Author Topic: Applying Rustins Plastic Coating  (Read 15365 times)

Al Heeley

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Re: Applying Rustins Plastic Coating
« Reply #30 on: July 07, 2008, 06:45:27 pm »
yep, at least a week in a dry, warm environment to make sure its all really reacted and cured well.
The best way to do it...is to do it. -Amelia Ehrhard

DiscoStu

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Re: Applying Rustins Plastic Coating
« Reply #31 on: July 07, 2008, 07:30:57 pm »
Fair enough.
I've been applying very thin coats, so it should go off pretty quick I reckon. I'll aim for a weekend of sanding down then.

drea

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Re: Applying Rustins Plastic Coating
« Reply #32 on: July 07, 2008, 09:37:07 pm »
For my first attempt I brushed complete coats with the body hanging from a rafter. I'd thinned about 1 to 1 with RPC thinners and I couldn't get it to flow out flat. I ended up sanding it all back then doing front x2, cure, back x2, cure, sides...bottom...cuts with the body lying on the bench.

I've got 6 hours of sanding done and I'm only up to 4000 grit ???  Starting to look good though.

DiscoStu

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Re: Applying Rustins Plastic Coating
« Reply #33 on: July 31, 2008, 05:57:00 pm »
I now officially hate RPC.

See here

prostheta

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Re: Applying Rustins Plastic Coating
« Reply #34 on: August 14, 2008, 06:50:15 am »
I've decided to invest in a compressor and spraygun at some point for RPC on the basis that brushing takes so goddamn many coats and so much sanding back to get a level surface. Then we'll see who's boss, RPC.
Bringer of that which is noisy.

DenisLancs

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Re: Applying Rustins Plastic Coating
« Reply #35 on: October 11, 2008, 01:47:01 pm »
Another good thing NOT to do is to leave any trace of moisture when you are sanding down with wet and dry between coats. The next coat wrinkles almost instantaneously!

If anyone asks me how I know I will kill them very very slowly. >:(

Before that happened, I had some excellent results spraying using one of these -http://www.screwfix.com/prods/92612/Power-Tools/Sprayers/Earlex-HV1900-HVLP-Spray-Kit-400W

£49.99 at Screwfix, which means free postage. I had never sprayed anything before, and was dreading it, but the first 2 coats went on like a dream. However, the smell is one of the worst I have ever experienced. Can anyone recommend an effective respirator?

Denis

PS - I meant to say a big thanks to everyone who contributed to this and the other threads on RPC - especially Wez - It gave me the courage to have a go.

BTW - standard cellulose thinners from my local car accessory place were £8.99 for 5 litres and cleaned up the gun really well.
« Last Edit: October 11, 2008, 05:58:31 pm by DenisLancs »

Jem

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DenisLancs

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Re: Applying Rustins Plastic Coating
« Reply #37 on: October 14, 2008, 09:58:40 pm »
Thanks a lot - I'll try and track one down tomorrow.

Finally finshed sanding back to bare wood, and got a coat of filler on the back. Quite heartbreaking when I looked at how good the finish was in some places that were actuall dry for the last coat. Still, It's a good lesson that I hope I won't forget!!

Denis

DenisLancs

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Re: Applying Rustins Plastic Coating
« Reply #38 on: October 17, 2008, 02:56:39 pm »
Well, Blow me down!!!!

It's done it again. This time without a trace of moisture on the 2 coats already applied.

I am in my garage, using a portable gas fire to bring the temperature up to around 70F (turning it off while I am spraying). Put the first coat on around 9am. Flushed the gun out with thinners then appied the second coat around 11:30 having sprayed the PC for about a minute to run the thinners thru. repeated the same procedure at about 2:30 - first back, then front then sides, and the sides stared to wrinkle almost immediately. Front and sides are not too bad

I have got most of the wrinkles off with thinners, but I am now loathe to do anything until I have an idea what's causing it.

PLEASE does anyone have any ideas????

Thanks

Denis

drea

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Re: Applying Rustins Plastic Coating
« Reply #39 on: October 17, 2008, 04:12:22 pm »
It might be the gas fire.

As I remember, unburned Calor gas decomposes to carbon dioxide and water when exposed to air. I believe there's some water after burning too.

Have you got an electric heater you could try instead?

DenisLancs

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Re: Applying Rustins Plastic Coating
« Reply #40 on: October 17, 2008, 08:55:01 pm »
It might be the gas fire.

As I remember, unburned Calor gas decomposes to carbon dioxide and water when exposed to air. I believe there's some water after burning too.

Have you got an electric heater you could try instead?

Thanks for that - sounds like it could be it. I don't have an electric fire that would get it up to a sensible working temperature that quickly, so I guess it's back to the wood burning stove. I am only burning off cuts and sawdust in it, so nothing should produce any significant moisture.

What I can't understand though is why only the sides wrinkled, and immediately on spraying.

The only other info is that Rustins say that the stuff goes thru a phase after about 12 to 14 hours where it is prone to wrinkling. I can't have left it for more than 3 hours in a temperature of about 75F. Even if their data is miles out, that wouldn't explain why it only happened on the sides.

I have sanded the sides back as best I can, and I'll leave it to go off till Monday, then have another go without using the gas fire. I'll also try bringing it back in the house to dry. Praying might be in order as well!!

Ho Hum

Denis

mlennon

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Re: Applying Rustins Plastic Coating
« Reply #41 on: October 17, 2008, 09:51:24 pm »
I've never used the stuff so I can only offer a best guess at what's happening.

Plastic coating dries as a result of a chemical reation and once this reaction starts to occur and until it's fully cured, any further application of the product will cause the previous coat to react with the freshly applied wet coat.

The Data sheet states that the product can be recoated after 30 minutes @ 15-25c So I'm guessing that whats happening has nothing to do with moisture but that you are leaving it too long between coats especially if your leaving it 3 hours at 75F. The heat will kick start the curing process.

The most likely explanation for the sides to wrinkle and for the faces to be ok, is that as you spray the front & back there will be some wet paint landing on the sides and your then also applying a wet coat to the sides, this combined coat will be wetter than on the front and back and will allow the solvent within the product to attack the previous coat.

Also be careful with any source of ignition where your spraying, gas heaters, woodburning stoves and flamable vapours isn't a good mix.

DenisLancs

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Re: Applying Rustins Plastic Coating
« Reply #42 on: October 17, 2008, 11:00:44 pm »
Thanks very much for that - I understand where you are coming from with the additional solvent on the sides.

I hadn't read the product data sheet, but have now. It contradicts the pack instructions in several areas, drying time is one; mixing proportions is another.

So............. I have the body sitting in the house and it feels rock hard. I also have a test piece that I have been spraying alongside the body. I think I will give that a coat tomorrow, and if it doesn't wrinkle, then I will have a go at putting multiple coats on both with a far shorter interval. Still partial to doing the praying as well.  ;)

Also, I do apperciate your comments re combustion. I am taking all the precautions I can while still wanting to get the job done.

Thanks again, and watch this space :-\

Denis

wezv

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Re: Applying Rustins Plastic Coating
« Reply #43 on: October 18, 2008, 07:58:49 am »
sounds about right.  with the PC you want to do lots of coats in quick succession.. but if you have a break for more than a few hours ( ithink it says 12 in the instructions but we have had it wrinkle in less time than that) you really need to let that coat cure fully before applying more


but, the stuff is very forgiveable, so just sand out those wrinkles and carry on


i am happy i dont do my own finishes any more!!

DenisLancs

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Re: Applying Rustins Plastic Coating
« Reply #44 on: October 18, 2008, 11:20:47 am »
Thanks all - it feels like I am tempting fate - but I have just (noon) sprayed the 4th coat today with no problems so far.

Temp is around 68F thanks to the wood burner, and it seems to be going touch dry in around 40 minutes to an hour.

Going to try for a few more coats this afternoon and then leave it till Tuesday when I can have another full day on it.

Aren't learning curves fun? Answers on a postcard please

Denis