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Re: Toroid Building



Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Thankyou David for your suggestions. For the sake of experimentation, I will fill the corrigation on this one as I do want to learn how significant the added weight is and I want to see what this does to the rigidity. My next toroid (10x40) will probably need more attention to weight savings. I also want to do a 12x48 toroid in time (but that will be for my next coil - 12x60). I will save your suggestions and use them in time.

Gerry R.


Original poster: "D&M's High Voltage, Inc." <dmshv.davmckin@xxxxxxxxxxx>

Gerry,

The taping (paper, masking tape, or even Aluminum foil tape - tried that too but forgot to mention it) was to make a smooth surface to start with (which also cuts down on weight) by eliminating having to fill up the corrugations of the duct. It's well worth the time spent. I would suggest covering the toroid first with one of mentioned tapes, and then apply one (thin) layer of resin (hot or not, just so it doesn't run). Sand the rough part down, then apply another layer of resin. Sand the rough parts, then fill in the large indentations with bondo, smoothing out as much as possible. Sand them down. Then apply another layer of resin. Sand down the rough parts, and then fill in the indentations with bondo. Apply another layer of resin, etc. Keep repeating until you have a smooth surface (should be a few layers and will require less with experience). Using masking or aluminum foil tape will stiffen the toroid quite nicely. Start sanding with large grit (I was limited to 60 Grit, but 30 if you can get it for your sander). Then when you get to the last fiberglass layer / sanding operation, step down to get a smooth surface without deep sanding swirls. I finished with 150 and 220 (final) paper. Make sure you use a vacuum system when sanding, or do it outside! Use acetone to get a very clean surface so the tape will stick really good.

Best regards,

David L. McKinnon
D&M's High Voltage, Inc.




----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx> To: <tesla@xxxxxxxxxx> Sent: Sunday, August 21, 2005 12:14 PM Subject: Re: Toroid Building


Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Tim,

I will probably try either the bondo or the redevil "onetime" product on this toroid. I will eventually make a 10x40 toroid after I learn from this one. David from D&M suggested, I think, paper taping the duct first (I presume to save weight), applying the bondo, and then doing the fiberglass resin coatings for strength. I'm thinking of applying the bondo and filling the corrigations, sanding, varnishing, and then adding the AL tape. I suppose, I will find out how heavy it becomes and alter the process for the 10x40 toroid. Dont know how heavy bondo is compared to the redevil product nor how much filling the corrigations will improve strength.

Gerry R

Original poster: Timjroche@xxxxxxx
Gerry R.,
have you tried bondo...easy working, stable, and cheap....or even the fiberglass bondo for rigidity.....good luck... i'd like to know what you do... i'll be doin te same in 2-3 weeks.....tim