Polypropylene welding

[Firebrick43]

I have a Steinel heat gun/hot air welder that I have welded PE and PVC quite a bit over the last few years but I have a large water tank I need to finish that will be made out of polypropylene (PP) due to the high heat that will be in the tank.

The tank is approximately 4’ x4’x 4’ so it’s large but will be supported by an outer support shell and encased in insulation

Several sources I have read state that PP needs nitrogen or argon as a shielding gas. Not only would I have to buy another welder like a seelye but would have to drag my large argon tank into the basement as the tank has to be built in place.

Other videos show PP being welded with fan based hot air welders.

Any one done any significant amount of PP welding and could enlighten me on the actual necessities?

There is scant little in searches.

 

[nadogail]

I have seen what I believed to be Poly Pro welded with a hot air torch. This was 23 or 24 years ago when I was employed at a Printed Circuit Board manufacturing plant.

 

[Firebrick43]

I have seen what I believed to be Poly Pro welded with a hot air torch. This was 23 or 24 years ago when I was employed at a Printed Circuit Board manufacturing plant.

For acid tanks and such?

 

[nadogail]

For acid tanks and such?

Exactly

 

[dchawk81]

I thought the title said polypropylene wedding.


I must say I'm rather disappointed.

 

[Firebrick43]

Bump

 

[no704]

When I was looking at doing this I found some good YouTube videos. Bought a heat gun/filler one. Haven’t used it yet. Mostly rv peeps.

 

[pvfjr]

Did you ever end up welding PP without a shielding gas? I've been told the same thing recently (that you need shielding gas), but could've sworn I've done it before. I know I've done a ton of ABS which is easy, some PVC which was less easy. Maybe I'm remembering wrong and I did HDPE, but I'd thought I'd done some PP before. I'll try some black poly pipe later tonight and see what happens.

 

[Firebrick43]

I have bought the a seelye welder and regulator but no I have not done it yet. The folks a seelye said PP will weld just fine without it but will be prone to cracking overtime and not reach full strength.

They also recommended stress relieving the seam if doing multiple passes with a heat gun for longevity as well.

 

[BombShelter]

I used to sell plastic fabrications but never did much welding although I still own my Seelye Welder, the cool one with the little compressor that go for silly money now. The guys in the shop used extreme care when designing the tanks, especially with the exterior supports. They also leak tested everything before sending it out.

I'm wondering if it might be easier and a fraction of the cost to buy an off the shelf Chemtainer or Snyder Tank. You might also like an IBC Tank, which is really close to your dimensions, I bought a couple used at auction for $25, they had been for soap so they cleaned up easily.

This place might have what you need

U.S. Plastic Corp. | Plastic Bottles, Tubing & Fittings, Tanks, Buckets, Pipe, Sheet & Labware

United States Plastic Corporation distributes industrial and commercial plastic products such as plastic bottles, plastic tubing & fittings, plastic tanks, plastic buckets & barrels, plastic sheet, rod & shapes, pipe, labware and much more.

www.usplastic.com

 

[Firebrick43]

I used to sell plastic fabrications but never did much welding although I still own my Seelye Welder, the cool one with the little compressor that go for silly money now. The guys in the shop used extreme care when designing the tanks, especially with the exterior supports. They also leak tested everything before sending it out.

I'm wondering if it might be easier and a fraction of the cost to buy an off the shelf Chemtainer or Snyder Tank. You might also like an IBC Tank, which is really close to your dimensions, I bought a couple used at auction for $25, they had been for soap so they cleaned up easily.

This place might have what you need

U.S. Plastic Corp. | Plastic Bottles, Tubing & Fittings, Tanks, Buckets, Pipe, Sheet & Labware

United States Plastic Corporation distributes industrial and commercial plastic products such as plastic bottles, plastic tubing & fittings, plastic tanks, plastic buckets & barrels, plastic sheet, rod & shapes, pipe, labware and much more.

www.usplastic.com

It’s too big to get a manufacture tank in place. It has to be made on site. Plus it’s a LOT cheaper to make it. I already have the supporting shell made and have the (3) 1/4” 4x8 sheets of PP bought and cut to size. I just need to refill the argon bottle and get determined to get the bottle down stairs.

IBC tote liners won’t work, can’t get the heat exchanger into them and they are HDPE which doesn’t have a high enough temperature rating