PVC filler

[Russ_NY]

I am trying some experiments forming 1/2 inch schedule 40 PVC pipe into a circle for a coil housing. I then mill a slot around the circumference so I can insert the coil. So far it works fairly well. The question I have is has anybody found or made a PVC compatible filler? I seem to recall someone mentioning disolving chips of PVC in some solvent and using it for a filler. If anyone has tried something like this please let me know how it worked out and what you used for a solvent.
Thanks

Russ_NY

[Reg]

Re: PVC filler

Hi Russ,

You can use ground up pieces of pvc pipe dissolved in MEK or acetone. Just make a thick paste if you are going to use it as a filler. MEK seems to work a little better. by using the same type of plastic pipe, you get a close color match.

The acetone used "clean" or to bond pvc pipe together normally leaves a purple color while the pvc cement already has a filler.

I have not tried exactly what you described on pvc pipe, but the technique I mentioned works well on many plastics and is what I use to bond the two halves of the ABS housings I use.

Reg

[Russ_NY]

Re: PVC filler

Thanks For the information Reg. I'm not sure if this method is really going to work out all that well. Making the circle is easy, as is milling the slot. The difficult part is going to be making the attachment for the shaft as well as some sort of strain relief and seal for the cable. Probably would have been a lot simpler to buy a shell and be done with it, but I am a tinkerer at heart and had to try to make one. I have quite a bit of experience working with fiberglass and may give that a try also. I want it to be as rigid as possible but also compact and dense to reduce any buoyancy to a minimum. Making a shell for the DD coil should really be interesting. I am presently doing a new circuit board layout. I have decided to do it on two boards and stack them to keep it as compact as possible and still use leaded components.
Thanks again

Russ

[Charles (NY)]

Try Smooth-on.com

These folks have some fantastic liquid plastics, I'm presently using Smoothcast 385 which is VERY rigid and will certainly not float, hardness is way up there around 85. I built a 21 inch coil (21 is not a typo) and it was so rigid (and heavy) that I built another coil mold slimming down all the dimensions.

[Reg]

Re: Try Smooth-on.com

Hi Charles,

I use the Smooth on lightweight plastic as a filler in my coil housings to keep the windings rigid. So far I haven't had any problems with it but it is still early in the game also.

Reg

[Charles (NY)]

Re: Try Smooth-on.com

I'm going to try some of that, if its rigid enough it should lighten my large coil quite a bit. She's weighing in at 3 pounds using the smoothcast 385.

[Reg]

Re: Try Smooth-on.com

Hi Charles,

I added more microspheres to their Feather Lite resin to make it lighter yet. It helped and didn't seem to lose any strength. I got them from another source though.

Reg

[Reg]

Re: Another trick

Hi Charles,

I have also used the rigid foam filler and then route out where the windings will fit with a little extra width and then filled in the extra with the Feather lite. This lightens things even more.

I got the rigid foam and microspheres from:
http://www.iasco-tesco.com/index.htm

I had to call the company for the price of the spheres though since their website didn't have them listed.

Reg

[Charles (NY)]

Re: Another trick

Thanks Reg, I ordered up some new resin and a couple of gallons of glass microspheres.