Author Topic: Coloring fiberglass resin (Read 20140 times)

imsmooth · « **on:** March 10, 2009, 02:15:46 AM »

I'm getting ready to cast my rotors with fiberglass resin. I am contemplating adding some color. Does anyone do this? I found some suppliers on the internet for fiberglass coloring agents. Instead of ordering this, can I use some oil-based paints for a coloring agent? Is there something I can buy at a craft store or Home Depot so I don't have to do a mail order?

richhagen · « **Reply #1 on:** March 09, 2009, 08:29:01 PM »

I've heard of a touch of acrylic paint being added to give a tint or color to the resin. see:

http://www.fieldlines.com/story/2005/3/8/144448/5295

I've also heard of folks painting the whole stator after it was done.

Have fun, Rich

Flux · « **Reply #2 on:** March 10, 2009, 01:45:20 AM »

There are pigments intended for this and you can probably get them form boat building sources.

If you want to use anything else then experiment first. Most likely in small quantities a lot of things will colour it but some may have side effects on the resin so just check that it still sets properly.

Flux

lglagasse · « **Reply #3 on:** March 10, 2009, 05:03:50 AM »

Hi imsmooth:

I used a few drops of food coloring when casting rotors. Seemed to work OK.

Good Luck

lglagasse

imsmooth · « **Reply #4 on:** March 10, 2009, 06:39:00 AM »

nice. it looks like you didn't put a layer of fiberglass mat on top of the magnets. Was this to allow some uneveness on the surface to encourage air flow?

lglagasse · « **Reply #5 on:** March 10, 2009, 08:03:29 AM »

Hi imsmooth:

I left about 1/8 inch from the top of rotors unpotted. Might creat some air movement aroung rotors for cooling. I started this project just before the 17 ft machine of OtherPower startde to have burnout issues. I should have had some cooling holes but the rotors are not big enough.

I have since painted the rotors and added ss bands for magnet retention. Its not flying yet though

good luck

lglagasse

imsmooth · « **Reply #6 on:** March 10, 2009, 11:13:53 AM »

I plan to put some holes in my stator using caulk to fill the hole. I'll leave a small gap so the resin keeps the coils from vibrating.

Do you think the SS band will make that much of a difference?

Flux · « **Reply #7 on:** March 10, 2009, 01:11:47 PM »

With that set up I think the stainless band is an excellent idea. The cast magnet set up really keeps the whole thing together but as shown in that picture the casting does effectively nothing, the magnets are free to fly out radially as there is no casting over the ends. If the magnets are stuck with something effective then the casting as shown is pointless, it gives no strength and no weather protection. If the magnets are stuck with superglue or polyester resin the whole thing is very weak.

If you don't need weather protection then the stainless band and some epoxy under the magnets should be indestructible. If you cast as well then there is no real need to shrink the band on, just a reasonable fit and the potting would be fine.

I think the weather protection is essential but in some climates it may not be needed and the whole resin thing is probably not needed and better air flow would be obtained without it. Casting to near the top of the magnets seems pointless you have no fan effect and no weather protection.

Flux

imsmooth · « **Reply #8 on:** March 10, 2009, 05:18:37 PM »

I've wrapped about 10 turns of fiberglass tape and I will pour epoxy about 1/2 way up with some fiberglass running radially. My magnets are 2" discs. Do you think this will work well to contain them? The last thing I need are flying magnets.

Flux · « **Reply #9 on:** March 11, 2009, 01:18:20 AM »

I think that the problem is far less than commonly imagined. I have run magnets on a test rig just held on by the magnetic attraction. The field holds them pretty well but at high speed they would move out radially.

Ones that I have stuck on with Loctite structural adhesive ( Multibond 330 here in UK) have never moved. I have some machines with the magnets stuck on with this and potted in polyester for weather protection, none have ever moved but I suspect the polyester block is not really stuck to the steel disc as rust seems to be forming under it on an early machine.

With a decent epoxy and proper surface preparation I don't think they will move. If you cast them in an epoxy block then they can only move together. To be of any real benefit you need to key the whole block so that it can't go off centre. This is what the stainless band does very well. In your case it sounds as though you have nothing to prevent the whole block moving off centre so you are no better off than epoxy alone.

If it already cast you could drill a few holes through the resin block into the steel discs, tap the discs and fit a few screws. These need only be small and even steel screws will not affect the field if you go somewhere between the magnets. Alternatively perhaps even simpler is to drill the holes and fit roll pins. With 4 1/8" roll pins the magnet/resin block will never move even if it comes unstuck.

I think much of this worry has come from cases where magnets have come off after a failure when the magnets have rubbed the stator. These magnets are demagnetised and have no natural tendency to hold to the disc and are a very different issue. As they are scrap it makes little difference if they come off. Just don't fry the stator and this is not going to be a practical situation.

Flux

luv2weld · « **Reply #10 on:** March 11, 2009, 09:31:05 AM »

Have you thought about the effects of UV on the fiberglass tape???

How are you going to prevent deterioration???

Ralph

imsmooth · « **Reply #11 on:** March 11, 2009, 01:27:29 PM »

The tape will be coated with epoxy. The epoxy will then get a spraying of automotive clear coat acrylic. This will protect it for several years.

imsmooth · « **Reply #12 on:** March 12, 2009, 06:01:16 AM »

Hum...

I have not cast the rotor, yet. Right now I have about 10 turns of fiberglass tape wrapped around the out edge of the rotor 1/4" steel disc. The band overlaps on 3/4 of the magnets. If the block tries to move the band will be around the disc. I would think this would be sufficient. If you disagree, I could look into a steel band.

Flux · « **Reply #13 on:** March 12, 2009, 10:22:43 AM »

If the glass tape overlaps the steel disc and the magnets and you cast it solid it will anchor the whole block. I assumed you only had it round the magnets.

Flux

Jason Wilkinson · « **Reply #14 on:** March 12, 2009, 06:21:36 PM »

Unless tou live in an area where there is little or no salt in the atmosphere then corrosion will get to those magnets and lift them off the steel,all the magnets shouls be enclosed in the fiberglass

jason

imsmooth · « **Reply #15 on:** March 12, 2009, 10:29:10 PM »

What I intend to do is cast them in epoxy (two part system) and leave about 1/4" or less exposed to swirl the air. Once hard, I will paint the exposed surfaces of the magnets and the steel rotor with epoxy paint to enclose the entire unit. The entire rotor will be encased. I will spray the unit with automotive clear coat to protect the epoxy from UV.

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