17 replies to this topic

[Hammered]

A while back a WP member said they called Flextank to see if they would produce a 15 gallon plastic tank and he reported they curtly declined. I've shopped all over the internet to find one that would also stand up to a vacuum pump and have minimum head space when filled and struck out.

So, like all my other devices, I decided to build one. Just finished it last night, and still need to check it for leaks, but here's what I came up with.



A racking cane will go through a #8.5 bung which will seal the top and the side barbed fitting will be connected to either a vacuum pump or my N2 tank depending on if I want to push or pull the wine. It is 16" wide by 12" deep by 20" tall and weighs about 3 lbs. I made it out of 1/4" thick HDPE sheet. Kind of fun playing with a new material like this.

The welds on the sides are still a bit rough so I'll sand them down to be smoother before I start filling it with wine.

[poni]

That is pretty cool. Now if only i could build it. Let me know when ya start selling these!

[West Seattle Winery]

Nice work Hammered!

Doubt you could pull a vacuum on one of these... but spiedel started making small format plastic tanks - http://morewinemakin...l_Plastic_Tanks but they certainly don't have the cool factor of a Hammered contraption.

First DIY project for book #2?

[Calamity Cellars]

I think you will be able to pull vacuum racking levels of vacuum with no problem. What was the material you used?

[GerardVineyard]

I think you will be able to pull vacuum racking levels of vacuum with no problem. What was the material you used?

" I made it out of 1/4" thick HDPE sheet."

Where do you get HDPE and what do you use to "weld" it?

[Tomer1]

HDPE sheets in different densities can be bought at any technical plastic shop.

I am however intrigued about your method of plastic welding\soldering as there are many types available in the industry.


I have a feeling the Speidel stuff is not manufactured in house other wise what reason they had to make them in this shape and not allow variable top at least for the larger 110L.

[Hammered]

I got these sheets locally from Tap Plastics, but US Plastics has it as well. The welding rod was harder to find, but I was able to get some from US Plastics who turned around my order very quickly.

I'm sure this will handle the vacuum. The 1/4" sheets, along with the corners makes it so rigid that I could stand on it without it flexing.

I first bent the back, bottom, front and top on a heat bending jig that I made from three halogen shop light holders and bulbs connected together in an insulated box controlled with a dimmer switch.








To weld it, I picked up a thermoplastic welding tool from Harbor Freight that is essentially an inline heat/air gun with a small (about 1/4") orifice. To run the weld, you simply hold the welding rod in place on the seam (which I beveled into a V) and then just heat the seam and rod until the rod melts into the V groove and fills it with melted plastic.





When it cools, it has formed into a single piece that is virtually indestructible. I'd never done this, so it took a bit of practice to get it looking decent, and even then it still needs a fair amount of finishing (sanding, rasping, heat troweling, etc.)

The spout is a PVC kitchen sink drain pipe with an arm designed to be connected to a dishwasher hose. PVC is not a thermoplastic, and didn't melt together with the HDPE, so I put the threaded end of a coupling into a piece of 1/2" thick circle of HDPE and melted it into the threads and then wrapped it above the threads with some welding rod Then I welded it to the top of the tank after cutting a 1-1/2" hole. Once cooled, I could pick up the whole thing by the spout. The top adapter fits into the coupling with a standard compression fitting and can be removed for a bung and airlock.

I designed this specifically so it would fit on my barrel room shelves and take up the least amount of space (unlike round kegs or tanks). I'd though about putting a bulkhead for a valve on the bottom, and may still do that, but with pumps, I'm not sure I'd ever use it that way. Another possibility would be to adapt the top with a valve and then flip the whole thing over and use it as a conical fermenter -- again, not sure if I'd ever use it in that configuration.

[Hammered]

I think you will be able to pull vacuum racking levels of vacuum with no problem. What was the material you used?

Actually I tried pulling a vacuum on a few different round plastic containers and they pretty much all collapsed. That's why I went with the 1/4". Once I saw a sheet of that, I was pretty confident it would handle anything I could throw at it, including positive pressure from Nitrogen transfers.

[bzac]

I had some custom water and wastewater tanks made for my sailboat out of that same material , with multiple sized intakes, vents and outlets.
very durable.

mine were custom shapes to fit my boat . I'm sure if you don't have steves skills you could get any size you wanted made up . http://barrplastics.com/page203.htm

[Leo Sperrazza]

Very impressive !

[Manda @ Our Wolf Den]

Wow, its amazing to me that you can now just build any size container you need. Thats awesome.

[Brett C.]

That's great Steve! I'll be interested to hear what kind of rate of oxygen transfer you get. With 1/4", I'd think it would kind of slow.

Brett

[saramc]

Impressive. When will you have your vacuum trial?

[Hammered]

Well, topic update.  I never used that tank for winemaking purposes.  Instead I brought it to some product engineers as a mockup to develop designs for a series of small batch wine tanks made from HDPE.  They are really turning out cool, after a long process of designs and revisions and re-revisions.  I just signed the contract with the plastics company to start making the molds and going into production, so I hope to have them for sale in July.

[S Hofner]

Very cool. I was going to increase my storage capacity this summer. I am currently torn between doing 1 or 2 flex tanks or 4 to 6 kegs. As soon as you have product info that can be made public, I am very interested in your tanks.