_id=3339 .any pointers for laying the pipes/media etc would be hugely appreciated :slight_smile:

#11

for that small of a part you dont need any piping.

Just a single line in wrapped in your flow media so it doesnt pop the bag and on the other end you have a single line out thats end is wrapped in peel ply for the same reason.

Id do the part from end to end in the longest view…make the resin travel down the long narrow path. This will help you make sure that you dont end up with a dry corner.

Just make sure you pull full vac and that you can shut off the pump and make it hold full vac as long as your work time is on your resin.

For some reason the work time seems to be a bit longer under vacuum and I have experienced problems when I release vacuum befor the stuff has full B staged. It will pull up the top layer of cloth and make bubbles. Just keep it under full vac untill you know its hard.

Should be a real easy piece to make.

#12

gtfour,i agree with hybrid for the lines, make sure the resin line has contact with the carbon through the flow media and the vac line is on peel ply and not carbon this will slow the flow a bit and ensure you infuse the whole part before resin reaches the vac line. What resin will you use? if using epoxy warm it a little before adding the hardener you`d be surprised how much better it will flow especially as the temp here is dropping now. Also dont forget to warm the mold otherwise warming the resin will be a waste of time. Believe me dont forget to do this.

You can stand the resin in its mixing tub in hot water say half an hour before you need it and if you have a heat gun gently warm the mold. You`ve picked an easy part so success should be no problem, dont be in a hurry to demold it.

Best of luck M8

Baz

#13

ive got plenty of west 105 epoxy so i will be using that for my experiments.so just the 12mm resin line in at the centre of one end and vac out at the opposite end.i have peel ply and the flow media you kindly gave me,im still a little unsure of where this should all be placed though…
ive managed to get the pressure pot to hold full vacuum for a couple of hours now,its dropped to 25 now though after about 3 hours though i think this will be fine,i may be able to improve this a little yet.need to practise sealing vac film over the mold 2morow and making sure that doesnt leak,that could be interesting,after i have got that sussed then im good to go for the weekend :slight_smile:
does this look about right? red is flow media,grey is peel ply,white squiggle is resin in with vac as it is at other end?

#14

Right, with the flow media cut a piece 12mm inside the actual finished part line/ridge dont overlap it there its not neccesary plus id be a bit worried it might bridge, then cut a strip to go under the resin feed about as wide as you have there over the ridge and ontop of the flow media already laid down. Ontop of the resin feed place another piece of flow media this will keep the resin line open, then peel ply ontop. Make sure you spray some 77 tac adhesive down before the first layer of carbon and ensure it conforms to the mold (no bridging)you can use a wooden popsicle stick to do this, do the same with subsequent layers. Also make sure the small piece of flow media to the resin feed and peel ply doesnt bridge. Youve got no ears in the bagging material but as this is basically a flat piece of carbon this should be ok, just mske sure when you pull the vacuum the bag conforms to the shape with no bridging. What i sometimes do is use my heat gun at this point and run it over the edges just to make sure the bag is into all the corners/edges.

Right at risk of repeating myself but i so want this to go right for you. The order is carbon, peel ply, flow media plus a small piece of flow media and peel ply over the resin line.

The West epoxy will be okay but do as i said and heat it and the mold first, heat the mold from the underside though. The West is a little thick and must be heated otherwise it`ll have trouble flowing.

Try and get the resin trap to seal 100% otherwise you wont know if you have a leak in the bag or not, as you know air is the killer in carbon. I did another part yesterday afternoon, pulled the vac and infused perfect shut the vac line and resin feed turned the pump off and shut the garage door. I checked this morning and the vac had lost 2mbar in 13hours and i bet thats only due to temperature change. Try and achieve that and you`ll get perfect parts every time.

Best of luck m8, let us know how it goes.

Baz

#15

ok so my peel ply outline is ok then? ive managed to get hold of a tap for my resin trap and am currently testing that to see if it now holds vac as well as yours…

#16

Bought this at harbor freight for $25. Its just a large moisture trap.

Both ends are O-ringed and held together by a rod that runs through the middle of the tube. Since both ends are removable cleaning it will be easy. I just have one fitting left to buy and it will be all set.

#17

The gauge will be a pressure gauge and not a vacuum one.

You might will be able to figure out a paper cup liner to help cleaning it out.

#18

I was thinking that I would throw it away after it fills up. Which will be a long time from now. But…

Good call on the paper cup. If I cut a 1/2" hole in the base of the cup, then seal it with duct tape and resin should never actually touch the trap.

And are you saying that guage needs to read pressure? Because I was going to replace the pressure guage (that came with it) with a vacuum guage.

#19

No, we are both correct as you need it to read vacuum…