Welding and Metalworking - Home Welded Plastic Conical Fermenter

Does anyone have any expierence welding food grade plastic buckets such as those 5 gallon buckets used to package pickles or eggs at a restaraunt. I have a small home brewery and am always lusting after a conical fermenter. I thought maybe I could just make my own out of one of those buckets and a food grade funnel. Ive seen some affordable plastic welders but really dont know where to start.

What type of plastic rods should you use for food grade welding?

What type of plastic are those buckets generally made of?

If I had to reduce the diameter of the bucket to fit the funnel, will the weld seam hold up especially with such a long seam?

Any help would be Sweet!!!

The food grade buckets that I see most often are made of HDPE. I have also seen some made of PP.

The important thing for welding them is that the bucket, funnel, and welding rod must all be the same material. Both HDPE and PP rods are commonly available. If you are concerned about the composition of the rods, you can use scraps of the same plastic from another bucket for the welding filler.

Plastic welds, much like metal welds, can be stronger than the original material. The key with HDPE or PP is to get the tempature and pressure correct. You must get a good mix of the materials and the filler. If done properly, you will not have a failure due to the length of the weld.

You might want to check out "The Book", from Urethane Supply. It has great information on all aspects of plastic welding. You can download it from http://www.urethanesupply.com/pdf/thebook.pdf .

Good luck and enjoy welding plastic,
Rip

The only thing I am concerned about are tiny crevaces and voids that could be difficult to clean and may hold some unwanted bacteria. Cutting the bottom of the bucket may create an uneven surface and then any irregularities in the weld will create very small nooks & crannies that will be difficult or impossible to clean. If there are some pits & crevaces I wonder if a more thorough sterilization could take care of the problem. I've always wondered what a clothing steamer would do. You could aim the jet of steam at the weld area to help sterilize the difficult areas.

I don't think the problem would be any worse then it would be with metal. A good weld will have small pits either way. You would want to clean plastic just as well as you would metal. I have several water holding tanks that I have made of PP and I just clean them with hot soapy water. Have not had any problems yet.

You could use steam but it might shorten the life of some plastics and cause them to get brittle.

Fermenters and other brewing equipment are specifically designed not to have any pits or crevases. Part of the reason stainless steel fermenters are so expensive is that they take great pains to insure a quality weld and any pits in the weld are re-welded (filled). Then they grind and polish the welds smooth so there is no place for bacteria to hide. Absolute cleanliness is a must if you wish to have consistency, control and quality in your brewing process.